Analysis of Water-Formed Deposits

Boiler Water Chemistry

Analysis of Water-Formed Deposits F. U. NEAT Consolidated Gas Electric Light & Power Co. of Baltimore, Baltimore, M d .

A. A. BERK Bureau of Mines, College Park, M d .

The composition of water-formed deposits frequently can be interpreted to provide a guide for practical preventive or corrective treatment, either of the water or of its environment, to avert operating trouble and costly shutdowns. Complete and detailed information may be very useful to show how to avoid the recurrence of failure; however, unless the information is accurate, i t can be most misleading. Accordingly, tried and tested methods are desirable for the chemical analysis of carefully selected samples. The procedures selected provide accurate results i n a reasonable time with equipment available i n most laboratories. A diagrammatic outline of the procedure is included so that unnecessary steps and undesired tests may be eliminated more easily in the event that a complete analysis is not required or certain components are not present. Alternate procedures are given when special unusual apparatus is required or use of certain chemicals may be prescribed. Results of analyses are often difficult to explain and all too frequently are subject to various interpretations. The analytical laboratory can be of real value if the analyst prepares the sample intelligently, knows approximately what he is looking for, and follows procedures that give accurate results.

A

BOUT 15 years ago a select group of power plant chemists each analyzed a portion of a well-mixed water-formed deposit. The analytical procedures ranged from the rapid, estimating variety to more complicated methods developed into master schemes for processing samples of such deposits. Some variation in results was expected from such heterogeneous methods, but the actual reports were in shocking disagreement. Several additional samples were distributed to another cooperating group, and again there were major discrepancies that could only result from the use of poorly selected analytical procedures. The dmerican Society for Testing Materials Committee D-19 on Industrial Water undertook to write a specification comprising a systematic scheme for analyzing water-formed deposits. Both authors have worked on the task group appointed for this purpose, and the senior author has been its chairman for several years. This paper is a progress report on the development of the scheme, which has reached the point of submitting it for round-robin testing to cooperating and referee laboratories. SCOPE AND APPLICATION

The task group was directed to write a method comprising procedures for estimating the individual components of waterformed deposits, A diagrammatic,outline was to be provided, and abridgments were to be indicated for eliminating unnecessary steps when complete analysis is not necessary. Where the preferred procedure-preferred because it is more rapid and consistently more accurate-requires special apparatus not usually found in the ordinary chemical laboratory or the use of chemicals ordinarily considered to be hazardous, alternate procedures were to be provided. The final method will cover all the components commonly found in water-formed deposits that occur in connection with the industrial use of water. Presumably, a scheme for deposits in heating and power plants only should be relatively simple. However, power-plant deposits go beyond the complex scales

May 1954

and sludges found in boilers, since they include deaerator sludges, evaporator scales, condenser slimes, corrosion deposits, turbine encrustation, and cooling-pond scums. Turbid feed waters have been known t o contribute unusual components to boiler scale and sludge, and baked sludges composed of alternate layers of metallic copper and magnetic iron oxide are not uncommon. Frequently, too, fly ash is blown by the wind into the vents of condensate storage tanks, and a dozen or more unusual elements, including germanium, may enter the boiler from this source to become part of deposits. Theoretically, a t least, the poxer-plant deposit could contain almost any of the reacting elements of the periodic table. It was not considered essential, however, that provision be made for every remote possibility, and the test procedures were written for only the more common and more probable components. It is estimated that the scheme presented will be applicable to 99.9% of water-formed deposits for which analyses are required in power plants. The Personal Factor. An analyst with a sample and a scheme of analysis has frequently been compared to a cook with a recipe and the ingredients. This is not a true parallel because to the chemist a scheme of analysis should be only a guide that he will abridge or modify to suit the particular sample. However, the chemist who does not have a good idea of what he is looking for will seldom find it quickly. Information useful to the analyst should therefore accompany the sample, as such information will simplify his work and result in an appreciable saving of time. The useful analyst also must be given proper tools for his work and must be allowed time to cope with unusual conditions. Even more important, he must be encouraged to develop a boundless curiosity, which is his one weapon for recognizing the unusual conditions that render analytical methods inadequate to meet special circumstances. Poor analytical data result from a blind adherence to the scheme, and many plants find that their analytical results are seldom worth very much except to keep the

INDUSTRIAL AND ENGINEERING CHEMISTRY

961

analyst a t work. Usually the fault will be found in the morale of the chemist and his lack of curiosity regarding the samples. Occasionally, however, such curiosity is carried too far. One analyst found zinc silicate in a sedimentary baked sludge consisting of alternate layers of magnetic iron oxide and metallic copper, and his explanation of the build-up of the deposit was based on the zinc. Fortunately, the water chemist had seen such scales build up without zinc silicate, and the presence of this component could readily be explained by the fact that small quantities of zinc and silica were being carried into the boiler with the feed water. I n another instance, an analyst became excited at finding a trace of copper sulfide in the deposit around a tube failure, and he attributed the corrosion causing the failure t o sulfite breakdown t o sulfide, which in turn corroded the steel. Here, too, the absence of sulfides in detectable amounts in the steam and a comparison of the failure with similar ones in other tubes and other plants led the water chemist t o discount the sulfide theory as more an explanation for the presence of a slight amount of copper sulfide than as an exposition of the mechanism of corrosion. However, the plant in which such enthusiasm is developed ordinarily is the plant that is most free from real trouble. Accordingly, it is strongly recommended that the analyst be told the source of the sample, the source of the water contributing t o the deposit, and the treatment of this water before its use in the process from which the deposit v a s obtained. He should also have details of the process during which the deposits were formed. If the analysis is a team job, then the chemist should be told what was found by the petrographer, the spectrographer, and the x-ray diffractionist. In this discussion it is assumed that the analytical work has not been assigned to a high school student who has no interest or training in water chemistry and no ambition or curiosity as to the importance of his job. Interpretation. Ordinarily, a chemical analysis of a waterformed deposit is made because the findings are expected to be useful, and the usefulness of analytical data generally is proportional to the accuracy of the interpretation that can be made from them. The ability t o recognize the factors that contribute to good interpretation and, particularly, the pitfalls that lead to completely erroneous conclusions is therefore important. The most important single factor is accurate sampling. Even a good sample may represent only the conditions that existed at the particular point at which the sample was taken. Kevertheless, unless the deposit is associated with more than a simple annoyance, only one sample is usually taken, and it may be only a crust or the more easily removed layers. Except upon the occasion of the rupture of a boiler, the emergency shutdown of a considerable part of the generating capacity, or the safety of personnel, it is often very difficult to obtain approval for expensive total and representative sampling, Thus, all too frequently, even though the analysis is accurate, the analytical findings are subject to variable interpretation and the annoyance is difficult t o explain. Recognizing this factor, engineers have learned to exercise caution and avoid being definite in their interpretation of analytical results. Accurate analysis is second only t o accurate sampling in importance. The constituent that has been overlooked is frequently the one missing fact that would enable the engineer to make a decision from a number of possible interpretations. For example, the presence of manganese in a corrosion deposit could indicate that the deposit was formed in place on the metal and was not an accumulation of corrosion products from the economizer or from the preboiler system. Conversely, the presence of zinc would tend to indicate that such deposits contained metals that had entered the boiler with the feed water. Phosphate in the absence of calcium and magnesium could indicate hide-out and relatively dry conditions. Conversely, phosphate in the presence of lime or magnesium might indicate baked sludge or eggshell scale, respectively. For this reason, a preliminary examination of the sample is a most important guide to the chemi-

