Ore Dressing

Flotation or froth flotation is a physicochemical property-based separation process. It is widely utilised in the area of mineral processing also known as ore dressing and mineral beneftciation for mineral concentration. In addition to the mining and metallurgical industries, flotation also finds appHcations in sewage treatment, water purification, bitumen recovery from tar sands, and coal desulfurization. Nearly one biUion tons of ore are treated by this process aimuaHy in the world. Phosphate rock, precious metals, lead, zinc, copper, molybdenum, and tin-containing ores as well as coal are treated routinely by this process some flotation plants treat 200,000 tons of ore per day (see Mineral recovery and processing). Various aspects of flotation theory and practice have been treated in books and reviews (1 9). 

The concentration of lead in ore bodies of commercial interest generally ranges from 2 to 6% the average is 2.5%. Improvements in ore-dressing techniques have made possible the exploitation of deposits having lead contents even less than 2%. 

Lead is usually processed from ore to refined metal in four stages. These are ore dressing, smelting, drossing, and refining (see Mineral recovery and processing). 

Ore Dressing. The principal lead mineral, galena, in most cmde ores, is separated from the valueless components, or gangue. Other valuable minerals that are present in the ore may be recovered either together with the lead, or in a separate step (2,3). Occasionally, the ores are sufftciendy rich in lead and low in impurities to be smelted direcdy. 

Batch Percolators The batch tank is not unlike a big nutsche filter it is a large circiilar or rectangiilar tank with a false bottom. The solids to be leached are dumped into the tank to a uniform depth. They are sprayed with solvent until their solute content is reduced to an economic minimum and are then excavated. Countercurrent flow of the solvent through a series of tanks is common, with fresh solvent entering the tank containing most nearly exhausted material. In a typical ore-dressing operation the tanks are 53 by 20 by 5.5 m (175 by 67 by 18 ft) and extract about 8200 Mg (9000 U.S. tons) of ore on a 13-day cycle. Some tanks operate under pressure, to contain volatile solvents or increase the percolation rate. A series of pressure tanks operating with countercurrent solvent flow is called a diffusion battery. 

Typical applications include primary devv atering of phosphate rock matrix and silica sand products following vv et screening. In ore dressing it is used rnainlv to protect large-diameter thickeners bv scalping out-l-65-mesh material,... 

D-O SiphonSizerThe D-O SiphonSizer (Fig, 19-25) is a high-efficienev hvdraiilic classifier developed originally for the washing and sizing of phosphate rock. In ore-dressing work it is normally a two-prodiict unit but bv use of an upper column sealed at the top and... 

A lot of natural as well as technological objects of analytical control are colloidal systems, i.e. human blood, biological liquids, sol and suspension forming in different technological processes (ore-dressing, electrochemical deposition, catalysis and other), food, paint-and-lacquer materials, sewage water and other. 

A. F. Taggart, Elements of Ore Dressing, John Wiley, New York, 1951. 

Liquid-solid distributions are involved in ion-exchange and other adsorption-based separation processes, separation processes based on crystallization or precipitation, flotation processes for ore dressing, and smelting processes. 

The dynamics of such a mode of semi-fluidization is similar to that of jigging in ore dressing, which is a common operation in coal or ore dressing, though little used in the design of chemical reactors. Thus, at least on a periodic basis, jigging yields the same advantages as other modes of fluidization with no net fluid flow. 

The third potentially most hazardous kind of projects is trunk pipelines. There are trunk pipelines in Ukraine that are tens, hundreds, and even thousands of kilometers long, through which hundreds of thousand and million cubic meters of oil, gas condensate, gas, ammonia, toxic chemical waste, mineral ore-dressing waste, including radio-active one, are pumped over long distances. 

Richards, R.H. (1909). A Textbook of Ore Dressing. McGraw-Hill, New York. 

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