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., […]
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 […]
Smectite Ceramics
Smectite is the name for a group of sodium, calcium, magnesium, iron, lithium aluminun silicates which include the minerals sodium montmorillorite, calcium montmorillonite, saponite, nontronite, and hectorite. The rock in which these smectite minerals are usually dominant is bentonite. The theoretical formula without considering lattice substitutions is (OH4Al4Si8O20 · N H2O (interlayer), and the theoretical composition […]
Diatomite Deposit Formation
Worldwide, diatomites occur within Tertiary to Recent lacustrine and marine sediment facies (see Table 1). Geologically, the oldest marine and lacustrine diatoms predate the effusive blooms of the post Oligocene depositional period, and are respectively found within Cretaceous and late Eocene sediments. In the U.S., marine species are found in rocks as old as the […]