Method for cogeneration of TiO2 and Al2O3 by using titanium-bearing blast furnace slag mineralized carbon dioxide

Abstract

The invention discloses a method for cogeneration of TiO2 and Al2O3 by using titanium-bearing blast furnace slag mineralized carbon dioxide CO2. The method comprises the following steps: (1) mixing and roasting titanium-bearing blast furnace slag and ammonium sulfate so as to obtain roasting slag and an ammonia gas, and absorbing the ammonia gas with water so as to obtain ammonia water; (2) leaching the roasting slag with water, and filtering so as to obtain leachate and leaching residues; (3) enabling the leaching residues of the step (2) and the ammonia water of the step (1) to react with carbon dioxide so as to obtain mineralized slag and mineralization mother liquor; (4) adjusting the pH value of the leachate of the step (2) by using the ammonia water of the step (1), performing fractional precipitation, and filtering so as to obtain metatitanic acid, aluminum hydroxide precipitate and a magnesium-enriched solution; (5) enabling the magnesium-enriched solution of the step (4), the ammonia water of the step (1) and the carbon dioxide to react to obtain magnesium carbonate precipitate and mineralization mother liquor; (6) mixing the mineralization mother liquor of the step (3) and the step (5), evaporating, cooling, and crystallizing so as to obtain an ammonium sulfate solid for cycle use; (7) respectively calcining the precipitate of the step (4), thereby obtaining TiO2 and Al2O3.

Description

technical field [0001] The invention belongs to CO 2 The field of emission reduction and solid waste resource utilization specifically involves the method of using titanium-containing blast furnace slag to mineralize and sequester carbon dioxide while producing high value-added titanium and aluminum oxides. Background technique [0002] Since the Industrial Revolution, the massive use of fossil fuels has contributed to atmospheric CO 2 The concentration has risen sharply, and the resulting greenhouse effect has caused global sea levels to rise. Droughts, floods, and extreme cold weather frequently occur, causing great harm to the earth's ecology and human life. At present, China has become the world's largest carbon emitter, and the Chinese government is facing enormous pressure from the international community to reduce emissions. Based on my country's "coal-rich, oil-deficient, and gas-poor" energy structure and the low proportion of non-fossil energy, terminal emissio...

AI Technical Summary

Problems solved by technology

my country emits about 20 million tons of TiO every year 2 Blast furnace slag with a content of 8-25%, a large amount of titanium-containing blast furnace slag piles up like a mountain, which not only takes up a lot of land, causes a waste of titanium resources, but also pollutes the environment

[0003] There are many reports on the utilization of titanium-containing blast furnace slag. For example, Chinese patent CN 1746126A discloses the method of using electromagnetic waves to irradiate titanium-containing blast furnace slag, and then using sulfuric acid to perform selective acidolysis, hydrolysis, and calcination to prepare titanium-rich materials. ; Chinese patent CN 86108511A discloses the process of preparing titanium dioxide by sulfuric acid leaching of titanium-containing blast furnace; Whether there is recycling, pollute the environment, and the added value of fertilizer is low; Chinese patent CN101988158A discloses a comprehensive utilization method of titanium-containing waste slag (actually titanium-containing blast furnace slag): (1) combine titanium-containing waste slag with ammonium sulfate, Potassium sulfate is roasted at 200-500°C to obtain massive solids and ammonia gas; (2) immerse and filter the above-mentioned massive solids to obtain filtrate and water leached slag, which are used as cement additives; (3) Pass ammonia gas into the filtrate, control the pH value to be 1.8~3.5, 5.8~7.5 respectively, recover titanium and aluminum in the form of hydrated titanium dioxide and aluminum hydroxide precipitation

The main problems of this method are: ① The main components of the water leaching residue are calcium sulfate and silica, and cement products have strict restrictions on the sulfur content, so the water leaching residue is difficult to use; ② Because the water leaching residue contains a large amount of Sulfate means that the amount of ammonia produced during the roasting process is much greater than that required for the precipitation of titanium and aluminum in the process. Therefore, this process will inevitably produce a large amount of ammonia by-product, making storage and transportation difficult

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