Development of Alumina Production Technology by sintering of TPP Waste

Abstract

Russia is experiencing a steady shortage of raw materials for the production of alumina, and therefore, the search for unconventional cheap raw materials for its production is very relevant.In this paper, we consider two types of raw materials for the alumina production -ash and slag waste from CHPP-9 (Angarsk) and New Irkutsk CHPP (Irkutsk) PJSC “Irkutskenergo”, and wet magnetic separation tails obtained after the separation of iron-containing components.Laboratory studies were conducted on the sintering of the charge from ash and slag waste, tailings of wet magnetic separation with limestone and soda.Self-moldering sinter obtained; the recovery of alumina from them during leaching was 87% forNew Irkutsk CHPP and 83% for CHPP-9. The optimal conditions of experiments on sintering samples of ash-and-slag materials were determined.Two-stage desiliconization and carbonization of sinter leaching solutions, and calcination of aluminum hydroxide experiments were carried out.Alumina, corresponding in composition to metallurgical alumina (alumina content of 97,77%) was obtained.The technological scheme of alumina production from ash and slag waste of thermal power plants of the Irkutsk region is proposed.

Low-Temperature Treatment of Boehmitic Bauxite Using the Bayer Reductive Method with the Formation of High-Iron Magnetite Concentrate

“…Sintering with soda (Na 2 CO 3 ) and lime (CaO) [ 3 , 4 ] acid methods [ 5 , 6 ] was developed for low-grade ores. However, almost all the alumina from such raw materials is currently produced by sintering and combined alkaline sintering processes [ 7 ], which are high energy-intensive and produce a large amount of solid waste (red mud or BR).…”

“…The reductive Bayer process is the most promising method from the perspective of BR elimination because it makes it possible to convert BR in the easy to process by-product with a high iron content in the form of magnetite (Fe 3 O 4 ) [17,18]. The mechanism of the magnetite formation can be described by Equations ( 1)- (3). The source of the Fe 2+ can be different: iron [19] and aluminum [20] that reacts with the alkaline solution with the formation of H 2 and following the reduction of Fe 3+ to Fe 2+ ; the addition of FeSO 4 [21,22] and the addition of organic matter [23].…”