Selecting Centrifugal Slurry Pump Based
Making a sketch of the pump system, including dimensions, is very helpful in determining the static heads, friction heads, etc. After determining the top size of the solids and solid size distribution by the results of a screen analysis of the material, we can select the materials to be used in the construction of the pump. […]
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, […]
Flotation Hydrodynamic
The Bureau of Mines conducted research on the flotation hydrodynamics of fine particle flotation to improve the flotation efficiency in our domestic minerals industry. The turbulent fluid velocity profile was measured in various flotation cells at different levels of dissipation energy. The importance of dissipation energy and bubble size within the flotation cells for the […]
Effect of Turbulence in Fine Bubbles Flotation
The U.S. Bureau of Mines examined the influence of turbulence on the fine bubble flotation of fine-sized (minus 10 micron) galena in order to improve flotation efficiency. Fine bubble flotation was carried out in a spinning-disk flotation cell and was compared to results obtained from flotation in a conventional cell at equivalent agitation levels. An […]
Redox Electrodes & Mineral Floatability
Gold spiral electrodes were fabricated as a 3-turn coil of 10 cm long wires of 0.5 mm diameter. Following the hypothesis that a black platinum electrode follows more closely the solution potential than the mineral potential due to its high porosity (area for contact with the solution being much larger than the projected area for […]
Slurry Volume Hold-Up of Overflow Ball Mills
Figure 1 shows the head-on view of a typical overflow discharge mill including the definition of symbols and specific mill volumes to be used. In this discussion it is assumed that the overflow discharge mill being operated at steady-state will demonstrate a reservoir effect, that is that the Volume 1 of Figure 1 will be […]
Carlin Trend Geology
Stratigraphy The stratigraphic sequence in the Carlin Trend Geological area is Lower Paleozoic marine sediments and Late Tertiary tuffaceous sediments. The Lower Paleozoic sediments consist of the Siluro-Devonian Roberts Mountains Formation, the Devonian Popovich Formation and the locally named Rodeo Creek Formation. The Rodeo Creek Formation had previously been described in the mine area as […]
Jarosite Production
Jarosite Production: The roast-leach-electrowin process for zinc production involves roasting zinc sulphide concentrate to produce calcine containing zinc oxide. Zinc concentrate roasted at Risdon typically contains about 11% iron, which is predominantly converted to zinc ferrite (ZnFe2O4) during the roasting operation. When the calcine is leached under weak acid conditions (pH ≤ 2) only the zinc oxide […]
No Conditioning Carbonate Flotation
Tests to study the effect of collectors and pH were randomly conducted on the phosphate matrix, using a 2k full factorial design for collector screening and process optimization. Star points needed to estimate non-linear factor responses were included in the optimization test series and in some reagent screening tests. For the fatty acids, the two […]
Calcium Montmorillonite Flocculation
The flocculation process involving fine particles and organic polymers can be depicted by the following sequence: adsorption of the polymeric species on particles, conformational changes in the adsorbed polymer molecules, and collisions between particles to form flocs through bridging. Flocculation is the result of mixing the polymer with the particle slurry in some device, e.g., […]