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A method for extracting phosphorus in sludge to produce phosphorus-containing compound fertilizer

A compound fertilizer and sludge technology, which is applied to phosphorus compounds, sludge treatment, biological sludge treatment, etc., can solve the problems of high energy consumption, phosphorus recyclables doped with heavy metals, poor phosphorus release effect, etc., and achieve low energy consumption , Phosphorus release effect is good, and the effect of phosphorus release period is short

Active Publication Date: 2019-10-11
TIANJIN ENEW ENVIRONMENTAL PROTECTION ENGCO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The invention proposes a method for extracting phosphorus in sludge to produce phosphorus-containing compound fertilizer, which solves the problems of poor phosphorus release effect, high energy consumption, and doping of heavy metals in phosphorus recovery products in the prior art.

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  • A method for extracting phosphorus in sludge to produce phosphorus-containing compound fertilizer

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Effect test

Embodiment 1

[0045] This embodiment is carried out according to the following steps:

[0046] Adjust the solid content of the remaining sludge from a sewage treatment plant to 5% to make the sludge solution evenly mixed; add dilute sulfuric acid solution to the evenly mixed sludge to adjust the pH to 2, and after 1 hour of reaction, the phosphate is released from the solid sludge into the solution; after the reaction, the sludge solution was statically precipitated, and the supernatant containing phosphate was taken out, and the PO in the solution was measured 4 3- Concentration is 579mg / L; add Fe to solution containing phosphate 3+ , such that PO 4 3- with Fe 3+ The molar ratio of the solution is 1:1, adding CaO turbid solution to adjust the pH of the solution to 3, after 10 minutes of reaction, gray-white iron phosphate FePO 4 Precipitation; adding sodium hydrosulfide solution to iron phosphate precipitation, Fe 3+ reduced to Fe 2+ , and accompanied by PO 4 3- Dissolution; After...

Embodiment 2

[0048] This embodiment is carried out according to the following steps:

[0049] The sludge in the secondary sedimentation tank of a sewage treatment plant was anaerobic at room temperature for 3 days, and the solid content of the sludge was adjusted to 10%, and mixed evenly; dilute hydrochloric acid solution was added to the sludge solution, and the pH was adjusted to 0.5. After 30 minutes of reaction, the phosphate was removed from the solid sludge The sludge enters the solution, the sludge solution settles still, the supernatant containing phosphate is taken out, and the PO in the solution is measured 4 3- The concentration is 513mg / L; add a certain amount of Fe to the solution containing phosphate 3+ , such that PO 4 3- with Fe 3+ The molar ratio of the solution is 1:1.5, and the pH of the solution is adjusted to 2.5. After 15 minutes of reaction, gray-white iron phosphate FePO is produced. 4 Precipitation: Pass hydrogen sulfide gas into the ferric phosphate precipita...

Embodiment 3

[0051] This embodiment is carried out according to the following steps:

[0052] The sludge of a sewage treatment plant was anaerobic at room temperature for 7 days, and the solid content was adjusted to more than 3%, so that the sludge solution was mixed evenly; the glacial acetic acid solution was added to the evenly mixed sludge, and the pH was adjusted to 2, and after 40 minutes of reaction, the phosphate Enter the solution from the solid sludge, the sludge solution settles still, take out the supernatant containing phosphate, and measure the PO in the solution 4 3- The concentration is 799mg / L; add a certain amount of Fe to the solution containing phosphate 3+ , such that PO 4 3- with Fe 3+ The molar ratio of the solution is 1:1.2, and the pH of the solution is adjusted to 4. After 12 minutes of reaction, gray-white iron phosphate FePO is produced. 4 Precipitation; add sodium hydrogen sulfide solution to iron phosphate precipitation, continue to add Ca(OH) after a ce...

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Abstract

The invention provides a method for extracting phosphorus from sludge to produce a phosphorus-containing composite fertilizer. The problems in the prior art that the phosphorus release effect is poor, the energy consumption is high, and the phosphorus recycled material is doped with heavy metal are solved. The method comprises the steps of 1, phosphorus release, wherein an acid solution is added into a sludge solution to make phosphate released into the solution; 2, phosphorus recycling, wherein supernatant with phosphate in the step 1 is taken out, PO43- and Fe3+ are made to generate ferric phosphate sediment by adding Fe3+ under preset conditions, and water washing is carried out several times on the ferric phosphate sediment; 3, phosphate fertilizer preparation, wherein a reducing agent is added into the ferric phosphate sediment, and Fe3+ is reduced into Fe2+, accompanied by dissolving of PO43+; MgO, Mg(OH)2 and CaO or Ca(OH)2 is added to adjust the pH so as to form a raw material of the phosphorus-containing composite fertilizer, and the raw material of the phosphorus-containing composite fertilizer is processed into the phosphorus-containing composite fertilizer. According to the method for extracting phosphorus from the sludge to produce the phosphorus-containing composite fertilizer, waste is turned into wealth, resource utilization of phosphorus in the sludge is achieved, and the resource utilization rate of phosphorus in the sludge can reach 92% or above.

Description

technical field [0001] The invention relates to the field of sludge treatment, in particular to a method for extracting phosphorus in sludge to produce phosphorus-containing compound fertilizer. Background technique [0002] Phosphorus in nature is a limited and non-renewable non-metallic mineral resource. It is mainly used for agricultural fertilization and consumes a lot every year. Phosphorus has been listed as one of the 20 kinds of minerals that cannot meet the needs of national economic development after 2010. . In the process of biochemical treatment of sewage, microorganisms can accumulate excess phosphorus in the form of phosphorus accumulation, in addition to the formation of iron phosphorus, aluminum phosphorus, calcium phosphorus and other precipitates, making the phosphorus content in sludge quite high, which can be as high as sewage 6.9% of the dry weight of the mud, which is of great recycling value. Therefore, releasing phosphorus in sludge through effectiv...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C05B17/00C05G1/00C01B25/37C02F11/00C02F11/04
Inventor 王学科马竞男范磊
Owner TIANJIN ENEW ENVIRONMENTAL PROTECTION ENGCO LTD