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 […]
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 […]
Compare NaCN Sodium Cyanide VS KCN Potassium Cyanide
There is probably no potassium cyanide now made for commercial purposes. With the development of the cyanide process the custom grew up, for economic reasons, of manufacturing what was called a “double salt” composed of potassium and sodium cyanides in varying proportions. This material was compounded so as to have a cyanogen content of 98% […]
List Sources of Cyanide Loss
Below is a list of things/factor which can cause cyanide loses in the leach process: The Precious Metals The amount of cyanide that combines with the gold in an average ore is negligible, but with silver it is different owing to the much larger quantity of metal that has to be dealt with to produce […]
Gold Circuit Carbon Sampling for Inventory and Movement
Metallurgical performance of gold and silver mineral processing flowsheets is typically evaluated using assay balance and production balance techniques. With assay balance the mill feed, tailings, and some intermediate streams are sampled and assayed. Gold circuit performance can then be evaluated using mass balance techniques. Unsteady plant conditions and difficulties in sampling and measuring moving streams are some problems with this method. Production balance measures […]
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 […]