The recovery of dissolved gold from slime pulp in the cyanide process was first accomplished by intermittent decantation. This simple process consists in mixing with the pulp containing the values in solution, a solution of lower gold content, settling the mixture in a tank and decanting the clear supernatant fluid. The thick pulp remaining in … Read more
The experimental work on the oxidized copper ore at the New Cornelia mine at Ajo, Ariz., ended on Jan. 12, 1916. On that date final decision was made on the general nature of the process to be used in the 5,000-ton leaching plant, and on many of the details, as far as experience on a … Read more
A 2,000-ton Copper Leaching plant for the treatment of the accumulated copper concentrator tailing was built and put into operation. During the experimental period, the first step was that of laboratory experiments or beaker leaches. The results on this small scale were so satisfactory that a small operating plant, capable of handling 5 tons of … Read more
The use of zinc dust for precipitating the precious metals from cyanide solutions is well established now in many places, and has many advantages over the shavings method of precipitation. Although much work has been done on methods of testing zinc dust, as yet no absolutely positive test has been devised to determine the value … Read more
The object of the first classification done in cyaniding work was to produce a leachable sand and overflow as small an amount of sand as possible with the ‘slime, which was usually run to waste. In the early days various arrangements of adjustable tank gates were used, and sometimes direct overflow of tanks filled with a … Read more
Recovery of Uranium In the extraction process practically all of the uranium in the ore is dissolved in the nitric acid, a little remaining in the insoluble residue because of incomplete washing. An average of 2.3 per cent of the uranium oxide in the ore has remained in the residue, varying in different carload lots … Read more
Radium Measurements One of the most essential factors in the successful production and concentration of radium consists in following the material being concentrated, by means of careful quantitative determinations, through all the various operations from the original ore to the final product. This involves the radioactive analysis of a large number of products differing widely … Read more
Refining in the Plant The first treatment of the radium-barium sulphates is of great importance, as the whole capacity of the plant, as far as the radium goes, depends upon this first treatment. If the sulphates can not be handled as rapidly as produced, the actual amount of radium refined each year must necessarily be … Read more
As the sodium uranate requires re-treatment, owing to the fact that it carries vanadium, it is not necessary to wash the cake as completely as might otherwise be required. Most of the sodium uranate carries 7 to 9 per cent V205. It has been found practically impossible to obtain a precipitate that does not carry … Read more
The method of treating carnotite, a uranium, ore used by the Bureau of Mines is outlined in this chapter. Leaching, Filtering, and Washing Ore The ore is ground to 20 mesh and is leached with strong hot nitric acid in acid-proof earthenware pots. The amount of acid used is 121 pounds of 100 per cent … Read more