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etc., has been well pointed out. Would not any method which would tend to overcome some of these difficulties be an advantage? Also, operators who have, unfortunately, had to rely on untrained firemen have found pyrometers to be of great assistance in preventing excessive firing and other injurious practices. It is undoubtedly true that the proper combination of the various factors, such as flow of distillate and temperature rise, will vary somewhat with different plants because of differences of size and condition of wood and the best adaptation of these principles will have to be worked out for the individual plant. The great value of knowing as accurately as possible these conditions in applying scientific control has been well demonstrated, and it is believed that a general adoption of pyrometer temperature control in the primary distillation will help to bring the wood distillation industry out of the somewhat empirical condition which has marked it up to within the last few years. FOREST PRODUCTS LABORATORY MADISON,WISCONSIN, February 11, 1916
R. C. PALMER
REMARKS ON THE PRODUCTION OF RADIUM BY THE BUREAU OF MINES Editor of the Journal of Industrial and Engineering Chemistry: The work of the Bureau of Mines in cooperation with the National Radium Institute Company in the production of radium has been given an unusual amount of newspaper publicity. The statements supplied by Dr. Parsons and others interested in the work have often been considerably altered or abbreviated in publication and a great deal of misconception in regard to the work prevails in the public mind. However, we read in the memorandum for the press, issued several months ago by the Secretary of the Interior, that the Bureau of Mines has “devised methods for the production of radium from carnotite ore of Colorado and Utah a t an average cost of $36,500 a gram, two-thirds cheaper than the market price of $IZO,OOO asked by foreign producers, the new cheaper methods making it more certain that medical institutions will be able to procure a sufficient quantity of radium for the treatment of cancer and malignant growths,” etc. The writer has been interested in the commercial production of radium from carnotite since 1912 and naturally has followed with interest the work of ,Dr. Parsons and his associates along this line. The problem t o be solved was clearly appreciated’ before any work was carried out by the Bureau of Mines and it was somewhat of a shock t o the writer to see how little has been accompljshed in the attack on the real problem as testified by the data given in a recent bulletin.2 Briefly, the problem consists in devising means for economically working up the lowgrade carnotite ore, which forms by far the greater proportion of the radium ore occurring in Colorado and Utah. This would involve a n economical process for concentrating the ore, as well as an efficient chemical method for extracting the radium, uranium and vanadium from the concentrates, and the refining of these products. The carnotite ore from the Colorado field will average about I per cent, or less, of uranium oxide and by, hand-picking from 5 tons of mine ore, it is usually possible to sort out a ton of material averaging between 1.5 and 2 . 0 per cent of uranium oxide. The remaining ore has in the past been considered too poor t o ship and so has accumulated on the ore dump, where through weathering, etc., losses of the values result. Up to date the company with which the writer is associated has shipped about 5,000 tons of carnotite ore from its mines to the reduction plant a t Canonsburg, Pa. Naturally, the endeavor has Bureau of Mines, Bull. 70 (1913), 8. Bureau of Mines, Bull. 104. “Extraction and Recovery of Radium, Uranium and Vanadium from Carnotite,” by C. L. Parsons, R. B. Moore, S. C . Lmd aad 0. C. Schaefer. 1
