阅读说明：本技术 一种一步法分离回收酸泥中硒和汞的方法 (Method for separating and recovering selenium and mercury in acid mud by one-step method ) 是由 张利波 杨坤 洪岩 潘锡剑 于 2021-07-23 设计创作，主要内容包括：本发明涉及一种一步法分离回收酸泥中硒和汞的方法,属于酸泥处理技术领域。本发明将酸泥与浆化液混合浆化30～120min得到浆化物；其中浆化液中含有酸液和氧化剂；浆化物置于温度为400～800℃条件下微波焙烧20～120min得到Hg和SeO-(2)的混合蒸气和焙烧渣,焙烧渣进行有价金属回收；Hg和SeO-(2)的混合蒸气冷凝分离出SeO-(2)粗蒸气和Hg单质；SeO-(2)粗蒸气通入吸收塔内水解得到H-(2)SeO-(3),通入SO-(2)烟气还原H-(2)SeO-(3)得到粗硒,粗硒干燥后进行精炼得到精硒。本发明直接将酸泥中的硒和汞物相焙烧处理为SeO-(2)和汞,汞经冷凝回收,二氧化硒还原回收并进行精炼,过程产生的含汞渣和含硒渣重新精炼,从而实现有害酸泥的高效简单处理。(The invention relates to a method for separating and recovering selenium and mercury in acid sludge by a one-step method, belonging to the technical field of acid sludge treatment. Mixing acid mud and slurrying liquid, and slurrying for 30-120 min to obtain a slurry; wherein the slurry liquid contains acid liquid and oxidant; placing the slurry at the temperature of 400-800 ℃ for microwave roasting for 20-120 min to obtain Hg and SeO 2 The mixed steam and the roasting slag, and valuable metal recovery is carried out on the roasting slag; hg and SeO 2 The mixed vapor is condensed and separated to obtain SeO 2 Crude vapor and elemental Hg; SeO 2 Introducing the crude steam into an absorption tower for hydrolysis to obtain H 2 SeO 3 Introduction of SO 2 Reduction of flue gas to H 2 SeO 3 Obtaining crude selenium, drying the crude selenium, and refining to obtain refined selenium. The invention directly bakes the selenium and mercury phases in the acid mud into SeO 2 And mercury is condensed and recovered, selenium dioxide is reduced and recovered, and is refined, and the mercury-containing slag and the selenium-containing slag generated in the process are refined again, so that the harmful acid sludge is efficiently and simply treated.)

1. A method for separating and recovering selenium and mercury in acid sludge by a one-step method is characterized by comprising the following steps:

(1) mixing the acid mud and the slurrying liquid for slurrying for 30-120 min to obtain a slurried substance; wherein the slurry liquid contains acid liquid and oxidant;

(2) placing the slurry obtained in the step (1) at the temperature of 400-800 ℃ for microwave roasting for 20-120 min to obtain Hg and SeO₂The roasting slag is subjected to pyrometallurgical valuable metal recovery;

(3) hg and SeO of step (2)₂The mixed vapor is condensed and separated to obtain SeO₂Crude vapor and elemental Hg;

(4) step (3) SeO₂Crude steam introductionHydrolyzing in an absorption tower at the temperature of 60-95 ℃ to obtain H₂SeO₃Introduction of SO₂Reduction of flue gas to H₂SeO₃And adding lead sheets into the absorption tower liquid, carrying out reduction and replacement at the temperature of 60-95 ℃ to obtain crude selenium II and a reduced liquid, and mixing and drying the crude selenium I and the crude selenium II and then refining to obtain refined selenium.

2. The one-step method for separating and recovering selenium and mercury from acid sludge according to claim 1, characterized in that: in the step (1), the mass content of mercury in the acid mud is 1-43%, and the mass content of selenium is 1-71%; the acid solution is sulfuric acid, hydrochloric acid or nitric acid, the oxidant is potassium permanganate, manganese dioxide, hydrogen peroxide or hypochlorous acid, and the slurrying temperature is 25-90 ℃.

3. The one-step method for separating and recovering selenium and mercury in acid sludge according to claim 1 or 2 is characterized in that: the acid concentration in the slurry is 20-200 g/L, and the oxidant concentration in the slurry is 2-100 g/L.

4. The one-step method for separating and recovering selenium and mercury from acid sludge according to claim 1, characterized in that: and (3) the microwave roasting atmosphere in the step (2) is air or oxygen atmosphere.

5. The one-step method for separating and recovering selenium and mercury from acid sludge according to claim 1, characterized in that: the condensation temperature in the step (3) is 20-75 ℃.

