Method for evaluating after-reaction strength of metallurgical coke

Abstract

The invention relates to the field of measurement of the quality of coke, specifically, to a method for evaluating the after-reaction strength of coke. The method comprises: after coke is heated to a lower limit value of a reaction temperature range, starting to lead reaction atmosphere in for a reaction; raising the temperature at a constant speed during the reaction while allowing the temperature to exactly reach an upper limit value of the reaction temperature range after the reaction is over, and keeping the flow of auxiliary atmosphere constant during the reaction; adjusting flow of CO and CO2 to make the actual weight loss rate fit the calculated weight loss rate of the coke from beginning to end till the coke reaches a set final weight loss rate; cooling the reacted coke; and performing a drum test to obtain the after-reaction strength of the coke. According to the method, a reaction process of coke in a blast furnace can be well simulated, so that the value of the after-reaction strength can truly express the use condition of the coke in the blast furnace. The cost of coal blending is greatly reduced, and overestimate of some performance of the coke is avoided. The cost of hot metal is ultimately reduced, and the quality of the hot metal is improved.

Description

technical field [0001] The invention relates to the field of coke quality measurement, in particular to a method for evaluating coke strength after reaction. Background technique [0002] The current test method for characterizing the reactivity and post-reaction strength of coke used in blast furnaces in the furnace is the national standard "Coke reactivity and post-reaction strength method" GB / T4000-2008. Make a coke sample into a 19-21mm block, shrink 200g, put it into the reactor, and mix it with 5 liters / min 100% CO under the condition of constant temperature of 1100℃ 2 After the gas reacts for 2 hours, the weight loss rate is the reactive CRI; after the reacted coke is rotated in the type I drum at a speed of 20 rpm for 30 minutes, the ratio of the coke larger than 10mm is measured, which is the post-reaction strength CSR. This method was first proposed by Nippon Steel in Japan. After it was put forward, it received widespread attention and rapid promotion in the coki...

AI Technical Summary

Problems solved by technology

[0003] The reaction process and post-reaction strength of coke in the blast furnace directly affect the coal blending structure and coke cost and ultimately affect the cost of molten iron. Therefore, when blending coal, the reactivity CRI and post-reaction strength CSR determined by the existing national standards are important coal preparation Indicators directly determine the coal blending plan; however, after long-term use, it is found that there is a big gap between the existing standard evaluation process and the actual situation of coke in the blast furnace

The first is the temperature. The coke in the blast furnace passes through the massive zone, the soft melting zone, and the dripping zone from top to bottom. The inner reaction atmosphere is not pure CO 2 atmosphere, CO 2 Concentration <10%; Finally, for blast furnaces with stable direct reduction degree and unburned coal powder rate, the total weight loss rate of coke is also stable, while the coke in the national standard method is mainly catalyzed by ash components, and the weight loss rate is unlimited. Three main factors determine the limitations of the national standard coke thermal performance evaluation method, which is also the main gap with the actual situation of the blast furnace; resulting in inaccurate coke quality standards, resulting in some high-quality coke being evaluated as low-quality coke, and low-quality coke Quality coke is evaluated as high-quality coke, the former increases production costs, and the latter may affect the quality of steel products

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