SOV., 1919
’
T H E J O U R N A L O F P N D U S T R I A L A,VD E N G I N E E R I N G C H E M I S T R Y
9-Carbon dioxide gas additions t o the soil changed t h e amounts of substances precipitable by ammonium hydroxide, which are extracted b y a normal potassium nitrate solution. Io--Calcium carbonate additions t o the soil did not decrease the weights of ammonium hydroxide precipitable material in proportion as they decreased t h e acidity results. Calcium will replace aluminum, and t h e results of such a reaction are apparent in the increased weight of precipitates from the potassium nitrate extract of t h e soil receiving double application of calcium carbonate. ~ r - - T h e form in which t h e phosphorus and nitrogen were applied was t h e cause of reactions which influenced t h e amount of material extracted b y the normal potassium nitrate solution. The increased amounts of substances obtained after extraction are evidence t h a t t h e fertilizing materials were the causes of soil solutions of different composition, which in t u r n affected t h e solubility of aluminum-containing compounds in the soil. Acid phosphate and sodium nitrate (soluble materials) gave entirely different potassium nitrate extracts from t h e extracted soils than dicalcium phosphate and dried blood (insoluble materials). ~z--Calcium carbonate additions t o the soil had comparatively little effect on the conductivities of the soil extracts. Two things undoubtedly account for this, the low solubility of the calcium carbonate and the low solubilities, as well as conductivities, of the substances in the soil t h a t the calcium replaced. 13--Phosphorus and nitrogen applied in different forms were t h e cause of water extracts of very different specific conductivities The extracts from the soils which had received dicalcium phosphate and calcium Carbonate had low specific conductivities in comparison t o the extracts from soil which received sodium nitrate or acid phosphate. t 4--The specific conductivities of extracts from t h e full application of sodium nitrate and acid phosphate are held t o show: The soluble sulfate ion from the calcium sulfate in the acid phosphate stayed in solution and kept u p the specific conductivity; carbon dioxide gas augmented the increased .conductivities; where sodium nitrate was applied, the sodium ions gave increased conductivity; t h e action of carbon dioxide gas on the soil constituents increased t h e ease with which sodium replaced substances in the soil; the conductivity decreased due t o the slight solubilities and ionization constants of t h e new substances formed; the loss of nitrates through bacterial activities and plant “absorption” were also concerned. I j--Chemical reactions are held t o be t h e causes of, and known laws of chemistry offer satisfactory explanations for soil acidity. 16--In conclusion, the reaction of a soil a t any time is dependent both on the nature of and t h e proportions in which its constituents are present with water. Changing the water content, removing substances from solution, and the addition of other subStances change the reaction in accord with the working of the law of mass action. T h e solubilities of sub-
I049
stances in, the possibilities of combination) and the rate a t which reactions take place in soil vary SO t h a t the condition of a soil a t any time can be corlsidered but a stage in its progress towards a constantly shifting equilibrium in accordance with the principle of LeChatelier. MEI,LON INSTITUT OF~ INDUSTRIAL RESEARCH U N I V I ~ I ~ S I TOYF PITTSBURGH
PITTSBURGH, PENNSYLVANIA
A FURTHER STUDY OF THE DEROODE METHOD FOR DETERMINING POTASH BY T. E. KEITTAND H. E. SHIVER Received March 31, 1919
We have provedl t h a t the Lindo-Gladding method for determining potash gives low results in the presence of certain constituents normally present in mixed fertilizers and present in some sources of domestic potash. As a substitute2 for the Lindo-Gladding method we have offered a modification of a method suggested by D e R ~ o d e and , ~ we have presented much concordant analytical d a t a t o prove its accuracy. With potash selling a t the present high prices i t is but just t h a t t h e producers of domestic potash shall have a fair valuation of their product, which will no doubt soon come in competition with foreign sources of potash. Treater dust is a case in point: this material shows about 0.6 per cent more water-soluble potash by t h e DeRoode method t h a n i t does by t h e Lindo-Gladding method. T h a t this potash is actually present in water-soluble form will be shown in this article. With water-soluble potash selling for $4.50 per unit, this means a loss of $ 2 . 7 0 on each ton of this material due t o a n inaccurate method of analysis. When $ 2 . 7 0 is multiplied b y t h e total tonnage produced annually, we readily see t h a t the aggregate loss is large. The high degree of accuracy obtained through t h e use of the DeRoode method, the lessened number of operations, and t h e elimination of platinum apparatus make the method highly desirable. Since the publication of our former article certain chemists have expressed doubt as t o t h e accuracy of the method in t h e presence of nitrate of soda, ammonium salts, high content of phosphates, and large amounts of organic matter. We had already tested the samples used in t h e former work for ammonia and had established its presence in most of them. We have since estimated quantitatively the percentage of ammonia present as ammonium salts, b y distilling over magnesium oxide. Table I shows t h a t t h e ammonia content ran as high as 1.87 per cent in these samples. An inspection of the following table shows t h a t eleven of t h e twenty samples contained less t h a n ‘/zper cent of ammonia, with a n average plus difference for the DeRoode method of 0.081 per cent. Three samples contained between l / ~ a n d I per cent of ammonia with an average plus difference of 0.1s per cent. Six samples contained between I and 2 1
2
a
THISJOURNAL, 10 (1918), 994. Ibid.? 10 (1918), 219. J . A m . Chem. SOC.,17 (1895),185.
