Leaching Fluorine from Copper Concentrate
Hydrometallurgical Removal of Fluorine from Copper Concentrates: CVRD Technology Center (SUTEC) has developed and patented an hydrometallurgical process route to remove fluorine from copper concentrates, as a result of an extensive testwork to investigate the effect of mineral acids on fluorite solubilization. The process developed consists of leaching the high fluorine copper concentrates with H2SO4 or […]
Typical Average Grinding Ball Consumption
Pressure Leaching of Galena to Recover Lead by Electrowinning
As part of the U.S. Bureau of Mines program to improve base metal leach systems, pressure leaching of galena (PbS) concentrates in fluosilicic acid (H2SiF6) solution was investigated. Lead extraction was 93 pct when PbS was pressure leached in H2SiF6 at 95° C with 200-psig O2 pressure for 40 min, using ferric nitrate [Fe(NO3)3] as […]
Electric Arc Furnace
The U.S. Bureau of Mines is conducting an ongoing research project to better understand the phenomena involved within electric arcs utilized in electric furnace steelmaking. With a better understanding of the physical and electrical characteristics involved, dynamic or predictive control of electric arc furnaces may be possible. A mathematical model is presented, but not solved, […]
Froth Flotation Bubble Collision
Collision efficiencies have been calculated using a two-particle model in a strong force field. The nondimensional equations of motion have been solved numerically, showing the effects of changes in K, W, and particle-to-bubble radius ratio R for both viscous and potential flow. The results of Flint and Howarth have been extended to include higher values […]
Electrorefining Calcium Metal Electrowinning
The U.S. Bureau of Mines developed an alternative electrochemical process for the production of calcium metal. The current industrial practice is costly, complex, and inefficient. The Bureau method involved electrowinning of a calcium-tin alloy followed by electrorefining to produce calcium metal. In the electrowinning cell, CaCl2 was fed to a KCl2-CaCl2 electrolyte. The calcium was […]
Column Flotation Testing Better & Improved Recovery
We investigated column flotation for recovery of a high-grade fluorite (CaF2) concentrate and byproduct concentrates from the Fish Creek fluorite deposit in Eureka County, NV. The recovery scheme consisted of (1) grinding the ore to minus 48 mesh, (2) fluorite rougher and cleaner flotation, (3) desliming the rougher fluorite flotation tailings at 20 µm, (4) […]
How to Recover Chromite
The USBM conducted laboratory research including operating a nominal 100 lb/h pilot plant to demonstrate the recovery and concentration of chromite by gravity and flotation operations. Gravity beneficiation test results show that concentrates contained as much as 52 pct chromic oxide (Cr2O3) with recoveries of about 80 pct. Results from the bench-scale unit operations of […]
Ground Sluicing Operations
In ground sluicing the gravel is excavated by running water not under pressure. Booming is a variation of ground sluicing in which water is stored in reservoirs and is intermittently discharged in large volumes over short periods to obtain the maximum erosional and transporting effect on the gravel. The most favorable conditions for ground sluicing […]
Sulfide Ore Treatment Gold – Silver – Copper – Cobalt – Zinc Recovery
A procedure was developed for recovering gold, silver, cobalt, copper, and zinc from a massive sulfide ore by a hydro-metallurgical process. The procedure consists of (1) oxygen pressure leaching; (2) iron, arsenic, and copper removal from the leach solution by precipitation; (3) selective extraction of cobalt and zinc from solution; (4) electro-deposition of the cobalt […]