INDUSTRIAL AND ENGINEERING CHEMISTRY
2948
and for the ferric oxide adsorbent by the equation
!Im
= 0.0523
x
co.zb
(5)
Ferric hydroxide adsorbs better t,han aluminum hydroxide as a comparison of t,hecoefficients and exponents of the two equations shoxs. Using 200 ml. of electrolyte, a current density of 100 X lo-’ amperes per cm. squared, and a copper anode of 0.3% antimony, the limiting permissible concent,ration of antimony in the electrolyte was reached after 4 hours; using 1 gram of iron as hydrated ferric oxide as an adsorbent, this time was extended to 13 hours. Also in this case a more favorable result could be obtained by applying 2 or 3 grams of iron and starting with a copper which contains only 0.03% of ‘antimony,as a good fire-refined copprr usually does. coN-cLusIo~
The purpose of this invest’igation was to explore the possibility of refining copper using an ammoniacal electrolyte. It was found that, gold and silver remain completely undissolved and are recovered in the anode slime. Bismut,h, lead, and iron are dissolved anodically, but offer few difficulties owing to the insolubility of t,heir hydroxides in the electrolyte.
Vol. 43, No. 12
Nickel and zinc are likewise dissolved, but remain in solution as ammonia complex compounds. Arsenic and antimony go into solution practically completely and in the trivalent form. Their maximum permissible concentrations in the electrolyte were determined for various current densities, Both can be adsorbed by precipitated hydrated iron or aluminum oxide, whereby the life of the electrolyte can be prclonged. Patents have been applied for. ACKNOWLEDGMENT
The author takes this opportunity to thank the Carnegie-Fisk Foundation for the support which made this investigation possible. LITERATURE C I T E D
(1) Bilt,z,TV., Ber., 37, 3138 (1904). (2) “Gesellschaft Deutscher Metallhutten- und Berpleute, Mitteilungen des Chemiker Fachausschusses,” Val. I, p. 67 ff., Berlin, 1924. (3) Gyory, 2 . anal. Chem., 32, 415 (1893). (4) Lockemann and Lucius, 2. physik. Chem., 83,75 (1913). (5) Lockemann and Paucke, 2. Kolloidchsm., 8,273 (1911). (6) Mecklenburg, W.,2. physik. Chem., 83, 609 (1913). (7) Schimmel, F. A , J . Phys. & Colloid Chem., 54, 841, (1950). (8) Yoe, John, J . Am. Chem. Soc., 46, 2390 (1924). RECEIVED Norember
21, 1950
CORRESPONDENCE DEARSIR: The article in your August issue [IND.ENG.CHEM.,43, 1874 (1951)], entitled “Pilot Plants-Tomato Juice Line,” by J. C. Moyer and associates, is very interesting. The men who norked out this pilot plant Ehowed a great deal of ingenuity in arranging the apparatus so that over-all efficiencies could be determined and in combining product storage and continuous processing to avoid excessive exposure of the product to air. However, in their screening operation, I feel that attention should be brought to the fact that neither their screening operation nor the equipment used ahead of the screen duplicates successful commercial installations operating in over eighty-two plants of sixty-five companies having a capacity in excess of 700 tons of tomatoes per hour. All these installations are operating under the supervision of government inspectors and plant control men and are producing on a basis of maximum yield, minimum manual trimmjng, good taste, good color, correct viscosity, and Ion. mold count. The screen used in the tests a t Geneva was an offset weight unit which will not feed the material uphill; consequently, it could not duplicate the action of a screen widely used in the commercial production of tomato juice. Also where decoring and destemming screens are used in the production of tomato juice, the prechopping of the tomatoes is very rough, with only enough work being done to break open the seed sacks. Vot only were clearances on the Geneva chopper very small but, after being chopped, the material was pumped on its way to the cooker and the screen through tubing having an
internal diameter of only 0.555 inch. This no doubt further broke down the material to a point where effective screening could not be accomplished. Properly set up vibrating screens which have a correct motion and which are preferably adjustable for both stroke and slope have proved a real boon to the tomato juice canners. H. L. BULLOCK Bullock-Smith Associates 136 Liberty St. New York 6, S. Y. September 25, 1951
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DEARSIR: We have read 1Ir. Bulloclr’s comments with interest and appreciate his kind remarks concerning our paper. With regard to Mr. Bullock’s question of our screening operation, we believe that he has raised t x o questions-namely, the value of a vibratory screen in the manufacture of tomato juice and, in particular, the superior merits of a vibratory screen that feeds the material uphill. It is our belief that such questions can only be settled by accurately measuring the quality of tomato juice manufactured from various types of raw stock and produced with and without various types of vibratory screens.
J. C. MOYER New York State Agricultural Experiment Station Geneva, N. Y. November 12, 1951
