What are the common methods for determining the mechanical strength of coke at present?
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In the past, the mechanical strength of coke was measured using either the coke drop strength or the drum strength. The drop strength tested only the resistance of coke to crushing, whereas the drum strength took into account both its resistance to crushing and its wear resistance. What methods are currently used to determine the mechanical strength of coke? How are specific impact strength and wear resistance measured?
The \"Method for Determining the Mechanical Strength of Coke\" specifies the principles, instruments and equipment for determining the mechanical strength of coke with particle sizes greater than 60 mm and 25 mm, the sampling and preparation of specimens, the test procedures, the calculation of results, and the precision. Refer to the **standard**. Book Title: Methods for Determining the Mechanical Strength of Coke
Author: Unknown
Publisher: China Standard Press
Standard Number: GB/T2006-2008
Editor in Charge: —
Format: 16
Publication Date: December 2008
Word Count: thousands of words
Binding: Paperback
Disc Included: No
Number of Pages: 8
Author: Unknown
Publisher: China Standard Press
Standard Number: GB/T2006-2008
Editor in Charge: —
Format: 16
Publication Date: December 2008
Word Count: thousands of words
Binding: Paperback
Disc Included: No
Number of Pages: 8
Coke is the solid product of high-temperature carbonization; its main component is carbon, and it has a cracked and irregular pore structure (or porous structure with pores). The number of cracks directly affects the strength and crush resistance of coke, with this property generally being measured by the crack density (referring to the length of cracks per unit volume of coke). The indicator for measuring the pore structure is primarily the porosity (the percentage of the pore volume in coke relative to its total volume), which affects the reactivity and strength of the coke. Coke intended for different purposes has varying requirements regarding the porosity index; generally, metallurgical coke requires a porosity of 40–45%, casting coke requires 35–40%, while coke intended for export needs a porosity of around 30%. The degree of cracking and porosity in coke are directly related to the type of coal used in coking; for example, coke produced from bituminous coal tends to have many cracks, a high porosity, and low strength ； Coke produced from coking coal as the base coal has fewer cracks, a lower porosity, and higher strength. Coke strength is usually expressed by two indicators: crush resistance and wear resistance. The crushing resistance of coke refers to its ability to withstand external impacts without breaking along the cracks or defects in its structure, and is expressed by the M40 value ； The wear resistance of coke refers to its ability to resist external friction forces without the formation of surface glass particles or powder, and it is expressed by the M10 value. The crackness of coke affects its crushing strength value M40, while the pore structure of coke influences its wear resistance value M10. There are many methods for determining the M40 and M10 values; in China, the German Migon drum test method is commonly used. After the transfer test is completed, sieving is carried out using sieves with pore sizes of 40 mm and 10 mm; the percentage of particles larger than 40 mm is denoted as the M40 value, while the percentage of particles smaller than 10 mm is denoted as the M10 value.