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been to ship as high a grade of ore as possible, consistent with the quantity requirements, since the ore must be packed to the foot of the trails by burro, then hauled 40 to 60 miles by wagon to the nearest railroad, making transportation charges very high. Rich claims have been stripped bare in this effort, and still the average on all of the shipped ore was 1.6 per cent of uranium oxide. Approximately 20,000 tons of low-grade ore were either not mined or not shipped owing to the poor quality of the ore.’ The results so far attained by the Bureau of Mines may be summarized briefly. About 1000 tons of high-grade carnotite ore (2.5 t o 2.6 per cent U308) have been treated (without concentration) by a method (extraction with concentrated nitric acid) which is not directly applicable to concentrates, and a fairly high extraction of radium has been attained (85 to go per cent). The uranium in the ore has been extracted as crude sodium uranate with an efficiency of about 85 per cent, and the vanadium as iron vanadate with an efficiency of 21.4 per cent. Nearly 5 grams of radium (element) have been extracted from the ore in the form of raw radium barium sulfates containing about I mg. of radium per kg. of salt, and of this material about half has been worked up to yield radium salts of sufficient purity for the designed therapeutic uses. hTothing essentially practical has been contributed to the art of radium production, and the cost data, as given, are of no great significance for actual large scale production of radium, since the conditions under which the Bureau of Mines produced the radium were abnormal and cannot be duplicated in present practice on account of the lack of high-grade ore.2 In Bulletin 104,there is no summary which would show the total amounts of each chemical required per ton of ore, and there is no cost price stated for the acids and alkalies. The result is that there is no simple way for an outsider to figure costs on the Bureau of Mines process. Furthermore, in figuring the cost of any article it is necessary to add 1 Since the beginning of 19 11, the carnotite ore shipped in Colorado and Utah had a uranium oxide content of approximately 200 metric tons Of this ore, about 55 per cent has been treated in the United States and the balance has been shipped abroad. In the earlier years a large proportion of the carnotite ore was shipped abroad by the General Vanadium Company for the recovery of vanadium. The radium is the residue after the extraction of the vanadium was not refined; however, these residues have since been offered for sale-so that the radium will probably be extracted. The total amount of radium in the carnotite ore so far mined and shipped amounts to about 66 grams and assuming an efficiency of extraction of 70 per cent the recovered radium would be about 46 grams, of which 25 grams should have been extracted in the United States and about 21 grams (including General Vanadium Co. residues) abroad. This represents the bulk of the world’s present supply of radium, since none of the other deposits of radium compare with the Colorado and Utah deposits. 2 Considering that these investigations were made in part (Bull. 104, p. 13) “to enable the miner and prospector to obtain a just return for the ores” it is hard to reconcile this statement with the pitifully inadequate prices paid to the miners by the National Radium Institute for high-grade ore-after the war had cut off the European ore market. Before the war carnotite containing 2 per cent Us08 was sold to French buyers a t $3.30 per lb. of uses, and offers went as high as $4.00 for this ore. These prices figure $132 and $160 per ton of 2 per cent ore, and a t the same rate, would give $178.20 and $216 per ton of ore containing 2.6 per cent UsOs, such as was worked by the Bureau of Mines, and shown in Bull. 104 in the costs at $96.36 per ton. I n addition to the ore mined from the Crucible Steel Mining and Milling Co.’s claims, ore was purchased directly from miners and for this ore the National Radium Institute paid in one known instance $1.70 per lb. of UaOs in about 25 tons of ore, f . 0. b. Placerville, Colo., that averaged 3.19 per cent UaOs or a t the rate of $108.46 per ton of ore. For ore containing from 2 per cent to 5 per cent U308 they offered, f . 0. b . Denver, $2 per lb. of UaOs, or $80 per ton of 2 per cent ore. (Freight rate Placerville to Denver $6 per ton, Placerville to New York sl1.57 per ton, Placerville to Hamburg or Liverpool, uia Galveston, $14.50 per ton.) When it was evident that the National Radium Institute was in the field to buy ore, the State Commissioner of Mines in Colorado made public announcement advising miners to hold their ore for a t least $2.50 per lb. of U308 in Z’per cent ore and proportionally higher prices for higher grade ore. Yet it is on the basis of the rich ore obtained “for a song” t h a t the Bureau bases its production figures for cheap radium. Consistency seems lacking in the argument,that the miner will profit by cheaper radium. It is possible t h a t the various arguments are to apply .independently, 0n.e to the miners, others for the physicians and hospitals, etc.
