RU2602564C1 - Method of charge preparation in alumina production - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention can be used in non-ferrous metallurgy for burden material preparation during production of alumina from low-quality aluminosilicate raw material. Method of charge preparation involves grinding aluminosilicate material on soda solution in mill, pulp hydrocycloning as per 0.25 mm grade, removal of hydraulic cyclone sands with particle size of more than 0.25 mm from process, hydraulic cyclone drain with particle size less than 0.25 mm on milling into mill operating in closed cycle with hydraulic cyclone, return of hydraulic cyclone sands with particle size of more than 0.063 mm to re-grinding in mill, direction of discharge with size less than 0.063 mm, which is finished product, to metallurgical processing.

EFFECT: method provides reducing power consumption for grinding and increased efficiency of concentrating and metallurgical devices and, consequently, reduced losses of valuable mineral components with slurries during aluminium-containing ores processing.

1 cl, 1 dwg

Description

The invention relates to non-ferrous metallurgy and can be used to prepare the mixture in the production of alumina from low-quality aluminosilicate raw materials, for example low-quality bauxite ores.

A known method of producing high-alumina cement (patent RU No. 2225363, publ. 27.05.2008), which includes chemical precipitation of the calcareous component from a suspension of aluminate solution and lime, its joint grinding with alumina-containing material to obtain a raw mixture, its firing and fine grinding of the firing product clinker.

The disadvantages of this method are the use of material with a high aluminum content and the inapplicability of this method in the processing of low-quality aluminum-containing raw materials.

A known method of producing high-alumina cement (patent RU No. 2052407, publ. 20.01.1996), which includes the preparation of a raw mix by mixing calcium carbonate 24-26%, alumina 74-76% and additives, forming two-layer granules, firing, cooling, crushing obtained clinker and grinding, firing is carried out at 1300-1380 ° C.

The disadvantages of this method are the high firing temperature and the duration of the process.

A known method of processing alumina-containing raw materials into alumina (patent RU No. 2326817, publ. 20.06.2008). This method involves the preparation of a mixture of high-iron chamosite-containing bauxite, soda ash, calcium-containing compound, sintering of the mixture, grinding and leaching of the cake, the dosage of the calcium-containing compound is based on the molar ratio of CaO to the total content (FeO + MgO) of 2.4 bauxite chamosite equal to -2.85: 1.0, sodium sulfate is additionally added to the mixture in an amount based on the weight ratio of SO ₃ to the content of Fe ₂ O ₃ in bauxite equal to 0.20-0.30: 1.0.

The disadvantages are the high specific energy consumption due to the high sintering temperature of the raw material mixture and the difficulty of implementing the technology in a production environment.

A known method of processing bauxite into alumina (patent RU No. 2181695, publ. 04/27/2002), which includes grinding low-silicon and high-silicon bauxite, leaching it, thickening, washing red mud and feeding it into the dump, decomposition of aluminate solution, evaporation of the mother liquor with the allocation working soda and obtaining a working alkaline-aluminate solution, calcination of aluminum hydroxide.

The disadvantages of this method are the inability to process low-quality aluminum-containing raw materials, as well as the complexity of the implementation of the technological scheme.

A known method of preparing a mixture of alumina production (USSR author's certificate No. 1512002, publ. 20.01.1997), adopted as a prototype. It includes grinding aluminosilicate raw materials in a soda solution, hydrocyclone pulps in the 0.08 mm class at 30-60 ° C, sending a + 0.08 mm fraction for grinding with aluminosilicate raw materials, and -0.08 mm fractions for regrinding with limestone.

The disadvantages of the prototype are the inefficiency in the processing by the method of sintering bauxite with a high content of chamosite, which is difficult to react when sintering with soda, causing increased losses of valuable components - alumina and sodium oxide - with the leaching residue (red mud).

The technical result is a reduction in energy consumption for grinding and an increase in the productivity of concentration and metallurgical apparatuses and, accordingly, a decrease in the loss of valuable mineral components with sludge.

The technical result is achieved by the fact that the raw materials are crushed in a mill, then the crushed material is fed for hydrocyclone in the class of 0.25 mm, the sands of a hydrocyclone with a particle size of more than 0.25 mm are removed from the process, the discharge of a hydrocyclone with a particle size of less than 0.25 mm is sent to grinding in a mill, operating in a closed cycle with a hydrocyclone, the sands of a hydrocyclone with a particle size of more than 0.063 mm are returned to the mill for grinding, and the discharge with a particle size of less than 0.063 mm, being a finished product, goes to metallurgical processing.

The method of preparing the charge in alumina production is illustrated in FIG. 1 - flow chart of the preparation of the mixture in alumina production.

The implementation of the method is as follows (Fig. 1). After primary crushing in the jaw crusher at a 200 mm mine, the ore is sent to the ore preparation mill for crushing into the medium-size cone crusher, where coarseness is reduced to 100 m, after which the crushed material enters the fine crusher. After fine crushing, the ore with a particle size of less than 30 mm enters the rod mill. Grinding is carried out to a particle size of 5 mm, then the crushed product with a particle size of less than 5 mm is fed into a ball mill with a central discharge of the MSC. The crushed ore is sent to a hydrocyclone for classification. Sands of hydrocyclones with a particle size larger than 0.25 mm with a low silicon module and a high content of Fe ₂ O ₃ are removed from the process and can be used for subsequent enrichment to an acceptable level of iron content as a component of the raw Portland cement mixture. The discharge of the hydrocyclone is sent for grinding to a VERTIMILL mill operating in a closed cycle with a hydrocyclone. The hydrocyclone sands are sent for regrinding, and the discharge with a particle size of less than 0.063 mm is sent to the metallurgical redistribution. Due to selective staged grinding, the silicon module of the crushed product is increased to 5.93 compared to the initial value of 4.15.

The developed method allows you to bring a large class of +0.25 mm with a low silicon module from the redistribution, providing the finished product with the required size (-0.063 mm) and quality.

Claims (1)

A method of preparing a charge in an alumina production, including grinding aluminosilicate raw materials in a soda solution, pulp hydrocyclone and regrinding, characterized in that the raw material is ground in a mill, then the ground material is fed for hydrocyclone in 0.25 mm class, hydrocyclone sands larger than 0.25 mm withdraw from the process, the discharge of a hydrocyclone with a particle size of less than 0.25 mm is sent to grinding in a mill operating in a closed cycle with a hydrocyclone, the sands of a hydrocyclone with a particle size of more than 0.063 mm are returned to grinding into a mill, and discharge of fineness less than 0.063 mm, being a finished product, goes to metallurgical processing.

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