RU2360943C1 - Method of preparing coal charge to coking - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: coal is mixed with water and sintering additive in disperser, whereupon it is dehydrated. As coal there are used coal slimes which are enriched by the method of oil agglomeration to ash content 4.0-7.6% wt and sulphur content 0.2-0.3% wt by means of a sintering additive at rate of mixing 1000-1500 rev/min. Produced coal-oil concentrates of dimension 2-3 mm are separated on a sieve, mixed with other grades of enriched coal-oil concentrates and are subject to coking.

EFFECT: upgraded quality of source coal charge, reduced contents of ash and sulphur in source charge and increased strength of coke.

3 cl, 2 tbl, 2 ex

Description

The invention relates to the production of coke, and in particular to a technology for preparing a coal charge for coking.

The known method [A.S. USSR No. 998493 dated 02.20.81, class С10В 57/12], consisting of fatty coke, gas, and sintering coals, including separate crushing of coals, applying fuel oil to fat coal, and mixing coal; Before applying fuel oil from the heavy coal, fine fractions of 0.0-0.5 mm are isolated and small fractions are introduced into the coal charge after mixing the coals.

The disadvantage of this method is the complexity, multi-stage process, as well as the creation of a certain temperature regime.

The closest to the achieved effect is the prototype [A.S. USSR No. 289117 from 08.25.67, class C10b 57/12], which describes a method of treating a coal charge, which consists in the fact that coal together with water and a sintering organic additive in the amount of 4-7% of coal are mixed in a dispersant at a temperature of 4 -70 ° C for 5-10 minutes, followed by cooling and dehydration.

However, the known method has the following disadvantages:

1) increased ash content of the charge A ^d to 28.7% (wt.) And, accordingly, an increase in the ash content of coke to 12.08%;

2) a high sulfur content S ^d = 0.68%;

3) when preparing the charge for coking, the coal is first crushed and the fraction of 0-3 mm is screened out;

4) the obtained coke has a strength of M40 - 78.6%;

5) the separation of moisture from the mixture occurs in a centrifuge.

The objective of the invention is to improve the quality of the initial coal charge, reducing the ash and sulfur content in the initial charge, as well as increasing the strength of coke.

To do this, in the process of preparation of the charge is not used source coal of various grades, but coal sludge - waste from the primary processing of coal.

However, all coal sludges in the dumps have a high ash content of 18.5 to 34.5% (wt.) And a high sulfur content of 0.58-0.60% (wt.), Which negatively affects the coking process. Therefore, for the enrichment of coal sludge, the method of oil sintering was chosen.

The problem is achieved in that the coal-water slurry from hydraulic dumps is placed in a granulator and then a sintering additive is added in an amount of 10-15% (wt.) Of the solid content. After mixing at a stirrer speed of 1000-1500 rpm in the aqueous medium, oil-oil concentrates of 2-3 mm in size are formed, which are separated from the water on a sieve. The obtained coal oil concentrates have an ash content of 4.0-7.6% (wt.), The sulfur content is 0.2-0.3% (wt.). The moisture content in the concentrates is 8-10% (wt.), Which is acceptable for the further coking process, therefore, the obtained coal-oil concentrates do not require additional drying.

Fuel oil, gas oil, and used engine oil are used as sintering additives. Waste engine oil contains a sufficiently large amount of metal chips, thereby it is utilized and metal chips are returned to metallurgical production.

The increase in consumption of sintering additives up to 10-15% (wt.) Compared with the prototype (4-7% wt.) Due to the fineness of the original sludge (particle size less than 1 mm). An increase in the total surface of coal particles with apolar properties requires an increase in the consumption of sintering additive, which covers the surface of the coal and thereby separates it from waste rock (tailings). In this case, the degree of coal extraction from the sludge is 80-85% (wt.).

The increase in the consumption of sintering additives more than 15% (wt.) Of the amount of sludge is impractical, because leads to excess binder. At the same time, the obtained coal-oil concentrates 2-3 mm in size begin to stick together, forming large agglomerates.

