Method for extracting aluminum oxide from sodium-free desiliconized fly ash

Abstract

The invention relates to a method for extracting aluminum oxide from sodium-free desiliconized fly ash, which comprises the following steps of: taking dried sodium-free desiliconized fly ash, carrying out saturation calcium matching with limestone powder and / or slaking slag powder, sintering at 1330-1390 DEG C, controlling to cool the sintered material to obtain the self-pulverizing material, putting into a Na2CO3 solution to quickly dissolve out aluminum oxide, separating a solid from a liquid, extracting aluminum oxide according to the conventional method, and washing residues to obtain the low-sodium calcium-silicon slag. In the method, sodium-free desiliconized fly ash from which silicon dioxide is extracted and sodium oxide is removed is adopted as the raw material; the limestone sintering process can be used for extracting aluminum oxide, and low-sodium calcium-silicon slag can be obtained after extracting aluminum oxide; and both the aluminum oxide and the low-sodium calcium-silicon slag can be used as the raw materials of cement, thereby thoroughly eliminating secondary pollution.

Description

technical field [0001] The invention belongs to the resource utilization of high-alumina fly ash, and relates to a method for extracting alumina from high-alumina fly ash, in particular to a high-alumina product that has extracted silicon dioxide and removed sodium oxide. A method for extracting alumina from fly ash desodium desilicate ash. Background technique [0002] The fly ash formed by pulverization and combustion of raw coal produced in many coal fields in my country is rich in alumina, Al 2 o 3 The content is higher than 37%, some even as high as 44%, which can be called high aluminum fly ash. This fly ash is rich in Al 2 o 3 In addition, it is also rich in SiO 2 , whose SiO 2 The content is generally between 45 and 50%. Therefore, the aluminum-silicon ratio of this kind of fly ash is relatively low, usually only about 0.8, which is difficult to meet the requirements of aluminum content and aluminum-silicon ratio in aluminum ore resources by traditional alumin...

AI Technical Summary

Problems solved by technology

[0005] In this patent application, although the soda lime sintering method can be directly used to effectively recover the Al in the desilication dust after silicon extraction 2 o 3 , but the process is complicated, the energy consumption is high, and the Na in the output red mud 2 The O content is high (about 1.75%), which cannot fully meet the requirements of cement raw material components, and cannot realize the waste resource utilization of "eat dry and squeeze clean"