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Method for reducing ardealite decomposition temperature

A decomposition temperature, phosphogypsum technology, 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, difficult to popularize and apply, etc. The effect of reduction, production cost reduction and process simplification

Inactive Publication Date: 2009-02-04
KUNMING UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
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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

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Example 1: Dry phosphogypsum at 100-110°C for 5 hours, remove free water, grind and pass through a 120-mesh standard sampling sieve, take 100g of dry phosphogypsum and dry coal and additives by 100 parts phosphorus Gypsum + 5 parts of coal + 3 parts of admixture (ingredient 2) 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, and the reaction is performed at a temperature of 700°C-850°C 3 hours until outlet flue gas SO 2 When the content reaches 14%, the heating is stopped, and the composition of the solid slag is measured after natural cooling. It is calculated that the decomposition rate of phosphogypsum is 97%, and the desulfurization rate is 91.5%.

Embodiment 2

[0042] Example 2: Dry phosphogypsum at 100-110°C for 5 hours, remove free water, grind it through a 120-mesh standard sampling sieve, take 100g of dry phosphogypsum and dry coal and additives by 100 parts 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. The heating rate of the tubular resistance furnace is controlled at 20°C / min, and the reaction is performed at a temperature of 700°C-750°C 3.5 hours until outlet flue gas SO 2 When the content reaches 14%, the heating is stopped, and the composition of the solid slag is measured after natural cooling. The calculated decomposition rate of phosphogypsum is 96.5%, and the desulfurization rate is 92%.

Embodiment 3

[0043] Example 3: Dry phosphogypsum at 100-110°C for 5 hours, remove free water, grind and pass through a 120-mesh standard sampling sieve, take 100g of dry phosphogypsum and dry coal and additives by 100 parts 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, add reducing gas (ingredient 5) at a flow rate of 5ml / min and react for 3 hours until the outlet flue gas SO 2 When the content reaches 14%, the heating is stopped, and the composition of the solid slag is measured after natural cooling. The calculated decomposition rate of phosphogypsum 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 ratios 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 be more 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 industrial waste generated during the production of phosphoric acid. Pile of phosphogypsum occupies a large amount of land. After soaking in rainwater, the soluble P 2 o 5 Harmful components such as fluoride and fluoride diffuse and infiltrate into the surrounding environment through the water body, causing serious pollution to soil, water, and the atmosphere. In May 2006, the State Environmental Protection Administration classified phosphogypsum as a hazardous waste. The production and stacking of a large amount of phosphogypsum has become a bottleneck restricting the sustainable development of phosphorus chemical industry. The harmless treatment and comprehensive utilization of phosphogypsum has become a research hotspot in the field o...

Claims

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Application Information

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