Method for preparing silicon/aluminium series product by taking gangue as raw material

Abstract

The invention discloses a method for preparing silicon / aluminium series product by taking gangue as a raw material, which is characterized in that gas or solid fluorinating agent is employed for high temperature fluorination calcination on gangue, easily volatile silicon fluoride and nonvolatile AlF3 are generated, so that effective separating of silicon and aluminium is realized. The volatile matter is absorbed and performed with condensation recovery, fluosilicic acid (H2SiF6) with mass concentration of 1-30% or fluosilicate with purity being more than 99% can be obtained, the silicon system products can be directly taken as a chemical product for usage, and can be taken as the raw material for preparing the white carbon black (SiO2.nH2O) with purity being more than 90% through a neutralization precipitation method. AlF3 content of the calcination products of the separated silicon can reach more than 80%, the calcination products can be taken as the raw material for producing Al2O3 by an alkali method or cryolite (3NaF.AlF3) used for electrolytic aluminium and AlF3. The purity of the prepared Al2O3 can reach more than 98%, and 3NaF.AlF3 and AlF3 purity can satisfy the industrial goods requirement. The silicon / aluminium series product has the advantages of multiple types, high purity and wide application.

Description

technical field [0001] The invention relates to a method for preparing silicon and aluminum series products using coal gangue as raw materials, and belongs to the technical field of combining comprehensive utilization of mineral resources with metallurgical and chemical extraction technologies to prepare high value-added products. Background technique [0002] Coal gangue is solid waste produced during coal mining and processing. The output of coal gangue in my country is about 15%-20% of the total output of raw coal, and the accumulation has reached 7 billion tons, covering an area of ​​70KM 2 , and the annual discharge is increasing at a rate of 150 million tons, accounting for more than 40% of my country's total industrial solid waste discharge. The excessive accumulation of coal gangue occupies a large amount of land, and releases a large amount of harmful elements during the accumulation process, causing a series of environmental pollution problems. The comprehensiv...

AI Technical Summary

Problems solved by technology

[0005] These invention patents or patent applications all adopt acid method (sulfuric acid leaching or hydrochloric acid leaching), alkali method (alkali leaching or alkali sintering), roasting (direct roasting or Chlorination roasting) or the joint method between them to recover aluminum and silicon from coal gangue or coal-measure kaolin to produce related products, such as alumina, electrolytic aluminum, aluminum sulfate, silicic acid or white carbon black, etc. These methods are Its own innovation and superiority, but the products recovered by most methods are relatively single, affected by the properties of raw materials, it is difficult to completely separate silicon and aluminum in raw materials, and the product purity and recovery rate are not high.