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[Co Friday, January 15, 1909. ARTICLES: reserved Tantalum, Niobium, and Titanium, by W. B. Giles... The Corrosion of Iron, by A. S. Cushman CORRESPONDENCE -Potential Energy of the Elements NOTICES OF Books ........... CHEMICAL NOTICES FROM FOREIGN SOURCES MISCELLANEOUS NOTES AND QUERIES.... Analyst (27) seeks Situation as Works Chemist Registered as [PRICE 44. a Newspaper. POST FREE, 4kd. NOTICE TO ADVERTISERS. To ensure insertion in next issue, Advertisements should be addressed to THE MANAGER. and must reach the Office not later than 10 a.m. on WEDNESDAY. INSTRUCTION IN PURE CULTIVATION OF YEAST. Courses for Beginners, as well as for Advanced Students, in Physi ology and Technology of Fermentations. Biological Analysis of Yeast. The Laboratory possesses a numerous collection of Yeasts (Brewers', Distillers', Wine, Disease Yeasts), Moulds, and Bacteria. Manuals: Alfred Jörgensen, Micro-organisms and Fermentation" (London and New York, Macmillan & Co., 1900); and "The Practical Management of Pure Yeast" (London, "The Brewing Trade Review," 1903). The Laboratory supplies for direct use Pure Cultures of Yeast for Further particulars on application to the Director- PRICE ONE SHILLING Net. Post free, 1s. 1d. DIAMONDS. at Kimberley. in Laboratory. Three and a-half years University College, A Lecture delivered before the British Association London, and five and a-half years as Works Chemist to well-known firm of Biscuit Manufacturers. Well up in general Analytical work and especially so in Food and Gas Analysis. Excellent references. Address, "Analyst," 116, Warwick Road, Carlisle. NEWS NOW READY. Cloth, 316; Paper covers, 216. THE WHEAT PROBLEM: Based on Remarks made in the Presidential Address to the British Association at Bristol in 1898. REVISED WITH AN ANSWER TO VARIOUS CRITICS By SIR WILLIAM CROOKES, F.R.S. VITH PREFACE AND ADDITIONAL CHAPTER, BRINGING THE With Two Chapters on the Future Wheat Supply of the United States, by MR. C. WOOD DAVIS, of Peotone, Kansas, and the HON. JOHN HYDE, Chief Statistician to the Department of Agriculture, Washington. OPINIONS of the PRESS. "In his bulky volume Sir William reproduces the gist of the sensational Bristol Address, and supplements it with carefully prepared answers to his chief critics and confirmatory chapters on the future wheat supply of the United States."-Morning Post. "The fuller examination of the problem as here conducted shows that Sir William Crookes did not speak unadvisedly with his lips."-Yorkshire Post. "The problem is one of importance, and Sir William Crookes presents it to us fortified by the opinions of two American experts."-Manchester Guardian. "Sir William Crookes's statistics seem to make good his alarmist statement."-British Weekly. "In the present volume Sir William Crookes replies vigorously to his critics."-Liverpool Daily Post. "The book is a useful one to all interested in the production of wheat both from the commercial and scientific points of view."-Knowledge. "It is a vital question, and considering the cheap issue of the volume all interested in the feeding of the millions ought to get it and read it carefully."-Crieff Journal. "If these somewhat gloomy prognostications result in drawing the attention of chemists more seriously to what has hitherto been only an interesting laboratory problem, Sir William Crookes will have conferred an incalculable benefit on the race."-Western Morning News. "Sir William discusses at length the criticisms passed upon his address, and he appends valuable papers supporting his arguments on the future wheat supply of the United States."-Globe. "The student of economic science and sociology will find this volume full of interesting material. . . The entire subject is of the profoundest interest, and an excellent pur pose has been served by the publication of these papers in a single volume."-The Eagle (Brooklyn, N.Y.). CHEMICAL NEWS OFFICE. 16 NEWCASTLE ST., FARRINGDON ST., E.C. SULPHUROUS ACID AND SULPHITES. Liquid SO, in Syphons, for Lectures, &c. PHOSPHORIC ACID and PHOSPHATES. CARAMELS and COLORINGS for all purposes. A. BOAKE, ROBERTS, & CO. (LIMITED), STRATFORD, LONDON, E. CHEMICAL NEWS, Tantalum, Niobium, and Titanium. 