RU2473478C1 - Furnace charge for obtaining alumina cement - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to field of alumina cement production. Furnace charge for obtaining alumina cement, including bauxite, limestone, metal component, coke, contains manganous limestone with manganese content 6-15 wt % and metal component in form of scrap with the following ratio of furnace charge components, ground together to coarseness 1-3 mm, wt %: bauxite 45-52, coke 0.7-0.8, said scrap 5-10, said limestone - the remaining part.

EFFECT: providing possibility of applying limestone with higher content of admixtures, obtaining alumina cement with lower heat-release and stable strength at 28-day age.

1 ex

Description

The invention relates to the production of alumina cement.

A known mixture for producing high alumina cement containing components, wt.%: Lime 45-55 and alumina 45-55, a mixture of which is subjected to heating in an electric arc furnace, followed by the introduction of an additional 20-25 wt.% Alumina into the melt (A.S. 1300856, published July 4, 1984, C04B 7/32).

A known mixture for producing alumina cement containing ferrous bauxite, limestone, iron scrap and coke, during blast furnace smelting of which iron is formed, which accumulates in the lower part of the hearth, and the molten alumina slag - clinker of alumina cement located above it. (Volzhensky A.V., Burov Yu.S., Kolokolnikov B.C. Mineral binders. - M., 1973, p. 466-449).

The closest analogue is the mixture of producing alumina cement, including, wt.%: Bauxite 15-25, limestone 5-15, metal shavings 22-25, coke 28-30 and mine rock from the mining of bauxite 10-25, which form during blast furnace smelting Cast iron and alumina slag - clinker of alumina cement. (A.S. 1541265, publ. 02/07/1990).

The objective of the claimed invention is the provision of the possibility of using limestone with a high content of impurities, obtaining alumina cement with reduced heat and stable strength at 28 days of age.

This goal is achieved in that the mixture to obtain alumina cement, including bauxite, limestone, a metal component, coke, contains manganese limestone with a manganese content of 6-15 wt.% And a metal component in the form of scrap in the following ratio of the components of the mixture, co-crushed to size 1-3mm, wt.%:

Bauxite 45-52 Coke 0.7-0.8 Specified scrap 5-10 Indicated Limestone rest

In the final slag (clinker of alumina cement) containing a small amount of manganese oxides of 1.5-4.0 wt.%, The main components are oxides of aluminum, calcium. Studies of the physicochemical properties of the Al ₂ O ₃ -CaO slag system have established that the amount of CaO taken in a certain ratio to Al ₂ O ₃ reduces the viscosity of the melts.

The following materials were used.

Bauxite containing, wt.%: Al ₂ O ₃ 45-53, SiO ₂ 3-5, CaO 3,5-4,2, Fe ₂ O ₃ 18-25.

Limestone with a manganese content of 6-15 wt.%.

Coke containing, wt.%: Al ₂ O ₃ 25.0-30.0, SiO ₂ 43-50, CaO 14-16, Fe ₂ O ₃ 10-12.

Scrap metal with an iron content of at least 80 wt.%

The following are examples of the execution of the invention, not excluding others in the scope of the formula.

Example

The ratio between the components of the mixture is the following, wt.%: Bauxite 50, coke 0.8, scrap metal, crushed to a size of not more than 300 mm 10, limestone with a manganese content of 15 wt.% 39.2. Methodology for smelting experiments.

All constituent components of the mixture were first crushed to a fraction of 5 mm, then ground to a particle size of 1-3 mm, after which each component was weighed in accordance with the composition of the mixture, mixed in a mixer until a homogeneous mass was obtained. The melts were carried out by a blast furnace process at a temperature of 1500 ° С, then the melt was poured out - the molten iron was poured from the lower part, and then the remaining melt, alumina slag, was poured into the molds, after cooling it was milled, in this example to 3500 cm ² / g, and determined properties of the obtained alumina cement. Studies have shown: the content of manganese aluminate in it is up to 5 wt.%, Heat dissipation is 50 J / g, the strength for the grade 500 on the first day is 34 MPa, after 3 days 60 MPa, after 28 days there is no decrease in strength. Heat transfer of 70 J / g and a drop in strength after 28 days are common with known aluminous cements, compared with strength at 3 days of age.

Analysis of the experiments shows that the use of manganese limestone in the composition of the mixture with the stated ratio of the components improves the properties of the resulting alumina cement. The technology can be implemented at any of the existing plants or organized without major capital investments in a new place. The resulting products - alumina cement and cast iron, respectively, have the following properties: cement - a stable increase in strength and low heat, and cast iron - high manganese content.

Claims (1)

The mixture for producing alumina cement, including bauxite, limestone, a metal component, coke, characterized in that it contains manganese limestone with a manganese content of 6-15 wt.% And a metal component in the form of scrap in the following ratio of the components of the mixture, together crushed to a particle size of 1 -3 mm, wt.%:
Bauxite 45-52 Coke 0.7-0.8 Specified scrap 5-10 Indicated Limestone Rest