Method for preparing lime raw material and SO2 by decomposing phosphogypsum from high sulphur refinery coke

Abstract

The invention discloses a method for preparing a calcium carbonate raw material and SO2 by utilizing high-sulfur petroleum coke to decompose phosphogypsum, i.e., the high-sulfur petroleum coke with the carbon mass fraction higher than 80 percent and the sulfur mass fraction higher than 2 percent to 6 percent is used for reducing and decomposing the phosphogypsum to prepare burner gas with the SO2 volume percentage higher than or equal to 15 percent. The burner gas can be directly used as qualified virgin gas for the two-conversion and two-absorption acid-making technology so as to produce the solid product, CaO, with the mass fraction of higher than 50 percent, and can also be directly used as a chemical raw material, for instance, for making cement. No waste is generated in the process, the decomposition rate of the phosphogypsum is higher than or equal to 95 percent, and the desulphurization degree is higher than or equal to 90 percent. By utilizing the technology for decomposing the phosphogypsum, pretreatment is not required and the concentration of SO2 is stable in the burner gas. The content and the thermal value of carbon in the high-sulfur petroleum coke are comparatively high, and the contents of nitrogen and sulfur are higher than that of other fuels, thereby reducing reaction temperature, energy consumption and production cost, simultaneously, environment pollution is not generated and waste is changed into valuable. The utilization of components of the phosphogypsum is maximized during the technical process so as to solve the problem of realizing the harmlessness and sales of the phosphogypsum as 'dangerous waste'.

Description

technical field [0001] The invention relates to a method for reducing and decomposing phosphogypsum by using high-sulfur petroleum coke. The method uses two kinds of solid waste phosphogypsum and high-sulfur petroleum coke to prepare calcareous raw materials with a mass percentage of CaO greater than 50% and high-concentration SO 2 Furnace gas is used as raw material gas for acid production, and belongs to the field of environmental protection and chemical technology. Background technique [0002] As a by-product of the petrochemical industry, high-sulfur petroleum coke has high carbon content, low ash content, and high calorific value. The main element is carbon, accounting for more than 80 wt%, and the rest are hydrogen, oxygen, nitrogen, and sulfur. and metal elements. Petroleum coke has its unique physical, chemical and mechanical properties. It is the non-volatile carbon of the heating part. The indicators of volatile matter and mineral impurities (sulfur, metal compou...

AI Technical Summary

Problems solved by technology

In the process of producing wet-process phosphoric acid by the dihydric method, 4 to 5 tons of phosphogypsum are produced for every ton of phosphoric acid produced. According to statistics, by the end of 2007, the annual discharge of phosphogypsum in the world reached more than 200 million tons, and China’s annual discharge of phosphorus Gypsum also reaches more than 20 million tons, while the comprehensive utilization rate is less than 10%

[0008] The above-mentioned method has the following disadvantages: (1) the reduction rate of calcium sulfate in phosphogypsum is not high; (2) the reduction and decomposition reaction of phosphogypsum raw meal and the firing reaction of cement clinker are set in one device to complete, resulting in high-temperature sintering The time is too long, which greatly increases the production cost

(3) SO in kiln gas 2 If the concentration is too low, the subsequent acid production process will be too long, which will further lead to high production costs

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