CN111235396A - Wet processing method for copper smelting acid making sludge - Google Patents

Abstract

The invention discloses a wet processing method for copper smelting acid-making acid sludge. The steps are as follows: adjusting the acid-making acid sludge, adding agent A and agent B for leaching after the mixing, and separating solid and liquid after the leaching to obtain a leaching solution. slag and neutral leaching solution, the leaching slag recovers lead, gold and silver; the obtained leaching solution is added to the agent C for reduction, and the final reduction potential is controlled to be 300mV~450mV, and the solid-liquid separation is performed to obtain the mercury-rich slag and the reduced liquid; after controlling the reduction The pH of the liquid is less than 1, and the agent D is added for reduction. After the reaction is completed, the solid-liquid separation is performed to obtain crude selenium and a liquid after precipitation of selenium. After the precipitation of selenium, the liquid is sent to a water treatment process to recover copper. The reagent E is reacted, and after the reaction is completed, solid-liquid separation is carried out, and industrial mercury is obtained after the solid is separated and dried, and the liquid can be recycled and treated regularly.

Description

A kind of wet processing method of copper smelting acid-making acid sludge

technical field

The invention belongs to the field of non-ferrous smelting and environmental treatment, and particularly relates to a wet processing method for copper smelting acid sludge.

Background technique

Non-ferrous smelting enterprises, especially pyro-smelting enterprises, generate sulfur dioxide flue gas during the smelting process. The flue gas contains sulfur dioxide, arsenic, lead, selenium, mercury and other elements, and also contains mineral powder to varying degrees. The flue gas is generally Enter the acid production system to produce industrial sulfuric acid. Although the flue gas has gone through the smelting electric dust collection and other dust removal links, it still contains certain impurities. In the acid production system, spray purification and cooling are firstly carried out to remove most of the remaining soot and sulfur trioxide in the flue gas. The soluble part of the water obtained by spraying is generally arsenic, fluorine, chlorine and other impurity elements, and the insoluble part of the impurity elements are mainly lead, copper, selenium, mercury, etc. are also captured into the polluted acid, and the insoluble elements are separated by solid-liquid separation. Impurities form acid sludge.

In addition to copper, lead, selenium, mercury and other elements, the acid mud also contains some precious metals such as gold and silver, and has high recovery value. Most of the research on acid-making acid mud at home and abroad focuses on fire treatment, roasting, selenium and mercury removal, and there is not much research on wet treatment process. Patent 201610252644.9 proposes a method for wet treatment of acid mud. It is simple and does not involve the most important problem of separation of selenium and mercury in acid sludge; patent 201710211864.1 proposes a process for treating acid sludge. The acid sludge does not contain heavy metal copper and only involves the separation of selenium and mercury, and the obtained mercury oxide needs to be distilled and purified , so as to obtain refined mercury; patent 201711327545.3 proposes a method for separating mercury, selenium and lead from non-ferrous smelting acid sludge. The acid sludge also does not contain copper. The lead and mercury are leached by oxygen pressure, and the final product is copper amalgam , oxygen pressure leaching equipment and process are much more complicated than atmospheric pressure leaching; patent 201810121491.3 proposes a method for comprehensive recovery of lead, mercury and selenium in copper smelting acid sludge, which does not involve copper recovery, and nitric acid leaching is used to easily disperse lead , is not conducive to the recovery of lead.

Aiming at the current status of acid sludge treatment in the acid-making system in the pyrometallurgical industry, and to solve the disadvantage of incomplete separation of copper, selenium and mercury in the acid sludge, the invention proposes a wet-process treatment method for copper-smelting acid-making acid sludge.

SUMMARY OF THE INVENTION

Aiming at the problem of incomplete separation of selenium, mercury, copper, lead and the like in the current copper smelting acid-making acid sludge, the invention provides a wet-processing method for acid sludge, which has the advantages of one-time leaching of copper, selenium and mercury. It has the advantages of separating and recovering copper, selenium and mercury from the leachate step by step. It has the advantages of simple operation, easy control of process parameters, and easy control of technical parameters. It realizes the resource treatment of mercury and selenium in acid sludge, and completely solves the problem of wet method To deal with the problem of incomplete separation of acid sludge-related elements, the reaction of the whole process is mild and controllable, and the operating environment is good.

