Elma-Asterion Trade, Saint-Petersburg, Russia

A. N. Grigorieva, CEO, Candidate of Engineering Sciences, an@td-elma.ru

The paper discusses the features of the use of agitators in reactors meant for implementing suspension in terms of a lime milk preparation tank at Gaisky Mining and Processing Plant, UMMC Holding. The agitator previously installed was a guide tube agitator. This configuration failed to ensure the required mixing efficiency because large sediments of lime were observed on the bottom of the reactor during discharging. Moreover, the lime milk pumps constantly broke down at the plant. The analysis of the velocity field created by the mixers of a similar assembly using mathematical modeling exhibited an insufficient velocity component in the bottom part of the apparatus. The scientific and technical literature review shows that the layout of the apparatus with a guide tube is recommended mainly for operation in a liquid–liquid system and for narrow and high containers. Based on the earlier developed selection methodology and the optimal suspension mode, a conical mixer of a new geometry was designed for the reactor. According to the results of the new mixer operation for three months, no lime deposits were observed on the bottom of the reactor, and the finished slurry pumps which constantly failed earlier demonstrated fault-free performance. At the same time, the energy consumption of the new agitator is more than 7 times lower compared to the previously installed agitator.

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