Process method for converting high-salinity wastewater into NaOH solution

A process method and converted technology are applied in the field of converting high-salinity wastewater into NaOH solution, which can solve the problems of difficult removal, difficult operation, equipment failure and shutdown, etc., and achieve the effect of simple method, small operation difficulty and small investment.

Pending Publication Date: 2020-08-28
导洁(北京)环境科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] With the rapid development of industry, people's requirements for wastewater discharge are gradually increasing, among which the chloride ion (Cl) mainly contained in high-salt wastewater - ) and sulfate ion (SO4 2- ) is difficult to remove. At present, low-temperature evaporation is used to remove chloride ions and sulfate ions in high-salt wastewater. This method requires expensive evaporation equipment, large investment, and requires a heat source. The cost of ton water treatment in actual operation is high. ; Difficult operation and frequent failures are difficult to overcome. Due to the complex composition of high-salt wastewater, a large amount of precipitation is easily generated during the evaporation process and easily adheres to the inner wall of the heat exchange tube to form complex and difficult-to-clean composite scales such as calcium sulfate and silicate, resulting in heat exchange. Efficiency drops, cost per ton of water doubles, and even blockage of water inlet or outlet leads to equipment failure; high pretreatment requirements, large investment and high maintenance costs

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Embodiment 1, embodiment 1a, in step 1, aluminum salt is aluminum oxide, and the mol ratio of the calcium element in the lime and the aluminum element in the aluminum oxide is 2:1, stirs 2 hours, and in the step 2, the mixed solution is in the settling tank Precipitation in medium for 2 hours, the heavy metal content of the clear liquid after treatment is 950 micrograms / L, the chloride ion and sulfate ion are within 195 mg / L, and the conversion rate into strong alkali can reach 90.48%.

[0026] Example 1b, in step 1, the aluminum salt is sodium metaaluminate, the molar ratio of the calcium element in the lime to the aluminum element in the sodium metaaluminate is 2:1, stir for 4 hours, the mixed solution in the step 2 is in the sedimentation tank Precipitation in medium for 2 hours, the heavy metal content of the clear liquid after treatment is 750 micrograms / L, the chloride ion and sulfate ion are within 160 mg / L, and the conversion rate into strong alkali can reach 92....

Embodiment 2

[0028] Embodiment 2, embodiment 2a, in step 1, aluminum salt is aluminum oxide, and the mol ratio of the calcium element in the lime and the aluminum element in the aluminum oxide is 3:1, stirs 2 hours, and in step 2, the mixed solution is in the settling tank Precipitation in medium for 2 hours, the content of heavy metals in the clear liquid after treatment is 849 micrograms / L, chloride ion and sulfate ion are within 181 mg / L, and the conversion rate into strong alkali can reach 90.38%.

[0029] Example 2b, in step 1, the aluminum salt is sodium metaaluminate, the molar ratio of the calcium element in the lime to the aluminum element in the sodium metaaluminate is 3:1, stir for 4 hours, the mixed solution in the step 2 is in the sedimentation tank Precipitate in medium for 2 hours, the content of heavy metals in the clear liquid after treatment is 641 micrograms / L, chloride ion and sulfate ion are within 146 mg / L, and the rate of conversion into strong alkali can reach 93.09%...

Embodiment 3

[0031] Embodiment 3, embodiment 3a, in step 1, aluminum salt is aluminum oxide, and the mol ratio of the calcium element in the lime and the aluminum element in the aluminum oxide is 4:1, stirs 2 hours, and in the step 2, the mixed solution is in the settling tank Precipitation in medium for 2 hours, the content of heavy metals in the clear liquid after treatment is 853 micrograms / L, chloride ion and sulfate ion are within 178 mg / L, and the conversion rate into strong alkali can reach 90.56%.

[0032] Example 3b, in step 1, the aluminum salt is sodium metaaluminate, the molar ratio of the calcium element in the lime to the aluminum element in the sodium metaaluminate is 4:1, stirred for 4 hours, the mixed solution in the step 2 is in the sedimentation tank Precipitation in medium for 2 hours, the content of heavy metals in the clear liquid after treatment is 639 micrograms / L, chloride ion and sulfate ion are within 148 mg / L, and the rate of conversion into strong alkali can rea...

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Abstract

The invention relates to a process method for converting high-salinity wastewater into a NaOH solution, which comprises the following steps: step 1, introducing the high-salinity wastewater into a reaction tank, adding calcium-aluminum composite salt into the reaction tank, controlling the pH value at 11-12, stirring and reacting for 2-6 hours, and removing sulfate ions and chloride ions to form amixed solution; 2, feeding the mixed solution into a sedimentation tank from the bottom, adding a flocculating agent, adding a heavy metal removing agent for removal if the mixed solution contains complex copper, and subjecting the mixed solution to sedimentation in the sedimentation tank for 1-2 hours to form a supernatant in the upper portion of the sedimentation tank; and step 3, overflowing the supernatant to a multi-medium filter tank for filtration, adding sodium carbonate into the multi-medium filter tank for precipitation if the calcium hardness is high during overflowing, and formingclear liquid containing a small amount of sodium chloride or sodium sulfate from the solution filtered by the multi-medium filter. The process method for converting the high-salinity wastewater intothe NaOH solution, provided by the invention, is simple, low in investment and low in operation difficulty.

Description

technical field [0001] The invention relates to the technical field of wastewater treatment, in particular to a process method for converting high-salinity wastewater into NaOH solution. Background technique [0002] With the rapid development of industry, people's requirements for wastewater discharge are gradually increasing, among which the chloride ion (Cl) mainly contained in high-salt wastewater - ) and sulfate ion (SO4 2- ) is difficult to remove. At present, low-temperature evaporation is used to remove chloride ions and sulfate ions in high-salt wastewater. This method requires expensive evaporation equipment, large investment, and requires a heat source. The cost of ton water treatment in actual operation is high. ; Difficult operation and frequent failures are difficult to overcome. Due to the complex composition of high-salt wastewater, a large amount of precipitation is easily generated during the evaporation process and easily adheres to the inner wall of the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C01D1/28C01D1/04C02F11/122C02F101/10C02F101/12
CPCC02F9/00C01D1/28C01D1/04C02F11/122C02F1/66C02F1/58C02F1/62C02F2001/007C02F1/001C02F5/02C02F2101/12C02F2101/101C02F1/52
Inventor 饶丽灵
Owner 导洁(北京)环境科技有限公司
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