In order to achieve the above object, the present invention provides the following main technical solutions:

A kind of wet processing method of copper smelting acid-making acid sludge, and its concrete processing steps are as follows:

Step 1: Neutral leaching of acid mud, adjusting acid mud according to the solid-liquid mass ratio of 1: (1~5), adding reagent A and reagent B for leaching after mixing, and the leaching temperature is 20 ℃ ~ 90 ℃ , after leaching for 1h~6h, carry out solid-liquid separation to obtain leaching slag and neutral leaching solution, and the leaching slag recovers lead, gold and silver;

Step 2: Potential reduction of the leaching solution, adding the leaching solution obtained in step 1 to the agent C for reduction, controlling the reduction temperature to be 20 ℃ ~ 50 ℃, and controlling the final reduction potential to be 300 mV ~ 450 mV, and continue to react for 1 hour and then carry out solid-liquid separation to obtain rich Mercury residue and reduction liquid;

Step 3: reduce the precipitation selenium, control the pH value of the solution after reduction to be less than 1, add agent D, and conduct a reduction reaction at 50 ° C ~ 90 ° C for 1 h ~ 10 h, after the reaction is completed, solid-liquid separation, obtain crude selenium and precipitated selenium liquid, and precipitated selenium. Copper is recovered in the post-liquid water treatment process, and crude selenium can be sold as a commodity;

Step 4: Mercury-rich slag treatment, adding water to the mercury-rich slag obtained in step 2 for slurry mixing, adjusting the liquid-solid mass ratio to 1:1~2, adding reagent E to the solution for reaction, reacting for 0.5h~1h, and reacting After the end, solid-liquid separation is carried out. After the solid is separated and dried, industrial mercury is obtained, which can be sold as a commodity. The liquid can be recycled and treated regularly.

Preferably, in the first step, the agent A is one of hydrogen peroxide, sodium peroxide, calcium peroxide or sodium chlorate, and the dosage of the agent A is 1.2-2.0 times the theoretical total mass of selenium and mercury;

In the described step 1, the agent B is one of sodium chloride, sodium nitrate or potassium iodide, and the added amount of the agent B is 1.5-3.0 times the theoretical total mass of selenium and mercury;

In the described step 2, the agent C is one of formaldehyde, sodium sulfite or metallic copper, and the amount of the agent C added is 1.5-3.0 times the theoretical mass of mercury;

In the third step, the agent D is a mixture of one or more of sodium sulfite, sodium metabisulfite and SO ₂ in any proportion, and the amount of the agent D added is 3.0-5.0 times the theoretical mass of selenium.

In the fourth step, the agent E is a mixture of one or more of oxalic acid or hydrazine hydrate in any proportion, and the amount of the agent E added is 2.0-10.0 times the theoretical mass of mercury.

Positive and beneficial effects of the present invention: the method for treating acid sludge by wet method has the advantages of leaching copper, selenium and mercury at one time, and completely solves the problem of incomplete separation of related elements in the wet treatment of acid sludge. By separating and recovering copper, selenium and mercury, relatively pure industrial mercury and crude selenium can be directly obtained, which can be directly sold. The method has the advantages of simple operation, easy control of process parameters, simple control of technical parameters, and good operating environment, and realizes the resource treatment of mercury and selenium in acid sludge, the recovery rate of lead is greater than 99%, and the recovery rate of selenium is greater than 97%. %, the recovery rate of mercury is greater than 99%.

Description of drawings

Fig. 1 is a process flow diagram of the present invention.

Detailed ways

Below in conjunction with the accompanying drawings and specific embodiments, the present invention will be further described:

Example 1

A kind of wet processing method of copper smelting acid-making acid sludge, as shown in Figure 1, its concrete processing method steps are as follows:

Take 1000g of acid sludge, and analyze its main chemical components: Au: 28.5g/t, Ag: 510.6g/t, Pb: 56.53%, Cu: 2.79%, Se: 3.99%, Hg: 0.921%. The acid mud was added to 1000 mL of water, the pH of the solution was about 4.5 after slurry mixing, the temperature was raised to 75 °C, 73.6 g of sodium chlorate and 88.0 g of sodium nitrate were added, reacted for 3 hours, and filtered to obtain leaching residue and leaching solution, and the leaching residue was used to recover gold. Silver and lead; 18.0g copper powder was added to the leaching solution, reacted at 20°C for 3h, and the terminal potential was 415mv to obtain 11.0g of mercury-rich slag and reduction solution. The mercury-rich slag contained 84.2% mercury, 0.51% copper, 0.12% selenium, and The mercury slag was mixed with water according to the liquid-solid mass ratio of 1:2 to obtain a mercury-rich slag slurry, and 15 g of hydrazine hydrate was added to the mercury-rich slag slurry for reduction, and the reaction was carried out at room temperature for 1 h to obtain metallic mercury with a grade of 99.3%. The liquid after mercury precipitation can be used for Mercury-rich slag mixing; after reduction (control the pH value of the solution <1, if the pH value of the solution is greater than or equal to 1, use sulfuric acid, hydrochloric acid or formic acid to adjust the pH value <1) and pass SO ₂ to reduce selenium, and the flow rate of SO ₂ gas is 65mL /min, the temperature was 80°C, and the reaction was carried out for 3 hours to obtain 38 g of crude selenium, containing 95.8% selenium and 0.65% copper. The recovery rate of lead was 99.2%, the recovery rate of selenium was 97.3%, and the recovery rate of mercury was 99.6%. The pH of the solution after selenium precipitation is 0.4, and copper is recovered in the water supply treatment process.

