Study And Industrial Application Of The Key Technologies For Manufacturing Anodes Used In Aluminium Reduction

Anode quality plays an important role for the performance of aluminum smelting cells. Therefore, the thorough study on the production process characteristics and fundamental theories and key-technology development for producing high quality prebaked anodes become an important and urgent research project for Chinese aluminum industry. Focusing on the regionalism and production characteristics of aluminiun-consuming anode coke and coal tar pitch, this paper carried out a fundamental research systematically. And combining with Chinese carbon anode production practice, series of process optimization and engineering technological innovation research were carried out. The theoretical and applied research results were obtained as follow:(1) A study on the regional distribution characteristics of the properties of Chinese domestic petroleum coke was first systematically carried out. The study results showed that the petroleum coke produced by northeast, with a lower content of S and V element, is the high-quality raw material for carbon anode production. However, it is of low amount and high price, and non-economic for anode production. Refinery in north and central China, which used import crude oil partly, produced petroleum coke with a higher content of V, S and Ca than those produced with domestic crude oil. Refinery in south China mainly used import crude oil and produced petroleum coke with high S, V content, and low Ca, Fe content.(2) The relation between the characteristics of cokes and carbon anode qualities in our country were studied comprehensively. The study results revealed the coupling effects behavior of the microelements in cokes and their influences of the catalysis and inhibition on carbon oxidation. Based on the study results, a selective coupling blending technology of varieties of cokes is developed creatively, which increases greatly the supply resource of raw materials for carbon anode manufacturing(3)The characteristics of Chinese coal tar pitch produced by thermal polymerization process were first studied systematically. The study results show the influences of the solid phases in coal tar pitch, such as mesophase and quinoline insoluble (QI) on the properties of the coke tar pitch. It was found that the coal tar pitch produced by high-temperature thermal polymerization with higher content of toluene insoluble matter, QI and mesophase has a viscosity 3-5 times higher than the one produced by flash distillation process at the same temperatures, which greatly impacts the mixing effect of the paste and the quality of green anodes as well.(4) The creative integration of coke selective coupling blending technology, new dry aggregates formulation technology, ball milling particle size online analysis technology, butt cleaning and large size particle butt formulation technology, new mixing technology of the pitch from thermal polymerization process and homogenization anode baking technology developed the packaged key-technologies for producing high quality prebaked anodes. And the engineering application was obtained, which made significant economic, social and environmental benefits.