Reducing the consumption of sintering additive less than 10% (wt.) Of the amount of sludge leads to incomplete oiling (wetting) of the surface of the coal particles and, accordingly, to a decrease in the degree of extraction of coal particles.

Limit values for sludge content in water depend on two factors. Firstly, the concentration of coal sludge in sedimentation tanks and sludge collectors is 100-150 g / l (10-15% wt.). This is a ready-made coal suspension, which is subjected to granulation. Secondly, coal slurry in the dumps is in a dry state. The concentration of sludge in the aqueous suspension should not exceed 20% (wt.), Because this worsens the process of extracting coal particles from the sludge, increases the ash content and size of coal-oil concentrates. A decrease in the concentration of the suspension of less than 10% (wt.) Increases the time of enrichment and reduces the efficiency of extraction of coal from the sludge.

The mixing speed of the suspension is 1000-1500 rpm An increase in the mixing speed of more than 1500 rpm leads to the formation of coal-oil concentrates of 1-2 mm in size. A decrease in the number of revolutions of less than 1000 rpm contributes to an increase in the size of the coal-oil granules to 3-4 mm, which is undesirable, since the optimal size of the charge should be within 2-3 mm.

The oil-oil concentrates separated from the aqueous medium are a finished mixture, which is subjected to coking individually or in a mixture with other brands of mixtures, for example, a mixture consisting of 50% (wt.) Concentrates of grade K, 25% (wt.) Of concentrates of grade G and 25% ( wt.) concentrates of grade J. A mixture of a mixture of different grades of coal makes it possible to involve slightly coking coals in the coking process.

EXAMPLE 1

1 kg of the initial aqueous suspension containing 15% (wt.) Of coal slurry of grade K with ash content A ^d = 34.5% (wt.) And sulfur content S ^d = 0.6% (wt.) Is taken from the hydraulic dump. Then add 10% (wt.) Fuel oil M-100 and mix for 7 minutes at a speed of 1000 rpm In this case, coal-oil concentrates 2-3 mm in size are formed, which are separated on a sieve. The resulting concentrates having an ash content of A ^d = 4.0% (wt.), A sulfur content of S ^d = 0.25% (wt.) And a moisture content of 10.0% (wt.) Were coked. The results of the coking of the charge are presented in table.2.

EXAMPLE 2

To 800 g of water add 200 g of dry coal sludge grade SS, having an ash content of A ^d = 18.5% (wt.) And sulfur content S ^d = 0.58% (wt.). The resulting suspension is stirred for 1-2 minutes and gas oil is added in an amount of 15% (wt.) Of the solid content. Then the three-phase system is stirred for 8 minutes at a speed of 1500 rpm until the formation of coal-oil concentrates, which are separated on a sieve. The resulting concentrates have an ash content of A ^d = 6.5% (wt.), A sulfur content of S ^d = 0.23% (wt.) And a moisture content of 8.35% (wt.). The resulting batch of CC grade is mixed with a batch of grade K in a ratio of 0.2: 0.8 (wt.) And coked. The characteristics of the obtained coke are presented in table.2.

Examples of limiting and transcendental values for the stage of coal sludge enrichment are summarized in table 1, for the stage of coking of the obtained mixture are presented in table 2.

Claims (3)

1. A method of preparing a coal charge for coking, comprising mixing coal with water and a sintering additive in a dispersant followed by dehydration, characterized in that coal sludges are used as coal, which are enriched by oil sintering to an ash content of 4.0-7.6 wt. % and sulfur content of 0.2-0.3 wt.% using a sintering additive with a stirring speed of 1000-1500 rpm, after which the formed oil-oil concentrates of 2-3 mm in size are separated on a sieve, mixed with other brands of enriched coal-oil concentrates and suspensions gayut coking. 2. The method according to claim 1, characterized in that fuel oil, used engine oil, gas oil in the amount of 10-15 wt.% By weight of coal sludge are used as sintering additive. 3. The method according to claim 1 or 2, characterized in that the concentration of sludge in the aqueous medium is 10-20 wt.%.