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the cost of marketing (which has not been done in the $37,599 per gram of radium-Bull. 104, p. 117) and a sum for the safe and certain profits on the investment. These charges are indispensable and very considerable items for an article like radium. Indeed, with an uncertain market such as radium has, the allowances for these items must be far higher in proportion to the cost of production than on such staples as gasoline, copper, etc., and for these articles the selling price is by no means the cost of production of the most favored producer. Average mining costs cannot be estimated by stripping out 800 tons of high-grade ore from one rich claim, nor will the mining of several hundred tons of ore on adjacent claims give an average for the whole Colorado field. In actual practice a great deal of preliminary work must be done before the ore is uncovered and only in rare cases are considerable bodies of highgrade ore found which would compare with the Maggie C claim, from which the Bureau of Mines secured most of the ore. With rich claims advantageously located, so that little if any packing by burro was necessary and with the good roads already constructed, it is not surprising if ore costs were low. Dissolving carnotite in strong nitric acid was the analytical method used more than ten years ago in the quantitative determination of radium in this material. This is the basis of the Bureau of Mines method and when applied to rich ore ground to 20 mesh gives an efficient extraction. The same method, however, will not apply to the zoo mesh concentrates, since the finely powdered silica in the concentrates makes it almost impossible t o filter the mixture (see also Bull. 104, p. 111). Low-grade ore containing 0.8 to I per cent U3O8 must be concentrated. A 2.5 per cent Us08 concentrate from such ore is much higher in Mg, Al, Fe and Ca salts than a straight 2 . 5 per cent ore and would require more nitric acid than the unconcentrated ore. It is not yet shown that the presence of considerable amounts of gypsum (which frequently occurs with the carnotite and would be found in the concentrates) would not introduce difficulties in the way of a poor extraction, should mechanical or other means be found to overcome the filtration difficulty. These are the problems of the practical radium producer which the Bureau of Mines has barely touched, problems of the highest importance for the real conservation of our radium deposits. Under the agreement made, the Crucible Steel Company, which owns the claims that were worked (Bull. 104,p. 8) “agreed that if the National Radium Institute should be formed these claims would be leased to the Institute on a 15 per cent royalty basis under an agreement providing for the return of the uranium and vanadium content of the ore t o the company.” Vanadium in the form of ferro-vanadium has a high value in the steel industry, and yet the Bureau was satisfied with an extraction process for radium where the vanadium recovery is shamefully low. This is admitted for we read (p. 107): “The process described in this bulletin could not be recommended were the recovery of the vanadium in the ore the main object.” However, in spite of the contract t o deliver to the Crucible Steel Co. the uranium and vanadium, we find that little effort was made to extract this vanadium for (p. I Q ~ )“lately, on a n average 55.5 per cent of the vanadium in the ore remains in the residue, and 13.6 per cent remains in the iron-calcium precipitate, while 8.1per cent appears in the sodium uranate and 21.4per cent in the iron vanadate. The total average recovery in vanadium, including that from the sodium uranate, is, therefore, a little less than 30 per cent.” No statement is made as to the amount of this material delivered nor as to the opinion of the Crucible Steel Co., with regard to the results of the process for uranium and vanadium. Doubtless such a method of extraction could hardly appeal to that company as satisfactory. As regards the mining and concentration of lower grade ore, Bulletin 104, p. 11, says: “A separate report on the mining
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and concentration of radium ores is being prepared and will shortly be published by the Bureau.” Dr. Parsons in a lecture a t the Chemists’ Club in New York, before the New York Section of the Society of Chemical Industry, on December 17, 1915, stated that the concentration experiments were being made using the air separator, the Raymond mill being used. He was not prepared to state results. However, the writer can say, as a result of the experiments of one company, that this mill will not give a n economical treatment of low-grade ores, and it can hardly be said that this result is due t o lack of experience, since the Raymond separator has been in use by the Standard Chemical Company since the beginning of 1912. In trying this particular apparatus the Bureau of Mines was only borrowing a method already in use. The National Radium Institute has profited largely by the cooperative agreement with the Bureau of Mines, since the conditions under which the agreement was made were such as t o insure either the delivery of the radium or the termination of the work if the radium could not be produced. However, it does not require the production of 5 grams of radium from highgrade ore by a “skimming the cream” method to determine whether or not radium could be produced by the Bureau of Mines, and it is significant that costs were figured on this method rather than on a method involving the use of the average ore. Costs, using the Bureau process and based on normal conditions, would show nearly double the stated cost of production and would, of course, not verify the earlier assertions of the officials of the Bureau with regard to their process. Having demonstrated the ability to prepare radium, it is rather odd that the purposes of the Bureau and the National Radium Institute, namely, the study of the mining and concentration of ores and the working up of the concentrates, has been delayed while radium was being extracted for a private corporation for use-in one instance at least-in a private hospital for private gain. According to Bull. 104 (pp. 8 and g), such a cooperative agreement is legal and justified