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pearance long before it is entirely reduced to metal. The author has had white scale t h a t would be brittle and grind to a black powder. However, when the reduction is complete the scale is no longer brittle and cannot be powdered, but is entirely metallic in its properties. 8th. The corollary from the fact t h a t white scale forms more slowly below 750’ C., is that, at still lower ranges, perhaps below 650°, it may not form at all. Further experiments covering this point will be made. 9th. By annealing steel in a closed tube with a small vent to permit egress of gases b u t sealed against ingress of air, at temperatures close to jooo C., the surface decarbonization is so slight t h a t no ring of coarser crystallization can be detected. Only a cupped effect can be noted around the margin of the fracture (see F, Fig. z ) , yet such steel will take on a suggestion of the aluminum-like finish. Here the surface decarbonization is confined to the thinnest skin. Such steel hardens file-proof immediately under this extremely thin zone. 10th. B y annealing steel t h a t had been polished free of all rust and scale, in a tube from which ALL OXYGEN had been expelled by CO, no surface decarbonization was noted and the steel hardened file-proof. The CO was generated by heating wood charcoal. 11th. A rod of polished steel was dipped in a solution of copper sulphate until i t was plated with metallic copper. After heating this rod in a closed tube, without expulsion of the air, for a few hours, the rod was removed from the tube and was found to be coated with a handsomely appearing metallic copper. During this experiment the tube was sealed against ingress of oxygen.
who is seeking generally for a desulphurizing agent, which barium sulphate does. Because of the high atomic weight of barium, one per cent. of sulphur combined with it means 7 . 2 8 per cent. of the whole, while one per cent. of sulphur in combination with calcium represents only 4 . 2 5 per cent. of the whole. The determination of the sulphur alone, therefore, does not tell the whole story. It therefore became a matter of first importance to devise a rapid means of properly valuing this material while i t is still on the cars.
BARIUM AND SULPHUR IN FLUORSPAR. B y HENRYG. MARTIN.
Received April 29, 1909.
The author has recently analyzed samples of fluor spar containing quantities, u p to ten per cent., of barium sulphate. The presence of this impurity is a more reasonable cause for condemnation of the material than either high silica or high percentage of carbonates, for while the presence of the latter substances, b y lowering the content of calcium fluoride, and thereby affecting the value of the material, gives legitimate cause for argument before paying the bill, neither one proves t h a t bane to the open-hearth furnace manager,
SL/NDST‘RO! - BOMB. SULPHUR /N FLUOR SPAR. BY h/.G.M?nw
For this purpose recourse were had to the method given by S.,117. Parr’ for the determination of sulphur in mineral matter, using a “Sundstrom” bomb2 for the combustion and oxidation. The bomb (see figure) was made in our machine shop out of seven per cent. nickel steel and was heavily nickel-plated. Jour. A m . Chem. Svc.. 30,764. Ibid.,25, 184.
MARTIN ON BARIUM A N D SULPHUR IN FLUORSPAR. The fusion mixture recommended b y Parr, I O grams sodium peroxide, 0 . 5 gram potassium chlorate, and 0 . j gram benzoic acid, g k e s entire satisfaction, working with 0 . j gram of the material, as the results below testify. A mineral having a total sulphur value of 1.61 per cent., determined by fusion with sodium carbonate and potassium nitrate, and proper removal of silica before precipitation, and a barium sulphate content of 9 . 8 0 per cent. and I O per cent., a s found by the buyer and seller, respectively, also determined by fusion with sodium carbonate, was used. Determination number. 1 .o 2 .o
Sulphur, per cent. Barium sulphate, per cent.
3.0
1.68 1.58 1.56
4.0 5.0
....
....
