阅读说明：本技术 一种NaOH浸出硫化砷泥膏制备砷酸镁方法 (Method for preparing magnesium arsenate by leaching arsenic sulfide mud paste with NaOH ) 是由 李瑞冰 肖宜彬 吴楠 庞博 张启旭 姚智馨 王振威 张吉祥 于三三 李双明 于 2020-12-31 设计创作，主要内容包括：一种NaOH浸出硫化砷泥膏制备砷酸镁方法,涉及一种制备砷酸镁方法,本发明采用废弃资源利用,用NaOH浸出硫化砷渣,用MgCl-2作为沉淀药剂,首先将硫化砷渣按液固比5-8,按碳酸钠过量20%比例与硫化砷渣混合,温度28-90℃,通入空气或氧化剂,搅拌速度150-500rpm对硫化砷渣浸出,浸出时间0.5-2小时,得到砷酸钠溶液。将砷酸钠溶液与氯化镁溶液混合,生成砷酸镁沉淀,过滤分离得到砷酸镁结晶。本发明具有浸出效率高,残渣率低的特点,浸出反应和镁转化反应速度都可在很短时间内完成,转化后的沉淀主要是5价砷砷酸镁(Mg(AsO-3)-(2#)·xH-2O),性质十分稳定。本发明操作简单、反应温度低、反应时间快速、成本低、是个获得砷酸镁的理想方法。(A method for preparing magnesium arsenate by leaching arsenic sulfide mud paste with NaOH relates to a method for preparing magnesium arsenate 2 As a precipitating agent, firstly, the arsenic sulfide slag is mixed with the arsenic sulfide slag according to the liquid-solid ratio of 5-8 and the proportion of 20 percent of excessive sodium carbonate, air or an oxidant is introduced at the temperature of 28-90 ℃, the arsenic sulfide slag is leached at the stirring speed of 150-. Mixing the sodium arsenate solution with the magnesium chloride solution to generate a magnesium arsenate precipitate, and filtering and separating to obtain the magnesium arsenate crystal. The invention has the characteristics of high leaching efficiency and low residue rate, the leaching reaction and the magnesium conversion reaction can be completed in a short time, and the precipitate after conversion is mainly 5-valent magnesium arsenate (Mg (AsO) 3 ) 2̦ ·xH 2 O), the properties are very stable. The method has the advantages of simple operation, low reaction temperature, quick reaction time and low cost, and is an ideal method for obtaining the magnesium arsenate.)

1. A method for preparing magnesium arsenate by leaching arsenic sulfide mud paste with NaOH is characterized by comprising the following steps:

(1) mixing the arsenic sulfide slag with a sodium hydroxide solution according to a liquid-solid ratio of 5-8 and a ratio of 20% excess of sodium hydroxide, introducing air or an oxidant, leaching the arsenic sulfide slag, and filtering to obtain leached slag and a sodium arsenate solution;

(2) mixing the sodium arsenate solution with the magnesium chloride solution to obtain a magnesium arsenate precipitate;

(3) filtering and separating the magnesium arsenate precipitate and the sodium chloride solution, and returning the solution to the leaching system;

(4) drying to obtain magnesium arsenate crystal.

2. The method for preparing magnesium arsenate from the arsenic sulfide paste leached by NaOH according to claim 1, wherein the mass fraction of the sodium hydroxide in the step (1) is 95-99%, the sodium hydroxide is weighed in excess according to the arsenic sulfide residue, the water is taken according to the water-arsenic sulfide liquid-solid ratio of 5-8, the sodium hydroxide is dissolved in the water, and then the arsenic sulfide residue is added to the sodium hydroxide solution.

3. The method for preparing magnesium arsenate by leaching arsenic sulfide mud paste with NaOH according to claim 1, wherein the leaching temperature in step (1) is normal temperature to 90 ℃, air or oxidant is introduced, the stirring speed is 150-.

4. The method for preparing magnesium arsenate from the arsenic sulfide mud paste leached by NaOH according to claim 1, wherein the oxidant in the step (1) is 10-30% hydrogen peroxide or industrial oxygen.

5. The method for preparing magnesium arsenate from the arsenic sulfide paste leached by NaOH according to claim 1, wherein the magnesium chloride in the step (2) is magnesium chloride hexahydrate with the mass fraction of more than or equal to 98%, a magnesium chloride solution is prepared according to the mass ratio of the magnesium chloride to the water of 20:100, the magnesium chloride solution and a sodium arsenate solution are mixed, and stirring is carried out for 1-3 minutes, so as to obtain a magnesium arsenate precipitate.

6. The method for preparing magnesium arsenate from the arsenic sulfide paste leached by NaOH according to claim 1, wherein the magnesium arsenate precipitate filtered in the step (4) is dried at a temperature of 80-120 ℃.