962

cal analyst. The spectroscope and spcctrograph are valuable aids not only because they indicate the metals that are present, but they also show what is not there and therefore need not be considered, either as a constituent to be determined or as an interference in the determination of the constituents. X-ray diffraction techniques and the petrographic microscopc also are useful in that they warn the analyst as t o what he is going to find in significant concentration and help the engineer in his interpretation by identifying molecular species. For example, the chemist could determine calcium and carbon dioxide in the deposit and assume the presence of calcium carbonate, but only the petrographer or the x-ray diffractionist could state whether the material was calcite or aragonite and thus provide a clue to the conditions under which the deposit was formed. A third factor, one that is frequently neglected, is the identification of microorganisms. For example, slime-forming organisms, a particular nuisance t o the power industry, are responsible for sludges that would hardly be explainable from the results of a chemical analysis alone-except that the loss on ignition might be higher than usual and so furnish a clue t o the presence of such organisms. On the other hand, deposits formed from water that is heavily polluted by certain wastes, such as domestic sewage, fish heads, and refinery products, are not worth the excessive time frequently spent in identification and interpretation. In such instances, the solution will generally be t o use a corrosionresisting alloy or to change the location of the equipment, and testing for this purpose should be begun as soon as possiblc. The biological microscope can therefore be a very important tool since it can be used for identifying microorganisms in sludgetype deposits and thus lead t o quicker and more accurate interpretation. Finally, watcr-formed deposits ordinarily are not homogcncous. Analytical findings of a chemical analysis of the so-called rcprcsentative sample, made homogeneous by grinding and mixing, may be accurate enough for this sample, but the interpretation based on such analysis may be far from correct. Accordingly, even though the laboratory is restricted in time and manpower and therefore is unable to make a complete chemical analysis on each distinct macrocomponent or layer of the deposit, the auxiliary tools of spectrography, microscopy, and x-ray diffraction should be used for a thorough examination of each formation that may be significant. For example, the interpretation of the aforementioned deposit consisting of alternate bands of magnetic iron oxide and metallic copper would differ considerably from the interpretation of an analysis showing only that the material contained certain quantities of iron and copper reported as oxides. Consequently, it is most important that all concerned with the analysis and the interpretation work together as a team. Also, the results obtained by such a team frequently will be useful in proportion to the curiosity with vhich the individual members of the team regard the sample and the ovcr-all problem of interpretation. APPLIC4TION OF JIASTER SCHEhIE

The analyst’s first step is the classification of the sample, in accordance with its physical structure, as a scale, sludge, or rombination of the two. Sometimes it is necessary to make a careful analysis of the mother liquor from which the sample was talrcn. Then, before the problem of analysis is attacked a careful selection is made to separate out parts of the sample for optical cxamination and possible identification. This optical data, or at least the portion that can be obtained quickly, should be available to the conference on how complete, if any, a chemical analysis is required. The analysis of water-formed deposits is complicated by the fact that many samples are wet and also contain oil in sufficient quantity so the sample cannot be dried and made homogeneous by grinding. The main sample is air-dried, or oven-dried if it


Vol. 46, No. 5


7

can be shielded from high temperature radiant heat, and examined for friability. If required to permit pulverizing, it is treated with chloroform in a large dish, the sample being broken up as well as possible. The chloroform is poured off through a filter, and extraction is repeated until the color indicates that extraction is complete. The sample and the material on the filter are freed from excess chloroform and any water that may be present by drying, and the dry sample is pulverized cautiously and the fines are removed a t frequent intervals through a 100-mesh sieve. Pieces that resemble parts of old rubber gloves or splinters of wood are removed during this process for separate and individual examination. Metallic particles, such as copper, are also set aside for separate and special treatment and suitable proportioning with the main sample. The pulverized sample is thoroughly mixed, and a 50- to 100gram portion is taken out to constitute the laboratory sample. As a check on the homogenizing operation, a similar portion may be taken, and on each of the two a determination is made for copper or another easily determined component. If the two check, it is reasonably certain that the portion selected is representative. When large and important samples are handled, this check is the “smart” thing to do. Although ground fine and made homogeneous, the sample is still not ready t o be analyzed until it has been freed from remaining oil and dried to constant weight a t 105” C. Having received the information from the optical laboratory, the analyst can now plan to follow those portions of the master scheme that provide for the presentation of each individual component of the deposit in such form that it alone will react with a calibrated or standardized reagent in stoichiometric relationship so that the component may be estimated as a percentage of the sample. Interferences in the method have been minimized or eliminated. Where tn.0 or more components are determined together, the interfering components are determined separately and the quantity present is deducted from the group determination. In general. all elements commonly found in water-formed deposits in the boiler plant may be determined by this master Echeme (Figure 1). The apparatus required is that ordinarily found in a reasonably well equipped laboratory. Howevcr, alternate procedures are supplied when apparatus is available for certain special tests that permit determinations of specific elemerits with exceptional speed, accuracy, or convenience. Having made his analysis, the chemist often is perturbed when the component parts do not total approximately 100%. Sometimes the distribution between ferrous and ferric iron provides the needed latitude because different quantities of oxygen are associated with the two forms. Other assumptions frequently can be made to “dress up” the report, but only the untutored thrust out their chins and say “determined” instead of using the much more conservative term “estimated.” MASTER SCHEME FOR WATER-FORMED DEPOSITS

1. Mother Liquor.

A. When samples are taken in contact with the water that produced the deposits, separate this water from the sample. In some instances, the character of the liquid is of interest. E. Filter off the mother liquor, using a filter paper and funnel suitable to the volume and pulverization of the sample. Rinse the sample container with filtered mother liquor and transfer all the sample to the filter. C. The weight or volume ratio of the mother liquor may be determined, if desirable, either in relation to the sample as received or the dry weight of the solids residue or in any other relationship necessary to the work of the particular laboratory. Determinations of the constituents of the mother liquor may be made according t o the various methods of analysis for constituents of industrial water, as given in the current ASTM Standards ( 6 ) or in the ASTM Manual on Industrial Water ( 1 ) . May 1954

2.

Preparation of Laboratory Sample.