25 THE CHEMICAL NEWS. fireclay or, preferably, in a plumbago crucible, and the VOL XCIX., No. 2564. TANTALUM, NIOBIUM, AND TITANIUM : OBSERVATIONS ON. PART II. ON THE OPENING-UP OF MINERALS CONTAINING By W. B. GILES, F.I.C. (Continued from p. 4). In smaller quantities I obtained tantalites and columbites from Finland, Sweden, Norway, Bavaria, Dakota, New Hampshire, Alabama, and other localities. It is curious that none of these minerals exhibit any sign of magnetic properties. When brought near to the poles of a powerful electro-magnetic they are not at all affected, even in a state of fine powder, while many titanium compounds, such as ilmenite, are, as is well known, decidedly attracted. The minerals were first broken up into coarse pieces in a small stone breaker; it was then seen, especially in the case of the Middleton columbite, that though the lumps of the material appeared to be very free from foreign matter, when they were crushed they disclosed thin inclusions of mica and other silicates. These were picked out as much as possible, and the minerals were then ground so that they would pass a 100-mesh sieve. Several kilogrms. of columbite and tantalite were prepared in this manner so as to form standards. In my first trials to remove the tin (which is so troublesome to deal with subsequently) I tried fusing the powdered minerals with cyanide of potassium. This was not at all satisfactory; at a low red heat a large amount of insoluble potassium tantalate and niobate was formed which enveloped the reduced tin so that it did not collect in globules. When the fusion was extracted with water there was left a porous mass which yielded up tin to hydrochloric acid, but a decided amount of the acids also eighths of an inch. These crucibles are placed in a large space between them is packed round nearly to the top of the smaller crucible with wood charcoal in fine powder well rammed down. The remaining space is filled up with lumps of charcoal about the size of nuts, so that the exterior lid will just go on. The accompanying figure shows the arrangement. B C A, The exterior crucible; B, the space filled with finely-powdered charcoal; c, the steel crucible and contents; D, the nut-like piece of charcoal. The crucible is put into the furnace and slowly brought up to a red heat to partially frit the materials, and to allow much of the carbonic acid to escape while the mass is still porous. The heat is then raised, and maintained at the highest temperature the furnace will give for one hour. I use one of Griffin's excellent radial burner gas furnaces which yield a temperature equal to the fusion of cast-iron without any blast of air being required. The exterior vessel for the size of the small steel pots mentioned is a No. 4 Morgan's plumbago crucible. Recently I have procured some much larger steel pots and covers which are 7 inches high by 5 inches diameter; these are pressed by hydraulic power out of steel one-eighth inch thick, and were made for me by Mr. McNeil, of the Kinning Park Ironworks, Glasgow. They require a No. 30 plumbago exterior crucible, and will deal with about a kilogrm. of material at a time. When the crucible is opened after the fusion the contents generally come out in one fused compact piece without any trouble; the top portion has a yellowwhite colour, while the bottom layer forms a black mass went into solution. It is difficult to obtain crucibles or vessels of any size that will withstand the action of cyanide of potassium at a full red heat without being attacked. Knowing that alkaline tantalites and niobates soluble in water can only be obtained by using high temperatures in the fusion with caustic alkali, I next tried attacking the|which can often be separated almost completely from the minerals with potassium carbonate at a high temperature top one by a blow with a hammer. If the columbite or in nickel and iron crucibles. This plan was successful to tantalite contains tin, as is almost invariably the case, the a certain extent, but the nickel and iron crucibles were interior of the steel crucible is tinned over. Some of the seriously affected and scaled, externally by the action of tin is frequently found as a spongy metallic mass mixed the air, and internally by the manganate which was formed with the black material, and often distinct globules and in the fusion. It then occurred to me that if the materials beads are noticed. The whole contents of the crucible were heated at a high temperature in wrought-iron or steel slightly broken up in a mortar are now treated with about vessels in a reducing atmosphere, not only would these 500 cc. of water (for 25 grms. of the mineral) when the difficulties disappear but that also one might expect to potassium tantalate and niobate pass rapidly into solution reduce all the tin, lead, antimony, &c., to the metallic as they are very soluble, while the heavy black sand-like state at the same time, and thus much trouble and material mixed with a little tin, &c., settles down almost uncertainty would be saved in the subsequent operations. immediately, occupying very little space; above this there When this plan was tried it more than answered my is a small amount of light green coloured precipitate which