SEPTEMBER 15, 1939
ANALYTICAL EDITION
I
TABLEI. FLOTATION DATA Solution Water a-Naphthylamine
Potassium ethyl xanthate
C p o n . of Reagent P. p . m.
...
170 170 170 340 340 340 340 25 25 25 50 50 50 100 100 100
Galena Grams 5.00 5.00 10.00
20.00 2.00 5.00 10.00 20.00 5.00 10.00 20.00 5.00 10.00 20.00 5.00 10.00 20.00
Pulp Density Recovery % % 10 10.2 10 40.0 20 22.2 23.1 40 4 57.8 60.4 10 63.7 20 57.8 40 10 75.9 20 87.5 40 87.6 82.2 10 20 87.5 40 72.0 10 84.5 20 85.8 40 92.7
Galena per Cc. Overflow Gram 0,011 0.057 0,092 0.145 0.020 0.061 0.162 0.327 0.118 0.199 0.319 0.117 0.208 0.351 0.094 0.228 0,501
from a dropping funnel to compensate for that lost a9 overflow The volume of solution added is usually 30 or 40 cc. The duration of each run is 15 minutes. The column of the cell is made of 2.5-cm. (1-inch) Pyrex tubing drawn out at one end to fit into the mouth of a suction flask which is used as an air reservoir. A standard No. 3 sintered-glass disk sealed into the column has been found to give good bubbling action. The recovery trough is sealed to the column and an out-
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let tube is sealed into the trough at the bottom, so that the overflow can be run directly into a filtering crucible for filtering and weighing if desired.
The data given in Table I are taken from unpublished work by Knoll, Leaf, and Baker on the collecting action of anaphthylamine on galena. The data on potassium ethyl xanthate are included to show the recovery of mineral when a better collecting agent than a-naphthylamine is used. The cell described in this paper was used in all cases, although results with the Oberbillig and Fahrenwald and Taggart, Taylor, and Ince cells are comparable. When solutions which contained no collecting agent were used in the cell, the weight of mineral (galena) recovered depended directly upon the volume of overflow. When solutions containing collecting agents were used in the cell, the percentage recovery of mineral (galena) was independent of the volume of overflow.
Literature Cited (1) Oberbillig, E., and Fahrenwald, A. W., Mining J. (Phoenix, Ariz.), 22, No. 1, 7 (1938). (2) Prausnitz, P. H., “Glas- und keramische Filter,” p. 129,Leipzig, Akademische Verlagsgesellschaft, 1933. (3) Taggart, A. F., Taylor, T. C., and Ince, C. R., Am. Inst. Mining Met. Engrs., Tech. Pub. 204, 25 (March, 1929).
A DippingType Conductivity Cell C. S. HOWARD Geological Survey, U. S. Department of the Interior, Washington, D. C.
T
HE accompanying illustration shows steps in the manufacture of a conductivity cell, which has been found very useful in measuring the conductivity of water samples in the field and in the laboratory. The cell is made of lucite and is of the commonly used dipping type, with a full-sized opening a t
the bottom and several holes a t the top to permit circulation of water through the cell. The cell illustrated is used for the measurement of conductivity of water of medium to high conductivity. The cylindrical shield is about 3.25 inches long, 1.25 inches in outside diameter, and 1 inch in inside diameter. The use of lucite makes it possible to remove the outer shield, which is a convenience in assembling and in cleaning. After the electrodes and lead wires are in place, the holes in the frame that holds the wires are sealed with a cement prepared especially for use with lucite. For field use a cylinder of lucite has been used, i n s t e a d of a g l a s s cylinder, to contain the sample during the measurement. T h e p l a t i n u m electrodes and the lead wires were purchased from a manufacturer a n d t h e cells were made in the Geological Survey instrument shops. PUBLISHED by permission of
STHIPS IN Tan CONBTRUCTION OF A CONDUCTIVITY CELL
t h e Direotor, Geological Survey, U. S Department of the Interior.