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
1050
per cent of ammonia with a n average plus difference for the DeRoode method of 0.089 per cent. These results indicate t h a t there is no error in t h e DeRoode method due t o t h e presence of as much as 1.8 per cent of ammonia. TABLE I-PERCENTAGE OF AMMONIAPRESENT IN SAMPLES USED COMPARING THE UNDO-GLADDING WITH THE DEROODE METHOD Difference N H s in Sample Potash Potash by between by I,.-G. DeRoode Columns SAMPLE Method Method 2 and 3 No Per cent Per cent Per cent Per cent 0.08 0.88 -4.02 18 0.90 54 2.18 2.19 0.01 1.27 59 4.34 4.46 0.12 0.17 4.57 0.12 0.43 74 4.45 90 2.71 2.79 0.08 0.34 93 4.60 4.66 0.06 0.45 160 0.90 0.93 0.03 0.34 247 1.84 1.84 0.00 1.87 302 4.75 4.89 0.14 1.36 311 4.61 4.85 0.24 0.51 0.19 313 3.52 3.59 0.07 2.89 0.01 0.17 335 2.88 0.42 356 1.64 1.74 0.10 357 2.54 2.71 0.17 0.25 386 0.25 0.26 0.01 1.44 421 0 95 1.10 0.15 0.09 641 1.74 1.94 0.20 1.27 694 1.73 1.87 0.14 1.19 770 1.38 1.40 0.02 0.51 961 0.86 0.93 0.07 0.68
FOR
b&11;,2"h","d
It seemed advisable, due t o the criticisms already mentioned, t o greatly exaggerate the percentage of ammonium salts and t o further test the accuracy of the procedure. With this end in view t h e samples used in Table I of a former article' were selected, and enough ammonium sulfate added t o furnish j per cent of ammonia ("8). With these large amounts of ammonium salts it was found t h a t the results obtained by our former procedure ran high, due t o the incomplete removal of t h e ammonia. A single treatment with aqua regia followed by an evaporation with hydrochloric acid was tried with unsatisfactory results. We next reversed the proportions of nitric a n d bydrochloric acids, and after evaporating t o dryness, added hydrochloric acid and evaporated t o dryness again, prior t o taking up with water and precipitating with platinic chloride. This procedure gave unsatisfactory results, again running too high. Next we tried two evaporations with aqua regia, using 3 0 cc. each time, followed by taking up with hot water and several cubic centimeters of hydrochloric acid, and evaporating t o dryness preparatory t o taking up with hot water and precipitating with platinic chloride. This procedure gave satisfactory results even in the presence of more t h a n 5 per cent of ammonia as shown in Table 11. The results given in Column 4 are the first and only determinations made by this method of procedure on these samples. The results obtained are in such close agreement with the results obtained in Column 3 t h a t duplication appears unnecessary, the average difference being 0.04 per cent. It is also worthy of note t h a t t h e results are not all too high, some being above and one below t h e results obtained b y the Lindo-Gladding method. T h e DeRoode method as finally applied is carried o u t as follows: Ten grams of material are transferred t o a 5 0 0 cc. flask, 300 cc. of water added, brought t o boiling and boiled for 30 min., cooled, made t o 1
LOG.
cit.