.4. Remove the drained sample from the filter paper, taking care that not too much of the filter paper is included in the sample. The filter paper may be examined according to the importance of the material not easily separated from the paper. In an extreme case the filter paper may be dried, washed with chloroform, and ignited and the ash treated as a separate sample. B. Describe the sample carefully as to odor, appearance, and size and record. This description should be checked with the description made a t the time of sampling. C. Test a little of the sample to determine whether or not it can be pulverized. If it is too wet, it should be air-dried. If oily, it should be air-dried and then extracted with chloroform. D. Air drying of a wet sample is necessary before it is pulverized. It may be spread out in a thin layer on a nonreactive, impervious surface or it may be dried in an oven as described for the air drying of coal [ASTM standards ( d ) ] . If the sample is too large and cannot be subdivided without loss of identity, then the entire sample must be dried. The loss of weight may be rerorded as air-dry moisture if required. NOTE 1. Samples containing organic matter must not be dried in the ordinary laboratory oven, as this exposee the sample to radiant heat and elevated temperatures,

E. Most of the chloroform-soluble material must be removed before a sample can be properlv pulverized. Prepare a funnel and paper of suitable size. Cover the sample, in a porcelain dish or beaker, with chloroform and ctir well. The dish and contents may be warmed t o haqten the action. Decant through the filter paper and repeat until thc chloroform pours off clear. Dry the filter paper and transfer any sample back to the original container. Evaporate the chloroform from the sample at 110’ C. The filter paper may be ashed and the residue analyzed according to the deqires of the particular laboratory. The extract may be evaporated and examined if desired. SOTE 2. In exceptional cases successive extractions with naphtha and benzene may be required. F. The air-dried and chloroform-washed sample may now be pulverized. If the sample is large, a ball mill may be used. Ordinarily, a jar and pebbles are suitable. If the sample is small, it should be pulverized in an agate or mullite mortar. The entire sample must be pulverized to pass a 100-mesh sieve and placrd in a tightly stoppered or capped bottle or jar of such size as t o be not more than two thirds full. Mix thoroughly by tumbling. If the sample is large, it may now be reduced to about 50 grams and placed in a smaller, tightly capped or stoppered bottle of such size as t o be not more than two thirds full.

NOTE3. I n grinding to lOO-rnesh, bits of rubbish and metallic elements which are not easily pulverized are frequently found and must be removed. Copper, for example, is often found in boiler scales. The importance to the individual laboratory of the presence of such material will govern the action. These large particles should not be mixed with the properly pulverized samples, as they will segregate. They can be dissolved in acids and analyzed if necessary after the proportion to the original sample is determined. 3.

Moisture.

Dry a fat-extracted Soxhlet thimble a t 105’ C. (Sote l), cool in a desiccator and weigh. Place more than 15 grams of the sample in the thimble and weigh. Dry the thimble and contents a t 105” C. (Sote 1) for 2 hours. Cool in a desiccator and weigh. Record the loss in weight as moisture. The moisture so determined may be added to the mother liquor and air-dry moipture to be recorded as total moisture if desired.

NOTE4. The desiccant used in this work shall be an indicator grade of silica gel, activated alumina, or a solid perchlorate. The indicator can be internal or external t o the desiccant.


963

4.

Dry a bit of absorbent cotton, previously extracted with chloroform, a t 105" C. and loosely plug the top of the Soxhlet thimble. Weigh the thimble, place in a Soxhlet apparatus, and extract with chloroform until the chloroform is colorless in the extraction chamber. Remove the thimble, dry at 105' C., cool in a desiccator, and weigh. The loss in weight is reported ae chloroform-soluble material and may be added to that previously found if desired. The extract may be evaporated and examined if important to the problem. 5.

Figure 1. Analysis of Water-Formed Deposits

Chloroform-Soluble Matter.

Analytical Sample.

Remove the cotton plug from the thimble, shake out the solid material into a weighing bottle, and place the weighing bottle in the desiccator. This is the analytical sample.

NOTE 5. Some samples will segregate by flotation or lack of wetting in the extraction with chloroform. Each must be treated separately. If the segregation is gross and seriously affects the sample by loss to the cotton plug or even by loss through the cotton plug, the sample can be wrapped tightly in filter paper and placed in the Soxhlet thimble for the drying and extracting periods which are thereby lengthened,

Wet and oily sample

1 -+ examine mother liquor if required 1 Air dry 1 Extract with chloroform + examine chloroform extract if required Separate from mother liquor

1

Pulverize to minus 100 mesh

-+

J

examine nongrindables

1 1 separate from trash 1 Weigh metal 1 Identify if possible

Mix and split to 50-gram lab sample I-Preliminary

study (see A)

1 Mix and take 20-gram portion l. Dissolve metal and proportion to lab Dry a t 105" -+ record moisture if required 1 sample if required Extract with chloroform in Soxhlet record oil if required 1 Analytical sample separate tests (see B) 1 -+

-+

Principal sample (see C)

4. Preliminary Study On lab sample + Spectrograph-most

-+

Spectroscope-many

cations and some anions cations and a few anions

+ X-ray diffraction-crystalline

6. Weighing of Analytical Portions.

A. The sample after being dried a t 105' C. may be hygroscopic. The analyst can determine how much this moisture nil1 trouble him by rapidly weighing a small portion and determining the gain in weight after several minutes on the balance pan. If the material is highly hygroscopic, weighing3 may be accomplished by removing a portion from the weighing bottle and determining the loss in rreight of the weighing bottle. B. Weighings are to be made to the nearest 1 mg. Whenever the instructions require a portion to be weighed, it is understood that a portion nearly of that size is t o be weighed t o the nearest 1 mg. The exact weight specified should not be attempted, as the time consumed in obtaining a portion weighing 1,0000 gram is much greater than the time required in calculating relative proportions in a portion not exactly 1.0000 gram. The error due to hygroscopic properties of the sample is less if the weighing time is short.

~

1

3

Petrographic microscope-crystalline

+ Chemical

I-+

compounds

microscope-qualitative

compounds analysis

Spot test-qualitative

B. Separate Tests On analytical sample

'

I-+ -+

Water soluble, if required

3

Tin

.+

Sulfide sulfur by evolution

.+

Carbonates by evolution

-+

Manganese by bismuthate

-+

Sodium and potassium by flame photometer

I-+

1

Loss on ignition, 950" C., if required

Special analysis for barium, calcium, magnesium, and lead if required

7 . Preliminary Examination. A. Where equipment is available, the use of the spectrograph, spectroscope, x-ray diffraction apparatus, petrographic microscope, chemical microscope, and spot tests are useful in determining such short cuts as may be posslble in the schematic analysis. The instruments are named in thc order of decreasing ease of detection of a multiplicity of components in a short spare of time. For example, all the elements present can be detected by spot tests. However, the time required would almost equal that required for the entire schematic analysis. Spot tests should be used for the detection of elements of particular interest. The spectrograph could detect virtually all the elements present and indicate the relative proportions in a very short time. The x-ray diffraction camera would indicate the elements in their molecular combination, but where two or more components are present identification is difficult. A separation under the petrographic microscope and then use of x-ray diffraction procedures on these fractions would increase the range 964

of identification a t the expense of time consumed. Instructions for the use of these instruments and methods for preliminary examination may be found in the BSTM Book of Standards (i), and a discussion will be found in the SSTM Manual on Industrial Water (a). B. Of particular interest in the preliminary examination are elements that give trouble with fusions in platinum (aluminum, phosphorus, tin, chlorine, lead, and others) and materials that may be lost by volatilization on acidification of the carbonate fusion, digestion with perchloric acid, or digestion with hydrochloric acid (tin, boron, fluorine, silica). Other elements of intercst are those that form insoluble or difficultly soluble sulfates, when sulfatcs are present, or insoluble or difficultly soluble chlorides such as lead, barium, sill-er, and mercury. Such insoluble salts contaminate the silica precipitate; they are not rcnioved by subsequent fusion and acid digestion and vdl again precipitate.


