Modification of poorly clinkering DG coal

In a recent issue of this journal, Malyi described experiments on the modification of DG coal for its subsequent use in coking batch in place of G coal. Analysis of that paper shows that, contrary to Malyi’s statements, there is no shortage of G coal, because the Donets Basin comfortably meets the demand. The model mixture that Malyi uses for modification is complex in composition and contains considerable sulfur. He does not state its properties or the available reserves. Malyi’s ideas regarding the pyrolysis of coal are shown to be very contradictory, while his experimental data prompt skepticism, since the measured ash content, total sulfur content, and clinkering properties of the batch differ from those calculated on the basis of the properties and proportions of the batch components. When using batch that contains modified DG coal in place of G coal, the coke yield is reduced, and its quality is impaired. These findings support the conclusion that Malyi’s research is unnecessary, unpromising, and unworthy of further consideration.     

Selection of nonclinkering and poorly clinkering coal for industrial use

The identification of nonclinkering and poorly clinkering coal suited to industrial use is of great importance. The classification of such coal by applicability is discussed. Criteria are needed for the selection of dual-purpose coals, with both fuel and nonfuel uses, within the framework of State Standard GOST 25543–2013.     

Effect of microwaves on poorly clinkering gas coal

The processes that occur in coal’s organic mass under the thermal action of microwave radiation are considered.     

Rank assignment of coal in terms of its clinkering and coking properties

Comparison of the clinkering and coking properties of coal from different basins indicates that the rank boundaries adopted in State Standard GOST 25543–2013 in terms of the plastic-layer thickness do not correspond to the boundaries in terms of the coking properties. The coal samples are arranged in order in terms of the coking capacity K^cc and the coke-forming capacity K^cfc, and a classification of coal ranks on the basis of the coking properties is proposed.     

Influence of the piece size of poorly clinkering coal on coke porosity

The influence of heat treatment (750 and 1000°C) of nonclinkering and poorly clinkering D, G, SS, and T coal on the pore structure and properties of coke is studied. The porosity of coke from coal pieces and crushed coal is significantly different.     

Organic clinkering additives in coking batch: A review

The use of organic waste from the coke and petrochemical industry as binder in coal batch is reviewed. A classification of these additives in terms of the source is proposed.     

Standards for determining the clinkering properties of coal

The replacement of State Standard GOST 9318-91 for the determination of coal’s clinkering properties (on the basis of the Roga method) by GOST R ISO 15585-2009 is assessed. It is shown that deficiencies of the ISO method limit the information that may be obtained. It is expedient to determine the clinkering properties of coal by the Roga method on the basis of the ISO 335:1974 standard.     

Additivity of clinkering measures when blending coal

The additivity of various measures of clinkering is verified for coal blends that contain imported coal.     

Modification and application of coking coal by alkali pretreatment in wastewater adsorption

Coking coal has been employed for coking wastewater adsorption treatment. The modification and adsorption of coking coal pretreated by alkali solution is discussed and compared in this study. Results demonstrated OH- could react with -COOH, -OH and minerals, which resulted in coal surface variations. As the hydroxide concentration is increased, surface hydrophobility increased and the zeta potential became less negative. A coal sample pretreated by 0.1 mol/L NaOH solution had the highest surface area and pore volume. The adsorption ability of the samples was improved significantly as surface changes. The coal sample pretreated by 0.1 mol/L NaOH solution had the highest adsorption capacity, and followed pseudo-second-order kinetics.     

Interaction of thermosetting plastics with clinkering coal

The influence of phenol-formaldehyde resin on the clinkering properties of coal batch is studied by means of the dilatometric method proposed by the Institute of Mining and Dnepropetrovsk Metallurgical Institute. For comparison, its influence on the clinkering ability is studied by the Roga method. The results show that this organic additive has a similar influence in both cases.     

Modification of sub-bituminous coal by steam treatment: Caking and coking properties

A Chinese sub-bituminous Shenfu (SF) coal was steam treated under atmospheric pressure and the caking and coking properties of the treated coals were evaluated by caking indexes (G_RI) and crucible coking characterizations. The results show that steam treatment can obviously increase the G_RI of SF coal. When the steam treated coals were used in the coal blends instead of SF raw coal, the micro-strength index (MSI) and particle coke strength after reaction (PSR) of the coke increased, and particle coke reactivity index (PRI) decreased, which are beneficial for metallurgical coke to increase the gas permeability in blast furnace. The quality of the coke obtained from 8% of 200 °C steam treated SF coal in coal blends gets to that of the coke obtained from the standard coal blends, in which there was no SF coal addition in the coal blends. The removal of oxygen groups, especially hydroxyl group thus favoring the breakage of the coal macromolecules and allowing the treated coal formation of much more amount of hydrocarbons, may be responsible for the modified results. The mechanism of the steam treatment was proposed based on the elemental analysis, thermo gravimetric (TG) and FTIR spectrometer characterizations of the steam treated coal.     

Optimizing the coal batch for coking

Optimization of coke production is considered. Mathematical experiment design, which is an active research method, calls for artificial changes in the input parameters. In actual production conditions, active experiments are not possible on account of material and time constraints. These problems may be eliminated on the basis of reserves of production data.     

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。     

高硫焦煤在配煤中的应用

通过研究高硫焦煤的理化性质,在配合煤中配入一定比例的廉价高硫焦煤,焦炭质量得到改善,主焦煤的使用比例减少,入炉煤成本大幅降低.     

煤岩分析在配煤炼焦中的应用

介绍了煤岩分析在进厂原料煤的分类、混煤辨别、优化配煤方案以及和用单种煤反射率分布图合成配合煤反射率分布直方图来预测焦炭质量等方面的应用,用于指导配煤炼焦生产,取得了明显的效果。     

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.     

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.