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Process for preparing modified ardealite by water-free calcining

A phosphogypsum, water-free technology, applied in the fields of building materials and phosphorus chemical industry, can solve the problems of large one-time investment in pretreatment process, serious secondary pollution of sewage discharge, lack of competitiveness, etc., shortening processing time and reducing energy consumption. , the effect of avoiding secondary pollution

Inactive Publication Date: 2009-12-09
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The above-mentioned process has problems such as large one-time investment in pretreatment process, high energy consumption, serious secondary pollution of sewage discharge, etc., and the product lacks economic competitiveness.
A lot of work is still needed to fully promote the application

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] According to the weight proportion of 91% phosphogypsum, 1% green vitriol, 1% aluminum sulfate, 2% quicklime, and 5% cement, mix them evenly, and dry them in a dryer. The drying temperature is controlled at 105°C, and the The moisture content of phosphogypsum is lower than 8%, and then enters the calciner to be calcined at 200°C. The high-temperature flue gas generated during the calcination process is recovered to a dryer to dry the phosphogypsum, and after 0.5 hours of calcination, the heating of the calcination furnace is stopped, and the modified phosphogypsum is obtained by natural cooling.

[0031] The measured product performance is as follows:

[0032] SO 3 Content 45%;

[0033] The fluoride ion concentration in the leachate is 0.4mg / L;

[0034] Standard consistency 60%;

[0035] The initial setting time is 7min;

[0036] The final setting time is 28min;

[0037] Flexural strength 2.6MPa;

[0038] Compressive strength 5.1MPa;

[0039] It meets the requir...

Embodiment 2

[0041] 91% of phosphogypsum, 1.5% of green vitriol, 1.5% of aluminum sulfate, 2% of quicklime, and 4% of cement are mixed evenly and dried in a dryer. The drying temperature is controlled at 105°C and made Phosphogypsum moisture is less than 8%. Then enter the calciner for calcination at 300°C. The high-temperature flue gas generated during the calcination process is recovered to a dryer to dry the phosphogypsum, and after 0.5 hours of calcination, the heating of the calcination furnace is stopped, and the modified phosphogypsum is obtained by natural cooling.

[0042] The measured product performance is as follows:

[0043] SO 3 Content 46%,

[0044] The fluoride ion concentration in the leachate is 0.35mg / L,

[0045] Standard consistency 60%,

[0046] Initial setting time 8min,

[0047] The final setting time is 29min,

[0048] Flexural strength 2.7MPa,

[0049] Compressive strength 5.4MPa,

[0050] It meets the requirements of "Building Materials Gypsum" GB9776-88 fo...

Embodiment 3

[0052] According to the weight ratio of 85% phosphogypsum, 2% green vitriol, 3% aluminum sulfate, 3% quicklime, and 7% cement, mix them evenly, and dry them in a dryer. The drying temperature is controlled at 105 ° C, and the Phosphogypsum moisture is less than 8%. Then enter the calciner for calcination at 200°C. The high-temperature flue gas generated during the calcination process is recovered to a dryer to dry the phosphogypsum, and after 0.5 hours of calcination, the heating of the calcination furnace is stopped, and the modified phosphogypsum is obtained by natural cooling.

[0053] The measured product performance is as follows:

[0054] SO 3 Content 46%,

[0055] The fluoride ion concentration in the leach solution is 0.42mg / L,

[0056] Standard consistency 61%,

[0057] Initial setting time 10min,

[0058] The final setting time is 30min,

[0059] Flexural strength 2.8MPa,

[0060] Compressive strength 5.5MPa,

[0061] It meets the requirements of "Building M...

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Abstract

The invention is a method for preparing modified phosphogypsum by calcining without water washing, that is: 1) adding a composite activator and a modifier to the phosphogypsum, wherein 85% to 95% of the phosphogypsum, 2 to 5% of the composite activator, and improved 3-10% additive, mix well; the composite activator is green vitriol + aluminum sulfate; the modifier is quicklime + cement; 2) After mixing evenly, dry, the drying temperature is 100-110°C, and the moisture content of phosphogypsum is less than 8%; 3) Enter into a calciner for calcination at 150-300°C for 0.5-1 hour, and cool naturally to obtain modified phosphogypsum. The invention decomposes and volatilizes harmful substances such as phosphorus, fluorine, and organic matter contained in phosphogypsum or converts them into calcium pyrophosphate, an inert substance harmless to products, which not only avoids secondary pollution, but also reduces or avoids trace amounts contained in phosphogypsum. The impact of harmful chemical components on product quality and performance; the processing time is shortened by 15-20%, the investment is saved by 3%-8%, and the energy consumption is reduced by 10%-20%.

Description

technical field [0001] The invention relates to the technical fields of phosphorus chemical industry and building materials, and specifically describes a method for preparing modified phosphogypsum by calcining without water washing. Background technique [0002] Phosphogypsum is the industrial waste produced by the reaction of phosphate rock and sulfuric acid in the production process of wet-process phosphoric acid. It is calculated that every ton of phosphoric acid produced will produce 4-5 tons of phosphogypsum. At present, the annual discharge of phosphogypsum in the world reaches 200 million Tons, but the utilization rate of phosphogypsum is not more than 10%. The treatment, disposal and comprehensive utilization of phosphogypsum has become a worldwide problem. my country's phosphate fertilizer output ranks first in the world. The production of high-concentration phosphate fertilizers (such as ammonium phosphate, heavy calcium, etc.) requires a large amount of wet-proce...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B11/26
Inventor 杨月红方祖国宁平张慧娜欧根能
Owner KUNMING UNIV OF SCI & TECH