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 […]
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 […]
Principles of Gold Cyanidation Explained
What is commonly known as the Cyanide Process has for its object the commercially profitable recovery of gold and silver from their ores, and this is accomplished by the solvent action of an alkaline cyanide solution on the precious metals. The first step in the Cyanidation process is to mill or grind the ore to […]
Chemistry of Cyanidation of Gold & Silver
The usual reaction given for the dissolution of gold and metallic silver in cyanide solution is known as Elsner’s equation. 2Au + 4KCN + O + H20 = 2KAu(CN)2 +2KOH Silver sulphide, the form in which silver most commonly occurs in its ores, involves a different set of reactions, which are usually expressed thus: First […]
Analytical Method for Copper Content in Cyanide Solution
Short Iodide Method To 200 to 500 cc of solution add 10 cc HCl, 5 cc HNO3. Evaporate to about 50 cc, then cool, and add 8 cc H2SO4. Evaporate almost to dryness. Cool, add 5 cc water and 5 cc H2SO4, and again evaporate almost to dryness. Cool, add 50 cc water, and heat […]
Free Cyanide Determination
You will perform this titration to obtain your Free Cyanide Determination. Take a 10ml aliquot of pregnant liquor. Make aliquot to 60ml with distilled water. Add 3 ml KI (10% solution) Add 5 ml of 1.5% NH4OH Titrate with 0.10 N Ag NO3 then; titre/100 = %CN Note: The endpoint is indicated by the first […]
Mineralogy & Density of Minerals
With the recognition of a need for a concise table of conversion factors, the following data applicable to metallurgical needs are taken from a compilation by Robert B. Fisher formerly of the Dorr Company for its staff: SLIME-DENSITY TABLE In Metallurgical and Chemical Engineering (now Chemical Engineering) for June, 1912, H. B. Lowden presented the […]
Mineral Processing Operating Cost Estimate of Ore Treatment
Only where a group of mines operates in a single district are costs comparable and then only with reservations. In general, cost systems are fairly uniform, yet in studying costs of a number of plants it is noticeable that in some cases there is a tendency to omit certain operations which are proper charges against […]
Manganese Silver Ore Treatment Method
The present is to discuss some of the current silver-treatment plants and also reviews briefly some of the older practices in important silver-mining areas since closed down. The greater part of the world’s production of silver is derived from the refining of the base metals, particularly lead ores, and complex ores of lead, copper, antimony, and […]