9.90 10.10 9.88 9.84 9.60
Sample KO.j had one gram of sodium carbonate added to the fusion charge, with the idea that perhaps some barium might become caustic, due to insufficient carbon to render all bases carbonates, and so become caustic, and so soluble in water. This procedure evidently had no value, b u t neither is i t likely t h a t i t caused the low result. The details of the method follow: The fusion charge is placed in the bomb, 0 . 5 gram of the mineral added and mixed by stirring, the bomb closed, after adjusting the fuse of soft iron wire, No. 31, and the latter fused with a 3 . 5 ampere current. The bomb is placed in a copper dish filled with water and which is made one pole, a copper wire curved so as to have considerable spring, resting on the cover, being the other pole. The explosion takes place very quietly. After a few minutes’ cooling, the melt is washed out into a beaker with hot water and placed on a steam table until the decomposition of the peroxide is effected, or i t may be boiled, but here enters the objection to boiling an alkaline solution over a gas flame, due to contamination by sulphur in the gas. I t is then filtered on pulp, the filtrate acidified with hydrochloric acid and the sulphur precipitated b y adding barium chloride. The filter, with the residue, is transferred to a beaker and sufficient dilute hydrochloric acid added to dissolve all mineral matter. The determination is then filtered from the paper and the barium precipitated b y adding sulphuric acid. The excess of sulphur over t h a t required to form the barium sulphate is calculated to calcium sulphate, and so reported, and this amount of cal-
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cium afterwards deducted from that found later as calcium fluoride. The determination of the remaining constituents of fluorspar is made as follows: Five-tenths gram of the material is placed in a small beaker, moistened with water and ten cc. acetic acid added (see Chemical Engineer, 3, No. 2 ) . This is allowed to stand for some time on the steam table and is then diluted and brought to a boil, and filtered on a n S.& S. 589 blue ribbon paper, From the filtrate, oxides of iron and aluminum, lime and magnesia are determined a s in limestone, the latter two being calculated to and reported as the carbonates. Should there be evidence of lead in the spar, it may be separated by passing hydrogen sulphide previous to precipitation of the iron and aluminum. The residue from the acetic acid treatment is placed in a platinum crucible and after burning off the paper a t a low heat is roasted for ten minutes in a n ordinary Bunsen flame, and theweight registered. A few cc. hydrofluoric acid are then added and the crucible heated gently until contents are dry, then roasted again for ten minutes in the same flame as before. The difference in weights is considered silica. One cc. sulphuric acid is then added and gentle heat applied until the calcium fluoride has all been converted to the sulphate, the crucible cooled, hydrochloric acid added and the whole washed into a beaker of 1 5 0 cc. capacity and diluted somewhat. After boiling, if no barium or lead be present, there will be no undissolved residue; if there be a residue, it may generally be discarded here, after filtering. However, if so desired, ignite it and weigh as a check on the first barium determination] or if it contain lead dissolve in ammonium acetate and separate with hydrogen sulphide. Hydrogen sulphide may also be passed through the filtrate, b u t there will always be some platinum precipitated here, which should not be confused with lead. This filtrate is now ready for the determination of oxides, lime and magnesia. The oxides are added to the weight of those dissolved b y acetic acid, the lime calculated to fluoride, after deducting such as may be required to form the calcium sulphate mentioned before, and the magnesium calculated to fluoride. These manipulations are all on the order of the “rough and ready” kind b u t without using them the average works chemist would never see the end of his day’s work. No claim is made for the accuracy of the silica determination for all sam-
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THE JOURrVAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY. July, 1909
ples but it has apparently given good results on all samples which have come under the author's notice. The two precipitations of barium sulphate are made in large bulk without reference to dissolved silica being present. All my results have checked closely with those obtained by fusion with sodium carbonate and removing silica by dehydrating and filtering, previous to precipitation. Treating the barium sulphate with sulphuric acid and hydrofluoric acid, evaporation and ignition have failed to show the presence of any silica. If lead be determined, i t should be calculated to the sulphide and the proper amount of sulphur deducted from that remaining after calculating barium sulphate, before calculating the remainder to calcium sulphate. Should the mineral exhibit evidence of the presence of iron pyrite it would be difficult to properly place all the sulphur, and a direct fluorine determination would be necessary unless one be willing to consider all the calcium, insoluble in acetic acid, as the fluoride, no sulphate being present. The whole scheme is offered merely as a means of quickly classifying a material which heretofore has required a long time for its proper analysis. LABORATORYOFTHELUXENSIRONANDSTEELCO., COATESVILLE, PA.
