Clarification method and apparatus for material contaminated with heavy metals

A technology for pollutants and heavy metals, which is applied in the restoration of polluted soil and the removal of solid wastes.

Inactive Publication Date: 2007-12-26
EBARA CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] However, in this method, there is a problem that since the cathode portion and the slurry are separated by the filter material, interstitial water flows from the anode side through the filter material to the cathode side, and the slurry cannot be reduced by the reduction potential of the cathode, On the contrary, sometimes there is a high possibility that the oxidation potential of the anode is maintained in an oxidizing atmosphere
[0007] However, in this method, there is a problem that the slurry cannot be kept in a reducing atmosphere due to the influence of chlorine gas, oxygen, etc. middle
[0009] However, even in this method, since no reduction potential is applied during the acid extraction, the fraction forming the above-mentioned insoluble adhesion form cannot be effectively extracted, and the concentration of heavy metals in the incineration ash cannot be sufficiently reduced.
[0010] In addition, in this method, there is also the following problem: the extraction of heavy metals into the solution and the separation from the aqueous solution cannot be carried out at the same time, but must be carried out in two stages, so the concentration of heavy metals in the aqueous solution increases during the extraction stage, especially Heavy metal salts with small solubility products cannot be completely dissolved
Furthermore, there is also the following problem: since the solid-liquid separation is performed in a state where heavy metals of high concentration are dissolved in the interstitial water, the heavy metals contained in the remaining interstitial water (sludge) cannot be removed from the incineration ash after the solid-liquid separation. remove
[0012] In addition, in these methods, there is a problem that in order to sufficiently dissolve heavy metals, the volume of the liquid phase as a solvent must be large due to the restriction of the solubility product as a poorly soluble substance, and as a result, the overall volume of the processing device becomes large. , it is difficult to miniaturize the device

Method used

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  • Clarification method and apparatus for material contaminated with heavy metals
  • Clarification method and apparatus for material contaminated with heavy metals
  • Clarification method and apparatus for material contaminated with heavy metals

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0203] [Example 1] Electrolytic extraction and removal test of lead-contaminated soil

[0204] As shown in Figure 1, a cation exchange membrane (NEOSEPTA CMB manufactured by Tokuyama Corporation) is set in the central part of a reactor made of organic glass with a volume of 2000 mL, and the reactor is divided into two zones: a cathode zone and an anode zone.

[0205] In the cathode zone, add 100g of poorly soluble lead contaminated soil (the lead concentration is 5000mg / kg dry soil; sampling location: A paint factory), 800mL tap water, 50mL 1:1 hydrochloric acid, made of Teflon (registered trademark) The resultant stirring blade was stirred at a speed of 500 rpm to obtain the system under test.

[0206] Insert the cathode electrode of the copper metal mesh into the test system and connect it to the anode through a constant potential device (constant voltage power supply device).

[0207] In the anode zone, add 800 mL of tap water, 5 mL of 1:1 hydrochloric acid, and insert the grap...

Embodiment 2

[0214] [Example 2] Electrode reduction and cleaning test of mercury contaminated sediment

[0215] As shown in Figure 2, a cation exchange membrane (NEOSEPTA CMB manufactured by Tokuyama Corporation) is installed in the central part of the reactor made of plexiglass with a volume of 2000 mL, and the reactor is divided into two zones: a cathode zone and an anode zone.

[0216] In the cathode zone, add 100g of insoluble lead contaminated sediment (total mercury concentration is 125mg / kg dry soil; sampling location: B pharmaceutical factory), 800mL tap water, 50mL 1:1 hydrochloric acid, using Teflon (registered trademark) ) The manufactured stirring blade was stirred at a speed of 500 rpm, and a nitrogen gas diffuser was inserted, and the cathode area was aerated with nitrogen at a speed of 10 mL / min as the system to be tested.

[0217] Insert the cathode electrode of the titanium metal mesh into the test system, and connect with the anode electrode through a potentiostat. In order t...

Embodiment 3

[0225] [Example 3] The influence of the diaphragm on the electrolysis removal of lead-contaminated soil

[0226] As shown in Figure 1, a cation exchange membrane (NEOSEPTA CMB manufactured by Tokuyama Corporation) is set in the central part of a reactor made of organic glass with a volume of 2000 mL, and the reactor is divided into two zones: a cathode zone and an anode zone. In the cathode zone, add 100g of poorly soluble lead contaminated soil (the lead concentration is 5000mg / kg dry soil; sampling location: A paint factory), 800mL tap water, 50mL 1:1 hydrochloric acid, made of Teflon (registered trademark) The resultant stirring blade was stirred at a speed of 500 rpm to obtain the system under test. Insert the cathode electrode of the copper metal mesh into the test system and connect it to the anode through a constant potential device (constant voltage power supply device). In the anode zone, 800 mL of tap water and 5 mL of 1:1 hydrochloric acid were added, and a titanium ano...

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Abstract

A clarification method and apparatus, which can reliably remove heavy metals, including their sparingly soluble fractions, from a contaminated solid material containing the heavy metals, such as soil, sludge, sediments, wastes, or incineration ash, are provided. A reaction vessel 2 is divided into an anode zone 10 containing an anode A, and a cathode zone 20 containing a cathode C, by a diaphragm M provided between the anode A and the cathode C. The cathode zone 20 is supplied with a contaminated solid material containing heavy metals via a contaminated solid material supply means 22, an acidic substance or an alkaline substance via an acidic substance or alkaline substance supply means 24, and in some cases, water via a water supply means 26. A slurry of their mixture is maintained in the condition of a reducing atmosphere and a strongly acidic or strongly alkaline atmosphere to dissolve the heavy metals and electrolytically deposit the heavy metals on the surface of the cathode, thereby separating the heavy metals from the contaminated solid material and interstitial water.

Description

[0001] This divisional application is based on the application number 200480029430.0 (International Application Number: PCT / JP2004 / 015032), the filing date is October 12, 2004, and the invention title is "Method and device for purification of substances contaminated by heavy metals" Divisional application of patent application. Technical field [0002] The present invention relates to the purification technology of substances contaminated by heavy metals, in particular to the separation and removal of lead (Pb), cadmium (Cd), mercury (Hg) from soil, sludge, sediment, waste, incineration ash and other solid pollutants. Purification method and device for other heavy metals. [0003] In addition, the present invention relates to the purification technology of substances contaminated by heavy metals, in particular to solids containing heavy metals such as soil, sludge, sediments, wastes, incineration ash, etc., to be contaminated by heavy metals, eluates from the above pollutants, and ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09B3/00B09B5/00B09C1/08
Inventor 足立昌则下村达夫
Owner EBARA CORP
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