Example 2

A kind of wet processing method of copper smelting acid-making acid sludge, and its concrete processing steps are as follows:

Take 1000g of acid sludge, and analyze its main chemical components: Au: 7g/t, Ag: 588g/t, Pb: 58.76%, Cu: 0.66%, Se: 1.85%, Hg: 0.453%. The acid mud was added to 1000 mL of water, the pH of the solution was about 4.0 after sizing, the temperature was raised to 85 °C, 36.8 g of sodium chlorate and 34.5 g of sodium chloride were added, reacted for 2 hours, and filtered to obtain leaching residue and leaching solution, and the leaching residue was recovered. Gold, silver and lead; add 6.5g of copper powder to the leaching solution, react at 30°C for 2h, the terminal potential is 385mv, and obtain 5.2g of mercury-rich slag and reduced solution. The mercury-rich slag contains 83.9% mercury, 0.45% copper, and 0.26% selenium. The mercury-rich slag was mixed with water according to the liquid-solid mass ratio of 1:2 to obtain a mercury-rich slag slurry, and 10 g of hydrazine hydrate and 10 g of oxalic acid were added to the mercury-rich slag slurry for reduction, and the reaction was carried out at room temperature for 1 h to obtain metallic mercury, with a grade of 99.5% and mercury deposition. The back liquor can be used for slurry mixing of mercury-rich slag; the post-reduction liquor is fed with SO ₂ to reduce selenium, the gas flow rate of SO ₂ is 65mL/min, the temperature is 60°C, and the reaction is carried out for 5h to obtain 18.2g of crude selenium, selenium content: 98.5%, copper content 0.33%, the recovery rate of lead is 99.5%, the recovery rate of selenium is 98.6%, and the recovery rate of mercury is 99.3%. The pH of the solution after selenium precipitation is 0.2, and the copper is recovered in the water supply treatment process.

Example 3

A kind of wet processing method of copper smelting acid-making acid sludge, and its concrete processing steps are as follows:

Take 1000g of acid sludge, and analyze its main chemical components: Au: 14.6g/t, Ag: 495.6g/t, Pb: 60.74%, Cu: 0.25%, Se: 2.87%, Hg: 0.676%. The acid mud was added to 1000 mL of water, the pH of the solution was about 4.5 after sizing, the temperature was raised to 80 °C, 42.6 g of sodium peroxide and 53.2 g of sodium chloride were added, the reaction was carried out for 2 hours, and the leaching residue and leaching solution were obtained by filtration, and the leaching residue was recovered. Gold, silver and lead; add 10.0g copper powder to the leaching solution, react at 30°C for 2h, the terminal potential is 385mv, and obtain 7.9g of mercury-rich slag and reduction solution. The mercury-rich slag contains 84.3% mercury, 0.38% copper, and 0.13% selenium. The mercury-rich slag was mixed with water according to the liquid-solid mass ratio of 1:2 to obtain a mercury-rich slag slurry, and 12 g of hydrazine hydrate and 12 g of oxalic acid were added to the mercury-rich slag slurry for reduction, and the reaction was carried out at room temperature for 1 hour to obtain metallic mercury, with a grade of 99.6% and mercury deposition. The after liquor can be used for sizing of mercury-rich slag; after reduction, the pH of the liquor is adjusted to 0.4 with concentrated sulfuric acid, 140 g of sodium metabisulfite is added to reduce selenium, the temperature is 60 °C, and the reaction is carried out for 5 h to obtain 29.0 g of crude selenium, selenium content: 99.2%, copper content 0.23 %, the recovery rate of lead is 99.1%, the recovery rate of selenium is 98.9%, and the recovery rate of mercury is 99.5%. The pH of the solution after selenium precipitation is 0.8, and the copper is recovered in the water supply treatment process.

