Method for removing impurity selenium in carbonylation alloy enriched noble metal material

Abstract

The invention discloses a method for removing impurity selenium in a carbonylation alloy enriched noble metal material, which comprises the following steps: S1, carrying out pulpifying washing on platinum concentrate with water until the pH value is 7, carrying out filter pressing separation, and drying filter residues until the water content is less than 0.5%; s2, carrying out oxidation absorption treatment by adopting an oxidation furnace, cooling to obtain oxidation furnace residues and secondary water, and collecting the oxidation furnace residues as platinum concentrate to be delivered to the next process for separation and purification of platinum, palladium and gold products; s3, absorbing the secondary water through an absorption tower to obtain an absorption liquid and filter residues which are relatively high-grade crude selenium, adjusting the pH value of the filtered liquid to 1.8-2.2 by using hydrochloric acid, heating to 85-92 DEG C, introducing sulfur dioxide for reduction, detecting the reduction end point by using thiourea, stopping reduction when the detected solution is colorless to obtain a 99.9% refined selenium product, and enabling the filtrate to pass through the absorption tower to obtain the 99.9% refined selenium product. And after absorption, entering the step S3 again.

Description

Technical Field

[0001] The present invention relates to the technical field of carbonyl alloy enrichment and purification of platinum, palladium and gold noble metals, and in particular to a method for removing impurity selenium from carbonyl alloy enriched noble metal materials. Background Art

[0002] At present, the raw materials for the precious metal smelting and enrichment process are gradually transformed from the original secondary alloy to carbonyl alloy. The raw material composition of the two has changed greatly. The content of platinum, palladium and gold has decreased slightly, but the content of selenium has increased significantly. The selenium content in the platinum concentrate produced from the secondary alloy is only 1%, but the selenium content in the platinum concentrate produced by the carbonyl alloy is as high as 6%. Selenium has a great impact on the production operation and product quality in the purification process of platinum, palladium and gold precious metals, especially in the extraction process of platinum, palladium and gold, which seriously affects the production operation and product quality, and the direct recovery rate and grade rate of platinum, palladium and gold cannot be guaranteed. Therefore, the enriched platinum concentrate must be removed of selenium and reduced in sulfur before entering the purification process to extract platinum, palladium and gold.

[0003] Therefore, a method for removing selenium impurity from carbonyl alloy-enriched precious metal materials is proposed. Summary of the invention

[0004] In view of the above technical problems, the present invention provides a method for removing selenium impurities from carbonyl alloy-enriched precious metal materials.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows: A method for removing selenium impurities from carbonyl alloy-enriched precious metal materials comprises the following steps: S1, platinum concentrate is washed with water slurry to pH=7, separated by filter press, and the moisture content of the filter residue is less than 0.5% when dried; S2. Use an oxidation furnace for oxidation absorption treatment. When the furnace temperature rises to 450°C to 480°C, slowly feed the material at a speed of 30kg / h, adjust the oxygen flow rate into each furnace to 16-18L / min, continue to heat the furnace to 540°C to 560°C, keep the temperature constant for 3h after the material is added, continue to pass oxygen during the constant temperature period, then cool down to obtain oxidation furnace residue and secondary water, collect the oxidation furnace residue as platinum concentrate and hand it over to the next process to separate and purify platinum, palladium and gold products; S3, absorbing the secondary water through the absorption tower to obtain absorption liquid, the filtered residue is the crude selenium with higher grade, the filtered liquid is adjusted to pH=1.8~2.2 with hydrochloric acid, heated to 85℃-92℃, and then introduced into sulfur dioxide for reduction, the reduction end point is detected by thiourea, and the reduction is stopped when the solution is colorless after the detection, and 99.9% refined selenium product is obtained, wherein the filtrate passes through the absorption tower, is absorbed and then enters step S3 again.

[0006] Wherein, in the step S1, the water slurry washing is performed twice.

[0007] Wherein, in step S2, a 60kw oxidation furnace is used.

[0008] The beneficial effects of the present invention are: 1. The present invention utilizes an oxidation furnace to oxidize and absorb selenium in platinum concentrate and volatilize sulfur to participate in the reaction under certain oxygen flow and high temperature, thereby removing selenium in the platinum concentrate and reducing the sulfur content therein, thereby obtaining platinum concentrate with qualified technical indicators.