expectations, for while the tin, antimony, &c., appeared quickly turns brown in contact with the air. By leaving to be completely reduced, the iron and manganese were the whole quietly in a tall beaker for an hour about nineobtained as protoxides in the form of a black heavy crystal- tenths of the yellow liquid can be drawn off quite bright line sand which could be very easily separated from the and clear, thus saving the trouble of filtering it. The soluble alkaline tantalate and niobate by treating with remainder is stirred up with water, and leaving all the water. I also found that the zirconia which some of these heavy material in the beaker the solution is filtered (best minerals contain was separated apparently almost quanti- by the pump and the use of a toughened filter) till all the tatively when the washed crystalline protoxides were dis- soluble matter is extracted. The small amount of precipisolved in dilute acids. In the first experiments small steel tate on the filter is washed back on to the black sand in crucibles and covers "spun" in the lathe from sheet-metal the beaker. The solution containing the potassium tantawere made use of, and these answer very well for quantities late and niobate is always yellow or brown coloured, and of mineral up to about 25 grms. These crucibles are contains traces of iron and manganese, probably as double 2 inches high, 2 inches broad at the top, and 1 inches potassium carbonates; this, however, does not afford any across the bottom. They are furnished with well-fitting hindrance to the separation of the tantalic and niobic acids covers which overhang the top of the crucible about three-in a pure state. Under this rather severe treatment the steel crucibles are not appreciably affected. I have made five or six successive fusions of 25 grms. of columbite in one of these small spun vessels without noticing any change except that the interior became rather heavily coated with tin. When this occurs it is well to discard them as they are so cheap rather than to run the risk of losing the contents. It does not appear to be necessary when working upon ordinary columbites and tantalites to add any reducing material to the contents of the crucible. With some of the stanno- or stibio-tantalites which contain much tin or antimony it may be advisable to add some black flux prepared from cream of tartar or similar material to the mixture. The minerals in this manner are resolved into two parts: A. A clear solution more or less yellow or brown coloured which contains nearly all the tantalic and niobic acids mixed with traces of iron and manganese, but free from tin, antimony, lead, or other heavy metals. B. A residue of black crystalline sandy matter containing nearly all the iron, manganese, and other bases mixed with some of the metals reducible by carbonic oxide or by the protoxides of iron and manganese, though most of these metals alloy and unite with the walls of the steel crucibles, especially when these are used for the first few times. A. The solution is treated as follows: When 25 grms. of mineral have been employed it will measure with the washings about 1 litre; to this is added a few cc. (four or five?) of potassium sulphide solution, and the whole well stirred up; this causes the liquid to become black. Rather more than enough pure hydrochloric acid than is equivalent to the potassium carbonate employed (80 to 100 cc.) is diluted with hot water to about a litre, and into this contained in a beaker holding 3 to 4 litres the black solution is poured with constant stirring. This causes a violent evolution of carbonic and sulphydric acids, and the tantalic and niobic acids separate out as a white flocculent precipitate. The beaker is then placed in a water-bath and heated until the precipitated acids appear to settle, then allowed to cool, and the clear portion, which should be about five-sevenths of the whole, is drawn off with a syphon, and the acids repeatedly stirred up with hot water, and washed by decantation till the last washings show no sign of chlorine with silver solution. The niobic and tantalic acids generally settle very quickly when thus treated, but occasionally they require a rather prolonged heating in the water-bath to make them do so. I have not been able to find out the cause of this; I have had two successive fusions treated exactly in the same way behave differently; one would settle quite easily even with cold water, while the other required considerable heating to make it do so. It does not save any time to try to filter these acids and so hasten the operation (at least with ordinary filters). The water passes through the filters readily enough, but it does not wash out the salts. Large cracks form, through