Slag-free production process using bauxite or red mud

Abstract

The invention provides a slag-free production process using bauxite or red mud. The method comprises the following steps: a) preparing a mixed raw material from bauxite or red mud, lime and coal in proportion; b) adding the mixed raw material into a rotary kiln for drying and pre-reduction so as to obtain a reduced material in a semi-melting state; c) adding the reduced material into a melting-separation furnace for melting and separation of slag and iron, wherein high-alumina clinker at an upper layer is discharged from a high-alumina clinker outlet, and hot molten iron at a lower layer flows out from a hot molten iron outlet; and d) allowing the high-alumina clinker discharged from the high-alumina clinker outlet to enter into an alkali dissolution tank containing a proper amount of alkali liquor and carrying out stirring and solid-liquid separation so as to obtain a sodium aluminate solution and solid light metal oxides of silicon, calcium, magnesium and titanium. The process provided in the invention has the following advantages: production cost is reduced, resource utilization of red mud is realized, alumina and iron in alumogoethite can be separated and extracted, and pollution to environment caused by generation of red mud is eradicated; separation and utilization of all the elements in bauxite and red mud are realized, operation cost is low, economic benefits are high, and the slag-free production process is green and environment friendly and has recyclicity.

Description

technical field [0001] The invention belongs to the technical field of metal smelting, and in particular relates to a slag-free production process using bauxite or red mud. Background technique [0002] Using bauxite to extract alumina, Bayer method, sintering method, and combined method are the conventional production processes for producing alumina in the world. Although this process is mature, stable and reliable, the biggest defect is that it will produce a large amount of Contaminant red mud. The main components of red mud are: 5% to 25% of alumina; 30% to 55% of iron oxide; 5% to 25% of silicon oxide; 3% to 9% of sodium oxide; 10% to 15% of loss on ignition; , magnesium oxide, calcium oxide, etc. 5% to 10%. It generally contains a large amount of iron oxide, and its appearance is similar to red soil, hence the name; it is the polluting waste slag discharged when the aluminum industry extracts alumina, its pH value is very high, and the pH value of the leachate is 12....

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Problems solved by technology

[0003] In order to solve this problem, people have tried to use blast furnace method, magnetic separation method (including superconducting magnetic separation method) or flotation method to extract iron from red mud, and thus "digest" a large amount of stockpiled red mud, but , because iron in red mud exists in the state of deep iron oxide, iron salt, etc., so magnetic separation (including superconducting magnetic separation), gravity separation or flotation cannot extract the iron at all; while blast furnace method , because it contains a relatively large amount of aluminum, titanium and their compounds, and these substances are very viscous, which not only prevents the gas-solid-liquid three-phase reaction in the blast furnace, but also makes it impossible for the blast furnace to "spit slag"; although it can be mixed with a large amount Calcium-containing compounds to solve the "sticky" problem, but it greatly increases the production cost, basically has no benefit, loses practicality, so it is no longer used

[0004] The "Bayer method", "sintering method" and "combined method" in the existing alumina production process cannot separate and extract the alumina in the acicular bauxite; the alumina content in this part of the raw material is still relatively high, Some as high as more than 30%, are all discharged into the slag as waste, resulting in a great waste of resources

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