6. The one-step method for separating and recovering selenium and mercury from acid sludge according to claim 1, characterized in that: and (4) the water amount in the absorption tower accounts for 10-70% of the volume of the absorption tower, and the acid concentration in the liquid of the absorption tower is 100-500 g/L.

Technical Field

The invention relates to a method for separating and recovering selenium and mercury in acid sludge by a one-step method, belonging to the technical field of acid sludge treatment.

Background

The treatment of mercury and selenium pollution has become one of the main concerns in the field of global environmental science and technology. The deep treatment of valuable smelting resources containing mercury and selenium becomes a challenge in the field of mercury pollution treatment, and research and development of the method for efficiently removing mercury and selenium in the valuable smelting resources becomes an urgent need for guaranteeing the safety of ecological environment.

In the prior art, the method for separating selenium, mercury and lead from acid mud by chlorination leaching comprises the steps of firstly adding sodium chlorate to leach mercury and selenium by oxidation, and then introducing SO₂Crude selenium is reduced, sodium sulfide is added to precipitate mercury, selenium, mercury and lead can be separated and recovered cleanly and efficiently, the comprehensive recovery rate of metal is improved, and environmental pollution is reduced; the invention relates to a method for comprehensively recovering selenium, mercury, lead and silver from acid sludge, which comprises the steps of adding dilute acid to selectively leach lead in conversion slag, adding sodium chloride to deposit silver, adding an oxidant and acid to chloridize and leach selenium and mercury to separate silver, reducing crude selenium by sulfur dioxide, and adding a vulcanizing agent to deposit mercury, wherein the method is a full-wet method for treating and smelting acid sludge, and is low in temperature, environment-friendly, the mercury yield of the full process is more than 99.5%, the lead content is more than 95.0%, and the selenium content is more than 98.0%; the method for separating mercury, selenium and lead from nonferrous smelting acid sludge comprises the steps of pressurizing, oxidizing and leaching mercury and lead, synthesizing copper amalgam by copper scrap displacement, and adding alkali into lead-containing liquid to precipitate lead.

However, in the prior art, the mercury is precipitated by using a wet process, and the sodium sulfide is added to generate the mercury sulfide, so that the added value of the product is low.

Disclosure of Invention

Aiming at the problems of complex technical process for treating the acid sludge, difficult separation of selenium and mercury and the like in the prior art, the invention provides a method for separating and recovering selenium and mercury in the acid sludge by one step, namely directly roasting selenium and mercury phases in the acid sludge to form SeO₂Mercury is condensed and recovered, selenium dioxide is reduced and recovered, and refined, and the mercury-containing slag and selenium-containing slag generated in the process are refined again, so that the high-efficiency and simple operation of harmful acid sludge is realizedAnd (5) single processing.

A method for separating and recovering selenium and mercury in acid sludge by a one-step method comprises the following specific steps:

(1) mixing the acid mud and the slurrying liquid for slurrying for 30-120 min to obtain a slurried substance; wherein the slurry liquid contains acid liquid and oxidant;

(2) placing the slurry obtained in the step (1) at the temperature of 400-800 ℃ for microwave roasting for 20-120 min to obtain Hg and SeO₂The roasting slag is subjected to pyrometallurgical valuable metal recovery;

(3) hg and SeO of step (2)₂The mixed vapor is condensed and separated to obtain SeO₂Crude vapor and elemental Hg;

(4) step (3) SeO₂Introducing the crude steam into an absorption tower, and hydrolyzing at the temperature of 60-95 ℃ to obtain H₂SeO₃Introduction of SO₂Reduction of flue gas to H₂SeO₃And adding lead sheets into the absorption tower liquid, carrying out reduction and replacement at the temperature of 60-95 ℃ to obtain crude selenium II and a reduced liquid, and mixing and drying the crude selenium I and the crude selenium II and then refining to obtain refined selenium.

In the acid mud obtained in the step (1), the mass content of mercury is 1-43%, and the mass content of selenium is 1-71%; the acid solution is sulfuric acid, hydrochloric acid or nitric acid, the oxidant is potassium permanganate, manganese dioxide, hydrogen peroxide or hypochlorous acid, and the slurrying temperature is 25-90 ℃;

the acid concentration in the slurry is 20-200 g/L, and the oxidant concentration in the slurry is 2-100 g/L, namely 0.1-5% of the mass of the acid mud;

the microwave roasting atmosphere in the step (2) is air or oxygen atmosphere, and the introduction flow of the air or the oxygen is 1-20L/min;

the condensation temperature in the step (3) is 20-75 ℃;

the water amount in the absorption tower in the step (4) accounts for 10-70% of the volume of the absorption tower, and the acid concentration in the liquid of the absorption tower is 100-500 g/L;

the drying temperature in the step (4) is 120-140 ℃.