Vol. 46, No. 5


1

Silica

-+On

I

100 ml, sulfate by barium chloride

Fume -+ residue

1

1

Silica Fuse Na2COa

I

Dissolve HCl

4

i

J

i Nickel by dimethylglyoxime

Ammonia

J

1

Ammonia, HIS, and ammonia

S d d ammonia to filtrate

i

J

1

Zinc as ZnO

1

Barium as barium sulfate

Cool to IO' C.; add cupfer+ ron to first white flash

1

H,SO*

Jgnite precipitate

1

Dissolve precipitate in HCl

1

Evaporate filtrate to about 150 ml. I

1

1

1

Ignite to Al2O3 and MnrOc

Calcium as oxalate

J

i

1

On bisulfate fusion of precipitate, get iron by permanganate and titanium by peroxide

Determine manganese after bisulfate fusion

Magnesium as phosphate

1

Aluminum by difference

8.

Loss on Ignition.

Ignite a porcelain crucible to constant weight a t 950' C. Cool in a desiccator and weigh. Weigh 1 gram of the sample into the crucible and ignite to constant weight a t 950" C. Cool in a deesicator and weigh. Record the change in weight as loss or gain on ignition.

NOTE6. Many samples contain metals or salts of low valence, which on ignition convert to higher valence oxides. Such samples may show a gain in weight on ignition. Others contain salts that convert t o oxides and thus show a loss in weight which does not represent organic matter and is not t o be recorded as such. Ordinarily, this determination is of little significance.

tents to constant weight a t 105" C. Record the loss in weight as water-soluble matter.

NOTE7. Ordinarily, there should be little water-soluble mat1,er in a water-formed deposit. However, much of the material in a sulfate, phosphate, or carbonate scale may be water-soluble. For example, in a pure calcium sulfate scale the 100-ml. portion of water would dissolve about one fifth of the sample, whereas actually the entire sample is water-soluble. A pure carbonate or phosphate scale is also totally water-soluble to a much lesser degree. If the distilled water contains carbon dioxide, the carbonates and phosphates are more soluble. Therefore, this determination should be made cautiously and the interpretation even more so. Ordinarily, it is of little significance. 10.

9.

Water-Soluble Matter.

Prepare a Gooch crucible, wash with water thoroughly, and dry to constant weight a t 105' C. Weigh 1 gram of the sample into a 250-ml. beaker. Add 100 ml. i f distilled water, co;er with a watch glass, and digest a t 60' to 70" C. for 1hour. Filter through the Gooch crucible, making sure that all residue is transferred to the crucible. Wash the residue with three or four 10-ml. portions of hot, distilled water. Dry the crucible and conMay 1954

Sulfide Sulfur.

The sulfide sulfur is determined according to the procedure described under the Tin Method in "Analytical Chemistry" by Treadwell and Hall (IO)using a 1-gram sample.

NOTE8. If the deposit is one not apt to contain acid-insoluble sulfides the method for iron and steel [ASTM designation E-30, ~~~~~~i~~ ~~~h~~ (s)l may be employed, using a sample. NOTE 9. Instances are known of relatively pure sulfide deposits such as would be produced in a piping system carrying


965

water in which hvdrogen sulfide is dissolved. I n such instances, the amount of sample must be greatly reduced, 11. Carbonates as Carbon Dioxide.

This proceduie determines the carbonates decomposable by acids. If sulfide sulfur is piesent, it also is released and must be removed by oxidation and absoiption before the carbon dioxide is absorbed. The procedure is described by Treadwell and Hall ( 1 1 ) . h similar procedure is described by Scott (9). Hydrochloric acid should be used instead of sulfuric acid -4 1-gram sample is used.

KOTC10. Pure carbonate scales and scales high in carbonate are known. The sample size of these scales must be reduced to bring the evolved carbon dioxide into the range of the absorbing medium. If the sulfur test indicates high sulfides, the oxidizing and absorbing solution must be of sufficient volume to remove the evolved hydrogen sulfide. 12.

'

Manganese.

Manganese is determined by the bismuthate method. Weigh 1 gram of the sample into a 30-ml. porcelain crucible and ignite for 30 minutes a t 950" C. Cool to room temperature, add 15 ml. of concentrated hydrochloric acid and 3 or 4 drops hydrofluoric acid and evaporate t'o dryness. Add the hydrochloric and hydrofluoric acids again and evaporate to dryness. Add 15 nil. of hydrochloric acid and 2 ml. of sulfuric acid and evaporat,e t o strong fumes of sulfuric acid. Cool to room temperature, place the crucible and contents in a 400-mi. beaker containing enough water t o cover the crucible, and digest at 60' to 70" C. for 1 hour. Remove the crucible and viash mith distilled water from a nash bottle, catching the rashings in the beaker. Transfer the contents of the beaker to a 250-ml. Erlcnmeycr Hasli; make sure that, all residue as nrll as solution is transferred and evaporate t o about 25 nil. Add 50 ml. of nit,ric acid (1:3) heat slowly to boiling, and boil until oxides of nitrogen are expelled. Remove from the heat, cool slightly, add about. 0.5 gram of solid sodium bisniuthat,e, and boil again t,o remove oxides of nitrogen. TT'hile the solution is still boiling, add a few drops of a 10% solution of sodium thiosulfate to clear the solution of any manganese dioxide precipitate or permanganate. Remove the flask from the heat and cool to 15' to 20" C. Add about 0.5 gram of solid sodium bismuthate and agitate or stir for 1 minute. Add 50 ml. of nitric acid (3:100) free of nitrous oxide and filt,er through an acid-washed Gooch crucible. Wash the crucible and residue with about, 100 ml. of nitric acid (3 : 100) free of nitrous oxide. Transfer the filtrate t,o a 500-ml. Erlenmeyer flask. Add 2 ml. of phosphoric acid, then just enough ferrous ammonium sulfate solution from a buret t o discharge the purple color, and t,hen 2 ml. excess. Titrate the excess ferrous ammonium sulfate with 0.1-1' potassium permanganate.

XOTE11. If the manganese exceeds 18% of the sample, the results will be erroneous. The F\-eight of sodium bismuthate for each addition must be a t least 26 times the weight of manganese in the sample. NOTE 12. The ferrous ammonium sulfate solution mujt be standardized against. the potassium permanganate used in the titration. 13, Tin. Weigh 1 gram of the sample into an iron crucible, add 8 grams of sodium peroxide, and miu well. Heat gradually until any violent action ceases and finally to a dull-red heat for about 15 minutes. Let cool t o rooin temperature and, while the fusion is solidifjing, imbed n platinum wirc in thc cake When cool, place a flame under the riucihle and lift out the cake on the platinum wire Place the rake in warm distilled mater. Rcmove the wire as soon as it 1s released from the cake and is clean. Place water in the iron crucible t o cover the fusion line and warm to dissolve the melt. 1175sh the contents of the ciucible into the

966

beaker. When the fusion is dissolved complet,cly, in not more than 200 ml. of mater, aFid hydrochloric acid slowlp to neutralize the caustic, then make 10% in free hydrochloric acid and cool to room temperature. -4dd a 6% solution of cupferron until prccipitation is complete and then 2 ml. excess. St,irvigorously until the precipit,ate becomes curdy, filter through a What,man KO. 30 paper or equivalent, and wash the precipitate with cold 10% hydrochloric acid several t,imes. Transfer t,he filter paper and contents t'o a porcelain crucible, and burn off t'he paper and organic matter by heating carefully to a bright red. Cool the crucible and moisten the contents with concentrated hydrochloric acid. WaEh into a 230-ml. beaker. Continue the moistening and washing until all the residue is transferred to the beaker. Karm and dilute to dissolve all t,he residue. If any silica was occluded in tmhecupferron precipitat,e, it will not dissolve and must be filtered off. Add 10 ml. of nitric acid and evaporate just t,o dryness, taking care not, t o bake the residue. Add 10 ml. of nitric acid again and evaporate just, to dryness. Add 10 mI. of nitric acid, dilute to 100 ml., and filt'er through a Whatman KO. 40 paper or equivalent, and nash with nitric acid ( 1 : l O ) . Transfer the paper and contents to a porcelain crucible previously ignited to constant weight. Carefully burn nff the paper and then ignite strongly for 30 minut>es. Weigh as stannic oxide. 14.

