Assessing the technological value of coal in coking

Coking coal of the same rank from different countries and fields may be distinguished in terms of use value by rating on the basis of seven technological and petrographic characteristics that determine the coke yield and properties: the ash content A^d; the total sulfur content S_t^d; the yield of volatiles V^daf; the plastic-layer thickness y; the vitrinite reflection coefficient R_o; the content of vitrinite-group macerals Vt; and the basicity index B_b. A range of values and a rating (on a scale from 1 to 10) are established for each of these parameters. Each rating corresponds to a particular score (from 0.1 to 1.0). Ranges of A^d, S_t^d, Vt, and B_b are established for the whole metamorphic series, while ranges of V^daf, y, and R_o are established for individual ranks and groups of ranks. Altogether, 105 coking coals from Ukraine, Russia, the United States, Australia, and Canada that are used at Ukrainian coke plants are investigated. The range of rating scores and their mean values are determined for individual coal ranks and groups. As an example, three bituminous coals from Ukraine, the United States, and Australia are compared by the proposed method. This method permits objective assessment of the technological value of coal within a single rank and the selection of the best purchase option.     

Determining the coking properties and technological value of coal and coal mixtures

A method is developed for determining the coking properties and technological value of coal from newly identified beds or new sections of existing mines. The coking properties are assessed on the basis of predictions of the strength and reactivity of coke obtained from batch containing coal from single beds and coal blends. The prediction of coke quality is based on the chemical and petrographic characteristics of the coal.     

Influence of the elementary composition of Kuznetsk Basin coal on the yield of coking products

The yield of coking products from Kuznetsk Basin coal concentrates is investigated as a function of their elementary composition. The yield of coking products (coke, coal tar, and raw benzene) is plotted against the content of the main elements in the coal’s organic mass (carbon and hydrogen). The basic laws governing the yield of those coking products are established.     

Similarities of Chinese smoked coal and Kuznetsk Basin lean coal

Chinese smoked coal is investigated. It is related to high-metamorphic lean coal. An analogous Kuznetsk Basin coal is T coal from the Krasnogorsk mine in the Tom-Usinsk region. In view of its composition and properties, such Chinese coal may be regarded as a satisfactory source of carbon for many metallurgical processes.     

Utilization of naturally oxidized Kuznetsk Basin coal

The possibility of producing humic materials and sorbents from naturally oxidized coal found in the stripped rock from some Kuznetsk Basin mines is considered. Means of producing ballast-free humic acids are considered.     

Carbon sorbents based on oxidized Kuznetsk Basin coal

Some physicochemical properties of carbon adsorbents produced by chemical activation with alkali are determined: specifically, their total ash content, the content of water-soluble ash, the total iron content (recalculated for Fe³⁺), and the content of water-soluble iron compounds. Their content of water-soluble ash and the total iron content are minimal; no water-soluble iron compounds are observed in the sorbents. However, the total ash content in the sorbents is impermissibly high. With increase in potassium content in the initial content, the total ash content of the sorbents is reduced to 16.5%.     

Technological value of coal used for coking

The technological value of coal used for coking is analyzed, with particular attention to clinkering coal, the coke group, and lean additives, as well as G and GZhO coal. A relation is established between the technological value of the coal components and their permissible content in coking batch so as to produce coke of constant strength (M ₂₅ = 87%). The precision in determining the technological value of coal is assessed.     

Technological value of coal concentrates for coking

Options are outlined for calculating the technological value of coal and coal concentrates in the context of contractual obligations and the quality of the coke produced.     

Assessing the value of coking coal in terms of coking properties and genetic compatibility

On the basis of new research by the Sapozhnikov method (State Standard GOST 1186), as well as data on the yield of volatiles (State Standard GOST 6382) and the petrological characteristics, new definitions are proposed in assessing the clinkering and coking of coal for bed coking. Under that proposal, clinkering properties and coking properties would refer exclusively to samples of individual coals; clinkering ability and coking ability would apply to coal blends and coal batch. As is shown, data for the petrographic composition and vitrinite reflection coefficient permit assessment of the genetic compatibility of coal, which may be used as a behavioral characteristic of coal in batch for blast-furnace coke production.     

山西省炼焦精煤的内在价值分析

从煤—焦—钢产业链出发,阐述了目前高炉技术发展对焦炭质量指标要求的变化以及高质量焦炭对炼焦过程经济性的影响;对山西省主要炼焦精煤品种的特性进行了重点分析,提出炼焦煤的定价机制亟需改进,优质炼焦精煤的定价原则不仅应体现优质优价,还应充分考虑其资源的稀缺性。     

炼焦煤焦化特性评价指标探讨

介绍了奥亚膨胀度、基氏流动度、罗加指数、胶质层指数、黏结指数和镜质组平均最大反射率等冶金煤焦化特性评价指标的建立和测试方法,以及各评价指标在我国的应用情况。同时讨论了各个指标对胶质体的原生黏结性、膨胀程度引起的黏着性和焦炭残留物强度这3个焦化特性的表征。     

Oxidized coal in coking: A review

A literature review shows that the oxidation of coal changes its granulometric composition, packing density, moisture content, and clinkering properties, the quality of the resulting coke, and the yield of coking byproducts. On account of the increased proportion of oxidized coal in coking batch, research is expedient in order to formulate recommendations regarding its use.     

Petrographic Characteristics of Kuznetsk Basin Gas Coal

The petrographic characteristics of bed samples of gas coal from different locations in the Kuznetsk Basin are studied. Analysis of reflection patterns permits identification of the petrographic features affecting the behavior of coal in high-temperature coking. Additional assessment of the physicochemical properties of the coal permits expanded utilization of the large reserves of gas coal in coke production.     

Use of semiacid clay of the Kuznetsk Basin

Conclusions Izhmorsk clays can be classed as kaolinite-hydrated micaceous raw materials (monothermite) with a large impurity-content of quartz. The properties of these clays are similar to those of Barzassk clays, and the two materials can be mineralogically classed as the same type.The Izhmorsk clays were used to obtain specimens of semiacid products with an apparent porosity of 18–23%, having a finely porous structure, and a compressive strength of 300–500 kg/cm².Since they are similar to the Barzassk semiacid clays that were studied in industrial conditions at KMK, we can consider Izhmorsk clays to be suitable for producing refractories.The basic condition for producing semiacid refractories, when employing the method normally used for firebrick, is careful observation of the firing cycle, which will ensure completion of mullite formation, while maintaining the quartz in the crystalline phase and the production of finely porous structures in the materials.Industrial testing of semiacid refractories in various conditions should be organized as a means of extending the application, and of solving the problem of using, semiacid products.An all-round exploitation of the Barzassk source of fireclays and the Izhmorsk source of sands is required in conjunction with the use of the large resources of semiacid raw materials with the basic refractory clays and sands.Translated from Ogneupory, No.3, pp. 11–17, March, 1968.     

Clinkering properties of rammed coking coal and coal batches

The clinkering properties of rammed coking coal and coal batches are investigated. There is a close relation between the clinkering properties and coke quality.     

Modified coal batch in coking

The influence of volatile products from low-metamorphic poorly clinkering G coal on plasticmass formation in rammed batch during coking is considered. An experimental batch of modified coke has been produced at PAO Alchevskkoks.     

Quality fluctuations of coking coal

The quality fluctuations of coal from different sources is assessed, in terms of technical analysis, petrographic analysis, and plastometric data. Considerable fluctuations are seen in the moisture, ash, and sulfur content, the thickness of the plastic layer, the vitrinite content, and the sum of lean components. To obtain stable coal quality, more consistent properties of individual coal ranks are required, as well as more effective blending.