Method for extracting aluminum oxide from fly ash and coproducing cement by carbide slag or cyanamide slag

Abstract

The invention provides a method for extracting alumina cement from dust coal by using carbide mud residue. It is characterized in that it takes aluminum- rich dust coal as aluminum source, and carbide mud residue or cyandiamide slag as calcium source, produces calcium aluminate and calcium aluminate sintering material through sintering, and prepares alumina through processes of soda digestion, de-silicon, removing carbon and sintering. The produced slag is used as silicon and calcium material for cement production, the sintering of carbide mud residue or cyandiamide slag and dust coal is carried out with wet grinding and dry coking process. The invention employs carbide mud residue or cyandiamide slag to replace lime carbonate and be used as medium for alumina extraction, which on one hand reduces lime carbonate mining, and on the other hand makes full use of s carbide mud residue or cyandiamide slag.

Description

[0001] Technical field: the invention belongs to the technical field of inorganic chemical industry, and relates to a method for extracting alumina from fly ash to produce cement by using carbide slag. Background technique:

[0002] The extraction of alumina from fly ash started in Europe in the 1960s. This process is called "Gerimek-Tatabon Method" ("Gerta Method" for short). Firstly, fly ash and limestone are mixed and calcined to form a sintered material of calcium aluminate and calcium silicate, and then soda ash (sodium carbonate) solution is used to convert the calcium aluminate in the sintered material into soluble sodium aluminate, sodium hydroxide and Solid calcium carbonate, after solid and liquid separation, carbon dioxide is passed into the filtrate, sodium aluminate becomes solid aluminum hydroxide and sodium carbonate, sodium hydroxide becomes sodium carbonate and remains in the solution for recycling, hydroxide The aluminum is sent to a calciner to remove moistu...