Chelyabinsk Zinc Plant PJSC, Chelyabinsk, Russia:

R. R. Asadulin, Head of the Leaching Plant
A. E. Pavlyuk, Deputy Head of the Leaching Plant (Operations)
O. V. Belyakov, Head of the Waelz Kiln Site, e-mail: obl@zinc.ru

This paper describes the results of an effort taken by the Chelyabinsk Zinc Plant to introduce and streamline the process of Waelz oxide calcination in tube kilns. The process flow, the equipment, as well as the composition of the obtained industrial products are described. As a result of revamping, the annual output of the calcination complex in 2019 rose to 63.3 th tons of Waelz oxide and 8.2 th tons of the delivered oxidized zinc material, which by 1.8 to 2.1 times exceeds the annual throughput of the previous years. With the chlorine sublimation rate maintained at a high level (around 95%), the fluorine sublimation rate during Waelz oxide calcination increased from 60 to 76%. In 2018, a new Waelz oxide granulation complex was commissioned at the Chelyabinsk Zinc Plant to raise the capacity and efficiency of Waelz oxide calcination. The new complex is designed to also process off-site zinc materials. Disc pelletizer TR 45 by Eirich serves as the main unit. The disc pelletizer is fed through 8 hoppers, which makes it possible to charge the current amount of Waelz oxide, the recirculation dusts of the calcinator, as well as off-site zinc material. Another tube kiln was also commissioned. With the diameter of 2.5 m and the length of 40 m, the second kiln is used as a Waelz oxide calcinator. Thus, it is equipped with a drum cooler, a mill for the calcined material, and a pneumatic conveying system. In 2019, a revamped secondary sublimate scrubbing line was commissioned with the annual capacity of up to 9.4 th tons. The line consists of two reactors and two automatically discharged membrane filter presses. A vibrating mill is installed upstream to grind the pelletized material. The optimized process helped raise the secondary sublimate scrubbing efficiency. Thus, up to 97% of chlorine and up to 93% of fluorine can be removed. Further streamlining of the Waelz oxide calcination process at the Chelyabinsk Zinc Plant and raising the annual throughput to potential 100 th tons and over would be down to revamping of the existing calcinator gas exhaust and dust collecting system, as well as the capability to process copper plant dusts. Revamping of the gas exhaust system will make it possible to process material with high concentrations of halogens (containing more than 1.2% of chlorine).

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