Example 4

A kind of wet processing method of copper smelting acid-making acid sludge, and its concrete processing steps are as follows:

Take 1000g of acid sludge, and analyze its main chemical components: Au: 9.5g/t, Ag: 546.3g/t, Pb: 57.55%, Cu: 0.51%, Se: 2.03%, Hg: 0.587%. The acid mud was added to 1000mL of water, the pH of the solution was about 4.6 after sizing, the temperature was raised to 80°C, 47.1g of sodium peroxide and 39.3g of sodium chloride were added, the reaction was carried out for 2h, and filtered to obtain leaching residue and leaching solution, and the leaching residue was recovered. Gold, silver and lead; add 10.5g copper powder to the leaching solution, react at 30°C for 2h, the terminal potential is 385mv, and obtain 6.9g of mercury-rich slag. The mercury-rich slag was mixed with water according to the liquid-solid mass ratio of 1:2 to obtain a mercury-rich slag slurry, and 11 g of hydrazine hydrate and 11 g of oxalic acid were added to the mercury-rich slag slurry for reduction, and the reaction was carried out at room temperature for 1 hour to obtain metallic mercury, with a grade of 99.2% and mercury deposition. The after liquor can be used for sizing of mercury-rich slag; after reduction, the pH of the liquor is adjusted to 0.4 with concentrated sulfuric acid, 100 g of sodium metabisulfite is added to reduce selenium, the temperature is 80 °C, and the reaction is carried out for 4 h to obtain 21.3 g of crude selenium, selenium content: 98.2%, copper content 0.13 %, the recovery rate of lead is 99.6%, the recovery rate of selenium is 99.1%, and the recovery rate of mercury is 99.0%. The pH of the solution after selenium precipitation is 0.8, and the copper is recovered in the water supply treatment process.

The above examples are only used to illustrate the preferred embodiments of the present invention, but the present invention is not limited to the above-mentioned embodiments, and any modifications made within the spirit and principles of the present invention within the scope of knowledge possessed by those of ordinary skill in the art , equivalent substitutions and improvements, etc., shall be regarded as the protection scope of this application.

Claims (6)

1. a wet process method for copper smelting acid-making acid sludge, is characterized in that, step is as follows: Step 1: Neutral leaching of acid mud, adjusting acid mud according to the solid-liquid mass ratio of 1: (1~5), adding reagent A and reagent B for leaching after mixing, and the leaching temperature is 20 ℃ ~ 90 ℃ , after leaching for 1h~6h, the solid-liquid separation is performed to obtain leaching residue and neutral leaching solution, and the leaching residue recovers lead, gold and silver; Step 2: Potential reduction of the leaching solution, adding the leaching solution obtained in step 1 to the agent C for reduction, controlling the reduction temperature to be 20 ° C ~ 50 ° C, reacting for 1 ~ 3h, controlling the final reduction potential to be 300mV ~ 450mV, solid-liquid separation, to obtain rich Mercury residue and reduction liquid; Step 3: Control the pH of the reduced solution to be less than 1, add agent D, and conduct a reduction reaction at 50°C to 90°C for 1h to 10h. After the reaction is completed, solid-liquid separation is performed to obtain crude selenium and precipitation post-selenium solution, and the post-selenium precipitation solution is sent to water for treatment Process to recover copper; Step 4: Mercury-rich slag treatment, add water to the mercury-rich slag obtained in step 2 for slurry mixing, the liquid-solid mass ratio is 1:1~2, add reagent E to the solution for reaction, react for 0.5h~1h, and the reaction ends After the solid-liquid separation is carried out, the industrial mercury is obtained after the solid is separated and dried. 2. the wet processing method of copper smelting acid sludge according to claim 1, is characterized in that, in described step 1, agent A is one in hydrogen peroxide, sodium peroxide, calcium peroxide or sodium chlorate The dosage of agent A is 1.2-2.0 times of the theoretical total mass of selenium and mercury. 3. the wet processing method of copper smelting acid sludge according to claim 1, is characterized in that, in described step 1, agent B is a kind of in sodium chloride, sodium nitrate or potassium iodide, and agent B adds The amount is 1.5-3.0 times the theoretical total mass of selenium and mercury. 4. the wet processing method of copper smelting acid sludge according to claim 1, is characterized in that, in described step 2, agent C is a kind of in formaldehyde, sodium sulfite or metallic copper, and agent C add-on is 1.5-3.0 times the theoretical mass of mercury. 5. the wet processing method of copper smelting acid sludge according to claim 1, is characterized in that, in described step ₃ , agent D is a kind of sodium sulfite, sodium metabisulfite or SO , and agent D add-on is 3.0-5.0 times the theoretical mass of selenium. 6. The wet processing method of copper smelting acid-making acid sludge according to claim 1, characterized in that, in the described step 4, the agent E is one or more mixtures in arbitrary proportions in oxalic acid or hydrazine hydrate , the dosage of reagent E is 2.0-10.0 times of the theoretical mass of mercury.

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