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Method for recovering calcium phosphate fertilizers from sludge incineration bottom ash

A technology of sludge incineration and calcium phosphate fertilizer, applied in phosphate fertilizer, chemical instruments and methods, phosphorus compounds, etc., can solve the problems of new solid substances hindering the reaction, low extraction rate, etc., to achieve short evaporation time, high phosphorus extraction rate, cost reduction effect

Pending Publication Date: 2020-08-18
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Aiming at the above-mentioned deficiencies in the prior art, the present invention provides a method for recovering calcium and phosphate fertilizer from sludge incineration bottom ash, which can effectively solve the problems that the existing method has a low extraction rate and new solid substances will be produced during the extraction process to hinder the reaction

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] A method for recovering calcium phosphate fertilizer from bottom ash of sludge incineration includes the following steps:

[0036] (1) Bake the bottom ash of the sludge incineration to a constant weight in an oven and cool;

[0037] (2) Prepare 15mL hydrochloric acid solution with a concentration of 1.5mol / L;

[0038] (3) Weigh 5g of sludge incineration bottom ash, and control the low liquid-solid ratio to 3mL / g;

[0039] (4) After preheating the hydrochloric acid solution in a 45°C water bath, mix the bottom ash of the sludge incineration with the hydrochloric acid solution;

[0040] (5) Control the speed of the mixer to 200 rpm, and use the mixer to stir the mixed solution of the bottom ash of the sludge incineration and hydrochloric acid. After stirring for 30 minutes, filter to obtain the phosphorus-rich extract, in which the extraction rate of phosphorus reached 92.6%;

[0041] (6) Control the molar ratio of calcium hydroxide to phosphoric acid to 0.5:1, and weigh calcium hyd...

Embodiment 2

[0045] A method for recovering calcium phosphate fertilizer from bottom ash of sludge incineration includes the following steps:

[0046] (1) Bake the bottom ash of the sludge incineration to a constant weight in an oven and cool;

[0047] (2) Prepare 30mL hydrochloric acid solution with a concentration of 2.5mol / L;

[0048] (3) Weigh 10g of sludge incineration bottom ash, and control the low liquid-solid ratio to 3mL / g;

[0049] (4) After preheating the hydrochloric acid solution in a 35°C water bath, mix the bottom ash of the sludge incineration with the hydrochloric acid solution;

[0050] (5) Control the speed of the mixer to 100 rpm, use the mixer to stir the mixed solution of the bottom ash of the sludge incineration and hydrochloric acid. After stirring for 5 minutes, the phosphorus-rich extract is obtained, and the phosphorus extraction rate is 90.3%;

[0051] (6) Control the molar ratio of calcium hydroxide to phosphoric acid to 6:1, and weigh calcium hydroxide;

[0052] (7) Put ...

Embodiment 3

[0055] A method for recovering calcium phosphate fertilizer from bottom ash of sludge incineration includes the following steps:

[0056] (1) Bake the bottom ash of the sludge incineration to a constant weight in an oven and cool;

[0057] (2) Prepare 15mL hydrochloric acid solution with a concentration of 2.0mol / L;

[0058] (3) Weigh 5g of sludge incineration bottom ash, and control the low liquid-solid ratio to 3mL / g;

[0059] (4) After preheating the hydrochloric acid solution in a water bath at 25°C, mix the bottom ash of the sludge incineration with the hydrochloric acid solution;

[0060] (5) Control the speed of the mixer to 200 rpm, use the mixer to stir the mixed solution of the bottom ash of the sludge incineration and hydrochloric acid. After stirring for 10 minutes, the phosphorus-rich extract is obtained, and the phosphorus extraction rate reaches 92.9%;

[0061] (6) Control the molar ratio of calcium hydroxide to phosphoric acid to 2:1, and weigh calcium hydroxide;

[0062] ...

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Abstract

The invention discloses a method for recovering calcium phosphate fertilizers from sludge incineration bottom ash. The method comprises the following steps: (1) drying sludge incineration bottom ash to a constant weight, and cooling for later use; (2) mixing a hydrochloric acid solution with the sludge incineration bottom ash, stirring for 5-60 minutes, and filtering to obtain a phosphorus-rich extract; (3) adding calcium hydroxide into the phosphorus-rich extract, reacting for 1-60 minutes, and evaporating and concentrating the reaction solution at 100-120 DEG C to form a crystal film on thesurface of the solution; and (4) naturally cooling and crystallizing at the room temperature, filtering, collecting upper crystals, and air-drying the crystals to obtain the phosphate fertilizer. According to the method, extraction is carried out in a low liquid-solid ratio manner; the generation of a large amount of waste liquid is avoided, due to the low liquid-solid ratio, an enriching effect is realized during the phosphate extraction process, the cost of subsequent treatment is reduced, meanwhile, hydrochloric acid is adopted for processing, no new substance is generated, the extraction is not hindered, the extraction rate is high, and the purity of the obtained phosphate fertilizer is high.

Description

Technical field [0001] The invention belongs to the technical field of resource recovery in sewage treatment plants, and specifically relates to a method for recovering calcium phosphate fertilizer from bottom ash of sludge incineration. Background technique [0002] With the reduction of phosphate rock reserves, the reduction of quality and the increase of phosphate rock prices, we are prompted to find new alternatives for agricultural phosphate fertilizer production. The bottom ash of sludge incineration is the ash residue obtained after incineration of the remaining sludge of a municipal sewage plant. It has a great resource potential because of its rich phosphorus. The wet chemical method, that is, chemical agents, can be used to treat the bottom ash of sludge incineration, and the phosphorus can be extracted from the bottom ash of sludge incineration. This can not only reduce the disposal pressure of bottom ash, but also recover phosphorus resources. [0003] At present, sul...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C05B1/04C01B25/455
CPCC01B25/455C05B1/04
Inventor 陈滢刘敏徐灵芳
Owner SICHUAN UNIV
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