Sodium and Potassium-Gravimetric.

A. I t is not usually necessary t,o determine t,he sodium and potassium content, of a Ivater-formed deposit unlesp the preliminary examination discloses considerable amounts or the complete analysis does not total 1007G. Usually, the time required for a gravimetric determination is a sufficient deterrent. ii procedure for the determination by flame photometry methods is provided as an alternat,e. B. The G. Lawrence Smith mrthod used. It is recommended that an analyst n-ho is not fam ar with this method should read pertinent section$ on the subject in "Chemical Analysis of Rocks" (12). C. TSTeigh 1 gram of the sample and an equal amount of ammonium chloride into an agate or mullite mortar. Grind together and mix n-ell. There should be no gritty particle \Then the grinding is complete. TT'eigh 8 grams of calcium carbonate, and place a small amount of it in the bottom of a 30-ml. platinum crucible. Of the remainder, put all but about 0.5 gram into the mortar m-ith the sample-ammonium chloride mixture: grind, and mix well. Transfer the contents of the mortar to the platinum crucible, tap the crucible to settle the contents, and covcr with the remainder of the calcium carbonate. NOTE 13. The ammonium chloride and calcium carbonate need not he xeighed accurately if they are free of sodium and potassium: if they are cont,aminated, the amount must, he knovn and the weighings accurat,e. I n either caw, the weight of ammonium chloride must a t least equal the n-eight of the sample, and t,he calcium carbonate must be a t leait eight, times the n-eight of the sample.

D. Cover the crucible m-itli a flat cover and in3ert in a tightfitting hole cut in a square of asbestos board so that only the loiTer third of t'he crucible is exposed to,the burner. Heat over a lox flame until all ammonia salts are driven off. Examine the cover near the end of the heating period to see that no ammonia salts have condensed. Place a small beaker, half filled with water, on thc cover of the crucible and increase the flame until the loner third of the crucible is a t a bright-red heat,. Hold t)his tempcrature for 45 minutes, replacing the water in the beaker as necessary. Cool the crucible and content,s to room temperature. NOTE 14. The temperature during the iiiitial heating mu& be just high enough to drive off t,he ammonia salts and the heating continued just long enough to drive off all the ammonia. Too little heat will leave ammonia t o cont,aminate the potassium precipitate, Too much heat may volat'ilize some of the sodium a n d potassium.

INDUSTRIAL A N D E N G I N E E R I N G CHEMISTRY

VoI. 46, No. 5

Boiler Water Chemistry NOTE 15. The beaker should be small enough to fit flat on the flat surface of the cover t o give maximum cooling contact. Otherwise, too much of the sodium and potassium will volatilize. E. Add just enough distilled water to the crucible to keep the contents covered until all slaking action ceases. Transfer the contents to a platinum dish with the aid of a platinum spatula and water from a wash bottle. Set the crucible aside with enough distilled water in it to reach above the top level of the sintered mass originally present. Rinse the spatula into the platinum dish. There should be no more than 50 ml. of water in the platinum dish. F. Rub the partly disintegrated mass pith an agate pestle to break up any stubborn particles. Rinse the pestle into the dish and add the water from the crucible. Boil gently for a few minutes, and decant the liquid through a Whatman No. 40 paper or equivalent, catching the filtrate in a 400-ml. beaker. Add a little more water to the dish, rub the residue with the agate pestle, rinse the pestle into the dish, and gently boil again for a few minutes. Decant through the filter and repeat the extraction of the residue once more. After the third digestion transfer the contents of the dish to the filter paper with the aid of hot water from a wash bottle. Wash the dish and filter with repeated small amounts of hot water until the volume of filtrate is about 300 ml. XOTE 16. Care must be exercised in rubbing the sample in the platinum dish. Abrasive particles may be transferred to an agate mortar, ground to powder with an agate pestle, and rinsed back into the dish for digestion. NOTE17. If the analyst has had little experience in this sintering, he should test the completeness of the reaction by dissolving a portion of the material from the filter in hydrochloric acid. Unless the sample is heavy with iron, silica, or material forming insoluble chlorides, solution should be complete. “ny residue should be fumed with sulfuric and hydrofluoric acids in platinum and the residue dissolved in water. If more than negligible residue is left, the fusion is incomplete. G. Proceed with the analysis according to the Method of Test for Sodium and Potassium in Industrial Water [ASTM designation D 1127-50T ( 7 ) ] beginning with the separation of the chlorides. 15.

Sodium and Potassium-Flame

Photometer.

A. Treat the sample exactly as described for the gravimetric determination through paragraph F. B. Carefully acidify the filtrate with hydrochloric acid and evaporate to dryness. Moisten the residue with a little dilute hydrochloric acid (3:8), scrubbing the bottom and sides with a rubber policeman. Add 25 ml. of concentrated hydrochloric acid and warm on a water bath. Dilute with 50 to 75 ml. of distilled water, heat to 80” C., and filter through a Whatman No. 40 paper or equivalent. Wash vith hot hydrochloric acid (1:20) and then several times with distilled water. C. Test the solution in a flame photometer calibrated with sodium and potassium chlorides in hydrochloric acid (1:20) solution. If the sample is too rich in sodium or potassium, it is diluted with hydrochloric acid (1:20) t o bring it into the range of the calibration. The flame photometer must be capable of measuring the sodium and potassium contents in the presence of ions emitting light of a wave length close to that of these alkalies.

KOTE18. Other ions in deposits may interfere with this determination, though not too seriously in low concentrations; therefore, dilution may offer the accuracy desired. Some flame photometers are more seriously affected than others. For the effect of some ions see “Flame Photometer in Analysis of Water and Rater-formed Deposits” (8). 16. Dissolving the Principal Sample.

Place 5 grams of the analytical sample in a 250-ml. beaker. Add 10 ml. of nitric acid, 30 ml. of hydrochloric acid, and 35 ml. May 1954

of distilled water, and cover the beaker. Allow the sample to digest at room temperature. When the reaction is completed remove the cover glass and add 20 ml. of concentrated nitric acid and 40 ml. of 60 to 70% perchloric acid. Evaporate to fumes of perchloric acid in a hood designed for such use of perchloric acid. Do not evaporate enough that the beaker contents will solidify. Cool, add carefully 20 ml. of 60 to 70% perchloric acid and again evaporate to fumes. Cover with a watch glass and boil for not more than 15 minutes but not enough to allow the contents to become pasty or solid. Cool and carefully dilute with about 150 ml. of distilled water. Stir until all salts are dissolved and filter through ashless filter paper, transferring all the silica residue to the filter paper. Wash four to five times with 0.6 N hydrochloric acid and four or five times with cool distilled water. Set the filtrate and washings aside. KOTE19. If the laboratory facilities do not permit the use of perchloric acid, the aqua regia digestion is evaporated to dryness without baking, and the mass is treated twice with 30 ml. of concentrated hydrochloric acid and evaporated to dryness without baking. 17.

