EP2103667A1

EP2103667A1 - Mixture of minerals and fluxes for obtaining metallurgical coke (variants)

Info

Publication number: EP2103667A1
Application number: EP07730439A
Authority: EP
Inventors: Boris Musokhranov
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-04-10
Filing date: 2007-04-10
Publication date: 2009-09-23
Also published as: WO2008122678A1; EP2103667A4; EA200801980A1; EA015018B1; AU2007350817A1

Abstract

The invention relates to coke chemical production, and more specifically it relates to compositions for producing metallurgical coke.

A charge for obtaining metallurgical coke, with an optimized proportion of components of regular coals of various ranks, containing:
(25 - 65) % b.w. fat or gas fat coals and (35 - 75) % b.w. low-coking caking coals; or
(25 - 65) % b.w. fat or gas fat coals and (35 - 75) % b.w. weak coking coals; or
(25 - 40) % b.w. fat coals, (35 - 60) % b.w. low-coking caking coals and (5 - 35)% b.w. weak coking coals; or
(30 - 55) % b.w. gas fat coals, (30 - 60) % b.w. low-coking caking coals and (5 - 20)% b.w. weak coking coals; or
(35 - 40) % b.w. fat coals, (5 - 15) % b.w. gas fat coals and (50 - 55)% b.w. low-coking caking coals; or
(10 - 30) % b.w. fat coals, (20 - 30) % b.w. gas fat coals, (20 - 60)% b.w. low-coking caking coals and (5 - 25) % b.w. weak coking coals.

Description

The invention relates to coke making production, and more specifically it relates to coal blends for metallurgical coke production.
Some typical features of coking coals are their high coking and caking properties characterized by the free swelling index (FSI) and a moderate volatile matter content or high vitrinite reflectance - R°, bringing about a high yield of coke. Initially, such coals were of the coking coal (CC) and "premium coking coal" (PCC). However, in our time, owing to the depletion of CC and PCC coking coal reserves, it has become highly pressing to use blends of different coking coals.
Various compositions are known of charge blends from coals of different ranks used for coke production. In most cases various additives such as coal pitch or tar, petroleum pitch or tar, crushed rubber and other additives have been added to these mixtures in order to improve their caking properties.
Thus, according to Russian Federation Patent No. 2124548 , Int. Cl. C 10 B 57/04, published on 10.01.1999, petroleum coke fines or breakage prepared by a specific technology are added to coals blends with a decreased content of a high plasticity coking coals.
The charge used in the method disclosed in Russian Federation Patent No. 2135543 , Int. Cl. C 10 B 53/08, C 10 B 57/08, published on 27.08.1999, containing the gas fat coking coal, fat coking coal, weak coking coal, and low-coking caking coal rank, uses an additive of phthalo-pitch-containing the refuse of the coke making production.
Furthermore, according to Russian Federation Patent No. 2186823 , Int. CI. C 10 B 57/06, C 10 B 53/08, published on 10.08.2002, an agent obtained from the refuse of the coke making production coated onto rubber crumbs derived from discarded rubber articles is added to the blend containing coals of various ranks - high volatile, middle volatile and low volatile coking coals, caking, weak-coking, coking and low-coking caking coals.
However, the use of all of these additives involves their special preparation and thus complicates the technology of preparing charge compositions. Moreover, it is widely known that pitches nowadays are almost entirely used by the electrode industry and are both in short supply and expensive. Petroleum products are likewise expensive starting materials. The use of rubber adds an extra amount of sulfur the coke content of which is subject to certain limitations.
The closest to the charge proposed in the present document by its coal composition is the charge for producing metallurgical coke (Russian Federation Patent No. 2224782 , Int. Cl. C 10 B 57/04, published on 27.02.2004) containing coals of ranks, % b.w.:

fat coals, 20 - 30;
gas fat coals, 15 - 20;
low-coking caking coals, 20 - 40;
weak caking coals;