[0009] 2. The whole process of the present invention is simple to operate, requires less reagents, and can remove 99.9% of selenium. It is the most thorough method of removing selenium impurities. At the same time, the elemental sulfur in the crude platinum concentrate can also be evaporated in the peroxidation furnace to participate in the reaction and remove impurities, further reducing the sulfur content in the platinum concentrate, providing necessary guarantees for the purification, separation and refining of platinum, palladium and gold in the next process, and also producing a certain amount of refined selenium by-products. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present invention is further described below in conjunction with the accompanying drawings and embodiments: Figure 1 It is a process flow chart of the present invention; DETAILED DESCRIPTION

[0011] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0012] The principle of the present invention is that when selenium is oxidized and burned at a certain temperature, selenium reacts with oxygen at the oxidation temperature to generate volatile selenium dioxide gas, which enters the absorption tank and dissolves in water to form a selenious acid solution, and then is reduced with sulfur dioxide to obtain 90% crude selenium. Most of the high-boiling point platinum, palladium, gold, nickel, and copper in the raw material crude selenium in the platinum concentrate do not volatilize at this temperature, and remain in the oxidation slag to become the platinum concentrate after selenium removal. The low-boiling point impurities (S, As, Hg, etc.) volatilize into the absorption tank together with selenium dioxide, participate in the reaction to generate crude selenium, and the unreacted ones are filtered and heated to pass sulfur dioxide to generate refined selenium. The unreacted sulfur dioxide in the oxidation furnace absorption is discharged with the tail gas because it is insoluble in water, thereby achieving the purpose of removing selenium and reducing sulfur.

[0013] The main reaction equation is: Se+O 2 =SeO 2 ↑ S+O 2 =SO 2↑ SeO 2 +H 2 O=H 2 SeO 3 H 2 SeO 3 +2SO 2 +H 2 O=Se↓+H 2 SO 4 .

[0014] Example 1 like Figure 1 As shown, after two slurry washings with water, the pH of the feed liquid was 7, and 600 kg of platinum concentrate was obtained by filter press separation, with a water content of 48%, which was 0.3% after passing through a dryer, and 313 kg of selenium-containing platinum concentrate was obtained, of which the selenium content was 5.9%. A 60 kW oxidation furnace was used. When the furnace temperature rose to 480 °C, the dried crude platinum concentrate was slowly added from the feed port at a speed of 30 kg / h, and the oxygen flow rate was 18 L / min. The temperature was continued to rise to a constant temperature of 560 °C for the furnace body. After 10 hours, the materials were added, and the furnace was stopped after continuing to pass oxygen for 3 hours. The temperature was cooled and 268.4 kg of oxidation furnace residue was collected. The direct recovery rate of platinum, palladium and gold in this process was 99.99%, and the total amount of platinum, palladium and gold was 16.93%. The sulfur content was reduced from the original 18.34% to 10.12%. The platinum concentrate after selenium removal was handed over to the next step for purification, and finally platinum, palladium and gold products with a purity of 99.99% were obtained. The secondary absorption tower of the oxidation furnace was liquid filtered, and the dry amount of crude selenium in the filter residue was 2.1 kg. The filtrate was adjusted to pH = 1.8 with hydrochloric acid, placed in an enamel kettle and heated to 90°C, and then sulfur dioxide was introduced for reduction. After the reduction end, it was filtered, washed and dried to obtain 15.8 kg of 99.9% refined selenium product, and the direct recovery rate of refined selenium was 95.6%.

[0015] Example 2 like Figure 1As shown, after two slurry washings with water, the pH of the feed liquid was 7, and 613 kg of platinum concentrate was obtained by filter press separation, with a water content of 50%, which was 0.3% after passing through a dryer, and 307.4 kg of selenium-containing platinum concentrate was obtained, of which the selenium content was 5.62%. A 60 kW oxidation furnace was used. When the furnace temperature rose to 489 ° C, the dried crude platinum concentrate was slowly added from the feed port at a speed of 30 kg / h, and the oxygen flow rate was 16 L / min. The temperature continued to rise to a constant temperature of 555 ° C for the furnace body. After 10 hours, the materials were added, and the furnace was stopped after continuing to pass oxygen for 3 hours. The temperature was cooled and 275.6 kg of oxidation furnace residue was collected. The direct recovery rate of platinum, palladium and gold in this process was 99.99%, and the total amount of platinum, palladium and gold was 16.89%. The sulfur content was reduced from the original 17.98% to 10.45%. The platinum concentrate after selenium removal was handed over to the next step for purification, and finally platinum, palladium and gold products with a purity of 99.99% were obtained. The secondary absorption tower of the oxidation furnace was liquid filtered, and the dry amount of crude selenium in the filter residue was 2.4 kg. The filtrate was adjusted to pH = 1.9 with hydrochloric acid, placed in an enamel kettle and heated to 92°C, and then sulfur dioxide was introduced for reduction. After the reduction end, it was filtered, washed and dried to obtain 14.9 kg of 99.9% refined selenium product, and the direct recovery rate of refined selenium was 95.01%.