in view of similar cooperative work betwen the Department of Agriculture and farmers, and the Assistant Secretary of the Interior approved of the arrangement. This explanation, however, really does not seem t o justify the actual arrangements made, for in the case of the Pepartment of Agriculture the results obtained benefit many others since the results are general in nature, whereas here a corporation has, tlirough some considerable expense to the Government, profited in securing much valuable material under special arrangements, and under conditions which do not offer equal opportunity to all. Ostensibly the purpose of this work by the National Radium Institute is to further the cause of radium therapy -and the production of radium. The results so far have been the exact reverse. The market for radium for therapeutic purposes in America has been killed, since the physician who reads in the newspaper that the Government has produced radium for one-third the present selling price hesitates to buy radium, and as a result of the statements widely spread both by the Bureau of Mines and by the president of the National Radium Institute to the effect that it is useless to try to cure cancer without the application of comparatively enormous amounts of radium,’ we find the surgeons and physicians hesiIn connection with the matter of high dosage it is of interest to note that the London Radium Institute, a charitable foundation not for gain, which has over 2 grams of radium for application, in the last report of work shows the following amounts of radium element as the highest used in the treatment of those malignant conditions which require heavy dosage: Cancer esophagus, 61 mg.; cancer uterus, 107; cancer bladder, 64.2, cancer breast, 187; cancer thyroid, 225; cancer rectum, 134; cancer prostate, 97; periosteal snrcoma, 86, lymphosarcoma, 225: lymphadenoma, 268; splenic leukemia, 145; fibroid disease of the uterus, 107; mediastinal tumor (patient died suddenly less than 2 months after treatment), 480. The quantities given are maximum and more frequently smaller amounts suffice. To the certain knowledge of the writer, there are in the United States, besides the hospitals benefited by the radium produced by the Bureau of Mines, 3 institutions and medical men possessing ZOO or more mg. of radium
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tating to venture into the field of radium therapy. The result, practically, is to confirm the National Radium Institute in a monopoly of radium for therapeutic purposes. Legislation in regard to the Government radium lands is again pending and it seems more than a coincidence that Bulletin 104should appear with its glitter of cheap radium-at this moment. STANDARD CHEMICAL COXPANY CHARLESH. VIOL PITTSBURGH, February 16, 1916
COMMENTS ON “GAUGING OF STORAGE TANKS”’ Editor of the Journal of Industrial and Engineering Chemistry: We have studied the above-mentioned article by Mr. Ogden with a great deal of interest. There is certainly a very real need of a simple and accurate method of gauging the volume of material contained in these storage tanks. Such a method should take account of the material contained in the bumped heads, should be reasonably accurate and should be simple and easy to apply. The writer is inclined to be of the opinion, however, that Mr. Ogden’s method scarcely meets this need satisfactorily, basing this opinion upon the following features of Mr. Ogden’s method: ( I ) lack of accuracy, ( 2 ) lack of simplicity or general applicability. DESCRIPTION OF METHOD
Mr. Ogden treats the contents of the tank as consisting of two component parts, ( I ) the content of material in the cylindrical portion of the tank, i. e., the tank exclusive of the bumped heads, and ( 2 ) the content of material held by the bumped heads. By determining the values of these component volumes for each vertical inch of height and adding them together, Mr. Ogden obtains the total content of material for each vertical inch of height. This amounts t o a virtual calibration of the tank for each inch of height. In discussing this article, we shall endeavor to follow this method of Mr. Ogden in treating the two-component volumes separately and we shall designate them as Vol. A (volume of cylindrical tank) and Vol. B (volume of a single bumped head). Then Total Vol. = Vol. A 2 Vol. B Volume A is equal to the product of the length of the tank and the cross-sectional area of the liquid formed in a plane perpendicular to the axes of the tank. This cross-sectional area is the segment of a circle. Mr. Ogden correctly states that its value can be obtained by integral calculus but that a simpler method consists in the use of trigonometry and geometry. Mr. Ogden seems to feel, however, that the latter method is still too complex for his purposes and he, therefore, adopts an approximation consisting substantially as follows: Vol. A is considered as consisting of a number of flat slabs I in. thick, of trapezoidal cross-section, and piled one upon the other. Mr. Ogden obtains by geometry the value of the medial line of each trapezoid. Multiplying this value in inches by the length of the tank in inches, he obtains the volume of each slab. Adding the volumes of these slabs, he obtains the varying values for Vol. A . Clearly this is quite cumbersome and only an approximation with its degree of accuracy dependent upon the ratio of the “unit of calibration” (in this case I in.) to the total qiameter of the tank. If the value of this ratio is small, the inaccuracy introduced is not very considerable. On the other hand, if this ratio is large, the method becomes very inaccurate. Regardless, however, of the degree of accuracy attained, there scarcely seems to be a very real need of a method of approximation since we have very accurate Engineering Tables which give accurately the area of
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element, and, besides these there are 10 institutlons and physicians that possess 100 or more mg., and 16 that have 50 or more mg available. The results in radium therapy reported by these institutions and physicians show that the quality of their work compares favorably wlth the work in institutions where over a gram of radium is available. the number of patients treated, of course, being smaller. 1 R.
