Coproducing cement technological method of producing acid using phosphogypsum and sulfur

Abstract

The present invention relates to a process capable of simultaneously preparing acid and producing cement by combining phosphogypsum with sulfur. It is characterized by utilizing waste slag phosphogypsum obtained by wet process phosphoric acid production to prepare acid and produce cement. In the concrete, the invented process includes the following steps: utilizing low-concentration SO2 gas discharged out from rotary kiln of phosphogypsum acid-making system and making said kiln gas undergo the processes of washing, cleaning and drying, then be mixed with high-concentration SO2 gas discharged from sulfur acid-making system to obtain the SO2 gas whose concentration is 8-9%; and adopting an advanced two-stage two-absorption acid-making process to prepare sulfuric acid; at the same time firing the phosphogypsum in the rotary kiln to obtain cement clinker, grinding and blending so as to obtain cement.

Description

Technical field: [0001] The present invention relates to a process method for combining phosphogypsum and sulfur to produce acid and co-produce cement. It uses wet-process phosphoric acid to produce waste residue phosphogypsum to produce cement sulfuric acid. Specifically, it refers to the use of phosphogypsum acid system to produce low-concentration SO from a rotary kiln. 2 Gas, the kiln gas is washed, purified and dried, and the high concentration SO 2 The gas is mixed to form SO with a concentration of 8-9% by volume 2 The gas is made into sulfuric acid by the advanced two-turn-two-suction acid production process, and at the same time, phosphogypsum is fired into cement clinker in a rotary kiln, and then cement is made into cement through grinding and batching. Background technique: [0002] The main component of waste phosphogypsum produced by wet-process phosphoric acid production is CaSO 4. 2H 2 O, is currently mainly used to produce cement and produce sulfuric acid...

AI Technical Summary

Problems solved by technology

[0004] ① Raw gas SO 2 The concentration is low, the conversion heat of two rotations and two suctions cannot be balanced, only one rotation and one suction can be used, the tail gas cannot be emptied directly, and the operating cost is high

[0005] ② Raw gas SO 2 The concentration of the acid is low, resulting in low production intensity of the production equipment, resulting in large investment and low efficiency of the acid plant

[0006] ③Due to the fact that the calcination process of the rotary kiln is easy to form rings and burn out, the processing time is long, and the follow-up equipment can only be produced, resulting in a low utilization rate of the equipment

At the same time, the temperature of each stage of conversion drops when waiting for production, and the conversion must rely on external heat to raise the temperature during production, which increases the production cost

[0007] ④The operation of the rotary kiln is not easy to master, and the working conditions fluctuate greatly, which has a great impact on the acid plant

When the kiln is in a strong reducing atmosphere, sublimated sulfur is produced, which blocks the pipes and equipment of the purification system; when the kiln is in a strong oxidizing atmosphere, phosphogypsum cannot be completely decomposed, resulting in kiln gas SO 2 The concentration is low, which has a great impact on acid production, and at the same time leads to unqualified quality of cement products

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