Phosphogypsum desulfurization calcining treatment system and method

Abstract

A phosphogypsum desulfurization calcining treatment system and method are included. the phosphogypsum desulfurization calcining treatment system comprises a low temperature dehydration system, a hightemperature calcination system and an acid making system, the low temperature dehydration system sequentially comprises a dryer, a drying mill and a pipeline furnace, the high temperature calcinationsystem sequentially comprises a preheating device, a rotary kiln and a cooler, natural water and crystal water are removed from phosphogypsum through low-temperature drying and high-temperature grinding and drying to obtain anhydrous gypsum, high-temperature calcination is carried out on the anhydrous gypsum, air cooling is carried out, the calcined anhydrous gypsum is sent to a cement productionline as a cement raw material, and gas generated in the calcination process is collected, and then sent to an acid making system to prepare sulfuric acid. According to the invention, a phosphogypsum acid making system and a cement system are separated, phosphogypsum dehydration, phosphogypsum decomposition, kiln gas acid making and resource comprehensive utilization of kiln slag are included, so that mutual interference between a desulfurization process and a cement process can be reduced, production of high-quality Portland cement and high-quality sulfuric acid is ensured, and harmless, resource and large-batch treatment of phosphogypsum is realized.

Description

technical field [0001] The invention belongs to the technical field of phosphogypsum calcining treatment, and in particular relates to a phosphogypsum desulfurization and calcining treatment system and treatment method. Background technique [0002] With the development of my country's phosphate and compound fertilizer industry, the utilization of industrial waste phosphogypsum has become a problem that cannot be ignored in the development of the industry. Every ton of phosphoric acid produced (100%P 2 o 5 ) produces 5-6t (dry basis) of phosphogypsum, and the actual amount is about 7t. In addition to CaSO in phosphogypsum 4 In addition, it also contains undecomposed phosphate rock, unwashed phosphoric acid, calcium fluoride, iron, aluminum compounds, acid insoluble matter, organic matter and other impurities. These impurities affect the utilization of phosphogypsum to a certain extent. According to relevant statistics, the annual output of phosphogypsum in my country is ...

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Problems solved by technology

[0005] The co-production of cement with sulfuric acid from phosphogypsum mainly has the following problems: (1) The simultaneous production of acid and cement interferes with each other. Due to the complex conditions of the calcination kiln, on the one hand, the quality of the fired cement clinker is difficult to achieve stable, high-quality and high-yield. SO in kiln gas 2 The content is low, and the cost of purifying acid is high; (2) The decomposition of phosphogypsum requires a reducing atmosphere, but cement production cannot have a reducing atmosphere. Therefore, there are unresolvable technical contradictions in the production process of one-step acid production and co-production of cement; (3) Phosphogypsum In order to increase SO in the kiln gas during acid production 2 Sulfur is used as a reducing agent, but the sublimation and melting of sulfur can easily cause pipeline blockage and affect the safe operation of cement kilns.

Utilizing the equipment system of the utility model, the industrial waste phosphogypsum is used as raw material to produce anhydrite powder, which can directly absorb a large amount of phosphogypsum containing water, and simultaneously modify, dry and grind the phosphogypsum containing water, and can quickly complete "dehydration + roasting" " process, and it is easy to effectively control the roasting quality, and the energy consumption is low. Although the application is a "dehydration + roasting" process, the final product prepared by gas is anhydrite, which is actually anhydrous calcium sulfate. Only the dehydration process is realized, and there is no Realize the real desulfurization process, and its products cannot be used in the acid production process, and still belong to the category of preparing building gypsum, and cannot process phosphogypsum in large quantities

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