Method for utilizing coal ash to prepare slow-release fertilizer

A technology of slow-release fertilizer and fly ash, which is applied in the direction of phosphate fertilizer, application, fertilization equipment, etc., can solve the problems of high cost hindering industrialization, and achieve the effects of low cost, reduced evaporation, and increased water seepage speed

Active Publication Date: 2018-12-11
湖南斯多瑞农业发展有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, magnesium ammonium phosphate is mainly prepared by magnesium salt, phosphoric acid and ammonium salt, and its industrialization is hindered by the high cost.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] A kind of method utilizing fly ash to prepare slow-release fertilizer, it is the following steps:

[0032] (1) Grind the fly ash, then pass it through an 80-mesh sieve, add sodium hydroxide and magnesium hydroxide to the obtained under-sieve, then mix evenly, put it into a rotary kiln for calcination, the calcination temperature is 420°C, and the calcination time is For 3h, obtain calcined material;

[0033] (2) Add the calcined material of step (1) into hot water to slurry, then filter to obtain the first filtrate and the first filter residue, add ammonium sulfate solution to the obtained first filter residue, stir at a temperature of 33°C for 55min, and then add phosphoric acid The solution adjusted the pH of the solution to 9.5, then added diammonium hydrogen phosphate, stirred and reacted at a temperature of 32° C. for 2.5 hours, and then filtered to obtain a second filtrate and a second filter residue;

[0034] (3) drying, crushing and screening the second filter ...

Embodiment 2

[0043] A kind of method utilizing fly ash to prepare slow-release fertilizer, it is the following steps:

[0044] (1) Grind the fly ash, then pass it through an 80-mesh sieve, add sodium hydroxide and magnesium hydroxide to the obtained undersieve, then mix it evenly, put it into a rotary kiln for calcination, the calcination temperature is 425°C, and the calcination time is Be 3.5h, obtain calcined material;

[0045] (2) Add the calcined material in step (1) to slurry with hot water, then filter to obtain the first filtrate and the first filter residue, add ammonium sulfate solution to the obtained first filter residue, stir at a temperature of 31°C for 125min, and then add phosphoric acid The solution adjusted the pH of the solution to 9.4, then added diammonium hydrogen phosphate, stirred and reacted at a temperature of 32° C. for 2.3 hours, and then filtered to obtain a second filtrate and a second filter residue;

[0046] (3) drying, crushing and screening the second fil...

Embodiment 3

[0055] A kind of method utilizing fly ash to prepare slow-release fertilizer, it is the following steps:

[0056] (1) Grind the fly ash, then pass it through a 100-mesh sieve, add sodium hydroxide and magnesium hydroxide to the obtained under-sieve, then mix evenly, put it into a rotary kiln for calcination, the calcination temperature is 440°C, and the calcination time is Be 4h, obtain calcined material;

[0057] (2) Add the calcined material in step (1) into hot water to slurry, then filter to obtain the first filtrate and the first filter residue, add ammonium sulfate solution to the obtained first filter residue, stir at a temperature of 33°C for 145min, and then add phosphoric acid The solution adjusted the pH of the solution to 9.8, then added diammonium hydrogen phosphate, stirred and reacted at a temperature of 29° C. for 2.9 hours, and then filtered to obtain a second filtrate and a second filter residue;

[0058] (3) drying, crushing and screening the second filter ...

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Abstract

The invention discloses a method for utilizing coal ash to prepare slow-release fertilizer. The coal ash is levigated and sieved, sodium hydroxide and magnesium hydrate are added into the obtained screen underflow and mixed to be uniform, the mixture is placed into a rotary kiln to be calcinated, and a calcinated material is obtained; hot water is added into the calcinated material to pulpify thecalcinated material, then the product is filtered, first filtered liquid and first filtered residue are obtained, an ammonium sulfate solution is added into the obtained first filtered residue, then aphosphoric acid solution is added to condition the pH value of the solution, diammonium hydrogen phosphate is added and stirred to react, the product is filtered, and second filtered liquid and second filtered residue are obtained; and the second filtered residue is dried, crushed, and screened, and the slow-release fertilizer is obtained. The slow-release fertilizer is obtained by taking the coal ash as the carrier and loading ammonium magnesium phosphate on the coal ash, the fertilizer efficiency release time is improved by 20% or above than simple ammonium magnesium phosphate slow-releasefertilizer, the soil property can be improved as well, the soil is loosened, the water permeating speed of the soil is increased, and the fertilizer can adsorb water, and achieves the effect of waterconservation.

Description

technical field [0001] The invention relates to a method for preparing slow-release fertilizer by using fly ash, which belongs to the field of waste recycling. Background technique [0002] Fly ash is the main solid waste of coal-fired power plants and one of the largest industrial wastes in the world today. In 2012, my country's fly ash output was 450 million tons, and it is estimated that by 2020, the total stockpile of fly ash will reach 3 billion tons. Fly ash contains a variety of chemical components and organic matter. Improper handling will pollute the environment and pose a threat to human health, such as land occupation, air pollution, water source and soil pollution. The comprehensive utilization rate of fly ash in China has reached 70%. On the basis of expanding the scale of waste utilization and improving the utilization level, it is of great significance to develop new application ways of fly ash and improve the comprehensive utilization level of fly ash in my ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C05G3/00C05G3/04C05G3/80
CPCC05B7/00C05G3/00C05G3/80C05D9/00
Inventor 郑忆依
Owner 湖南斯多瑞农业发展有限公司
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