I. Ogden, THISJOURNAL. 8 (1916), 58.
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the circular segment from a knowledge of the ratio of its height to the diameter of the circle.1 In determining Volume B there is more warrant for an approximation since no method has apparently up to the present time been published which gives this volume content accurately. Vol. B consists of a portion of the segment of a sphere. Mr. Ogden treats the radius of this sphere as equal to the diameter of the tank which assumption, in view of the practice of tank design, is essentially correct. Mr. Ogden’s method of determining Vol. B is substantially as follows: Volume B is considered as consisting of a number of I in. slabs piled one upon the other. Through the center of each of these slabs, Mr. Ogden passes a horizontal plane. The area of the plane section is, strictly speaking, a circular segment, but is regarded by Mr. Ogden as parabolic. The base and altitude of this parabolic section are determined geometrically by hIr. Ogden and the area of the section taken as ‘/a of their product. The volume of each slab is then determined as the product of this area and the thickness I in. and Vol. B is determined for varying heights as the sum of the volumes of these slabs. This method of calculation is not only inaccurate by reason of the assumption of the section being parabolic, but it is also inaccurate in assuming the volume of each slab to consist of the product of the area of the medial section and the thickness of the slab. As in the case of Vol. A , the magnitude of the latter error is dependent upon the ratio of the “unit of calibration” to the diameter of the tank. ACCURACY-AS stated previously, Mr. Ogden’s method introduces a number of inaccuracies, the magnitude of which is chiefly dependent upon the ratio of the “unit of calibration” to the diameter of the tank. For a given tank of 7 ft. diameter, the error introduced is not very large if the tank is calibrated for each I in. of height. The calculation, however, involved in making this calculation for each I in. of height is very large and consumes a great deal of labor. On the other hand, if the calibration is made for 3 or 4 in. intervals, the labor of calculating is decreased, but errors of considerable magnitude are introduced. It, therefore, becomes a method which requires the sacrifice of accuracy or of simplicity of calculation At the conclusion of hIr. Ogden’s article, he gives an example attempting to compare the true volume of a cylindrical tank and the volume obtained by using his method. This comparison is somewhat misleading. In the first place, it is made between the total volumes of the tank and not between volumes of material partially filling the tank. The errors introduced by Mr. Ogden’s method are by no means a t their maximum percentage value in the case of the calculation of the total volume of the tank. A true index of the accuracy of Mr. Ogden’s method can be obtained only by making the comparison a t the point a t which the errors of Mr. Ogden’s method are a t their maximum percentage value. SIMPLICITY OF CALCULaTION AXD GENERAL APPLICABILITY-
The main criticism of Mr. Ogden’s method does not rest, however, with its inaccuracy, but rather with its lack of simplicity and difficulty of application. As seen from the foregoing description of Mr. Ogden’s method, the determination of the volume content of material in any tank requires a long and laborious calculation of the volume content of each inch of material in the tank, which amounts to a virtual calibration of the tank. Clearly the labor involved in such a calculation which must be made in the case of each tank containing material to be measured, is a feature which argues strongly against this method. I n the past, it has been the custom of engineers to treat these storage tanks as though they were true cylinders. The vertical “innage” of material in the tank is measured and is expressed as a decimal fraction of the diameter. Reference is then made to the engineering tables for “Area of Circular Segments” and a factor is found which corresponds to the above 1
See Kent, “Mecb. Eng. Handbook.” 8th Ed., pp. 121-122.