A major shortcoming of the charge of this composition is the need to use a caking additive that complicates the production technology and steps up the cost of coal blend preparation.
An object of this invention is to obtain mixture compositions with an optimized proportion of the components of regular coals of different ranks, for the production of quality coke without the use of additives (which would have otherwise complicated the coal blends preparation technology and raised its cost), while expanding the initial material base for coal blend production.
This object is attained in that the following options of the blend composition are proposed:

a charge for metallurgical coke production, containing fat (F) or gas fat (GF) and low-coking caking (LCC) coals, with the coals taken in the following proportion of components, % b.w.:
- fat or gas fat coals, 25 - 65;
- low-coking caking coals, 35 - 75; or
a charge for metallurgical coke production, containing fat or gas fat coals, additionally containing weak coking (WC) coals, with the coals taken in the following proportion of components, % b.w.:
- fat or gas fat coals, 25 - 65;
- weak coking coals, 35 - 75; or
a charge for metallurgical coke production, containing fat and low-coking caking coals, additionally containing weak coking coals, with the coals taken in the following proportion of components, % b.w.:
- fat coals, 25 - 40;
- low-coking caking coals, 35 - 60;
- weak coking coals, 5 - 35; or
a charge for metallurgical coke production, containing gas fat and low-coking caking coals, additionally containing weak coking coals, with the coals taken in the following proportion of components, % b.w.:
- gas fat coals, 30 - 55;
- low-coking caking coals, 30 - 60;
- weak coking coals, 5 - 20; or
a charge for metallurgical coke production, containing fat, gas fat and low-coking caking coals, with the coals taken in the following proportion of components, % b.w.:
- fat coals, 35 -40;
- gas fat coals, 5 - 15;
- low-coking caking coals, 50 - 55; or
a charge for metallurgical coke production, containing fat, gas fat and low-coking caking coals, additionally containing weak coking coals, with the coals taken in the following proportion of components, % b.w.:
- fat coals, 10-30;
- gas fat coals, 20 - 30;
- low-coking caking coals, 20 - 60;
- weak coking coals, 5 - 25.

In the selection by trial of charge compositions with an optimized proportion of components, the capacity of coals of different ranks to enhance the coking properties of one another was used by way of searching for the optimized ratio of the free swelling index (FSI) and high vitrinite reflectance - R° as required for the output of quality coke. It has been established that the adequate quality for coke output would be offered by blends of coals of various ranks with an FSI index value from 5 to 7 and the R° value of 1.15% to 1.25% - these being the characteristics of coking and premium coking coals.
The quantitative proportions of the components in the composition versions have been chosen to meet the above requirements (see Table). To ensure more freedom of choice, the formulation of the proposed compositions was based on an approach of compensating for the properties of one component by its replacement with two other components.
The best coking plasticity is obtained with the two component mixture of F (fat) and LC (low-caking) coals, but the cost of the mixture is high and the maximum R° value is hard to attain.
A mixture of two coals - GF (gas fat) and LC (low-coking) - is less expensive, but the coking plasticity is poorer and the R° value is lower.
A mixture of three components - GF, LC and WC (weak coking) - brings about a high R° value; however, its coking plasticity is somewhat low, which narrows down the usability range of the obtained coke.
A mixture of three other components - F, LC and WC - produces a good coking plasticity and a high value of R°. It is, however, more expensive than the previous one.
A mixture of four components - GF, F, LC and WC - allows having adequate coking plasticity and R° values when the proportion of the components is varied correspondingly. However, the very process of mixture preparation becomes somewhat more complicated in this case.
On the other hand, the preparation of all of the above-disclosed types of mixtures does not involve any supplemental operations added to the coking technology at the coke making enterprises - unlike the other previously known and mentioned methods of charge preparation and mixture compositions. Thus, the herein disclosed compositions of mixtures for the coking process allow obtaining quality coke and significantly expanding the initial material base for charge production.

An example of coal blend preparation.

