SU1411312A1 - Method of producing lime in shaft furnace - Google Patents

Abstract

The invention relates to the building materials industry and the ferrous metallurgy, mainly to the production of lime in a shaft furnace. The aim of the invention is to improve the quality of lime by increasing its degree of burning and activity. A mixture of limestone with steel curved chips in the amount of 0.10 - 0.45 of the feed mass of limestone or an additive containing 8-24 wt.% Of aluminum oxide in the amount of 10-55 g per 1 m of combustion products is loaded into the shaft furnace. The degree of roasting 84.2 - 98.7%, content. free lime is 66.2 - 84.8%. 4 tab. S (l

Description

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The invention relates to the production of building materials and ferrous metallurgy, mainly to the production of lime in a shaft furnace,

The purpose of the invention is to improve the quality of lime by increasing its degree of burning and activity.

The method is carried out as follows .10

A mixture of limestone and steel-curved shavings is loaded into the experimental shaft furnace with a reaction volume of 0.0375 m. In all experiments, the masses of the loaded limestone 15 were 31 kg, the sizes of the limestone pieces were 20–40 mm. The amount of chips in the experiments varies from 0.05 to 0.50 (0.05; 0.10; 0.25; 0.45; 0.50), i.e. at a relative flow rate of 20 chips, 0.05 its weight is 1.55 kg, at 0.01 - 3.10 kg, at 0.25 - 7.75 kg, at 0.45 - 13.95 kg, and at 0 , 50 - 15.50 kg.

The displacement with limestone 25 chips are crushed, providing the length of its turns within 5-20 mm, and the diameters of the turns of crushed chips are 4 -.9 mm.

An additional pulverized additive, 30 also supplied to the combustion zone of the fuel, was obtained by mixing the bauxite dust (with a content of 47.3%) with lime dust.

These granulometric compositions - “converter, lime and bauxite dust are given in table. one.

Calcination is carried out by natural gas combustion products previously obtained in a remote combustion chamber Q, which are fed to the layer of limestone with a temperature of 1245 - 1285 s. Consumption of natural gas 4.2, roasting time 3 hdds

A mixture of converter dust and powdered lime is used as an iron-containing dust additive. The total content of iron oxides in the converter unit (FeO +) is 84%.

The particle size distribution of the converter and lime dust is given in Table. 2

Amount of iron oxides in dust,. a prominent additive after mixing converter and lime dust of 52%. Dust additive is introduced into the combustion zone in the amount of 25, 145 and

141131.22

265 g / m of combustion products, t, e. with

taking into account the lower and upper limits of the consumption of the additive, as well as at its average consumption by the recommended cost range in the known mode.

The firing quality is estimated by the degree of firing and the content of free lime in the finished product, as well as by the activity of the obtained lime, which is determined by the growth of the reaction mixture during the first 5 seconds and the time to lime.

The results of burning lime by the products of combustion of natural gas with an iron-containing dust-like additive in an experimental shaft furnace with different amounts of steel chips loaded together with lime are given in Table. Sv

The results of the test of calcination of the lime with an iron-containing pulverized additive with a different amount of alumina containing additional pulverized additive are given in Table. four.

As can be seen from the table. 3 and 4, when the amount of additional dust additive is less than 10 g / m of its products, in particular at 5 g / m, as well as when the amount of dust is 55 g / m, namely at 60 g / m, the quality of the finished product practically remains at the level of roasting without additional dust additive. At the same time, in the mode with the consumption of an additional dusty additive of 60 g / m of combustion products, when unloading the charge from the furnace after firing, a local accumulation of dust-like additive is observed in the near-wall areas of the burning layer.

In the entire range of consumption of the pulverized additive, the quality of lime obtained by calcining lime with steel chips is higher than without it. At the same time, in all tested modes there are no signs of sticking of the particles of the calcined product and the local accumulation of dust-like additive.

Claims (1)

Invention Formula A method of producing lime in a shaft furnace by burning fuel in a remote firebox and heat treating the limestone with its combustion products with an iron-containing fluid additive, characterized in that. taking into account the lower and upper limits of consumption of the additive, as well as at its average consumption at the recommended cost range in the conventional method. The quality of calcination is assessed by the degree of calcination and the content of free lime in the finished product, as well as by the activity of the obtained lime, which is determined by the growth of the reaction mixture during the first 5 seconds and the lime slaking time. The test results of lime burning by the products of combustion of natural gas with an iron-containing dust-like additive in an experimental shaft furnace with various amounts of steel chips loaded together with lime are given in Table. Sv The test results of calcining a lime with an iron-containing pulverized additive with a different amount of alumina containing additional pulverized additive are given in Table. four. As can be seen from the table. 3 and 4, when the amount of additional dust additive is less than 10 g / m of its products, in particular at 5 g / m, as well as when the amount of dust is 55 g / m, namely at 60 g / m, the quality of the finished product practically remains at the level of roasting without additional dust additive. At the same time, in the mode with the consumption of an additional dusty additive of 60 g / m of combustion products, when unloading the charge from the furnace after firing, a local accumulation of dust-like additive is observed in the near-wall areas of the burning layer. In the entire range of consumption of the pulverized additive, the quality of lime obtained by calcining lime with steel chips is higher than without it. At the same time, in all tested modes there are no signs of sticking of the particles of the calcined product and the local accumulation of dust-like additive. Invention Formula A method of producing lime in a shaft furnace by burning fuel in a remote firebox and heat treating the limestone with its combustion products with an iron-containing fluid additive, characterized in that. 3Un3t24 that, in order to improve the quality of 0.10 - 0.45 of the loaded limestone mass by increasing its degree or additive containing 8 - burning and activity, an additional 24 wt.% of apyumini oxide in the amount of steel chips are added in an amount of 10%. - 55 g per 1 m of combustion products. Table 1 Dust The particle size distribution of dust,%, with the size of particles, microns Less than 50 Converter Izvestkova Bauxite Dust Particle size distribution of Piti,%, with the size of dust particles; um Less than 50 Converter 28.2 Izvestkova 100 - 250 50 - 100 100 - 250 250 - 500 19.1 64.1 28.3 3.2 18.1 19.7 table 2 E: 50 - 100 100 - 250 250 - 500 49.5 10.1 3.2 17,8 64.1 18.1 Table 3 The degree of roasting,%. 92.5 Content of free lime (CaO),% 77.5 Continuation of table 3 92.5 94.7. 97.8 96J 92.9 77.5 79.5 84.0 81.9 77.8 The growth of the temperature of the reaction mixture for the first 5 with lime slag. Time to extinguish, min 2.42 Continuation of table 4 27 32 29 25 2.42 2.00 1.58 1.83 2.33