Silica.

A. Transfer the filter paper and contents to a weighed platinum crucible and ignite t o constant weight. Moisten the contents with distilled water and add 5 ml. of hydrofluoric acid and a few drops of sulfuric acid. Carefully evaporate to dryness and ignite at red heat for 15 minutes. Cool in a desiccator and weigh. The loss in weight is recorded as silica. B. Fuse the residue with sodium carbonate and dissolve the fusion in the minimum amount of dilute hydrochloric acid (1:3) required, taking care to avoid spattering. Boil after reaction is complete, cool to room temperature, and filter. Examine the precipitate, if significant, for sulfates and chlorides and metals forming insoluble sulfates and chlorides. Transfer the filtrate t o a 500-ml. volumetric flask. Add the filtrate from step 16 and add enough distilled water to make 500 ml. This is now the sample for the following work. 18. Sulfur Trioxide.

A. If the residue after the silica volatilization is significant, so that it was fused as in step 17B, the sulfur trioxide determination mupt be made on the original sample. Take 1 gram of the original sample and grind in an agate (mullite) mortar until there are no gritty particles. Place in a 250-ml. Erlenmeyer flask and add 100 ml. of a 5% solution of sodium carbonate. Boil for 1 hour and filter while hot. Wash the residue several times with a hot 5% solution of sodium carbonate. Acidify the filtrate and washings with hydrochloric acid and precipitate as in step 18B with barium chloride. B. Pipet 100 ml. of the sample into a 250-ml. beaker. Add 5 ml. of hydrochloric acid and heat to boiling. While boiling, add 10 ml. of barium chloride and continue boiling for 10 to 15 minutes; then allow to stand 2 hours (preferably overnight) at 200’ F. Filter through a Whatman KO. 40 paper or equivalent, and wash with hot distilled water until free of chlorides. Ignite in a tared porcelain crucible, cool in a desiccator, and weigh as barium sulfate. 19. Separation of Tin, Copper, and Lead. -4. A large part of the tin probably has been lost. The tin value obtained on the 1-gram portion of the original sample is the value to be reported. B. Pipette 200 ml. of the sample into a 400-ml. beaker. Adjust the acidity to 0.3N hydrochloric acid. Place on a hot plate and heat to 150’ F. and hold t o about this temperature. Pass hydrogen sulfide through the liquid a t a modenate rate for


967

10 minutes. Remove from hot plate and keep the hydrogen sulfide flowing for another 20 minutes. Allow the precipitate t o settle, filter on Whatman No. 30 or equivalent, and wash with a solution composed of sulfuric acid (1:99) saturated with hydrogen sulfide. The precipitate contains tin, copper, and lead if present in the sample. C. Boil the filtrate to remove hydrogen sulfide, filter off any sulfur formed, add 5 ml. of nitric acid to the filtrate and Jyashings, and boil again. Set the liquid aside for further use and discard the sulfur precipitate. 20.

Removal of Tin.

Transfer the precipitated sulfides to a porcelain dish and treat with 25 ml. of nitric acid (1:3). Digest for 20 minutes on a hot plate and evaporate to about 5 ml. Filter off any precipitate and wash with hot 1% ammonium nitrate. Discard the precipitate. 21.

distilled water and an excess of ammonium hydroxide. Boil, allow the precipitate to settle, and filter. The precipitate contains the iron, aluminum, phosphorus, manganese] nickel, and titanium. Wash thoroughly with hot distilled water containing a little ammonium hydroxide. Set the filtrate and washings aside. B. Dissolve the precipitate in dilute nitric acid (1:3) and add ammonium molybdate solution until all the phosphorus is precipitated. Filter through Whatman No. 40 paper or equivalent, and check the filtrate for complete solution. Dissolve the precipitate in sodium hydroxide and reprecipitate with molybdate. Filter, wash with potassium nitrate solution, and again check the filtrate and washings by adding a little more molybdate reagent. After both filtrates have set for 1 hour or more ~vithont further phosphate precipitation, combine them and discard the precipitate. 24.

Copper and Lead.

A. Make the filtrate and washings from step 20 about 10% in nitric acid, add a drop of 0.1N hydrochloric acid, and dilute to 150 ml. Insert a pair of xeighed platinum electrodes in the solution, cover with a split watch glass, and electrolyze until the solution is colorless at a current density of about 0.5 amp. per square dm. When the solution is colorless, wash dorm the cover glass, electrodes, and sides of the beaker and continue the electrolysis until the deposition of copper is complete as indicated by failure t o plate on a new surface when the solution level is raised. B. With current still on, lower the beaker slowly (raise the electrodes) while washing the electrodes with water. When the electrodes are out of the solution, turn off the current. Remove the cathode, rinse with water, and dip into two successive baths of ethanol or methanol. Dry in an oven (Note 1) a t 110' C. for 3 to 5 minutes, cool, and weigh. The difference in weight is copper. C. Remove the anode, rinse thoroughly with water, and dry a t 110' C. (Note 1) for 30 minutes, cool, and weigh. The difference in weight is lead dioxide.

ildd ammonium hydroxide to the filtrate from step 23B until precipitation is complete. The precipitate contains iron, aluminum, titanium, and manganese. Filter on What,man No. 30 paper or equivalent, and wash thoroughly with distilled water containing a little ammonia. Combine the filtrate and washings with the filtrate from step 23A and set aside for nickel and zinc. Dissolve the precipitak in 1.25N hydrochloric acid and cool t o 10" C. Add a litt,le filter pulp and precipitat,e t,he iron and titanium with an excess of cold 6% cupferron solution in xater. Stop the addition of cupferron with the first flash of white precipitate (after the iron is precipitated) at contact of precipitant with solution. Stir 3 minutes, filter on coarse ashless paper, and wash with cold 1 N hydrochloric acid containing 1% cupferron. Set the filt,rate aside for aluminum determination. Dry t,he filter and transfer to an ignit,ed and tared porcelain crucible. Char the filter and precipitate a t low temperature; then ignite at bright red heat t o constant weight. The increase in n-eight is ferric oxide plus titanium dioxide. 25.

22.

Phosphorus.

Evaporate the filtrate from 19C t o less than 200 ml. Cool and transfer to a 200-ml. volumetric flask with distilled rrater. Pipet an aliquot containing not more than 5 mg. of phosphorus pentoxide into a 500-ml. Erlenmeyer flask, add 50 ml. of nitric acid (1:3), and boil. Cool t o about 75' C. and add 85 nil. of ammonium molybdate solution. Stopper with rubber and shake vigorously for 10 minutes; allow to stand for 2 hours or more. Filter through a Whatman No. 40 paper or equivalent, washing the flask, stopper, precipitate, and paper 10 t o 15 times with a 1% potassium nitrate solution. The mashing should be continued until 10 ml. of the washings show alkaline t o phenolphthalein, vhen 1 drop of 0.1-Y sodium hydroxide is added. Return the filter paper and precipitate to the precipitation flask, add 50 ml. of recently boiled and cooled distilled Tyater, stopper, and shake vigorously to break up the filter paper. Add an excess of 0.LV sodium hydroxide to dissolve the precipitate, shake well, add phenolphthalein indicator and more KaOH, if necessary, and let stand for about 5 minutes. Remove the stopper, mash it into the flask with recently boiled distilled water, add 50 ml. of recently boiled distilled water, and immediately titrate the excess sodium hydroxide nitli 0.LV nitiie acid.

