JP2008119690A5

JP2008119690A5 -

Info

Publication number: JP2008119690A5
Application number: JP2007318184A
Authority: JP
Filing date: 2007-12-10
Publication date: 2009-08-13
Anticipated expiration: 2026-08-22

Description

本発明者らは、上記課題を解決するために鋭意研究した結果、５価の砒素を含む溶液に２価の鉄イオンを加えて、溶液中の砒素に対する鉄のモル比（Ｆｅ／Ａｓ）を１以上にし、酸化剤を加えて大気圧下で撹拌しながら温度７０℃以上で反応させた後、固液分離して固形分を回収することにより、砒素の溶出濃度が非常に小さい鉄と砒素の化合物として回収することができることを見出し、本発明を完成するに至った。 The present inventors have made intensive studies to solve the above problems, the addition of bivalent iron ions in a solution containing pentavalent arsenic, the molar ratio of iron to arsenic in the solution to (Fe / As) Iron and arsenic with a very low elution concentration of arsenic by adding an oxidizing agent and reacting at a temperature of 70 ° C. or higher while stirring at atmospheric pressure and then separating the solid and liquid to recover the solid content. As a result, the present invention was completed.

すなわち、本発明による砒素含有溶液の処理方法は、５価の砒素を含む溶液に２価の鉄イオンを加えて、溶液中の砒素に対する鉄のモル比を１以上にし、酸化剤を加えて大気圧下で撹拌しながら温度７０℃以上で反応させた後、固液分離して固形分を回収することを特徴とする。 That is, the processing method of the arsenic containing solution according to the present invention, in addition to bivalent iron ions in a solution containing pentavalent arsenic, the molar ratio of iron to arsenic in the solution to 1 or more, the addition of oxidant large After reacting at a temperature of 70 ° C. or higher while stirring under atmospheric pressure, the solid content is separated and solid content is recovered.

この砒素含有溶液の処理方法において、砒素に対する鉄のモル比が１〜１．５であるのが好ましく、反応温度が９５℃以下であるのが好ましい。また、溶液中の砒素の濃度が１０ｇ／Ｌ以上であるのが好ましく、２０ｇ／Ｌ以上であるのがさらに好ましい。また、５価の砒素を含む溶液に２価の鉄イオンを加えて、溶液のｐＨを２以下にするのが好ましい。また、２価の鉄イオンとして硫酸鉄（ＩＩ）七水塩を溶液に加えるのが好ましい。さらに、酸化剤として酸素ガスを使用することができる。
In this method for treating an arsenic-containing solution, the molar ratio of iron to arsenic is preferably 1 to 1.5, and the reaction temperature is preferably 95 ° C. or lower. Further, the concentration of arsenic in the solution is preferably 10 g / L or more, and more preferably 20 g / L or more. Further, it is preferable to add divalent iron ions to a solution containing pentavalent arsenic so that the pH of the solution is 2 or less. Further, it is preferable to add iron (II) sulfate heptahydrate as divalent iron ions to the solution. Furthermore, oxygen gas can be used as an oxidizing agent.

Claims

The solution was added divalent iron ions containing pentavalent arsenic, the molar ratio of iron to arsenic in the solution to 1 or more, at a temperature 70 ° C. or more while stirring under atmospheric pressure by adding an oxidizing agent After that, a method for treating an arsenic-containing solution, wherein solid content is separated and solid content is recovered.

The method for treating an arsenic-containing solution according to claim 1, wherein the molar ratio of iron to arsenic is 1 to 1.5.

The method for treating an arsenic-containing solution according to claim 1 or 2 , wherein the temperature is 95 ° C or lower.

The method for treating an arsenic-containing solution according to any one of claims 1 to 3, wherein the concentration of arsenic in the solution is 10 g / L or more.

The method for treating an arsenic-containing solution according to any one of claims 1 to 3 , wherein the concentration of arsenic in the solution is 20 g / L or more.

The treatment of an arsenic-containing solution according to any one of claims 1 to 5, wherein the divalent iron ions are added to the solution containing pentavalent arsenic to make the pH of the solution 2 or less. Method.

The method for treating an arsenic-containing solution according to any one of claims 1 to 6 , wherein iron (II) sulfate heptahydrate is added to the solution as the divalent iron ion.

Characterized in that the oxidizing agent is oxygen gas, the processing method of the arsenic containing solution according to any of claims 1 to 7.

The arsenic-containing solution is obtained by adding an arsenic-containing substance to an alkaline solution and leaching the alkali while oxidizing to obtain a leaching solution containing arsenic by solid-liquid separation and oxidizing the alkaline-earth metal or its A step of solid-liquid separation after adding a salt to obtain a residue containing an arsenic and alkaline earth metal compound, a step of washing the residue and adding it to a sulfuric acid solution, and then solid-liquid separation to obtain an arsenic-containing solution; The method for treating an arsenic-containing solution according to any one of claims 1 to 8 , wherein the arsenic-containing solution is produced by a method comprising:

In manufacturing the arsenic-containing solution, an arsenic-containing material containing sulfur is used as the arsenic-containing material, or when the arsenic-containing material does not contain sulfur, sulfur is added to the arsenic-containing material or the leachate In addition, the amount of the alkaline earth metal or salt thereof added to the leachate should be more than the amount of the alkaline earth metal or salt required to produce the arsenic and alkaline earth metal compound. The processing method of the arsenic containing solution of Claim 9 characterized by these.