Vol.
11,
No.
11
volume, thoroughly shaken, and filtered through a dry, folded filter paper, t h e first runnings being discarded. A 50 cc. aliquot is placed in a 2 0 0 - 2 5 0 cc. thin porcelain dish and 3 0 cc. of a i u a regia added after putting t h e dish on t h e hot plate. T h e hot plate should preferably be located under a good hood. After evaporating t o dryness another 3 0 cc. of aqua regia are added and the solution again evaporated t o dryness, the residue TABLE11-EFFECTIVENESS OF T W O EVAPORAI'IONS WITH AQUA REGIA FOLLOWED BY O N E WITH HYDROCHLORIC ACID, PREPARATORY TO TAKING UP WITH HOT WATERAND ADDINGTHE PLATINIC CHLORIDE SOLUTION
N
N
0.19 0.28 0.25 0.27 0.19
0.19 0.39 0.35 0.32 0.15
R
58 160 547 850 1229
3.15 2.71 5.98 2.68 3.10
3.34 2.97 6.23 2.95 3.29
3.34 3.08 6.33 3.00 3.23
5.17 5.08 5.17 5.25 5.34
0.00 0.11 0.10 0.05 -4.06
taken up with a small volume of hot water, I O cc. concentrated hydrochloric acid added, and t h e solution again evaporated t o dryness. The residue is taken up with hot water and platinic chloride solution added. When the solution is almost evaporated t o dryness, we prefer t o remove from the water bath, on which the final evaporation is accomplished, and whirling the dish, cover t h e dried portion with t h e liquid portion, avoiding a baked condition. The precipitate is covered with acidulated alcohol prepared as previously described' and allowed t o stand for about a n hour, thoroughly breaking up the precipWe used tared filter papers, itate with a policeman. either Whatman No. 42, 9.5 cm., or S & S No. 589, 7 cm. Blank determinations on the filter paper showed -0.007 per cent loss. The precipitate is washed with acidulated alcohol until the runnings are colorless, then a t least seven times with I O cc. portions of Lindo's ammonium chloride wash. T h e washing is continued five times with 80 per cent alcohol, washing t o the top of the funnels. The following results obtained with treater dust serve t o confirm the evidence already secured. TABLE 111-INFLUENCEOF OCCLUSION ON THE DIFFERENCE FOUNDBY Two METHODS
THE
I n a former article' we have accounted for the increased percentage of water-soluble potash as shown by the DeRoode method and have shown t h a t t h e errors incident t o the Lindo-Gladding method are partially compensating, being due t o (he occlusion 1LOG.
cit.
t
SOV.
*
,
1: 9 I 9
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
of potash by the precipitates formed on t h e addition of ammonia and ammonium oxalate, and due t o the diminution in volume occasioned b y the volume of the precipitates so formed, the former causing a minus error and the latter a plus error. The above table shows t h a t there is a constant difference in the potash content of the two samples of treater dust estimated by the two methods under discussion. Further, the potash occluded by the ammonia and the ammonium oxalate precipitate, which is formed when the solution is made for the determination by the Lindo-Gladding method, is constant, the determinations in the last column being made on an acid solution of the precipitated material by the DeRoode method. These results, as well as those in Table I11 of a former article,' indicate t h a t the phenomenon is a chemical one, and t h a t it is dependent upon the nature and amount of impurities present. To further test the efficiency of the DeRoode method in the removal of ammonia, determinations were made using I O g. of ammonium sulfate. The result obtained with the DeRoode method was 0.09 per cent potash (KzO), while the result obtained by the LindoGladding method was 0.04 per cent, showing a difference of only 0.05 per cent potash on an ammonium salt for the DeRoode method. This work clearly establishes the non-interference of ammonium salts with the accuracy of the DeRoode method. Having successfully devised a procedure t h a t will take care of ammonia greatly in excess of what we find combined as ammonium salts in manipulated goods, we then proceeded t o ascertain if this procedure is accurate in the presence of varying amounts of nitrate of soda and organic matter in the mixtures. These mixtures were made up in 2 5 0 g. lots from materials previously analyzed. These determinations were made by the DeRoode method as outlined in this article, and represent the water-soluble content of potash. The weighings were made on torsion balances and for t h a t reason would only approximate the following formulas. TABLG IV-THEORETICALWATER-SOLUBLE POTASH CONTENT OF
