A Study On The Characteristics Of The Minerals In Coal And Their Effects On Structures And Properties Of The Coke

In this paper, coking experiments of different ranks of coal were carried out, and the characteristics of minerals in different ranks of coal and their structural and morphological changes during the process of coking were studied. And on this basis, the effects of different minerals on coke’s structure and properties that refined by different ranks of coal were analyzed. The main concents and results showed that:(1) The main mineral elements with higher content in the gas coal, fat coal, coking coal, lean coal and 1/3 coking coal are silicon, aluminum, titanium, iron and calcium, while the elements with less content are potassium, sodium, strontium, magnesium, phosphorus and zinc. And the main minerals in coal are clay(kaolinite, illite), quartz, hematite, titanium dioxide and so on. The clay minerals changed significantly in the process of coking, some of the amorphous phases of kaolinite and illite were converted to crystalline phases of mullite. However, as inert mineral, the structure of the quartz did not change obviously during the process of coking.(2) The refining coke’s MSI and SSI reduced after adding different minerals to one single kind of coal. Adding or adsorpting the same mineral to four kinds of coal, the order of coke’s PRI was that coking coal coke<fat coal coke<1/3coking coal coke<gas coal coke, while the order of coke’s PSR was opposite, which was the same with the those without minerals. Boric acid had negative catalytic effect after adding minerals through two different ways, the coke solution loss reaction was represses, coke’s PRI was reduced, and coke’s PSR was increased. Sodium chloride, ferric chloride, aluminium chloride and calcium chloride had positive catalytic effects, that accelerated the coke solution loss reaction, increased the coke’s PRI and reduced coke’s PSR.(3) Adding two different valence states of iron salt(ferric chloride, ferrous chloride) to coking coal before coking, the refining coke’s MSI and SSI reduced, coke’s PRI increased. And the degree of the reduce or increase of refining coke’s MSI, SSI and PRI increased with the increase of the adding amount of ferric chloride and ferrous chloride. However, the effect of ferric chloride to coke’s MSI, SSI and PRI was larger than ferrous chloride.(4) Adding different minerals to coal before coking, the sum of isotropy organizations, fine particle inlay, fusain and fragment(I+Mf+FF) of refining coke increased, the sum of anisotropy index(OTI) decreased, and the anisotropy of coke decreased. Adding the same mineral to four kinds of coal, the I+Mf+FF of four kinds of refining coke presentd the order that gas coal coke>1/3coking coal coke>fat coal coke>coking coal coke, while for the OTI of four kinds of refining coke, the order was that fat coal coke>coking coal coke>1/3coking coal coke> gas coal coke, except boric acid.(5) Deashing had little effect on the caking property of coal. Adding different minerals to deashed coal before coking, the sum of isotropy organizations, fine particle inlay, fusain and fragment(I+Mf+FF) of refining coke increased, while the sum of anisotropy index(OTI) decreased. For one same mineral, the degree of the increase of refining coke’s I+Mf+FF and the decrease of refining coke’s OTI increased with the increase of the adding amount. The surface of refining coke became "rough", while the surface pores of refining coke became lager and coke quality became poorer. Adding minerals also made coke’s microcrystalline structure change, the Lc, which is coke’s microcrystalline height became smaller, the d002, which is coke’s microcrystalline layer spacing increased. And most of minerals added to the coal made La, which is coke’s microcrystalline middle piece diameter increase.