Technical Field

The invention relates to a method for preparing magnesium arsenate, in particular to a method for preparing magnesium arsenate by leaching arsenic sulfide paste with NaOH.

Background

Magnesium arsenate (Mg (AsO)₃)_2̦·xH₂O) was originally used to make pesticides because of their strong toxicity, and all arsenic pesticides were listed by the ministry of agriculture in the list of bans and limits in 2018. Mg (AsO)₃)_2̦·xH₂O absorbs the energy of photons in sunlight because electrons in atoms in molecules of O, then the electrons jump to a higher energy level, the electrons are unstable after the electrons are at the high energy level, certain energy is released after the electrons jump to a lower energy level, and fluorescence with an emission spectrum of 630-680 nm in red light wave band can be emitted. Recently, it has been used to produce phosphor coating materials using Mn ions as an activator, and published by MgO or MgCl in Tang Ming Dynasty, Zhao Cheng Ji, and Du Guo et al₂And As₂O₅Method for preparing fluorescent powder for synthetic scarlet fluorescent lamp (Tangmingdao, Zhao Chengjiu, Jungguanggao, etc.. fluorescent powder for scarlet fluorescent lamp and its preparation [ Z]CN 87104810.8), Geheron proposed MgO or MgCl₂And As₂O₅Improved method for synthesizing fluorescent magnesium arsenate material₆As₂O₁₁: improvement of Mn luminescent material preparation method [ J]The university of Hebei (Nature science edition), 2001,21(3): 251-.]. Yang Zong is described by MgCl₂And As₂O₅Method for synthesizing fluorescent magnesium arsenate material [ Poplar cong, method for preparing fluorescent magnesium arsenate [ J ]]The chemical world, 1957, (11): 499.]. Forest establishment in recent yearsA process for preparing magnesium arsenate from the waste acid liquid containing As generated by smelting copper (Zhaohuo), the process for preparing magnesium arsenate from waste acid liquid containing As]CN201610939859.8 Linjianzi a method for comprehensive utilization of arsenic-containing waste liquid generated in copper smelting process [ Z]CN 201110315629.1.). The method provides a method for preparing NaH by leaching arsenic sulfide paste which is waste residue from copper smelting as a raw material by NaOH₂AsO₃Then with MgCl₂Reacting to prepare Mg (AsO)₃)_2̦·xH₂And O. The method has the advantages of wide raw material source, high purity, and simple preparation process. Arsenic sulfide sludge and MgCl₂All are solid wastes discharged in the non-ferrous metal smelting process. The arsenic sulfide and the magnesium chloride are used as raw materials to prepare the magnesium arsenate, so that solid waste materials generated in the smelting industry can be utilized, and useful raw materials for agriculture, electronic industry and military industry can also be produced, thereby promoting the development of green production and circular economy.

The arsenic sulfide generated by acid wastewater in the sulfuration method is mostly amorphous arsenic sulfide, has various component compositions and mineral structures, is a gel or floccule formed by aggregating nano-particle structures, has large specific surface area and high porosity, is very unstable in solution or air, is very easy to absorb moisture and oxidize and decompose, and is easily decomposed and converted into arsenate when being subjected to alkali.

Disclosure of Invention

The invention aims to provide a method for preparing magnesium arsenate by leaching arsenic sulfide paste with NaOH. The method has the advantages of simple operation, low reaction temperature, quick reaction time and low cost, and is an ideal method for obtaining the magnesium arsenate.

The purpose of the invention is realized by the following technical scheme:

a method for preparing magnesium arsenate by leaching arsenic sulfide mud paste with NaOH comprises the following steps:

(1) mixing the arsenic sulfide slag with a sodium hydroxide solution according to a liquid-solid ratio of 5-8 and a ratio of 20% excess of sodium hydroxide, introducing air or an oxidant, leaching the arsenic sulfide slag, and filtering to obtain leached slag and a sodium arsenate solution;

(2) mixing the sodium arsenate solution with the magnesium chloride solution to obtain a magnesium arsenate precipitate;

(3) filtering and separating the magnesium arsenate precipitate and the sodium chloride solution, and returning the solution to the leaching system;

(4) drying to obtain magnesium arsenate crystal.

The method for preparing the magnesium arsenate by leaching the arsenic sulfide paste with NaOH comprises the following steps of (1) weighing the sodium hydroxide with the mass fraction of 95-99%, weighing the sodium hydroxide excessively according to the arsenic sulfide slag, taking water according to the water-arsenic sulfide liquid-solid ratio of 5-8, dissolving the sodium hydroxide in the water, and then adding the arsenic sulfide slag into the sodium hydroxide solution.

