System and process for decomposing calcium sulfate and recovering sulfur and calcium oxide through carbon-sulfur cooperation

Abstract

The invention discloses a system and a process for decomposing calcium sulfate and recovering sulfur and calcium oxide through carbon-sulfur cooperation. The process comprises the steps as follows: calcium sulfate, a catalytic carbon material and sulfur are heated to the temperature of not lower than 800 DEG C, so that calcium sulfate is decomposed, decomposition smoke and calcium oxide at the temperature not lower than 700 DEG C are produced, the content of SO2 in the decomposition smoke is controlled to be not smaller than 5wt% through the addition amount of sulfur, a reduction carbon material is added to the decomposition smoke for a carbon heat reduction reaction, SO2 in the decomposition smoke produces elementary sulfur, reduction smoke produced after carbon reduction of the decomposition smoke not only contains elementary sulfur, but also contains the reduction carbon material not participating in the reduction reaction, one part of reduction carbon material not participating inthe reduction reaction is used as the catalytic carbon material, and one part of elementary sulfur is used as a sulfur material for catalyzing calcium sulfate decomposition. The problem that gypsum isdifficult to treat can be relieved, gypsum can be recycled, sulfur and calcium oxide can be recovered, and the current situation of shortage of sulfur resources can be relieved.

Description

technical field [0001] The invention relates to the field of resource utilization of solid waste, and relates to a system and a process for synergistically decomposing calcium sulfate with carbon and sulfur to recover sulfur and calcium oxide. Background technique [0002] The statements herein merely provide background information related to the present invention and may not necessarily constitute prior art. [0003] With the rapid development of high-concentration phosphate fertilizer and phosphoric acid industry, the output of by-product phosphogypsum has increased sharply. The main component of phosphogypsum is CaSO 4 2H 2 O, also contains a small amount of other metal ion sulfate. At present, the annual discharge of phosphogypsum is nearly 100 million tons, and the cumulative accumulation is nearly 500 million tons. As far as the inventor knows, although there are certain ways to utilize phosphogypsum at present, they all have certain problems, and the treatment volu...

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Problems solved by technology

[0005] In order to solve the shortage of low-grade gypsum such as phosphogypsum and desulfurized gypsum, and to solve the problems existing in limestone and sulfur mining, the present invention provides a system and process for synergistically decomposing calcium sulfate with carbon and sulfur to recover sulfur and calcium oxide. Alleviate the problem of low-grade gypsum (mainly calcium sulfate) that is difficult to handle, and at the same time, it can also make resource utilization, recover sulfur and calcium oxide, alleviate the current situation of shortage of sulfur resources, and reduce the external dependence of sulfur resources

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