Method for co-producing sulfuric acid by synergistically reducing gypsum with gaseous sulfur and high-sulfur bauxite to produce sulphoaluminate cement

Abstract

The invention relates to a method for producing sulfuric acid by co-reducing gypsum with gas sulfur and high-sulfur bauxite to produce sulfoaluminate cement. Iron sulfide is used as a reducing agent, and high-sulfur bauxite is used as the main ingredient to prepare sulfoaluminate cement to co-produce sulfuric acid. Compared with the prior art, the present invention can not only obtain a high decomposition rate of gypsum in the cement raw meal, completely use the CaO decomposed by gypsum to replace CaO in the limestone, but also can use the calcium oxide which is difficult to be directly affected by alumina, refractory, building materials and cement industries at present. The high-sulfur bauxite used is used as raw material, in which Al 2 O 3 As an aluminum raw material in cement, FeS 2 As an auxiliary reducing agent for the decomposition of iron raw materials and gypsum, and by further supplementing the reducing agent sulfur gas, the decomposition reaction of gypsum can be carried out quickly and efficiently, and a high concentration of gas-phase SO can be obtained. 2 The flue gas provides the best process conditions for the subsequent co-production of sulfuric acid.

Description

technical field [0001] The invention relates to building materials and chemical products, in particular to a method for synergistically reducing gypsum-containing raw meal to produce sulphoaluminate cement and co-producing sulfuric acid by sulfur gas and high-sulfur bauxite. Background technique [0002] Sulphoaluminate cement has the advantages of low alkalinity, high early strength, micro-expansion, corrosion resistance and frost resistance, and is especially suitable for use in coastal and cold areas and emergency repair projects. Traditional sulfoaluminate cement uses limestone, [0003] — [0004] Calcium sulfoaluminate (C 4 A 3 S), dicalcium silicate (C 2 S) is the main mineral phase composition, and then mixed with a small amount of gypsum and ground to obtain sulphoaluminate cement products. Compared with ordinary Portland cement, due to the reduction in the amount of raw material limestone, the firing temperature is also 100-150°C lower than that of Portland ce...

AI Technical Summary

Problems solved by technology

At present, the annual output of desulfurized gypsum in my country is about 80 million tons, and the comprehensive utilization rate is about 83%; the annual output of phosphogypsum is about 80 million tons, and the comprehensive utilization rate is less than 40%; other by-product gypsum is about 25 million tons, and the comprehensive utilization rate is about 40%.

The purpose of the above-mentioned inventive method is to maximize the utilization of industrial by-product gypsum as calcium and sulfur raw materials, provide a good idea for the resource utilization of industrial by-product gypsum, and can get through in the process; but the above methods mostly use activated carbon or Solid coke or anthracite is used as a solid reducing agent, and gypsum, clay, high-quality bauxite, fly ash, iron slag, high-sulfur coal, etc. are calcined together to produce sulphoaluminate or belite sulphoaluminate cement clinker , carbon reduction generally has high investment energy consumption and high CO 2 Emissions, furnace gas SO 2 The concentration is low, the co-production of sulfuric acid is difficult for "two conversions and two absorptions", and the operation cost is high. There are problems in operation, environmental protection and economic cost.

[0012] There are also some patents or literature reports, using phosphogypsum or desulfurization gypsum or titanium gypsum and other industrial by-product gypsum and limestone together as the source of calcium and sulfur in cement ingredients, and other raw materials such as bauxite to configure the required cement raw materials. Calcination to produce sulphoaluminate cement clinker or belite sulphoaluminate cement clinker, these methods are a small part of the use of gypsum decomposition to replace a part of CaO in limestone, can not effectively use industrial waste gypsum on a large scale, calcination SO in flue gas 2 The concentration cannot reach the concentration requirements of conventional industrial production of sulfuric acid, and the SO 2 It also increases the burden of environmental protection

[0013] Existing documents and patents have been searched, and there are reports on the method of using sulfur or sulfur gas to reduce gypsum to produce calcium oxide or Portland cement, but no information has been found on the use of sulfur gas and high-sulfur bauxite to synergistically reduce gypsum to produce sulfur aluminum A report on the process technology or method of co-production of sulfuric acid with salt cement

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