Stepwise removing method of phosphate and sulfate radicals in iron phosphate wastewater

A technology of iron phosphate and phosphate radicals, which is applied in chemical instruments and methods, preparation/separation of ammonia, water pollutants, etc. It can solve the problems that phosphate radicals and sulfate radicals cannot be removed and recovered step by step, and achieve a high degree of resource utilization Effect

Active Publication Date: 2018-12-11
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In view of the problems existing in the prior art, the object of the present invention is to provide a step-by-step removal method for phosphate and sulfate in iron phosph

Method used

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  • Stepwise removing method of phosphate and sulfate radicals in iron phosphate wastewater

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Example Embodiment

[0064] Example 1

[0065] The step-by-step removal of phosphate and sulfate in ferric phosphate wastewater is as follows:

[0066] 1) Take iron phosphate production wastewater, test the concentration of phosphate and sulfate, and add lye to adjust the pH of the wastewater = 6-9;

[0067] 2) According to the test phosphate concentration, add ferric sulfate solid with the number of moles of iron ion 0.5 times that of phosphate ion, and stir the reaction for 30 minutes;

[0068] 3) Add lye again to adjust pH=3-3.5, stir for 2min;

[0069] 4) Add 5% PFC, and the volume ratio of iron phosphate wastewater is 1:2000, stir the reaction for 10 minutes, let the precipitation stand for 30 minutes, and filter to obtain a solid containing iron phosphate and the filtrate. The filtrate is analyzed for the sulfate concentration and phosphate concentration. ;

[0070] 5) Determine the sulfate concentration in the filtrate in step 4), and add calcium hydroxide solid at a molar ratio of calcium to sulfate...

Example Embodiment

[0077] Example 2

[0078] The step-by-step method for removing phosphate and sulfate in iron phosphate wastewater, the specific steps are as follows:

[0079] 1) Take iron phosphate production wastewater, test the concentration of phosphate and sulfate, and add lye to adjust the pH of the wastewater = 6-9;

[0080] 2) According to the concentration of test phosphate, add iron sulfate solid with the number of moles of iron ion as 2 times of phosphate ion, and stir for 2h;

[0081] 3) Add lye again to adjust pH=7-8, and stir for 2min;

[0082] 4) Add 3% PAS and stir and react for 2 minutes, and the volume ratio to iron phosphate wastewater is 1:500. The precipitate is left standing for 5 minutes and filtered to obtain a solid containing iron phosphate and a filtrate. The filtrate is analyzed for the concentration of sulfate and phosphate;

[0083] 5) Determine the sulfate concentration in the filtrate in step 4), and add calcium hydroxide solid at a molar ratio of calcium to sulfate of 1.2...

Example Embodiment

[0090] Example 3

[0091] The step-by-step method for removing phosphate and sulfate in iron phosphate wastewater, the specific steps are as follows:

[0092] 1) Take iron phosphate production wastewater, test the concentration of phosphate and sulfate, and add lye to adjust the pH of the wastewater = 6-9;

[0093] 2) According to the test phosphate concentration, add ferric sulfate solid with the number of moles of iron ions 1.2 times that of phosphate ions, and stir the reaction for 30 minutes;

[0094] 3) Add lye again to adjust pH=3.5-4.5 and stir for 2min;

[0095] 4) Add 0.5% PFS and stir and react for 5 min, and the volume ratio to ferric phosphate wastewater is 1:1500. The precipitate is allowed to stand for 30 min and filtered to obtain a solid containing ferric phosphate and a filtrate. The filtrate is analyzed for the concentration of sulfate and phosphate;

[0096] 5) Determine the sulfate concentration in the filtrate in step 4), and add calcium hydroxide solid at a molar ra...

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Abstract

The invention relates to a stepwise removing method of phosphate and sulfate radicals in iron phosphate wastewater. The method comprises the following steps of: (1) adding alkali liquor to the iron phosphate wastewater to adjust the pH (potential of Hydrogen) value to 4-11; (2) adding iron sulfate to carry out precipitation reaction; (3) adding the alkali liquor again to adjust the pH value to 3-9; (4) adding a flocculating agent, stirring and standing to obtain a filtrate and an iron phosphate-containing solid via solid-liquid separation; and (5) adding calcium hydroxide to the filtrate obtained in the step (4) and carrying out the precipitation reaction to obtain filtrate and a calcium sulfate-containing solid via the solid-liquid separation, wherein the alkali liquor comprises any one or a combination of at least two of sodium hydroxide, potassium hydroxide or ammonia water. The method has the advantages that the phosphate and sulfate radicals are separately removed, the calcium sulfate is recovered and the resource utilization degree is higher than that of the prior art; and in the final effluent, the content of the phosphate radical is less than 0.5 g/L and the content of thesulfate radical is less than 1.5 g/L.

Description

technical field [0001] The invention relates to the field of industrial wastewater treatment, in particular to a step-by-step removal method for phosphate and sulfate in iron phosphate wastewater. Background technique [0002] In the production process of iron phosphate, a large amount of comprehensive wastewater containing high concentrations of phosphate, sulfate and ammonia nitrogen will be produced. Pollutants in iron phosphate wastewater are represented by ions as NH 4 + (ammonium ion), SO 4 2- (sulfate ion), PO 4 3- (phosphate ion). If the treatment is not up to standard, the phosphate and ammonia nitrogen will cause serious pollution to the environment. Moreover, the high-concentration ions in the wastewater have not been recovered, resulting in a waste of resources. The traditional lime dosing method to simultaneously remove phosphate and sulfate in wastewater produces a large amount of mixed sludge, which cannot be treated or recycled, resulting in waste of ...

Claims

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Application Information

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IPC IPC(8): C02F1/52C01C1/10C02F101/10
CPCC01C1/10C02F1/001C02F1/04C02F1/5236C02F1/5245C02F2001/007C02F2101/101C02F2101/105
Inventor 刘晨明李雅曹宏斌
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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