Heavy-mineral processing

Figure 2.35 (A) Flowsheet for heavy mineral processing in Thailand. (B) Flowsheet for processing bastnasite from mountain pass, California.

Size reduction (qv) or comminution is the first and very important step in the processing of most minerals (2,6,10,20—24). It also involves large expenditures for heavy equipment, energy, operation, and maintenance. Size reduction is necessary because the value minerals are intimately associated with gangue and need to be Hberated, and/or because most minerals processing/separation methods require the ore mass to be of certain size and/or shape. Size reduction is also required in the case of quarry products to produce material of controlled particle size (see Size measurement of particles). In some instances, hberation of valuables or impurities from the ore matrix is achieved without any apparent size reduction. Scmbbers and attritors used in the industrial minerals plants, eg, phosphate, mtile, glass sands, or clay, ate examples. 

Rikers, R.A., Rem, P. and Dalmijn, W.L., Improved method for prediction of heavy metal recoveries from soil using high intensity magnetic separation (HIMS), Int. J. Miner. Process., 54, 165-182,... 

The ilmenite production from heavy mineral sands exclusively utilizes a physical separation method using magnetic separation, gravity concentration and electrostatic separation. Flotation is practiced mainly for beneficiation of fine mineral sands containing rutile, ilmenite and zircon. The ilmenite that is produced in a number of operations in Western Australia, India and the USA is high in chromium, which makes the ilmenite unusable. This section discusses a new process that was developed for chromium removal from ilmenite concentrates. 

These deposits are formed in the natural process of weathering, transportation, and concentration at the site of heavy minerals originating from some primary source rock. Commercially, beach placers are the most important along with alluvial streams aeolian deposits are insignificant. 

Another aim of this study is to determine which elements are most reliable and useful for fingerprinting specularite and other heavy minerals commonly associated with it. Preliminary analyses and previous literature (5, 10, 11) indicate that transition metals (TM) and rare earth elements (REE) have unique signatures associated with genetic and metamorphic processes. This study will... 

Chitosan possesses flocculating properties, which are used in water processing engineering as a part of the filtration process. It may remove phosphorus, heavy minerals and oils from the water. In the same manner, it is used to clarify wine (as a substitute for egg albumin) and beer. 

Land disturbance and exposure of buried geologic strata to the open environment leads to sulfide oxidation (if present) and, as a consequence, water-quality degradation of runoff. For water-quality-control purposes, sedimentation ponds required by law are used as water treatment basins. Often, the pH of such basin waters is below 6, and the concentration of heavy metals is above acceptable levels. Water treatments include neutralization and removal of heavy metals as precipitates. Similar water-quality problems arise from other industrial sources, including heavy steel industries, electronics, food processing, mineral processing, and waste-disposal leachates. This portion of the chapter deals with some of the chemical agents used for neutralization purposes and some of their limitations. 

Extractive industries include mining of mineral deposits (principally metal-bearing ores and coal deposits), oil and natural gas production, and quarrying for building and roadmaking materials. Poorly operated or abandoned mine sites are often significant sources of water contamination contaminants of particular health concern from these sources include heavy metals, and mineral-processing chemicals, such as cyanide. 

Mineral Beneficiation Electrostatic methods are widely used in the processing of ores with mineral concentrates. Generally, electrostatic separation is used as a part of an overall flow sheet comprising various combinations of physical separation procedures. It is particularly well established in the processing of heavy-mineral beach sands from which are recovered ilmenite, rutile, zircon, monazite, silicates, and quartz. High-grade specular hematite concentrates have been recovered at rates of 1000 tons/h in Labrador. Applications also include processing tin ores to separate cassiterite from columbite and ilmenite. Refer to Fig. 19-61 . 

The enrichment of ilmenite in beach sand in existing or fossil coastlines is important for 1102 production. The action of surf, currents, and/or wind results in concentration of the ilmenite and other heavy minerals such as rutile, zircon, monazite, and other silicates in the dunes or beaches. This concentration process frequently leads to layering of the minerals. Attack by seawater and air over geological periods of time leads to corrosion of the ilmenite. Iron is removed from the ilmenite lattice, resulting in emichment of the Ti02 in the remaining material. The lattice is stable... 

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