The invention has the beneficial effects that:

(1) the method has the advantages that the selenium and the mercury are separated by the one-step method, the mercury is separated by the elemental mercury, the selenium is separated by the selenium dioxide, the separation efficiency is high, and the separation of the selenium and the mercury can reach more than 99 percent;

(2) the method has the advantages of short mercury separation flow, closed process and no mercury leakage;

(3) the lead-containing slag after the selenium and mercury are extracted can be directly returned to the system, and the safety and the controllability are high.

Drawings

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

FIG. 2 is the XRD pattern of the acid mud material of example 1;

FIG. 3 is the XRD pattern of the roasted slag after the acid sludge is subjected to selenium and mercury removal in example 1.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments, but the scope of the present invention is not limited to the description.

Example 1: the method for separating and recovering selenium and mercury in acid sludge by one-step process (see figure 1) comprises the following steps:

(1) slurrying: mixing the acid mud with the slurry, and slurrying at 25 deg.C for 120min to obtain slurry; wherein the mercury content in the dried acid mud is 1% by mass, the selenium content is 1% by mass, the solid-to-liquid ratio g: mL of the acid mud to the slurry liquid is 1:6, the slurry liquid contains hydrochloric acid and an oxidant (potassium permanganate), the concentration of the hydrochloric acid in the slurry liquid is 20g/L, and the concentration of the oxidant in the slurry liquid is 2 g/L;

(2) roasting: placing the slurry obtained in the step (1) at the temperature of 400 ℃ and roasting the slurry in the air atmosphere for 20min to obtain Hg and SeO₂The total content of mercury and selenium in the roasting slag is not more than 1 percent, and the roasting slag is used for recovering valuable metals by pyrometallurgy; wherein the flow rate of the air is 1L/min;

(3) condensing and recovering mercury: hg and SeO of step (2)₂The mixed steam is condensed and separated into SeO by a water cooling tank with the temperature of 20 DEG C₂Crude steam and Hg simple substance, the water cooling tank is composed of a water cooling circulation system and a mercury recycling tank;

(4) absorption and reduction: step (3) SeO₂The crude vapor is introduced into an absorption tower, the water content in the absorption tower is 10 percent of the volume of the absorption tower, and the crude vapor is introduced into a vapor-liquid separatorSeO at a temperature of 60 DEG C₂Hydrolysis to give H₂SeO₃Introduction of SO₂Reduction of flue gas to H₂SeO₃Obtaining crude selenium I and absorption tower liquid, SO₂The flow of flue gas does not need to be controlled, the flue gas can be absorbed at the tail gas end of the absorption tower, and the tower liquid after absorption contains about 100g/L of acid; the absorbed tower liquid enters a reduction tank, lead sheets are added into the absorption tower liquid, reduction and replacement are carried out at the temperature of 60 ℃ until the absorption tower liquid is colorless after thiourea detection to obtain crude selenium II and reduced liquid, and the crude selenium I and the crude selenium II are combined and then placed at the temperature of 120 ℃ for drying and then refined to obtain refined selenium; wherein the refining is performed by a liquation furnace or a vacuum furnace, and the selenium slag is returned to the step (2) for roasting;

in the embodiment, the XRD pattern of the acid sludge raw material is shown as 2, the XRD pattern of the roasting residue after the acid sludge is subjected to selenium and mercury removal is shown as 3, and the comparison between the figures 2 and 3 shows that the phase containing selenium and mercury after roasting treatment is completely disappeared, and only PbSO is left₄Namely, the acid sludge realizes safe treatment, and the roasted lead slag can be returned to the Isa furnace for lead smelting;

in the embodiment, the recovery rate of mercury is 99%, the recovery rate of selenium is 99%, and the total content of mercury and selenium in the roasting slag after removing mercury and selenium is 0.02%.

