Merrill Crowe Slurry Filtration Circuit Post-Agitated Leach
The object of the post agitated leach drum filtration circuit is to recover as much of the dissolved gold and silver as possible. The efficiency of recovery can be increased significantly by utilizing two successive stages of filtration such as the two stage system applied in this plant. Recovery of the precious metals is also improved […]
Agitated Leaching Circuit Operation
Ground slurry from the trash screen enters this EXAMPLE Agitated Leach circuit at a rate of 35.5 cubic meters per hour, and 45% solids. The slurry passes through each of the four tanks, and should remain in each tank for a period of approximately 12 hours. Each tank is 8 meters in diameter by 8.5 […]
Dissolve Gold and Silver with Cyanide
The addition of gold or silver to an alkaline sodium cyanide solution will cause the gold and silver to react with the cyanide and dissolve into the solution in a process called cyanidation. This process is more frequently referred to as leaching. As well as reacting with the precious metals, the cyanide will react with […]
Effect of Cyanide on Steel and Iron Minerals Leached by Cyanide
The corrosion of black rolled mild steel in sodium cyanide solution is negligible. A piece of steel suspended in a sodium cyanide solution maintained at 0.05% NaCN and 0.001% CaO, in the presence of air, lost 0.002% of its weight in two weeks, this was equivalent to a penetration of 0.76 micron per year.Oxidized iron minerals […]
Leach Gold using Hyposulphite of Sodium
The fact that gold will dissolve in sodium hyposulphite solutions is known from the lixiviation of silver and gold ores. The gold will dissolve only in small quantities. According to researchers, if gold leaf is treated for a time with sodium hyposulphite solutions of varying strengths,’ solution takes place in every instance, the deviation in […]
Cyanide Diffusion pH and Oxygen
Whether lime titrations or pH control is belter depends, I think, on the level of control. If the level was down around 0. 1 lb per ton of solution, titration is a bit difficult without a highly skilled man, which is not always available. Around a pH of 11 or 11.5, a pH meter is […]
Effect of Oxygen on Gold Leaching
In simplified terms, the Effect of Oxygen on Gold Leaching can be summarized in saying: The dissolution rate of gold in alkaline cyanide solutions under atmospheric conditions, and at practical cyanide levels, is directly proportional to the dissolved oxygen concentration. The rate of dissolution of gold in alkaline cyanide solution is dependent on a number of […]
Cyanide Leaching and Decomposition of Pyrrhotite
Research on cyanidation methods brought considerable discussion on the reactions involved in the leaching and decomposition of pyrrhotite in cyanide solutions. Pyrrhotite has one loosely held sulphur atom which readily reacts with cyanide to form thiocyanate: Fe5S6 + NaCN = NaCNS + 5 FeS The ferrous sulphide oxidizes rapidly to the sulphate which reacts with cyanide to […]
Eliminating Copper from Gold Ore
When reviewing Methods of Eliminating Copper from Gold Ores we see that several methods have been suggested to eliminate copper from ores prior to cyanidation. Preliminary extraction of the copper with sulphuric or sulphurous acids may be applicable to ores containing oxidized copper minerals such as malachite, azurite and chrysocolla but these acids have but little […]
Effect of Pre-Aeration and Oxygen on Gold Cyanidation
In your process development you may sometime want to test and see what effect (for your particular ore sample) would the use of oxygenation and pre-aeration have on silver and gold kinetics leach rates and recoveries. Some situations show improved precious metal recoveries, others show an impact of the leach agent’s consumption rate. Here, a […]