KOTE20. Use ASTM method D-515 ( 6 ) for deposits high in phosphorus. 23. Separation of Iron, Aluminum, Phosphorus, Manganese, Nickel, and Titanium.

A. To the remaining portion of the filtrate from qhich the phosphorus sample v a s takcn, add 10 nil. of bromine-saturated 968

Iron Oxide

Titanium Oxide-Gravimetric.

Add potassium acid sulfate and a drop or t\To of sulfuric acid t o the iron-titanium precipitate from step 24 and fuse until a clear melt is obtained. Cool, carefully add 6 ml. of concentrated sulfuric acid, and heat gently until the melt is dissolved. Cool and dilute t o 200 ml. lvith distilled water. Precipitate the iron and titanium viith ammonia, filter on Whatman Xo. 30 paper or equivalent] and wash with distilled water containing a little ammonia. Dissolve the precipitate in 50 to 60 ml. of hydrochloric acid (1: 10) (the paper and precipitate may be boiled in a beaker), dilute to 300 ml. with distilled water, nearly neutralize with ammonia or ammonium carbonate, and saturate with sulfur dioxide. Boil until the titanium is precipitated and the solution smells faintly of sulfur dioxide. Filter on dense ashless paper, wash with hot water containing sulfur dioxide, and transfer the filter and precipitate to an ignited tared porcelain crucible. Dry, char, and ignite a t bright-red heat to constant Tveight. Veigh as TiOz. 26.

Titanium Oxide-Colorimetric,

Titanium in small amounts is best estimated colorimetrically. Dissolve the potassium acid sulfate fusion in 6 ml of sulfuric acid, cool, and dilute t o 100 ml. with distilled mater. Cool and estimate the iron present by titration with 0 1N potassium manganate. Increase the volume to 500 ml. in a volumetric flask by adding 2 N sulfuric acid. To 25 ml. of this solution add 2 ml. of 3% hydrogen peroxide free of fluorides and phosphates, and dilute xith 2N sulfuric acid to the mark in a 50-ml. Sessler tube. Compare against titanium dioxide standards containing the same amount of iron as tho Pample prepared in


Vol. 46, No. 5

Boiler Water Chemistry-, 2N sulfuric acid and 2 ml. of 3% hydrogen peroxide per 50 ml. of solution. There are various photocolorimeters available to expedite this comparison. 27.

Aluminum Oxide.

A. Take the second filtrate from step 24, make alkaline with ammonia, and allow the precipitate to settle for 30 minutes. Filter off the aluminum hydroxide on ashless paper and wash thoroughly with hot water containing a little ammonia. Transfer the filter and precipitate to an ignited, tared porcelain crucible, dry, char, and ignite to constant weight as aluminum oxide contaminated with manganous oxide. B. Fuse with potassium acid sulfate, cool, and dissolve in 65 ml. of distilled water, 15 ml. of concentrated sulfuric acid, and 20 ml. of concentrated nitric acid. .4dd 0.2 to 0.4 gram of solid potassium periodate, boil 1 or 2 minutes, keep hot 10 to 15 minutes, and then cool and dilute t o proper volume for comparison against solutions of known manganese content prepared in the same manner. Not more than 1 mg. of manganese per 50 ml. of solution should be present. There is no interference except manganese content of reagents, if any. The manganese content as Mn,Od is subtracted from the aluminum precipitate. 28.

Nickel Oxide.

Neutralize the combined filtrates from steps 23A and 24 with hydrochloric acid and add distilled water to make 200 ml. Add 20 ml. of tartaric acid solution (250 grams per liter) and treat with a slight excess of a 1% solution of dimethylglyoxime in alcohol. Carefully neutralize with ammonia and add 1 ml. excess. Digest for 1 hour a t 60' C. Cool to room temperature, filter through a weighed Gooch crucible, never allowing the mat to become dry, and wash the precipitate thoroughly with cold distilled water. Save filtrate and washings for zinc. Dry the precipitate and crucible at 105' C. to constant weight. Cool and weigh as nickel dimethylglyoxime. 29.

Zinc Oxide.

Keutralize the filtrate from step 28 with hydrochloric acid and evaporate to about 150 ml, Transfer to a 250-ml. Erlenmeyer flask and cool. Add 2 ml. of ammonia, saturate with hydrogen sulfide, and add another 2 ml. of ammonia. Dilute with boiled distilled water to the neck of the flask, stopper, and let stand for 3 hours. Filter without interruption and wash without interruption with cold 2% ammonium chloride solution containing a little hydrogen sulfide. Set the filtrate and washings aside for determinations of alkaline earths. Dissolve with precipitate in hydrochloric acid (1: l), reprecipitate as above, and wash with distilled water saturated with hydrogen sulfide. Transfer filter and precipitate to an ignited, tared porcelain crucible, char, and ignite a t 950" C. to constant weight as ZnO. 30. Barium, Calcium, and Magnesium.

NOTE 21. If the silica precipitate was contaminated by a significant amount of metals forming insoluble sulfates, the determination of barium, calcium, lead, and magnesium must be made on the original sample (step 31). A. Evaporate the combined filtrates and washings from the zinc determination t o about 150 ml. Filter off and discard any sulfur. Evaporate to dryness and volatilize the ammonia salts. Add 10 ml. of 7147 sulfuric acid and make sure that the residue is all in solution. Evaporate to dense fumes of sulfur trioxide, removing most of the sulfuric acid. Cool, add 100 ml. of water, and heat to boiling. Filter off any barium sulfate and wash the filter with hot water. Ignite wet in a platinum crucible to constant weight.

