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A mechano-chemical process called Rapid Oxidative Leach174 ROL174 is the gamechanger for miners struggling to extract copper and gold from low-grade ores. The technology leaches 97-99 percent copper directly on-site in six to eight hours from concentrates as low as 5 percent copper. In gold ROL has the potential to unlock the value of undeveloped refractory gold deposits with less than 3 gt gold headGet A Quote
A mechano-chemical process called Rapid Oxidative Leach174 ROL174 is the gamechanger for miners struggling to extract copper and gold from low-grade ores. The technology leaches 97-99 percent copper directly on-site in six to eight hours, from concentrates as low as 5 percent copper. In gold, ROL has the potential to unlock the value of undeveloped refractory gold deposits with less than 3 gt gold head
A old-time metallurgiststated that in treating cupriferous gold and silver ores by the Hunt Process, the strength of ammonia in the solution is varied according to the copper content as well as to the combinations in which the copper is found. It was in use before for treating amalgamation tailings. This material contained a few pounds of copper per ton, present mostly as oxide. In its treatment, it was found necessary to use 8 lb. of caustic ammonia per ton of solution. The strength of the cyanide was 0.05.
Another example was that of an ore treated inCalifornia, which contained cupriferous,pyrites and silicate of copper. The cyanide consumption was 7 to 8 lbs. per ton which using a0. 15cyanide solution. When 6 lbs. of ammonium chloride was added to each ton of solution together was sufficient lime to convert all of the ammonium chloride to the hydroxide, the consumption of cyanide was reduced to 1 lb. per ton of ore.
In another eliminationmethod the copper mineral is dissolved out by means of ammonia after which the ore is cyanided as usual. The copper and ammonia are recovered from the preliminary leach solution by distillation, the copper remaining as an oxide precipitate. The success of this process will depend largely upon the relatively complete solubility in ammonia of those copper minerals which dissolve in cyanide.
In this study, the extraction of gold from a copper-bearing gold ore by ammoniacal cyanide leaching was studied. Furthermore, ammonia leaching as a pretreatment process ahead of cyanide leaching was also examined. Only 12 of gold was extracted by direct cyanide leaching of the ore. The addition of lead nitrate did not affect the leaching of gold.
Many gold ores contain minerals that react in cyanide solution, consuming oxygen or cyanide or both, and negatively influencing the rate or extent of gold leaching. The most common interfering minerals are the sulfides of iron, arsenic, antimony, copper, zinc and tellurium Fleming, 1998. SGS MINERALS TECHNICAL BULLETIN 2004-03 5
One method depends upon the property of cuprocyanide of potassium to dissolve copper in certain minerals. This cuprocyanide is obtained by heating the cupriferous ore with cyanide solution. When the cuprocyanide has dissolved its maximum of copper, part of the copper in the solution is precipitated electrolytically during which a partial regeneration of the cyanide is said to take place. The treated ore is then cyanided in the usual way and the gold recovered by electrolytic precipitation. Whether or not any precious metal was dissolved in the preliminary cyanide treatment was not stated.
Rich ores is usually done in a mill-oatmill-oat MF2 open cir- ... in conjunction with PGMs and coppergold ores. 3.2.4. Sulfate-based leach processes ... from the pregnant rich leach ...
Severe interference by the copper containing sulphides with cyanide leaching of gold is observed at NaCN5 gL. This is consistent with speciation calculations.
The Hunt method-calls for the direct treatment of the ore with a solution of potassium cyanide to which ammonium hydroxide has been added. The gold is thus extracted together with some copper, and the metals are recovered by electrolytic precipitation, the gold, silver and copper falling to the bottom of the vats as a sludge. Zinc precipitation may also be used. The product is low grade.