The fineness is the same as the pulp quality score and an important indicator in the beneficiation process. Although the fineness is closely related to the particle size, its meaning is different. The so-called fine refers to the mass of all particles smaller than a certain particle size in the material, the percentage in all materials, and the particle size refers to the actual size of the particles.
The fineness is expressed by the content of -200 mesh. There are various methods for determining the fineness, and direct measurement methods and indirect measurement methods are commonly used in mineral processing. (1) Direct measurement method. The direct measurement method is to filter and dry the slurry after sampling, and take out a dry sample of a certain mass q 0 (g) (the sampling quality is representative ) , and then completely sieve it with a specified sieve ( such as a 200 mesh sieve ) ( dry method) , wet or wet and dry combined method, generally sieved for more than 0.5h) , said the product quality on the sieve q 2 or the quality of the product under the sieve q 1 , the fineness The results of this method are accurate, but the long measurement time is difficult to guide production, and the results are generally used in production statistics. (2) Indirect measurement method. The method is to measure the fineness by measuring the mass fraction of the slurry. Also known as rapid screening. That is, the ore sample is taken and weighed with the calibrated mass fraction kettle, and the mass Q 1 (g) of the slurry before the sieving is obtained, and the slurry mass fraction K 1 (%) is obtained , and then the slurry is placed on the designated sieve ( Usually , it is sieved by 200 mesh ). After sieving, the residue on the sieve is returned to the original mass fraction pot. After filling with water, weigh the weight of the sieve and add water Q 2 (g) . After the pulp mass fraction K 2 (%) , the fineness For example, to measure the fineness of the graded overflow of a spiral classifier for a closed-circuit grinding operation: the quality of the slurry after sampling is Q 1 = 1540g , the mass fraction is obtained as K1=38% , and then sieved by a 200- mesh sieve. After sieved, the product on the sieve is poured into a mass fraction. The water is added and the mass Q 2 is 750g , the corresponding mass fraction is K 2 =15% , then the fineness
