Assaying Zinc Determination Methods
Zinc occurs in nature most commonly as sulphide (blende); it also occurs as carbonate (calamine) and silicate (smithsonite). Each of these is sufficiently abundant to be a source of the metal. The metal is known in commerce as “ spelter ” when in ingots, and as sheet zinc when rolled. It is chiefly used in […]
Assaying Cobalt Determination Methods
Occurs less abundantly than nickel. Its chief ores are smaltite and cobaltite, which are arsenides of cobalt, with more or less iron, nickel, and copper. It also occurs as arseniate in erythrine, and as oxide in asbolan or earthy cobalt, which is essentially a wad carrying cobalt. It is mainly used in the manufacture of […]
Assays for Titanium
Titanium only occurs as a mineral in its oxidised state, or as titanic oxide (TiO2). It is a substance which has little commercial value, and is generally recognised as one of the rare bodies; although, in small quantities, it is widely disseminated. It occurs in granite, basalt, and other igneous rocks in quantities up to […]
Tungsten Assaying
The ammonic carbonate filtrate from the silica is evaporated to dryness, ignited strongly over the blowpipe, and weighed. The residue is tungstic acid, WO3. The tungsten may be conveniently reported in this form, although it is probably present as a lower oxide. The acid filtrate from the silica and tungstic acid is treated with sulphuretted […]
Separating Minerals by Electromagnetic
The magnetic properties of certain minerals have long been recognized, and their concentration through magnetism can lay no claim to novelty. A patent was awarded in England on a process for separating iron minerals by means of a magnet in 1792, and in this country a separator having a conveyor belt for presenting ore beneath […]
Electrostatic & Magnetic Separators
The gradual depletion of high-grade mineral deposits and the necessity for development of lower-grade deposits, together with the increased demand for nonmetallic minerals, has increased the importance of the ore-dressing field during recent years. There is strong need for development of new ore-concentration methods and machines to keep pace with the constant changing of marketing […]
Gold and Silver in Eddy Current Separator
The Bureau of Mines investigated the concentration and distribution of precious metals in the various fractions produced from mechanical processing of obsolete military electronic scrap. Whole avionic units, printed circuit cards, and electrical connectors were processed and analyzed. Materials recovered included baghouse lights, wire bundles, magnetics , and metal concentrates from eddy-current and high-tension separation. […]
Batch Thickening Theory
Kynch showed that a constant concentration layer propogates upward at constant rate in batch thickening tests under the assumption that settling velocity is a function of only the concentration, as described earlier under Continuous Thickening Theory. His conclusion can be expressed as: Where Ci is the concentration of solids in the layer, and Vi is […]
Selecting Thickener Depth Determination
Where there is little significant effect of compression factors, the bed depth can be selected based upon operating characteristics of the thickener installation. In this case, information must be available (or assumed) concerning the normal fluctuations in feed rate and concentration. Also, sludge storage requirements should be considered. For illustrative purposes, the following example of […]
Flocculation
The flocculation behavior of coal, quartz and clay was studied by measuring the turbidity of the supernatant liquid after one hour of settling. Figure 14 is a plot of turbidity and adsorption density against equilibrium concentration. The turbidity of the supernatant liquid decreases until a minimum is reached and tends to rise thereafter. The results […]