A process and system for combined production of lime and sulfur by gypsum reduction and oxidation cycle calcination

Abstract

The disclosure belongs to the field of resource utilization of solid waste, and specifically provides a system and process for gypsum reduction and oxidation cyclic calcination and joint production of lime and sulfur. It includes the following steps: firstly, the gypsum is reduced and calcined and then oxidized and calcined, the reaction temperature of both the reduction and calcination and the oxidation calcination is controlled at 700-1200°C, and the gas air coefficient is an excess air coefficient; the flue gas separated during the reduction and calcination process is Sulfur dioxide is generated after carbothermal reduction, and the flue gas produced in the oxidative calcination process carries the oxidized calcination material back to the reduction calcination process for cyclic calcination until the mass fraction of the collected solid material reaches the requirement of the quicklime product. The prepared quicklime contains calcium sulfide, which greatly reduces the quality of the quicklime, and in the prior art, sulfur products cannot be co-produced in the process of preparing quicklime from gypsum, which pollutes the environment.

Description

technical field [0001] The present disclosure belongs to the field of solid waste resource utilization, and specifically provides a process and a system for gypsum reduction and oxidation cycle calcination to jointly generate lime and sulfur. Background technique [0002] The statements herein merely provide background information related to the present disclosure and do not necessarily constitute prior art. [0003] At present, my country's industrial by-product gypsum produces about 118 million tons, and the comprehensive utilization rate is only 38%. Among them, desulfurized gypsum is about 43 million tons, with a comprehensive utilization rate of about 56%; phosphogypsum is about 50 million tons, with a comprehensive utilization rate of about 20%; other by-product gypsum is about 25 million tons, with a comprehensive utilization rate of about 40%. At present, the accumulated stockpile of industrial by-product gypsum has exceeded 300 million tons, of which more than 50 m...

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Problems solved by technology

[0009] Aiming at the problem that the quicklime prepared from gypsum in the prior art contains calcium sulfide, which greatly reduces the quality of the quicklime, and the process of preparing quicklime from gypsum in the prior art cannot co-produce various sulfur products

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