Method for producing aluminum oxide by sintering calcium carbide mud, fly ash and coal gangue

Abstract

The invention discloses a method for producing aluminum oxide by sintering a calcium carbide mud, fly ash and coal gangue. The method sequentially comprises the following steps of preparing of raw materials, sintering of clinker, dissolving-out of the clinker, separating and washing of red mud, dealkalizing of the red mud, desilicication of crude liquid, preparation of crystal seeds, carbonation decomposing of concentrated liquid, separating and washing of aluminum hydroxide, roasting of aluminum hydroxide, and evaporation of mother liquid. The method is characterized in that by using the carbon as the main material and using the crystal seeds as the auxiliary material, the particle size of aluminum hydroxide is controlled by adjusting the temperature and rotation speed; in the preparationprocess of the raw materials, the coal gangue is used for providing an aluminum source, and the internal combustion temperature is provided; the calcium carbide mud is used as a calcium source; in the processes of dealkalizing of the red mud and desilicication of the crude liquid, the calcium carbide mud is used for replacing lime emulsion as the calcium source; the washing liquid of the red mud,the washing liquid of the dealkalized red mud, and the washing liquid of the aluminum hydroxide are respectively used for adjusting the causticity ratio of a reaction system when the clinker is dissolved out next time. The method has the advantages that the utilization rate of the existing resources is effectively increased, and the production cost is reduced.

Description

technical field [0001] The invention discloses a method for producing alumina by sintering calcium carbide mud fly ash and coal gangue, belonging to the field of alumina preparation. Background technique [0002] Alumina is a high-hardness compound with a melting point of 2054°C and a boiling point of 2980°C. It is an ionic crystal that can be ionized at high temperatures and is often used in the manufacture of refractory materials. Alumina is an extremely tight industrial product in my country. The growth of China's alumina production is far from meeting the growth of my country's market demand. At present, the distribution of bauxite, the raw material for alumina production, is very unbalanced, and 98% of the mineral deposits are diaspore. , the impurity content is high, the ore is difficult to dissolve, the production is difficult and the cost is high. At present, regardless of the acid leaching method or the sintering method, Al is extracted from fly ash. 2 o 3 There a...

AI Technical Summary

Problems solved by technology

The acid method is divided into sulfuric acid leaching method, hydrochloric acid leaching method, fluorine ammonium solubilization method, some common problems of the acid method, the separation process of aluminum and iron in the pretreatment stage is complicated, the acid slag and acid gas are not easy to handle, and the requirements for equipment are relatively strict, which is not conducive to carrying out large-scale industrial production

Alkali method is divided into limestone sintering method and soda lime sintering method. The sintering temperature of limestone sintering method is high, at 1300-1400 ℃, the energy consumption is high, the cost is high, and the amount of red mud produced at the same time is large, which brings new pollution; soda lime sintering This method requires high aluminum content in fly ash, complicated process, high dissolution temperature in desiliconization stage, high energy consumption and high cost.

Images