Metallurgy for Recovering Gold from Telluride Ore
Gold ore associated with Telluride is hardly soluble in ordinary cyanide solutions and special treatment is necessary for its extraction. There are two methods in use in such cases. Roasting The ore is ground dry to about 30 mesh and roasted; it is then ground to a slime in water or cyanide solution, usually in grinding […]
Discrepancy Between Actual and Expected Recovery: Gold Metallurgy Accounting
Everyone connected with cyanide plants has at some time or another been confronted with a real or apparent shortage of bullion in the clean-up, that is, the bullion recovered has been less than the amount expected when calculated from the assays of head and tail and the tonnage treated. Such a shortage will often occur […]
Continuous Gold Leaching and Tanks Short-Circuiting
The system of continuous treatment consists in allowing the stream of pulp to flow continuously through a connecting series of agitator tanks, as distinguished from the intermittent system where a charge is placed in a tank and agitated therein until the dissolution of the precious metals is complete. It may be applied to almost any […]
Calculating Gold Losses in Continuous Countercurrent Decantation
This is an interesting development of the old decantation process, and while it contains the same principle, of displacement by successive dilutions, the action is much more rapid, the same result is attained by the use of considerably less barren solution and it is continuous in action needing little power and practically no attention. For […]
Pulp and Slurry Thickening Test and Calculations
The slime pulp or slurry on leaving the sand classifier with its proper admixture of lime is first led to some form of thickening device if, as is usually the case, the ratio of liquid to solid is too large for economic handling in the cyanide treatment. The form of thickener almost universally used in […]
Leaching Fine Gold
Many definitions of the word “slime” have been attempted to Leaching Fine Gold but the one that best expresses its meaning from a practical point of view is that given by Park that it is that part of the pulverized ore that is not percolable on a commercial scale without the use of pressure. The […]
Leaching Gold from Finely Crushed Ore (Sand Leach)
When the cyanide process was first introduced its application was confined to leaching, that is, treatment by percolation. By this method only such material could be worked as was sufficiently granular in texture to allow the necessary amount of solution to percolate through it in a reasonable time. By crushing the ore dry, it is […]
Free Cyanide vs Total Cyanide Determination
It is obviously of the highest importance in controlling the action of a solution to find out what strength of cyanide and alkali it contains at any given time. Under this head are the tests for free cyanide, “total” cyanide, hydrocyanic acid, and free or “protective” alkali. Besides these cyanide constituents, which have to be […]
Determine Oxygen Content in Leach Solution
Here is a way how to determine the oxygen content during gold leaching and Estimation of available Oxygen Content in Cyanide Solutions. Until recently no simple and reliable method has been known for the estimation of free oxygen in working cyanide solutions so that the one here described supplies something that has long been needed. The matter […]
Assay Method of Gold or Silver in Leach Solution
Gold & Silver Assay Method No. 1 Evaporate a known quantity in a square boat made of lead foil, scorify, and cupel. This is not reliable for low grade solutions because the amount that can be taken for assay is too small. Gold & Silver Assay Method No. 2 Evaporate a known quantity in a large porcelain dish whose […]