A method for sorting limestone chips using a fluidized bed

Abstract

The invention relates to the field of sorting limestone, in particular to a method for sorting limestone chips by utilizing a fluidized bed. The method comprises the following steps of a, feeding to-be-screened limestone chips into the fluidized bed, wherein the longitudinal section of a dense-phase zone, which is vertical to material flowing direction, of the fluidized bed is trapezoidal, a length-width ratio of the cross section of the fluidized bed is (4-20) : 1, the width of the surface of the trapezoidal dense-phase zone of the fluidized bed is 2-8 times as big as that of the bottom part of the dense-phase zone, and air is blown into the fluidized bed from the bottom part of the fluidized bed; b, controlling the standard state empty tower gas velocity of the bottom part of the fluidized bed to be 0.3-1.5m / s and the average residence time of the to-be-screened limestone chips in the dense-phase zone of the fluidized bed to be 6-20 minutes, and respectively obtaining coarse lime particles, fine lime particles and fine lime powder. Through the method, the limestone chips with different particle sizes in mixed limestone chips of which the particle sizes are smaller than 10mm can be efficiently classified to be sorted, and thus different industrial requirements can be met.

Description

technical field [0001] The invention relates to the field of limestone separation, in particular to a method for separating limestone chips using a fluidized bed. Background technique [0002] When mining stones such as stone heads, marbles or slabs from the quarry, a large number of limestone chips with a particle size of less than 10mm will be discarded, which not only wastes resources but also pollutes the environment. Numerous studies have shown that lime fired at 800-900°C has high activity due to its high specific surface area. Therefore, after the circulating fluidized bed combustion boiler appeared in 1960, the idea of ​​calcining lime with a circulating fluidized bed calciner appeared, and the raw material should be limestone chips with a particle size of less than 10mm. [0003] At present, after the stone is collected in the quarry, the remaining waste limestone with a particle size of less than 10mm is mixed with various sizes of limestone. From the perspective ...

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Problems solved by technology

[0003] At present, after the stone is collected in the quarry, the remaining waste limestone with a particle size of less than 10mm is mixed with various sizes of limestone. From the perspective of good calcination, the limestone chips with a particle size of less than 10mm need to be replaced. Fine particle size classification and then sieving, but with the existing technology requires a lot of labor

[0004] The initial method is to use manual screening, specifically using a sieve screen, which is not only time-consuming and labor-intensive, but also has low screening efficiency

Later, with the advancement and development of science and technology, mechanical screening was used, and its screening efficiency was relatively improved, but it still could not meet the market demand, and the screening accuracy was limited, the environment was seriously polluted, and it was also very harmful to the health of workers.

[0005] At present, it has developed to rapid pneumatic screening, and its screening efficiency has been greatly improved. However, the equipment structure is complex, the cost of manufacturing a new equipment is extremely high, and at the same time, the cost of use is increased. At the same time, the energy consumption is high, and the power resources consumed are too high. Ultimately The cost price of limestone chips is too high, which is not conducive to industrial production and application

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