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Method for reducing ardealite decomposition temperature

A technology of decomposition temperature and phosphogypsum, applied in the direction of sulfur dioxide/sulfurous acid, calcium/strontium/barium oxide/hydroxide, etc., can solve the problems of high decomposition temperature, unreasonable economy, difficulty in popularization and application, etc., and achieve production cost The effects of lowering, lowering decomposition temperature, and lowering energy consumption

Inactive Publication Date: 2010-09-01
KUNMING UNIV OF SCI & TECH
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  • Abstract
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Problems solved by technology

[0005] Since the 1950s in my country, the research work on gypsum decomposition to produce sulfuric acid co-production of cement has been carried out. However, due to the high decomposition temperature and the long-term problems of key equipment, it has been difficult to popularize and apply it.
In the 1980s, Sanhuan Chemical Co., Ltd. (formerly Yunnan Phosphate Fertilizer Factory), a subsidiary of Yuntianhua Group, built a set of cement raw material equipment with an annual output of 100,000 tons of sulfuric acid from phosphogypsum using dry-process hollow kiln technology. Since the commissioning of the device in 1987, due to the high energy consumption of the rotary kiln and unreasonable economics, it has not been put into production

Method used

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  • Method for reducing ardealite decomposition temperature

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Embodiment 1: phosphogypsum was dried at 100-110 ° C for 5 hours, free water was removed, 120 mesh standard sieves were ground, and 100g of dry phosphogypsum and dry coal and admixture were obtained by 100 parts of phosphorus Gypsum + 5 parts of coal + 3 parts of admixtures (ingredient 2) are mixed evenly and placed in a quartz tube and placed in a tubular resistance furnace. 3 hours until exit flue gas SO 2 When the content reaches 14%, the heating is stopped, and the solid slag composition is measured after natural cooling. The calculated phosphogypsum decomposition rate is 97%, and the desulfurization rate is 91.5%.

Embodiment 2

[0042] Embodiment 2: phosphogypsum was dried at 100-110 ° C for 5 hours, free water was removed, 120 mesh standard sieves were ground, and 100g of dry phosphogypsum and dry coal and admixture were obtained by 100 parts of phosphorus Gypsum + 5 parts of coal + 3.5 parts of admixture (ingredient 3) are mixed evenly and placed in a quartz tube and placed in a tubular resistance furnace. 3.5 hours until exit flue gas SO 2 When the content reaches 14%, the heating is stopped, and the solid slag composition is measured after natural cooling. The calculated phosphogypsum decomposition rate is 96.5%, and the desulfurization rate is 92%.

Embodiment 3

[0043] Embodiment 3: phosphogypsum was dried at 100-110 ° C for 5 hours, free water was removed, 120 mesh standard sieves were ground finely, and 100g of dry phosphogypsum and dry coal and admixture were pressed by 100 parts of phosphorus. Gypsum + 6 parts of coal + 3 parts of admixture (ingredient 4) are mixed evenly and placed in a quartz tube and placed in a tubular resistance furnace. The heating rate of the tubular resistance furnace is controlled at 20°C / min. At the same time, the reducing gas (ingredient 5) was added at a flow rate of 5ml / min and reacted for 3 hours until the outlet flue gas SO 2 When the content reaches 14%, the heating is stopped, and the solid slag composition is measured after natural cooling. The calculated phosphogypsum decomposition rate is 98%, and the desulfurization rate is 93.5%.

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Abstract

The invention relates to a method for decreasing the decomposition temperature of phosphogypsum and belongs to the technical field of phosphate chemical treatment. The invention respectively adopts gaseous reducing agents of -CO and H2S and powder of solid reducing agents such as fly ash and coal gangue as well as the gas-solid, solid-solid complex reducing agents as admixtures and adds the admixtures into the phosphogypsum to decompose and control the double-atmosphere reaction, thus achieving the purposes that the decomposition temperature of the phosphogypsum is decreased, and the high decomposition ratio and vulcanization rate are ensured, and the decomposition temperature of the phosphogypsum is caused to be less than or equal to 1000 DEG C, and the decomposition rate is caused to bemore than or equal to 95 percent and the resource SO2 can be stably recovered.

Description

1. Technical field [0001] The invention relates to a method for reducing the decomposition temperature of phosphogypsum, and belongs to the technical field of phosphorus chemical treatment. 2. Background technology [0002] Phosphogypsum is an industrial waste produced in the production process of phosphoric acid. Phosphogypsum stacks occupy a lot of land. After being soaked in rainwater, the soluble P 2 O 5 In May 2006, the State Environmental Protection Administration classified phosphogypsum as hazardous waste. The production and stacking of a large amount of phosphogypsum has become a bottleneck restricting the sustainable development of phosphorus chemical industry. [0003] However, the resource utilization of phosphogypsum is not satisfactory, and the effective utilization rate of phosphogypsum in the world is only about 4.5%. The utilization rate of phosphogypsum in developed countries such as Japan, South Korea and Germany is relatively high. Taking Japan as an e...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F11/04C01B17/48
Inventor 马丽萍宁平杜亚雷
Owner KUNMING UNIV OF SCI & TECH