Method for preparing high-pressure-resistance alumina grinding medium through roll forming

Abstract

The invention discloses a method for preparing a high-pressure-resistance alumina grinding medium through roll forming. The method is especially suitable for preparing 13 mm-30 mm dry grinding balls used in the dry grinding field. The method includes the steps that firstly, spray drying is carried out, and conventional alumina granulation powder is directly obtained and serves as granulation powder A; superfine collected dust powder collected from a dust collector in preparation of the conventional granulation powder A serves as granulation powder B; a large amount of PVA is added, the spray drying temperature is increased, and granulation powder C is obtained; the granulation powder A, the granulation powder B and the granulation powder C are rolled in a coater according to a certain proportion and then screened, and semi-finished ball blanks with the diameter of 10-20 mm are obtained; the semi-finished ball blanks are rolled with a grinding material A till a 13-30 mm target semi-finished product is formed; finally, drying and firing are carried out, and the finished product is obtained. According to the method, the ball blanks similar to those prepared through isostatic forming are obtained by compounding the granulation powder with different characteristics, so that the ball blanks contain certain air holes, cracks caused by heat shock in the firing and cooling processes are reduced, and the reinforcing and toughening effects are achieved.

Description

technical field [0001] The invention relates to a method for preparing high-pressure-resistant alumina grinding media by roll forming, and belongs to the technical field of ceramic materials. Background technique [0002] The alumina grinding medium is due to the direct impact on the material during the grinding process, and the lack of a buffer stage between the impact and the alumina ball stone, which eventually leads to broken balls, slag drop, cracking, deformation and other symptoms. The above-mentioned various defects will lead to lower and lower ball milling efficiency, greatly reducing the service life of alumina balls, and at the same time, a large number of falling impurities will cause destructive pollution of the ground materials. The above problems are particularly prominent when the compressive strength of the alumina balls is low. [0003] Isostatically formed grinding balls have a much higher compressive strength than roll formed grinding balls. For example...

AI Technical Summary

Problems solved by technology

However, the isostatic pressing process is complicated and the investment in equipment is high. Especially for dry grinding balls with a diameter of 13mm to 30mm, the large-scale production is severely limited, the efficiency is low, and the product cost is high.

However, the compressive strength of the grinding balls prepared by the traditional roll forming method is limited, and it cannot be applied in the field of dry grinding.

After research, the main reason for the low compressive strength of rolling balls is that during the rolling process of rolling balls, the hollow granulated powder round particles are broken and refined, the density of semi-finished products is high, and the products are too dense after firing. The source of micro-cracks is ubiquitous, and the cracks are easy to expand after being stressed, the impact resistance is deteriorated, the strength is low, and problems such as wind crystal bursting and foaming are prone to occur.

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