ADDRESSES. SOME INTERESTING POINTS I N THE MANUFACTURE OF C. P. CHEMICALS.' By J. T. BAKER.
The source from which the manufacturing chemist obtains his supply of raw material and the methods employed for making the various chemical products are subjects of considerable interest and inquiry t o those who have never paid much attention to the manufacturing side of chemistry. T h e analytical chemist who is interested only in the purity of his reagents is not particularly concerned a s to their origin or method of preparation, nor is the student particularly interested, a s his attention is taken up solely i n experimenting with such chemicals as are placed before him. The manufacturer, however, is interested from a n economical point of view and is looking for the cheapest source and the most economical methods. It is sometimes imagined b y those who are totally ignorant of the nature of chemicals t h a t there is something mysterious and uncanny about chemical manipulations and chemical preparations are imagined by them to be derived from roots and herbs or some other mysterious sources on the earth. To a certain extent this is true, for we shall not go very far in our search for a source of supply before reaching Mother Earth. The chemical manufacturer, however, especially the manufac1 Paper
read before the Philadelphia Section, February IS,1909.
turer of C. P. chemicals, seldom resorts the raw material a s if i t comes from the earth, for the greater part of his raw material is the product of other industries in which the material as found in nature is converted into a commercial product better suited to his requirements, as for instance the various metals, copper, zinc, cadmium, etc., brimstone, nitrate of soda, salt, alkalis and many other crude salts. I n a great many instances i t is more economical t o use raw material in a partly purified form rather than t o attempt to follow out every step of the preparation from the natural material to the finished product. This is especially true in the case of the manufacturer of C. P. chemicals, for his products cover a large field and include a great variety of chemicals, the demand for many of which is comparatively small, so t h a t he is dependent to a great extent upon other industries for a large part of his supply. The chemist of old was very independent in this respect, for previous to the time that chemistry became a distinct science, the chemist sought his own raw material and prepared his limited stock of reagents himself, but a s the field of chemistry enlarged and his wants increased he began to realize his limitations and became either a n analyst or a manufacturer. This resulted in a division of labor and a specialization which is the condition which we find to-day. The manufacturer also, instead of attempting t o cover the whole field of chemical products, takes up special lines, as commercial chemicals, C. P. chemicals, pharmaceutical preparations, etc. The division of labor and devotion t o specialties seems to be inevitable, not only because the field of labor is so large and man's capabilities are limited, b u t because concentration of energy is necessary to gain perfection. Even in large industries where a great variety of products are manufactured, the greatest efficiency is gained by dividing the work into departments devoted to special lines. The manufacture of C. P. chemicals is a specialty and requires a knowledge and experience peculiar to itself. While the preparation of chemical compounds is to be found described more or less in books, these descriptions are intended mainly for laboratory experiments and are seldom of practical value when working on a commercial scale. Two requisites confront the manufacturer in his efforts to keep down the cost of production, first a cheap source of supply, and second economical methods of manufacture. Vbe' are principally concerned at this time with the source of supply. C. P. acetic acid is prepared by distilling glacial acetic acid of commerce which is the product of the d r y distillation of certain kinds of wood. The commercial acid can be obtained in a number of grades of strength and purity, but the glacial is the most suitable for making C. P. acid. C. P. arsenious and arsenic acids are prepared from the arsenious acid of commerce, obtained a s a sublimed product from roasting various kinds of arsenical ores. C. P. boric acid is prepared by recrystallizing boric acid of commerce. The latter is derived indirectly from the borax deposits in the earth, mainly from the great borax beds found in Southern California. C. P. chromic acid is made from bichromate of potash, a n article of commerce made on a large scale from chrome iron ore. C. P. citric acid is prepared by recrystallizing citric acid