THE
VARIOUS hfIXTURES
105I
quently analyzed by both methods. The results of these analyses of mixtures containing nitrate of, soda are shown in Table V. TABLEV-ANAGYTXCALDATAPROVING THE NON-INTERFERENCE OF NITRATE OF SODA WITH THE ACCURACY OF T E E DEROODE METHOD
8-0-4 8-1-4 8-2-4 8-4-4 8-7-4
0.00 1.00 2.00 4.00 7.00
3.59 4.02 4.15 4.41 4.79
3.76 3.92 4.06 4.27 4.46
4.14 4.03 4.11 4.41 4.74
-0.13 -0.10 4 . 0 9 -0.14 -0.33
0.23 0.01 -0.06 0.00 -0.05
-0.38 -0.11 -0.06 0.14 -0.28
The foregoing table shows t h a t the Lindo-Gladding method averaged 0.16 per cent lower than the calculated results, while the DeRoode method was 0.026 per cent higher than the calculated results. These results indicate t h a t the Lindo-Gladding method gives low results; t h a t this is due t o occlusion of potash will be shown later. It further shows t h a t t h e DeRoode method is accurate within experimental error. We will now prove t h a t the lower results obtained by the Lindo-Gladding method are due t o occlusion of potash in the combined ammonia and ammonium oxalate precipitates. Solutions were made as outlined for the Lindo-Gladding method' and filtered. T h e volume of the filtrate was measured, and 50 cc. aliquots for the determination of potash were taken and analyzed. These are the results used in Table V. The combined residues and precipitates on each filter were saturated with concentrated sulfuric acid in a porcelain dish, ignited, digested with hydrochloric acid until dissolved, transferred t o the flask in which the solution had been made up, and further digested. A separate series was run by filtering from t h e insoluble residue of the sample, washing filter, returning to original flask, and bringing t o a boil before adding ammonia and ammonium oxalate. These precipitates were treated in the same manner as the above-mentioned series. Potash was determined in each case by the DeRoode method and the results were so concordant t h a t there appears t o be practically n o hydrochloric acid-soluble potash in the residue. These results are averaged in Table VI. TABLEVI-EFFECTS
OF OCCLUSION AND DIMINUTION OF VOLUMEON T H E ACCURACY OF THE LINDO-GLADDING METHOD
125 125 125 125 125 000 CSM CSM. Mix. 115
8-0-4 8-1-4 8-2-4 8 4 4 8-7-4
0.375 0.375 0.375 0.375 0.375 0.000 0.345
000 000 000 000 000 250 115
0.00 0.00 0.00 0.00 0.00 4.45 2.05
00.00 14.00 28.00 56.00 95.00 00.00 00.00
0.000 0.322 0.644 1.288 2.254 0.000 0.000
20.00 20.00 20.00 20.00 20.00 00.00 20.00
9.356 3.89 9.356 4.02 9.356 4.15 9.356 4.41 9.356 4.79 0.000 1.78 9.356 4.70
The various materials used show the following water-soluble potash contents: acid phosphate 0.30 per cent, cottonseed meal 1.78 per cent, sulfate of potash 46.78 per cent, and nitrate of soda 2 . 3 0 per cent potash (KzO). These small batches of material were thoroughly mixed on manila paper and bottled, being subse1
Lor
cit
8-0-4 8-1-4 8-2-4 8-4-4 8-7-4
475 470 468 470 472
3.76 3.92 4.06 4.27
4.46
3.57 3.65 3.80 4.02 4.21
0.51 0.36 0.36 0.45 0.46
4.08 4.01 4.16 4.47 4.67
4.14 4.03 4.11 4.41 4.74
3.89 4.02 3.15 4.41 4.79
0.38
0.11
0.05 0.14 0.28
0.06 0.02 -0.05 -0.06 0.07
The foregoing table shows t h a t the DeRoode method a t one operation averaged within 0.008 per cent of t h e results obtained by the Lindo-Gladding method 1
Bureau of Chemistry, Bulletan 101 (Revised), p 1 I .
