CN111072176A - Treatment method of leaching solution containing arsenic acid - Google Patents

Abstract

The invention discloses a method for treating arsenic acid-containing leachate, which comprises the following steps: (1) adding hydrogen peroxide into the arsenic acid-containing leaching solution, stirring at room temperature, and carrying out oxidation reaction; (2) adding liquid polymeric ferric sulfate into the solution after the reaction is finished, controlling the pH value of the solution to be 5-6, stirring at room temperature, and performing arsenic precipitation reaction; (3) and after the arsenic precipitation reaction is finished, filtering the solution, carrying out liquid-solid separation, sampling and analyzing filtrate, and drying filter residues. The method has the advantages of short process flow, low production cost, environmental friendliness and wide applicability.

Description

Treatment method of leaching solution containing arsenic acid

Technical Field

The invention relates to a wastewater treatment method, in particular to a treatment method of arsenic acid-containing leachate generated in a non-ferrous smelting process.

Background

Arsenic, a nonmetallic element widely distributed in nature. However, arsenic compounds are extremely toxic and easily accumulate in the human body, resulting in chronic arsenic poisoning. Arsenic is one of the water pollutants that is preferably controlled in many countries around the world because arsenic is harmful to human health mainly through drinking water. The conventional treatment method of the arsenic acid-containing leachate comprises the following steps: adsorption, ion exchange, membrane separation, biological, chemical precipitation, and the like. The chemical precipitation method is a common method for treating arsenic, and is a main treatment method of the leaching solution containing arsenic acid, and the engineering is relatively common. The chemical precipitation method is implemented by adding (or originally existing in the waste water) Fe³⁺、Fe²⁺Plasma is generated and adjusted to a proper pH value by alkali, so that hydroxide colloid is formed to adsorb and react with arsenic in the wastewater to generate insoluble salt precipitateIt is removed. Such methods have long treatment times for As³⁺The removal rate is low, a single treatment mode is adopted, the treatment requirement is difficult to meet, the treatment is generally a comprehensive treatment of a plurality of treatment modes, and with the gradual improvement of the environmental protection requirement, a rapid and efficient arsenic removal method is urgently needed to meet the increasingly severe environmental protection requirement.

On 09.12.2015, chinese patent application publication No. CN105130048A discloses a method for treating low-concentration arsenide in water, wherein it is disclosed that pH is controlled within 7.0-9.0 by adding pH adjuster sodium hydroxide; adding hydrogen peroxide solution with the dosage of 0.02-0.1L/m3, adding ferrous sulfate solution according to the arsenic compound concentration and the condition that Fe/As is more than or equal to 2, and stirring for reaction for 5-15 min. The method organically combines the traditional flocculation coprecipitation method with a hydroxyl radical oxidation system, and forms hydroxyl radicals with strong oxidability by utilizing the oxidation system consisting of iron ions and hydrogen peroxide. The Fe- (. OH) reaction system consisting of iron ions and hydroxyl can efficiently finish the conversion of trivalent arsenic, destroy part of reducing substances in water, and generate iron ion complex which continuously participates in the reaction in the process of generating the. OH so as to generate FeAsO with low solubility₄The arsenicals are removed in the form of precipitate, the ferric hydroxide has the functions of adsorbing and coagulating some fine particles which are difficult to settle, and the formation process of hydroxyl free radicals enhances the flocculation and precipitation functions of the reaction. The method provides a hydroxyl free radical oxidation sedimentation system, solves As³⁺The problem of difficult getting rid of, the flocculation and precipitation is effectual, and reaction time is short, need not aeration equipment, reduce cost, but hydrogen peroxide solution consumption is great.

Disclosure of Invention

The invention aims to overcome the technical obstacles in the background art and provide a treatment method for treating arsenic acid-containing leachate.

The technical scheme adopted by the invention for solving the technical problems is as follows: a treatment method of leachate containing arsenic acid comprises the following steps:

(1) adding hydrogen peroxide into the arsenic acid-containing leaching solution, stirring at room temperature, and carrying out oxidation reaction to obtain a solution A; wherein the molar ratio of the hydrogen peroxide to the arsenic content in the arsenic acid leaching solution is 0.5-2: 1; the time of the oxidation reaction can be 30 min-120 min;

(2) adding liquid polymeric ferric sulfate into the solution A, controlling the pH value of the solution to be 5-6 by using a pH regulator, stirring at room temperature, and performing arsenic precipitation reaction to obtain a solution B; wherein the time of arsenic precipitation reaction is 30-120 min; the mass ratio of the liquid polymeric ferric sulfate to the arsenic content in the arsenic acid leaching solution is 0.5-2: 1;

(3) and filtering the solution B for liquid-solid separation, sampling and analyzing filtrate, and drying filter residues.

Optionally, the pH adjusting agent is sodium hydroxide.

Compared with the common arsenic acid-containing leachate treatment method, the method has the technical effects that: the method has the advantages of short process flow, low treatment cost, environmental friendliness and wide applicability, and by optimizing the process, hydrogen peroxide is added into the arsenic acid-containing leaching solution, and then liquid polymeric ferric sulfate is added for flocculation and precipitation, compared with CN105130048A, the method has the advantages of simple condensation effect of Fe- (. OH) formed by iron ions and hydroxyl groups, low hydrogen peroxide consumption and simple treatment method.

Detailed Description

The present invention will be further described with reference to the following examples, but the present invention is not limited to the following examples.

Example 1

Putting 1000ml of arsenic acid-containing leachate with arsenic concentration of 3100mg/L into a beaker, adding 30% hydrogen peroxide by mass for oxidation reaction, stirring and oxidizing for 30min, adding liquid polymeric ferric sulfate, adjusting the pH value of the solution to 6, continuously stirring for dearsenization reaction, filtering for liquid-solid separation after reacting for 45min, sampling and analyzing the filtrate, and drying the filter residue. Detection shows that the arsenic content in the treated filtrate is 0.481mg/L, and the removal rate of arsenic is 99.98%.

The foregoing has described the general principles, principal features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims (1)

1. A treatment method of leachate containing arsenic acid comprises the following steps:

(1) adding hydrogen peroxide into the arsenic acid-containing leaching solution, stirring at room temperature, and carrying out oxidation reaction to obtain a solution A; wherein the molar ratio of the hydrogen peroxide to the arsenic content in the arsenic acid leaching solution is 0.5-2: 1; the time of the oxidation reaction can be 30 min-120 min;

(2) adding liquid polymeric ferric sulfate into the solution A, controlling the pH value of the solution to be 5-6 by using a pH regulator, stirring at room temperature, and performing arsenic precipitation reaction to obtain a solution B; wherein the time of arsenic precipitation reaction is 30-120 min; the mass ratio of the liquid polymeric ferric sulfate to the arsenic content in the arsenic acid leaching solution is 0.5-2: 1;

(3) and filtering the solution B for liquid-solid separation, sampling and analyzing filtrate, and drying filter residues.