which the wash-water runs unchanged. When the decanted wash-waters cease to contain any chloride the acids are brought upon a filter, dried at 100° C., and then pulverised. They then yield a pure white soft powder resembling oxide of zinc or magnesia. They contain no sulphuric acid, chlorine, or potassium, no iron, manganese, tin, or heavy metals, and as they dissolve almost immediately in cold hydrofluoric acid, oxalic acid, &c., they are in a condition eminently adapted for their separation by Marignac's process. The acids so obtained from the columbite from Middleton when dried at 100 C. gave, on strong ignition, 9071 per cent of anhydrous acids and 9'29 per cent of water. When washing the precipitated tantalic and niobic acids by decantation, the supernatant fluid is always opalescent, and in order to see what loss this may occasion, and also to ascertain how much iron and manganese were present in the yellow fluid from 20 grms. of columbite, I evaporated the whole amount of the washings to dryness in a platinum dish with a slight excess of sulphuric acid, on taking up with water and boiling, there was obtained o 038 of ignited acids equal to 0.19 per cent on the columbite. In the NEWS So that if the object is merely the preparation of tantalic and niobic acids, it would obviously never pay to deal with these filtrates, but it shows how slight the solubility of the acids is in the small excess of hydrochloric acid employed, and also how small an amount of iron is really contained in the yellow or brown alkaline solutions. By this process I have not at present been able to trace with certainty the small amount of tungstic acid (0:26 per cent) which is said to exist in this Middleton columbite by Hermann, though in other analyses of this mineral it is not indicated. In order to ascertain what amount of carbonate of potassium is necessary I have made a good many trials with different proportions with columbites and tantalites; four parts of carbonate to one of mineral gave no better results than 3 to I. Three parts of carbonate gave a slightly better yield than 2 to 1, and finally I found 2 to I was as good as 3 to 1; so for ordinary columbites and tantalites these are the proportions I generally employ. B. The black sandy matter which is left on treating the fusions with water is a mixture of ferrous oxide, manganous oxide, reduced iron, small globules of tin, zirconia, silica, &c. It oxidises rapidly on exposure to the air, and so it is advisable to wash it as speedily as possible from the alkaline tantalate and niobate, or ochreous precipitates form which pass the filters. It is treated with hydrochloric acid diluted with its own volume of water, when all the black sand like matter dissolves at once, leaving some white residue undissolved. Generally there seems to be a little metallic iron present, since after the black matter has dissolved small particles are seen dissolving with strong evolution of hydrogen. The tin also is alloyed with iron, for it is very little attacked even by strong acid (Lassaigne, "Gmelin's Chem., v., 314). As it is heavier than the white residue it is possible to separate it entirely from this by elutriation. The acid liquid, including the white matter, is then evaporated to dryness in a porcelain or glass basin and taken up with dilute hydrochloric acid, the insoluble matter is collected on a filter, washed, dried, and ignited. This material is yellowish white in colour. It varies in amount from different minerals and also somewhat with the temperature reached and the amount of potassium carbonate employed. In the case of the Middleton columbite it ranged from 5 to 7 per cent on the weight of the mineral started with, but about half of this was silica. 1420 grms. of ignited residue treated with hydrofluoric and sulphuric acid, gave— Matter insoluble in HF and H2SO4 Silica volatilised Total. 0.7195 0.7005 I'4200 The material freed from siiica was fused in a small platinum crucible at the highest temperature that could be obtained with a powerful blast lamp with an excess of pbtassium carbonate. Though the fusion was maintained for a long time and the carbonate volatilised rather freely, a considerable amount of the material would not dissolve but floated about in the fused carbonate. The fused mass was digested in water, when a heavy white precipitate remained undissolved; this was filtered off, washed, and treated with hydrochloric acid, which left it apparently unchanged. It was again filtered off, washed, dried, and ignited, when it weighed 0.310 grm. This was fused with sodium pyrosulphate, when it went entirely into solution and dissolved clear in water. This solution gave no sign at all of titanium with peroxide of hydrogen. It gave a |