SU1731844A1 - Method for preparation of lime-containing burden for pelleting - Google Patents

Abstract

Usage: the invention relates to metallurgy and can be used in the agglomeration of metallurgical materials. The essence of the invention: the moisture content W of the charge before mixing it with lime is maintained depending on the maximum molecular moisture capacity (MMB) of this mixture and the mass fraction of quicklime Pu introduced into the mixture, within W MMW + (0.3-2.5) RI . This moisture level provides the amount of free water necessary for interacting with lime, which is not bound to the surface of the charge particles, which significantly reduces the duration of quenching, and does not reduce the strength of the raw lumps and aggregates obtained. The use of this method makes it possible to shorten the lime quenching time in the charge by 2–5 times, which reduces the operational and capital costs for the preparation. 2 tab. (L

Description

The invention relates to metallurgy and can be used in the agglomeration of metallurgical charges.

The purpose of the invention is to intensify the process without reducing the strength of the raw pieces.

In the proposed method, the components of the mixture, when there is a shortage of water, are moistened and mixed with a given amount of quicklime, while the humidity of the mixture supplied to the mixture with lime is maintained within

L / IIM + (0.3-2.5) RI,

where W is the humidity of the mixture to be mixed with lime,%;

The IMB is the maximum molecular moisture capacity of the mixture fed to mixing with lime,%;

Re is the mass of quicklime in the charge,%.

This moisture level provides the amount of free water required to react with lime, which is not bound to the surface of the charge particles, which significantly reduces the quenching time.

The prepared lime-containing mixture is held and, after slaking, lime is ground by known roasting and unburned methods,

Dry sludge from Kuznetsky blast furnace gas cleaning is used as charge.

H with

with

4 of the metallurgical plant (KMK), de-oiled scale of the Sinarsky Pipe Plant (STZ) and magnetite concentrate of the Kachkanar mining and enrichment plant. Tested two samples of lime of different activity with a particle size of 0-3 mm. Characteristics of the starting materials are given in table. one,

After dosing of the components, moistening and mixing, the charge of the charge is placed in a Dewar vessel with a volume of 0.5 l and, according to the indication of the thermometer, it is heated. The duration of the quenching is taken as the period from the start of mixing the wet mixture with lime until the maximum temperature of its heating is reduced due to the heat from the quenching of lime. Then briquettes are prepared from the charge with a pressing force of 500 daN / cm2 and their compressive strength is determined.

Example 1. In accordance with the gas cleaning slurry, KM K (100 g) is mixed with 10 g of lime (sample 1) and moistened with an amount of water 5 times higher than the theoretically necessary for slaking lime (13 g). Theoretically, for the slaking of 10 g of lime with a CaO 82% mass fraction, 2.6 g of water are needed. Duration of slaking 64 minutes, compressive strength of raw briquettes was equal to 12.0 daN / cm2.

Example 2. In accordance with the prototype scale, the STZ (100 g) is mixed with 10 g of lime (sample 1) and moistened with an amount of water 5 times higher than the theoretically needed for slaking lime (13 g). Duration of slaking is 49 min, compressive strength of raw briquettes is 9.0 daN / cm2.

Example 3. In accordance with the prototype, magnetite concentrate (100 g) is mixed with 5 g of lime (sample 2) and moistened with an amount of water 5 times higher than the theoretically necessary for slaking lime (6.5 g). Duration of slaking 30 minutes, compressive strength of raw briquettes

4.2 daN / cm

Example 4. Magnetite concentrate (100 t) is moistened with 8 g of water and mixed with 5 g of lime (sample 2). The excess water above the MMB of the charge (7.5%), related to the amount of lime (M value), is 0.1. Duration of quenching is 29 minutes, i.e. close to prototype. The compressive strength of raw briquettes 4.0 daN / cm2.

Example 5. In accordance with the method, the magnetite concentrate (100 g) is moistened with 9 g of water and mixed with 5 g of lime (sample 2). The value of M is 0.3. The duration of the slaking reduced to 19 minutes

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five

The compressive strength of raw briquettes is 4.3 daN / cm2.

Example 6. In accordance with the method, the magnetite concentrate (100 g) is moistened with 14 g of water and mixed with 5 g of lime (sample 2). The value of M is 1.3. Duration of slaking was 8 minutes. The compressive strength of raw briquettes is 4.5 daN / cm2.

Example 7. In accordance with the method, the magnetite concentrate (100 g) is moistened with 20 g of water and mixed with 5 g of lime (sample 2). The value of M was 2.5. Duration of quenching is 6 minutes. The compressive strength of raw briquettes 4.0 daN / cm2.

Example 8. A magnetite concentrate (100 g) is moistened with 26 g of water and mixed with 5 g of lime (sample 2). The value of M is 3.7. Duration of quenching is 6 minutes, the compressive strength of raw briquettes due to high humidity decreased to 3.1 daN / cm2, i.e. turned out to be lower compared to the prototype.

Example 9. In accordance with the method, gas cleaning sludge KM K (100 g) moistened with 35 g of water and mixed with 10 g of lime (sample 1). The value of M is equal to 0.8. Duration: 34 min. The compressive strength of raw briquettes is 13.5 daN / cm2.

Example 10. In accordance with the SCZ scale method (100 g), wet 17 g of water and mix with 10 g of lime (sample 1). The value of M is 0.4. Duration of quenching is 25 minutes, the strength of raw briquettes is 11.6 daN / cm2.

The test results are shown in table 2.

Thus, the method makes it possible to shorten the lime quenching time in the charge by 2-5 times, which reduces the operational and capital costs during the preparation.

Claims (1)

Invention Formula The method of preparing lime-containing mixture for agglomeration, including wetting, mixing with lime and lime quenching in the charge, characterized in that, in order to intensify the process without reducing the strength of the raw pieces, the components of the charge are moistened before mixing them with lime, while maintaining their moisture content W within W MMB + (0.3-2.5) Pn, where MMB is the maximum molecular moisture capacity of the mixture fed to mixing with lime,%; Ri is a massive amount of quicklime in the charge,%. Table 1 Prototype Slurry Gas-27.0 Purification Used bystrogeses sche with lime (sample 2) Editor M. Jankovic Compiled by L. Pannikova Tehred M. MorgentalKorrektor T. Paliy 6lit2 ten 6.5 61. 66 12.0