May 1954

B. Neutralize the combined filtrate and washings from the barium determination with ammonium hydroxide. Acidify with an excess of citric acid, heat to boiling, and add an excess of a 401,solution of ammonium oxalate. Stir, boil for a few minutes, and allow to stand hot for 1 hour. Filter, and wash with the minimum amount of distilled water. Reserve the filtrate and washings for magnesium determination. Dissolve the precipitate in 50 ml. of warm hydrochloric acid (1:10),wash into the beaker in which the precipitation was made, and dilute to 100 ml. Add 1 ml. of a 4% solution of ammonium oxalate, heat to boiling, and add ammonium hydroxide slowly until the solution is alkaline to methyl red. Add an excess of 1 ml. of ammonium hydroxide. Boil for a few minutes and allow t o stand hot for 1 hour. Filter and wash with the minimum amount of distilled water. Add the filtrate and washings to the solution reserved for the magnesium determination. Ignite the filter and precipitate in a platinum crucible to constant weight as CaO. The weighing must be done quickly, as calcium oxide is highly hygroscopic. C. Evaporate the filtrates and washings from step 30B to less than 300 ml. Add methyl red indicator, about 5 ml. of hydrochloric acid and 10 ml. of saturated solution of diammonium hydrogen phosphate. Add ammonium hydroxide slowly, while stirring, to neutralize and, when the precipitate is well formed, add an excess of 10 to 15 ml. of the phosphate. Let stand for a t least 4 hours, preferably overnight, filter, and wash with distilled water containing 3y0 by volume of ammonium hydroxide. Dissolve the precipitate with warm hydrochloric acid (1 :5) and dilute the solution to 100 to 150 ml. Add methyl red indicator and about 1 ml. of the ammonium phosphate solution. Cool and precipitate as above, let stand as above, filter, and wash with the 3% ammonia solution. Transfer filter and contents to a porcelain crucible, char without flaming, and ignite a t low temperature with the crucible lid adjusted to permit circulation of air. Finally, ignite to constant weight and weigh as Mg2PO. 31. Barium, Calcium, Magnesium, and Lead 'on Originil Sample. A. Place 1 gram of the original dried and extracted sample in"a platinum crucible and treat with 10 ml. of sulfuric acid (1 :4) and 5 ml. hydrofluoric acid. Carefully evaporate on a steam bath, then take to fumes on a hot plate. Repeat if the solution is not complete. Cool and dilute with 30 ml. of distilled water in a 150-ml. beaker and filter off any barium, calcium, magnesium, or lead precipitate. Wash with alcohol until free of magnesium. If large amounts of magnesium are present, it will be necessary to digest the precipitate with a small amount of water, then add 95% alcohol to make the alcohol content of the solution 50%, and filter before washing with alcohol. Reserve the filtrate for magnesium determination. B. If lead was found in the preliminary examination, extract the residue with a 10% solution of ammonium acetate until all the lead is removed. Calcium also passes into the filtrate. Add 10 ml. of sulfuric acid (1 :4) to the extract and evaporate to fumes. Cool, take up the residue in distilled water, and add enough solid sodium hydroxide to dissolve the lead. Filter off the calcium on ashless paper, wash with the minimum amount of distilled water, and ignite in a platinum crucible. Fuse the ignited residue with sodium carbonate, extract with water, filter, and dissolve the carbonate residue in hydrochloric acid. Neutralize with ammonium hydroxide, acidify with an excess of citric acid, heat to boiling, and add an excess of a 4% solution of ammonium oxalate. Stir, boil for a few minutes, and allow to stand hot for 1 hour. Filter, and wash with the minimum amount of distilled water. Add the filtrate and washings to the solution reserved for magnesium determination. Ignite the filter and precipitate in a platinum crucible to constant weight as CaO. C. Dilute the sodium hydroxide solution of lead to 100 ml. and make 10% in sulfuric acid. Filter through a dried and

INDUSTRIAL A N D ENGINEERING CHEMISTRY

969

tared Gooch crucible, wash with the minimum amount of water, dry at 110” C. and weigh as PbSOa. D. Wash the residue from step 31B (ammonium acetate extraction) free of acid with distilled LTater, transfer to a porcelain crucible, ignite a t not above cherry-red heat for not more than 0.5 hour, and weigh as BaSO4. E. Evaporate the filtrate from step 318 plus that from the calcium determination to less than 300 mi. Determine magnesium as in step 30C. LITERATURE CITED

( I ) Am. Soc. Testing Materials, Philadelphia, Pa., Manual on In-

dustrial Water (1953).

(2) Ibid., pp. 108-13. (3) Ibid., hiethods for Chemical Analysis of Metals pp 92-4 (1950). (4) Ibid., Standards, Part 5, pp. 807-33 (1952). (5) Ibid., Part 7, pp. 1082-1263. (6) Ibid., pp. 1203-6. (7) \ , I h i d.., no _ . . 1216-20 ~ _ ~ . ( 8 ) Ibid., Speciel Tech. Pub. 116, 10j-14 (1951). (9) Scott, W. W.,“Standard Methods of Chemical Anrtlysis,” 5th ed., Vol. 1, pp. 235-7, F e w York, D. Van Nostrand Co., ~~

1939. (10) Treadwell, F. P., and Hall, W. T., “Analytical Chemistry,” 9th ed., Vol. 2, pp. 318-19, New York, J. Kiley 8r Sons, 1942. (11) Itid., PP. 324-7 (12) Washington, H. R., “Chemical Analysis of Rocks,” 4th ed., Kew York, J. Wiley 8r Sons, 1930. RECEIVED for review SEPTEMBER 14, 1953.

ACCEPTEDFebruary 19, I954

Scheme for Analysis of Industrial Water J

J. H. PHILLIPS AND K. G . STOFFER The Babcock & W’ilcox Co., Research Center, Alliance, Ohio

At the request of the Executive Committee of A4STMCommittee D-19, a task group was appointed to set up a scheme for analysis of industrial water, including a comprehensive list of the properties and constituents of industrial water for which analyses are made. The scheme divides the properties and constituents into four principal categories based on whether they are affected or unaffected by contact with the atmosphere, and according to the type of sample or sampling conditions required. A system of lines and sample group blocks is employed to associate properties and constituents with their appropriate sample groups and to indicate possible successive analyses of several constituents from a preceding analysis. The scheme for analysis of industrial water should become an important analytical aid for i t brings together in a manageable outline form the methods for determining the many properties and constituents of industrial water.

I

T HAS become apparent over the past several years that, in order to provide proper uniformity among laboratories, it is necessary to have available for ready refeience an analytical outline or scheme incorporating the many accepted physical and chemical methods for water analysis. Such a scheme would not only facilitate close agreement among laboratories but would also be of immeasurable assistance to the individual analyst charged with industrial water control. The Executive Committee D-19 of the American Society for Testing Materials shared the desire for such a scheme, and in 1950 a task group was appointed by Subcommittee IV of ASThl Committee D-19 to operate under the chairmanship of J. H. Phillips. senior author of this paper, to set up an aeceptable scheme for analysis of industrial m t e r . It Ras the hope of the committee that it would be possible to establish a scheme which would be workable for any industrial water sample and which, after refinement, could be included in the ASTM “Manual on Industrial Water” as a standard procedure. It was not difficult to determine the desired scope of such a scheme. To be of real value to the analyst the order of application of the many methods for chemical and physical measurements needed t o be indicated to permit the determination of existing constituents and properties in logical sequence. As might be imagined, the niechanics of arranging the analyti-

970

cal methods in a logical order proved to be the most difficult part of the problem. This is understandable when it is realized that there are not less than 50 individual constituents and properties which need to be included in order to set up a practical, workable scheme. The complexity of the problem became apparent when it mas first attempted to set down all these tests in sequence and to indicate by one means or another the interrelationship of the various analyses to each other. The fact that certain constituents and properties may be adversely affected by sampling procedures and contact with air, or both, also prcsented a complication in the arrangement. In order to acquire some idea of what schematic outlines, if any, were being used in other laboratories, members of the task group submitted outlines of water analyses being used in their laboratories. None of these, of course, was as comprehenfive iis the scheme €or analysis desired by ASTM, but they did indicate constituents and properties of importance to various agencies and industries. The order of sequence, if any, and the different physical arrangements of the schemes were also indicated. The outlines submitted by task group members were peculiar to individual laboratory needs. Some were set up in the familiar block type of outline commonly used in qualitative analysis schemes; others simply enumerated the properties and constituents in an order suited to specific needs; and still others used a


V O ~46, . No. 5

Analysis of Water-Formed Deposits

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