I052
T H E JOURNAL OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
calculated t o the volume on which 50 cc. were taken for analysis, and t o which was added the amount due t o occlusion as determined in a n acid solution by t h e DeRoode method. All of the Lindo-Gladding results are below the DeRoode results, the average being 0.19 pet cent. On the other hand three DeRoode results are higher and two lower t h a n the recalculated Lindo-Gladding results t o which occluded potash was added, and all analyses check within t h e limits of good analytical work. The value of this procedure was then tested in t h e presence of large amounts of organic matter. I n this work we used a cottonseed meal and a cottonseed meal mixture, the last two samples of Table IV. Table VI1 shows the results obtained. I t is well t o mention in this connection t h a t the moist combustion as prescribed ifi the DeRoode method gave perfectly clear solutions both with cottonseed meal and with the cottonseed meal mixture. It is quite difficult t o burn off cottonseed meal t o a white residue as prescribed in the Lindo-Gladding method. TABLEVII-ACCURACYOF THE DEROODEMETHOD IN THE PRESENCE . LARGEAMOUNTSO F ORGANIC MATTER
CSM C$M. Mix.
1.78 4.70
1.70 4.69
1.78 4.70
-0.08 -0.01
0.00 0.00
OF
-0.08 -0.01
I n the foregoing table the results are well within the limits of experimental error, therefore we went through t h e work as already reported in Table VI t o ascertain if the close agreement is due t o the balancing of the two sources of error already shown for the LindoGladding method. Table VI11 summarizes the results so obtained. Table VI11 shows t h a t cottonseed meals and fertilizers containing a large proportion of cottonseed meal
Vol.
11,
NO.
TI
show practically no occlusion, beyond the potash cantent of the volume occupied by the precipitate. TABLE VI11
We have already shown t h a t precipitated phosphates, as well as the hydroxides of iron and aluminum, occupy large volumes in the flask when the LindoGladding method is used.' Each bf the mixtures used in these studies contained a large percentage of phosphatic material, a n d in no case is there a n y indication t h a t this affected the accuracy of the DeRoode method. SUMMARY
I n summarizing we claim t h a t the DeRoode method as herein outlined is accurate in the presence of a n y amount of ammonium salts, organic matter, nitrate of soda, or phosphatic matter t h a t will be used in a manipulated fertilizer, or t h a t may be present in natural fertilizing materials. The method is easy of manipulation and dispenses with platinum apparatus; but above all else, i t is more accurate than the LindoGladding method, the latter method varying in accuracy with the kind and amounts of impurities present in the material. ACKNOWLEDGMENT
T h e work herein reported was begun b y us a t t h e South Carolina Experiment Station, and b y agreement with the director of t h a t station was continued and completed here. LABORATORY OF THE GEORGIA EXPERIMENT STATION EXPERIMENT, GEORGIA 1
L O G Lit.
LABORATORY AND PLANT A NITROGEN GENERATOR FOR LABORATORY USE By W. I,. B A D G ~ R Received June 26, 1919
The usual process for obtaining nitrogen in the laboratory depends on a furnace containing copper, whether the copper is used as the means of fixing the oxygen, or whether i t is merely an indicator, as in Hulett's meth0d.l Both are inconvehient; the first where considerable quantities of nitrogen are required, the second where a steady stream is wanted over a long period of time. Van Brunt2 describes an apparatus for the preparation of nitrogen for laboratory purposes by the use of copper and ammoniacal solution of an ammonium salt. His apparatus works satisfactorily, but is more complicated than is necessary; and the glass blowing required is a little difficult for many laboratory workers. The apparatus here 1
J . A m . Chem. SOL.,37 (1905), 1415.
2
Zbid., 86 (1914), 1448.
described was suggested by a desire t o simplify the above apparatus. A wide-mouthed bottle, A, is filled with the reagent and with as much metallic copper as can be got into it-preferably in the form of straight wires standing vertically, as this gives more thorough contact with the gas. B is a Liebig condenser shell with the lower water connection sealed off. It is filled with copper turnings or punchings. A tube, D, is connected t o the upper water connection, and goes nearly t o the bottom of the bottle A. At the upper end of the condenser should be a bulb, C, though the trap as shown is not necessary. The gas inlet should also go nearly t o the bottom of the bottle. The lower end of t h e condenser may be cut off a t an angle or left square. A fourth tube may be added for blowing out spent reagent, if desired. On passing in air or commercial nitrogen by the tube E, most of the oxygen is removed by the copper in the bottle, and the tower is usually
