FIELD: metallurgy.
SUBSTANCE: group of inventions relates to a method for assessing the quality of coal used as a raw material for metallurgical coke, and to methods for preparing a coal mix using the values measured in the method for assessing the quality of coal, and also relates to a method for producing coke from the coal mix produced by the above method for preparing a coal mix. Method for assessing the quality of coal includes the following stages: preparing coal samples with different amounts of an inert component by grinding a single grade of coal; measuring the amount of the inert component of the corresponding coal samples and measuring the surface tension of the semi-coke produced by heat treatment of the corresponding coal samples; determining the surface tension γ100 corresponding to the 100% amount of the inert component, and the surface tension γ0 corresponding to the 0% amount of the inert component, using a regression line based on said amounts of the inert component and said surface tensions; and calculating the absolute value of the difference between the surface tension γ100 and the surface tension γ0; wherein the coal with an absolute difference value between γ100 and γ0 of 6 mN/m or more is not suitable as a raw material for coke, and coal with an absolute difference value between γ100 and γ0 of less than 6 mN/m is suitable as a raw material for coke. Method for preparing a coal mix containing at least two coal grades includes the following stages: determining the surface tension γ100 and the surface tension γ0 of each coal grade in the coal mix from the regression line determined by the above method for assessing the quality of coal, wherein the surface tension γ100 corresponds to the 100% amount of the inert component, the surface tension γ0 corresponds to the 0% amount of the inert component; determining the interphase tension of the coal mix based on said surface tension γ100, said surface tension γ0, the mixing ratio of each coal grade in the coal mix, and the mass fraction of the inert component and the mass fraction of the reactive component in each coal grade; determining the correlation between said interphase tension and the strength of coke produced from the coal mix; determining the interphase tension corresponding to the sought strength of coke based on said correlation; determining the mass fractions of said at least two coal grades so as to achieve the interphase tension corresponding to the sought strength of coke or a lower interphase tension; and preparing a coal mix by mixing said at least two coal grades in the above mass fractions.
EFFECT: development of methods for preparing a coal mix used to produce coke of the sought strength, and accurate determining of the mass fractions of these types of coal.
5 cl, 4 dwg, 5 tbl, 2 ex
