Method for recycling lead and mercury from acidic wastewater

A technology for acidic wastewater and wastewater, applied in the field of mercury and lead recovery, can solve the problems of affecting the mercury grade in sludge, secondary pollution, and the difficulty of separating heavy metal wastewater one by one, and achieve the effect of low cost and simple process

Active Publication Date: 2014-10-22
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method has the following defects: first, the insoluble salt HgS produced by flocculant precipitation is used, which affects the grade of mercury in the sludge; second, the pH value is controlled between 9-11, and it is difficult to separate wastewater containing various heavy metals one by one , a large amount of alkali needs to be added to the acidic wastewater to adjust the pH value, and the pH value of the treated wastewater is too high to be discharged directly; the third is Na 2 The amount of S used is too large, residual S in the water after treatment 2- easy to cause secondary pollution

Method used

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  • Method for recycling lead and mercury from acidic wastewater

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Hg at pH 1.0 2+ , Pb 2+ For waste water with a concentration of 10mg / L, add n(S 2- ) / n(Hg 2+ ) is sodium sulfide of 1.2, maintain the pH value, react at a rotating speed of 200r / min for 12min, then pour it into the flotation tank, add butylammonium black medicine and terpineol to float and reclaim the mercury residue. The wastewater after a stage of flotation is then adjusted to a pH value of 5.0, adding n(S 2- ) / n(Pb 2+ ) is 1.5 sodium sulfide, stirred at 200r / min for 12min and then poured into the flotation tank, adding butyl ammonium black medicine and terpineol to recover lead slag. Residual Pb in wastewater after secondary flotation 2+ The concentration is less than 0.20mg / L, Hg 2+ The concentration is less than 0.01mg / L, and the pH is about 8; the grade of mercury in the first-stage flotation slag is 79.45%, and the lead grade in the second-stage flotation slag is 84.20%. After drying, the scum can be sold as mercury products and lead products respectively ...

Embodiment 2

[0023] Hg at pH 1.5 2+ , Pb 2+ For wastewater with a concentration of 100mg / L, add n(S 2- ) / n(Hg 2+ ) is sodium sulfide of 1.1, maintain the pH value, react at a rotating speed of 300r / min for 10min, and then pour it into a flotation tank, add butyl ammonium black medicine and terpineol to float and reclaim mercury residue. The wastewater after one stage of flotation is then adjusted to a pH value of 4.0, adding n(S 2- ) / n(Pb 2+ ) is 1.5 sodium sulfide, stirred at a rotating speed of 180r / min for 14min and then poured into the flotation tank, adding butyl ammonium black medicine and terpineol to recover lead slag. Residual Pb in wastewater after secondary flotation 2+ The concentration is less than 0.20mg / L, Hg 2+ The concentration is less than 0.01mg / L, and the pH is about 7; the grade of mercury in the first-stage flotation slag is 79.85%, and the lead grade in the second-stage flotation slag is 84.38%. After drying, the scum can be sold as mercury products and lead pr...

Embodiment 3

[0025] Hg at pH 1.2 2+ , Pb 2+ For wastewater with a concentration of 200mg / L, add n(S 2- ) / n(Hg 2+ ) is sodium sulfide of 1.2, maintain the pH value, react at a rotating speed of 200r / min for 12min, then pour it into the flotation tank, add butylammonium black medicine and terpineol to float and reclaim the mercury residue. The wastewater after one stage of flotation is then adjusted to a pH value of 4.0, adding n(S 2- ) / n(Pb 2+) is 1.5 sodium sulfide, stirred at 200r / min for 12min and then poured into the flotation tank, adding butyl ammonium black medicine and terpineol to recover lead slag. Residual Pb in wastewater after secondary flotation 2+ The concentration is less than 0.20mg / L, Hg 2+ The concentration is less than 0.01mg / L, and the pH is about 7; the grade of mercury in the first-stage flotation slag is 79.42%, and the lead grade in the second-stage flotation slag is 83.45%. After drying, the scum can be sold as mercury products and lead products respectively ...

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Abstract

The invention discloses a method for recycling lead and mercury from acidic wastewater. The method comprises a two-section precipitation flotation step that is used to process acidic wastewater containing mercury ions and lead ions. Through controlling the concentration of S<2-> in wastewater and the pH vale of wastewater, the mercury-containing flotation slag and lead-containing flotation slag can be individually separated in a form of sulfide precipitate by the flotation technology. The method has the advantages of simple technology process and low cost, and can high efficiently separate lead ions and mercury ions in wastewater. The contents of residual heavy metals in the wastewater which has been processed by the method all reach the A level standard of GB8979-1996 'Integrated Wastewater Discharge Standard'. The mercury grade in the separated mercury concentrate slag and the lead grade in the separated lead concentrate slag are high, and the resources are comprehensively utilized.

Description

technical field [0001] The invention relates to a method for recovering mercury and lead from acidic wastewater. The method adopts two-stage precipitation and two-stage flotation to realize the selective recovery of mercury and lead. The residual mercury and lead ions in the treated wastewater are lower than the national sewage discharge Standard, which belongs to the field of heavy metal wastewater treatment. Background technique [0002] Heavy metal acid wastewater is acid wastewater containing copper, lead, zinc, cadmium, mercury, arsenic, manganese, chromium and other heavy metal ions mainly from mining, chemical industry, iron and steel, non-ferrous metal smelting, machinery, electroplating and other industries. This type of wastewater has the characteristics of large discharge, long duration, and unstable concentration. The metal elements in the wastewater have high recycling value and cannot be decomposed and destroyed. Direct discharge will pollute the environment an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C22B7/00C22B13/00C22B43/00
CPCY02P10/20
Inventor 李骞姜涛杨永斌范晓慧邓蓬李光辉郭宇峰陈许玲张元波徐斌陈达佳
Owner CENT SOUTH UNIV
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