The method for preparing magnesium arsenate by leaching arsenic sulfide mud paste with NaOH comprises the steps of (1) leaching at normal temperature to 90 ℃, introducing air or an oxidant, stirring at the speed of 150-.

The method for preparing the magnesium arsenate by leaching the arsenic sulfide mud paste with NaOH comprises the step (1) of using 10-30% of hydrogen peroxide or industrial oxygen as an oxidant.

The method for preparing the magnesium arsenate by leaching the arsenic sulfide mud paste with NaOH comprises the following steps of (2) preparing a magnesium chloride solution by using magnesium chloride hexahydrate with the mass fraction of more than or equal to 98% according to the mass ratio of the magnesium chloride to water being 20:100, mixing the magnesium chloride solution and a sodium arsenate solution, and stirring for 1-3 minutes to obtain a magnesium arsenate precipitate.

According to the method for preparing magnesium arsenate by leaching arsenic sulfide mud paste with NaOH, the magnesium arsenate precipitate filtered in the step (4) is dried at the temperature of 80-120 ℃.

The invention has the advantages and effects that:

the invention uses waste resource utilization, uses NaOH to leach arsenic sulfide slag, uses MgCl₂As a precipitating agent, the magnesium-arsenic-free magnesium-arsenic alloy has the characteristics of high leaching efficiency and low residue rate, the leaching reaction and the magnesium conversion reaction can be completed in a short time, and the precipitate after conversion is mainly magnesium arsenate (Mg (AsO)₃)_2̦·xH₂O), the properties are very stable.

Drawings

FIG. 1 is a process flow diagram of the present invention;

FIG. 2 is a photograph showing the appearance of the arsenic sulfide slag sample as a raw material in the example of the present invention;

FIG. 3 is an SEM image of a raw material arsenic sulfide slag sample in an embodiment of the invention;

FIG. 4 is an XRD pattern of a raw material arsenic sulfide slag sample in an embodiment of the invention;

FIG. 5 is a photograph of the appearance of a slag sample after a magnesium conversion reaction in accordance with an embodiment of the present invention;

FIG. 6 is an XRD pattern of a slag sample after magnesium conversion reaction according to the embodiment of the present invention.

Detailed Description

The invention will be further described with reference to the following examples.

The arsenic sulfide compositions employed in the examples of the present invention are shown in table 1.

Example 1

Dissolving 27.5g of sodium hydroxide in 150mL of distilled water, adding 50g of arsenic sulfide slag (with the water content of 53.6%) into a sodium hydroxide solution, leaching at the temperature of 29 ℃, stirring for 0.5 hour at the stirring speed of 150 rpm, and filtering to obtain a sodium arsenate solution.

80g of 6-water magnesium chloride is taken and dissolved in 100mL of distilled water, the sodium arsenate solution and the calcium chloride solution are mixed, the reaction is completed instantly, and the calcium-magnesium arsenate precipitate is obtained by filtering 49.2 g.

Example 2

Dissolving 27.5g of sodium hydroxide in 150mL of distilled water, adding 50g of arsenic sulfide slag (with the water content of 53.6%) into a sodium hydroxide solution, leaching at the temperature of 90 ℃, stirring for 0.5 hour at the stirring speed of 150 rpm, and filtering to obtain a sodium arsenate solution.

80g of 6-water magnesium chloride is taken and dissolved in 100mL of distilled water, the sodium arsenate solution and the calcium chloride solution are mixed, the reaction is completed instantly, and the magnesium arsenate precipitate 44.2g is obtained by filtration.

Example 3

Dissolving 27.5g of sodium hydroxide in 150mL of distilled water, adding 50g of arsenic sulfide slag (with the water content of 53.6%) into a sodium hydroxide solution, leaching at the temperature of 29 ℃, stirring for 2 hours at the stirring speed of 150 rpm, and filtering to obtain a sodium arsenate solution.

80g of 6-water magnesium chloride is taken and dissolved in 100mL of distilled water, the sodium arsenate solution and the calcium chloride solution are mixed, the reaction is completed instantly, and the magnesium arsenate precipitate is obtained by filtering 45.9 g.

Example 4

Dissolving 27.5g of sodium hydroxide in 150mL of distilled water, adding 50g of arsenic sulfide slag (with the water content of 53.6%) into a sodium hydroxide solution, leaching at the temperature of 90 ℃, stirring for 2 hours at the stirring speed of 150 rpm, and filtering to obtain a sodium arsenate solution.

Dissolving 80g of 6-water calcium chloride in 100mL of distilled water, mixing the sodium arsenate solution and the calcium chloride solution, completing the reaction instantly, and filtering to obtain 40.4g of magnesium arsenate precipitate.