Modelling Solvent Extraction of Copper in Ammoniacal Systems
A mathematical modeling method was developed by the Bureau of Mines for the prediction of the principal equilibrium species in the solvent extraction of copper. The use of models for predicting the amount of metal extracted can reduce the amount of experimental work required to characterize a system for purposes such as optimization studies. Models […]
Recovering Lithium from Clays
Preliminary Lithium Extraction Tests: In the preliminary McDermitt clay studies, several lithium extraction methods were investigated. Water disaggregation, hydrothermal treatment, acid leach, alkaline roast-water leach, sulfate roast-water leach, and chloride roast-water leach were techniques used in the treatment of both McDermitt A and B clays. Only the higher grade McDermitt B clay was treated by the […]
Iodide Pressure Oxidation Gold Leaching – Autoclave
The pressure oxidation process is especially suitable for the sulfide type of refractory ores. It includes two stages of operation. First, the refractory ore is subjected to an autoclave oxidation. At elevated temperatures usually above 180°C and in acidic or alkaline medium and pressurized oxygen, sulfide minerals are oxidized for a period of 1-2 hours. […]
Ammonia Gold Dissolution Leaching
Processes for gold extraction usually depend on how gold is associated with its environment. Although cyanide leaching remains the overwhelming option for the treatment of gold ores, because of its economy and simplicity, it suffers from certain inherent drawbacks such as toxicity, low leaching rate and its inefficiency of treating certain classes of refractory ores. […]
High Pressure Roll Grinding for Copper Heap Leaching
Technology improvements in copper mining operations have been the key factor for increasing productivity. Beyond dump leaching, the industry will increasingly use various heap leach techniques in SX-EW operations in the coming years in order to optimize recovery and maintain low production costs. They include: Finer comminution followed by agglomeration. Finer comminution followed by coarse […]
Gold Extraction in Carbonaceous Ore using Thiosulfate
The U. S. Bureau of Mines has been investigating the application of thiosulfate to recover gold directly from low grade refractory carbonaceous ores for the past four years. Statistical experimental methods were used to determine the effects of various leaching parameters on both gold extraction and thiosulfate consumption. Seven variables were investigated, including thiosulfate, copper, […]
Optimum Carbon Loading CIP Circuit
Figure 1 simplifies a CIP circuit, implied are the transfer and screening mechanisms. Gold/silver are dissolved, activated charcoal (carbon) is moved countercurrently to the flow of ore adsorbing gold/silver. The charcoal is removed from the circuit, stripped of its metal content, regenerated and then returned to the circuit to continue the cycle. The amount of […]
Countercurrent Tower Process Gold Leaching
The Kamyr countercurrent tower leach process consists of a true countercurrent leach with a flocculated ore and fibre mixture entering the top of the tower and a cyanide solution or alternative lixiviant as well as a barren wash solution entering the bottom of the tower. The Kamyr countercurrent tower leaching system has been developed for […]
Lithium Spodumene Bio-Leaching
A culture of niger used in this study was obtained from Professor Stoyan Groudey of Higher Institute of Mining and Geology, Sofia, Bulgaria. It was maintained on Czapex-Dox agar medium (Booth, 1971) containing 100 x 10 -6 m³ distilled water, 3.0 x 10-³, kg sucrose, 0.3 x 10-³, kg NaNO3, 0.1 x 10-³ kg K2HPO4, […]
Prevent Permeability Loss in Heap Leaching
The Bureau of Mines Twin Cities Research Center conducts research to assist in solving problems that occur during solution mining of metals. Solution mining of uranium involves injecting a carbonate-bicarbonate (basic) or sulfate (acidic) leach solution through injection wells into an ore body where the lixiviant dissolves the uranium from the ore. Uranium bearing lixiviant […]