A mixture for the coking process is prepared from the raw coals of the FC (fat coal) rank produced at the Chertinskaya-Koksovaya Coal Mine and the raw coal of the WC (weak coking coal) rank obtained from the Novobachatski Coal Strip Mine. From the raw coal silos at the Belovskaya Central Coal Washery the regular coals are metered out layer-wise onto the blending conveyer belt in the proportion of 40% rank FC coal and 60% rank WC coal. This two-layer blend is fed from the conveyer belt for primary crushing to a size below 200 mm, and is subsequently taken through hydraulic classification where the size class below 0.5 mm is separated and forwarded for flotation. Meanwhile, the size class of 13 - 200 mm is taken for cleaning in dense-media separators, whereas the 0.5 - 13 mm class is fed for cleaning in jigging machines. The clean coals from the jigging machines and from flotation are taken together for drying. Following the drying, the clean coals are mixed on a blending belt conveyer with the clean coal from the dense-media separators, this clean coal (concentrate) having been dewatered on vibrating screens. The obtained blend of concentrates has the FC to WC rank ratio of 30:70 given the dressability of these ranks. The blend thus produced has a vitrinite reflectance 1.20%, a free swelling index 6, and a plastic layer thickness 17 mm, which makes it suitable for coking either by itself or in a mixture with other coals.

Other examples of the blend preparation carried out in a similar manner are shown in the Table below where quantitative values of the components are cited by the versions.

Table

Example No.	Blend Composition, %				Quality Parameter
Example No.	FC (fat)	LC (low-caking)	GF (gas fat)	WC (weak coking)	Free Swelling Index (FSI), units	Vitrinite Reflectance, R°, %
1	0	35	65	0	6	1.15
2	0	75	25	0	5	1.20

3	25	75	0	0	5	1.25
4	65	35	0	0	7	1.15

5	25	0	0	75	6	1.20
6	65	0	0	35	7	1.15

7	0	0	25	75	5	1.20
8	0	0	65	35	6	1.15

9	25	60	0	15	5	1.25
10	40	35	0	25	6	1.15
11	25	40	0	35	5	1.20
12	35	60	0	5	5	1.20

13	0	60	35	5	5	1.20
14	0	35	55	10	5.5	1.15
15	0	30	55	15	5.5	1.15
16	0	50	30	20	5	1.25

17	35	50	15	0	5.5	1.15
18	35	55	10	0	6	1.20
19	40	55	5	0	6.5	1.20

20	30	20	25	25	7	1.15
21	20	45	30	5	6	1.20
22	10	60	20	10	5	1.25

Claims

A charge for metallurgical coke production, containing fat or gas fat coals and low-coking caking coals, characterized in that the coals are introduced with the following proportion of components, % b.w.:
fat or gas fat coals, 25 - 65;

low-coking caking coals, 35 - 75.
A charge for producing metallurgical coke, containing or gas fat coals, characterized in that it additionally contains weak coking coals, with the following proportion of components, % b.w.:
fat or gas fat coals, 25 - 65;

weak coking coals, 35 - 75.
A charge for producing metallurgical coke, containing fat coals and low-coking caking coals, characterized in that it additionally contains weak coking coals, with the following proportion of components, % b.w.:
fat coals, 25 - 40;

low-coing caking coals, 35 - 60;

weak coking coals, 5 - 35.
A charge for producing metallurgical coke, containing gas fat coals and low-coking caking coals, characterized in that it additionally contains weak coking coals, with the following proportion of components, % b.w.:
gas fat coals, 30 - 55;

low-coking caking coals, 30 - 60;

weak coking coals, 5 - 20.
A charge for producing metallurgical coke, containing fat coals, gas fat coals and low-coking caking coals, characterized in that the components are introduced in the following proportion, % b.w.:
fat coals, 35 - 40;

gas fat coals, 5 - 15;

low-coking caking coals, 50 - 55.
A charge for producing metallurgical coke, containing fat coals, gas fat coals and low-coking caking coals, characterized in that it additionally contains weak coking coals, with the following proportion of components, % b.w.:
fat coals, 10 - 30;

gas fat coals, 20 - 30;

low-coking caking coals, 20 - 60;

weak coking coals, 5 - 25.