SU1534003A1 - Method of melting normal electric corundum - Google Patents

Abstract

The invention relates to abrasive production, in particular the production of normal electrocorundum. The aim of the invention is to reduce the specific energy consumption. At the beginning of the smelting, it is proposed to mix 50–70% of the reducing agent required for smelting into 4-8 mm fractions with agglomerate, and after melting the top of the furnace, to load the rest of the reducing fraction not more than 4 mm. By reducing the rate of melt expansion during the fractional separation of the reducing agent, the electric melting mode is stabilized, the working time with the open top and the loss of slagging materials are reduced, which ensures a reduction in the specific energy consumption. 1 tab.

Description

one

{21) 4384599 / 31-02

(22) 02.25.8Е

(46) 07.01.90. Bul IP 1

(71) Leningrad Institute of Technology. Lensoveta

(72) A.A. Iedro, V.V. Rdbotnov, A.S. Tatishchev, N.M. Burkov, A. B.Oc-.j-O-Gori and V.A. Pisarev

(53) 661.862.222 (088.8)

(56) USSR Author's Certificate No. 516642, cl. C 01 F 7/38, 1974.

Polubelova A.S., Krylov V.I. and others. Production of abrasive materials. - L .: Mechanical Engineering, 19b6, p. 43.

(54) METHOD OF MELTING NORMAL ELECTRIC CORRAND

(57) The invention relates to abrasive production, in particular, to the production of normal electrocorundum. The aim of the invention is to reduce the specific energy consumption. At the beginning of smelting, together with the agglomerate, it is proposed to load 50-70% of the reducing agent, which is not melted, of a fraction of 4–8 mm, and after the top melt is melted, the rest of the recovery of PHTHJ i fraction is not more than 4 mm. - no melt npi. Fractional separation of reducing agents stabilizes the electric melting mode, reduces the operating time with an open top and loss of mothering: slagging, which ensures a reduction in the specific power consumption. Table I

about

This invention relates to abrasive production, in particular, to the production of normal alumina.

The purpose of the invention is to reduce specific energy consumption.

The carbonaceous reducing agent is divided into two fractions of 4-8 mm and not more than 4 mm. First, 50-70% of the reducing agent of the total consumption is charged to the furnace in a fraction of 4-8 mm, and after the top melt is melted, the rest of the reducing agent is charged with a fraction of not more than 4 mm. The proposed method of loading the reducing agent reduces the operating time of the open-top furnace and thereby reduces heat loss during melt adjustment. The fact that not all of the reducing agent is loaded at the beginning of smelting allows the mixture to melt faster, and the temperature of the underestored melt (1800-I900 ° C) resulting from this is lower than the temperature of the melt obtained by loading the entire reducing agent at once.

In shaft furnaces, which also include furnaces for obtaining normal electrocorundum, in order to maintain good hydrodynamics of the charge layer, it is recommended that the maximum size of the loaded pieces be no more than two minimum. Therefore, when first loaded, the reducing agent has a size of 4 - 8 mm,

Since during the second loading the agent gets into the liquid bath, in this case the particle size distribution

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with

its composition does not matter. On the contrary, a smaller reducing agent, having a large relative surface, reacts more intensively with the melt, i.e. the process of recovery of impurities from the melt goes faster. As a result, the content of A1.05 in the melt increases and its viscosity increases. This leads to the fact that until the entire charge loaded in the furnace is completely melted, it still works for some time with the closed furnace, also reduces heat loss from the furnace. After completion of the process of impurity reduction, the final melting of the top furnace occurs, the melt overheats and is released from the furnace.

Loading into the furnace at the beginning of the melting of the fine fraction of the reducing agent (no more than 4 mm), which has a greater relative surface than the larger (4-8 mm), leads to an excessive intensive recovery of impurities in the sinter and melt boiling. This causes slagging of the upper layers of the charge, deterioration of its convergence and gas permeability. That is why, according to a known method, when the entire reducing agent containing a larger amount of the fine fraction is loaded at once, the first 0.5-1.0 hours from the start of smelting must be operated at reduced power.

Testing the proposed method and determining the optimal costs of the reducing agent in both parts of the melt is carried out on open furnaces with a capacity of 10.5 MVD with three self-burning electrodes. A bauxite agglomerate is used as one of the charge components, having a composition, wt.%: A1403 not less than 62; SiOi not more than 4; CaO not more than 0.15; ppt 0.9,

The second component of the mixture is anthracite (having a composition, wt.%: The ash content is not more than 6.3; total sulfur is not more than 1.4; CaO is not more than 0.4; total moisture is not more than 6.0,

After the end of the previous melting and discharge of the melt, a new bath is built up. Melting is conducted at the highest stage (228 V) and a current of 25.0 - 27.0 kA. The bath deposition lasts about half of the entire melting and ends

five

0

five

with full melting of the top furnace, i.e. with the appearance of an open melt mirror. With full penetration of the top furnace while maintaining the same power consumption, the transformer switches to a lower voltage of 203 or 182.5 V. In this mode, the melt is refined or refined. In this period only correction load is usually carried out. agglomerate ..

Melting 1 is carried out by a known method, i.e. initially, the entire reducing agent and part of the sinter required for smelting are loaded. The rest of the agglomerate required for smelting is reloaded as the previously loaded charge is charged. The grain size of the loaded reductant is within a maximum of 8 mm.

Melting 2-6 carried out by the proposed method. Consumption of the reducing agent and the results of melting are presented in the table.

Claims (1)

With the consumption of the reducing agent fraction 4–8 mm less than 50%, after loading the small part in the second stage of melting, an intensive boiling of the top furnace with slagging of the furnace is recorded, which leads to the loss of charge materials. At a consumption of a large fraction of more than 70%, a steady decrease in the specific energy consumption is not fixed, Formula the invention The method of smelting normal elskorundu, including smelting 51534003 agglomerated bauxite in the presence of a pre-divided of carbonaceous reducing agent into two fractions of 4-8 mm and no more fractions no more than 8 mm in ore-term-4 mm and at the beginning a 50 kiln furnace is loaded into the furnace with a periodic distribution of reducing agent No. of the total wastage of corundum and ferroalloy, Yes, smelting by a fraction of 4-8 mm the melting of the top furnace is an ostat with the aim of reducing the specific consumption of the reducing agent, not a fraction of boelectric energy, carbon less than 4 mm.