Method for treating mercury-containing wastewater during PVC (Polyvinyle Chloride) production through two-step process

A waste water and step method technology, which is applied in natural water treatment, chemical instruments and methods, water/sewage multi-stage treatment, etc., can solve the problems of high cost mercury removal technology and treatment methods, and achieve saving consumption, less power equipment, and adding less effect

Inactive Publication Date: 2013-02-20
赵建军
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] The object of the present invention is to provide a comprehensive, economical, efficient and convenient two-step method for treating PVC production without any mercury loss in view of the high cost of the existi

Method used

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  • Method for treating mercury-containing wastewater during PVC (Polyvinyle Chloride) production through two-step process

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Experimental program
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Embodiment 1

[0021] Before the sample was processed, the mercury content was measured by cold atomic absorption method, which was alkaline wastewater with a mercury content of 3 mg / l and a pH value of 12.5. Then add 0.3% calcium chloride solution of the total amount of wastewater (calcium chloride concentration is 20%), stir for 30 minutes; then use acid to adjust the pH to 7-8, then slowly add PAC and PAM (total addition 30mg / l), after slow stirring for 30 minutes, stop, let stand for 1 hour, and discharge slag; then start aeration, and at the same time start the adsorption tower circulation pump to absorb the gas with sodium sulfide solution to entrain mercury, and stop aeration after 1 hour; use The diatomite filter will filter the treated water and send it to the next step. At this time, the mercury content of the system is measured by cold atomic absorption method and the result is <1mg / l.

[0022]The treated water is filtered by the diatomite filter and stored in the storage tank. A...

Embodiment 2

[0024] Before the sample treatment, the neutral wastewater with a mercury content of 30mg / l and a pH value of 6.5, first added the corresponding molar sodium sulfide solution according to 91% of the molar mercury content, and stirred for 30 minutes; then slowly added PAC and PAM (adding total amount of 30mg / l), stirring at a slow speed for 30 minutes, stop, let stand for 1 hour, and discharge slag; then start aeration, and start the adsorption tower circulation pump at the same time to absorb the gas with sodium sulfide solution to entrain mercury. After 1 hour, stop Aeration; use a diatomaceous earth filter to filter the treated water and send it to the next step. At this time, the mercury content in the system is measured by cold atomic absorption method and the result is <2mg / l.

[0025] The clear liquid filtered by the diatomite filter is stored in the storage tank, and the treated water passes through the activated carbon filter in series, and then through the mercaptan re...

Embodiment 3

[0027] Before the sample treatment, the acid wastewater with a mercury content of 120mg / l and a pH value of 2.5, first added the corresponding molar sodium sulfide solution according to 95% of the molar mercury content, and stirred for 30 minutes; then adjusted the pH value to 6-8, At this time, slowly add PAC and PAM (the total amount added is 30mg / l), stop stirring after 30 minutes at a slow speed, let it stand for 1 hour, and discharge the slag; then start aeration, and at the same time start the adsorption tower circulation pump to absorb gas with sodium sulfide solution After 1 hour, stop the aeration; filter the treated water with a diatomaceous earth filter and send it to the next step. At this time, the mercury content in the system is measured by cold atomic absorption method and the result is <5mg / l.

[0028] The clear liquid filtered by the diatomite filter is stored in the storage tank, and the treated water passes through the activated carbon filter in series, and ...

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Abstract

The invention discloses a method for treating mercury-containing wastewater during PVC (Polyvinyle Chloride) production through a two-step process. The method comprises the following steps of: firstly, completing primary removal of mercury, copper, ferrous and ferric iron, cadmium, zinc, manganese, lead and suspending impurities of above 10mg/l by using a precipitator and a flocculating agent, regulating PH to 6-8 and then adding the flocculating agent and stirring for 30 minutes, standing for above 1 hour, discharging slag and aerating, absorbing mercury carried away by a gas phase through a sulfide adsorber, purifying water by using a plate type kieselguhr filter, removing residual suspended matters; and 2, carrying out complete reaction on the mercury in the wastewater by using an active carbon and a mercaptan and thiourea resin combining method again for being removed, and finally reaching the standard that the content of the mercury is less than 0.005mg/l. The treated wastewater can be recycled to salt melting or an acetylene generator, so that zero emission of the treated wastewater is achieved; and the mercury-containing waste acid water of hydrochloric acid desorption in the industry of chlor-alkali can be treated, the consumption of acid is reduced, and the great popularization significance is achieved in the industry of chlor-alkali.

Description

technical field [0001] The invention belongs to a wastewater treatment method, in particular to a method for treating mercury-containing wastewater in PVC production through a two-step method with high efficiency and low cost. Background technique [0002] The currently known technical methods for treating mercury-containing wastewater include sulfide direct reaction precipitation method, ion exchange mercury removal method, activated carbon combined adsorption removal method, solution extraction method, and membrane method. [0003] The known and operating sulfide direct precipitation method requires extremely high weighing and adding requirements, so it is easy to cause excess or deficiency of sulfide in actual operation. When the excess is excessive, it will be dissolved again due to the complexation of sulfide ions and mercury sulfide , so it is difficult to achieve the goal of less than 5mg / l in a stable manner; the ion exchange method cannot adapt to the situation when...

Claims

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Application Information

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IPC IPC(8): C02F9/04C02F103/38
Inventor 赵建军
Owner 赵建军
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