Example 2: the method for separating and recovering selenium and mercury in acid sludge by one-step process (see figure 1) comprises the following steps:

(1) slurrying: mixing the acid mud with the slurry, and slurrying at 60 deg.C for 60min to obtain slurry; wherein the mass content of mercury in the dried acid mud is 43%, the mass content of selenium is 8%, the solid-to-liquid ratio g: mL of the acid mud to the slurry is 2:1, the slurry contains sulfuric acid and an oxidant (hydrogen peroxide), the concentration of the sulfuric acid in the slurry is 90g/L, and the concentration of the oxidant in the slurry is 35 g/L;

(2) roasting: placing the slurry obtained in the step (1) at the temperature of 600 ℃ and roasting the slurry in the air atmosphere for 60min to obtain Hg and SeO₂The total content of mercury and selenium in the roasting slag is not more than 1 percent, and the roasting slag is used for recovering valuable metals by pyrometallurgy; wherein the flow rate of the air is 10L/min;

(3) condensing and recovering mercury: hg and SeO of step (2)₂The mixed vapor is condensed by a water-cooling tank with the temperature of 60 ℃ to separate SeO₂Crude steam and Hg simple substance, the water cooling tank is composed of a water cooling circulation system and a mercury recycling tank;

(4) absorption and reduction: step (3) SeO₂Introducing the crude vapor into an absorption tower containing 50% of water at 80 deg.C, and SeO₂Hydrolysis to give H₂SeO₃Introduction of SO₂Reduction of flue gas to H₂SeO₃Obtaining crude selenium I and absorption tower liquid, SO₂The flow of flue gas does not need to be controlled, the flue gas can be absorbed at the tail gas end of the absorption tower, and the tower liquid after absorption contains about 300g/L of acid; the absorbed tower liquid enters a reduction tank, lead sheets are added into the absorption tower liquid, reduction and replacement are carried out at the temperature of 70 ℃ until the absorption tower liquid is colorless after thiourea test to obtain crude selenium II and reduced liquid, and the crude selenium I and the crude selenium II are combined and then placed at the temperature of 130 ℃ for drying and then refined to obtain refined selenium; wherein the refining is performed by a liquation furnace or a vacuum furnace, and the selenium slag is returned to the step (2) for roasting;

in the embodiment, the recovery rate of mercury is 99.5%, the recovery rate of selenium is 99%, and the total content of mercury and selenium in the roasting slag after removing mercury and selenium is 0.5%.

Example 3: the method for separating and recovering selenium and mercury in acid sludge by one-step process (see figure 1) comprises the following steps:

(1) slurrying: mixing the acid mud with the slurry, and slurrying at 90 ℃ for 100min to obtain a slurry; wherein the mass content of mercury in the dried acid mud is 9%, the mass content of selenium is 71%, the solid-to-liquid ratio g: mL of the acid mud to the slurry liquid is 6:1, the slurry liquid contains nitric acid and an oxidant (hypochlorous acid), the concentration of the nitric acid in the slurry liquid is 200g/L, and the concentration of the oxidant in the slurry liquid is 100 g/L;

(2) roasting: placing the slurry obtained in the step (1) at the temperature of 800 ℃ and in the air atmosphere for microwave roasting for 120min to obtain Hg and SeO₂The total content of mercury and selenium in the roasting slag is not more than 1 percent, and the roasting slag is used for recovering valuable metals by pyrometallurgy; wherein the flow rate of the air is 10L/min;

(3) condensing and recovering mercury: hg and SeO of step (2)₂The mixed steam is condensed by a water-cooling tank with the temperature of 75 ℃ to separate out SeO₂Crude steam and Hg simple substance are cooled in a water tankA water-cooling circulation system and a mercury recovery tank;

(4) absorption and reduction: step (3) SeO₂Introducing the crude vapor into an absorption tower, wherein the water content in the absorption tower is 70% of the volume of the absorption tower, and the SeO is carried out at the temperature of 95 DEG C₂Hydrolysis to give H₂SeO₃Introduction of SO₂Reduction of flue gas to H₂SeO₃Obtaining crude selenium I and absorption tower liquid, SO₂The flow of flue gas does not need to be controlled, the flue gas can be absorbed at the tail gas end of the absorption tower, and the tower liquid after absorption contains about 500g/L acid; the absorbed tower liquid enters a reduction tank, lead sheets are added into the absorption tower liquid, reduction and replacement are carried out at the temperature of 80 ℃ until the absorption tower liquid is colorless after thiourea test to obtain crude selenium II and reduced liquid, and the crude selenium I and the crude selenium II are combined and then placed at the temperature of 140 ℃ for drying and then refined to obtain refined selenium; wherein the refining is performed by a liquation furnace or a vacuum furnace, and the selenium slag is returned to the step (2) for roasting;

in the embodiment, the recovery rate of mercury is 99.9%, the recovery rate of selenium is 99.72%, and the total content of mercury and selenium in the roasting slag after removing mercury and selenium is 0.3%.

While the present invention has been described in detail with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, and various changes can be made without departing from the spirit and scope of the present invention.