[0016] Example 3 like Figure 1 As shown, after two slurry washings with water, the pH of the feed liquid was 7, and 623 kg of platinum concentrate was obtained by filter press separation, with a water content of 42.3%, which was 0.2% after passing through a dryer, and 360 kg of selenium-containing platinum concentrate was obtained, of which the selenium content was 5.49%. A 60 kW oxidation furnace was used. When the furnace temperature rose to 480 °C, the dried crude platinum concentrate was slowly added from the feed port at a speed of 30 kg / h, and the oxygen flow rate was 18 L / min. The temperature was continued to rise to a constant temperature of 560 °C for the furnace body. After 10 hours, the materials were added, and the furnace was shut down after oxygen was continued for 3 hours. After 3 hours, the furnace was shut down, and 268.4 kg of oxidation furnace residue was collected for cooling. In this process, the direct recovery rate of platinum, palladium and gold was 99.99%, and the total amount of platinum, palladium and gold was 17.45%. The sulfur content was reduced from the original 18.97% to 10.34%. The platinum concentrate after selenium removal was handed over to the next step for purification, and finally platinum, palladium and gold products with a purity of 99.99% were obtained. The secondary absorption tower of the oxidation furnace was liquid filtered, and the dry amount of crude selenium in the filter residue was 2.8 kg. The filtrate was adjusted to pH = 1.8 with hydrochloric acid, placed in an enamel kettle and heated to 90°C, and then sulfur dioxide was introduced for reduction. After the reduction end, it was filtered, washed and dried to obtain 17.99 kg of 99.9% refined selenium product, and the direct recovery rate of refined selenium was 94.2%.

[0017] Example 4 like Figure 1 As shown, a method for removing selenium impurities from carbonyl alloy-enriched precious metal materials comprises the following steps: S1, platinum concentrate is washed with water slurry to pH=7, separated by filter press, and the moisture content of the filter residue is less than 0.5% when dried; S2. Use an oxidation furnace for oxidation absorption treatment. When the furnace temperature rises to 450°C, slowly feed the material at a speed of 30kg / h, adjust the oxygen flow rate into each furnace to 16-18L / min, continue to heat the furnace to 540°C, keep the temperature constant for 3h after the material is added, continue to pass oxygen during the constant temperature period, then cool down to obtain oxidation furnace residue and secondary water, collect the oxidation furnace residue as platinum concentrate and hand it over to the next process to separate and purify platinum, palladium and gold products; S3, absorbing secondary water through an absorption tower to obtain absorption liquid, the filtered residue is crude selenium with a relatively high grade, the filtered liquid is adjusted to pH = 2.2 with hydrochloric acid, heated to 85 ° C, and then introduced into sulfur dioxide for reduction, the reduction end point is detected by thiourea, and the reduction is stopped when the solution is colorless after the detection, and 99.9% refined selenium product is obtained, wherein the filtrate passes through the absorption tower, is absorbed, and then enters step S3 again.

[0018] Wherein, in the step S1, the water slurry washing is performed twice.

[0019] Wherein, in step S2, a 60kw oxidation furnace is used.

[0020] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

Claims

1. A method for removing selenium impurities from carbonyl alloy-enriched precious metal materials, characterized in that: The following steps are involved: S1, platinum concentrate is washed with water slurry to pH=7, separated by filter press, and the moisture content of the filter residue is less than 0.5% when dried; S2. Use an oxidation furnace for oxidation absorption treatment. When the furnace temperature rises to 450°C to 480°C, slowly feed the material at a speed of 30kg / h, adjust the oxygen flow rate into each furnace to 16-18L / min, continue to heat the furnace to 540°C to 560°C, keep the temperature constant for 3h after the material is added, continue to pass oxygen during the constant temperature period, then cool down to obtain oxidation furnace residue and secondary water, collect the oxidation furnace residue as platinum concentrate and hand it over to the next process to separate and purify platinum, palladium and gold products; S3, absorbing the secondary water through the absorption tower to obtain absorption liquid, the filtered residue is the crude selenium with higher grade, the filtered liquid is adjusted to pH=1.8~2.2 with hydrochloric acid, heated to 85℃-92℃, and then introduced into sulfur dioxide for reduction, the reduction end point is detected by thiourea, and the reduction is stopped when the solution is colorless after the detection, and 99.9% refined selenium product is obtained, wherein the filtrate passes through the absorption tower, is absorbed and then enters step S3 again.

2. A method for removing selenium impurities from carbonyl alloy-enriched precious metal materials according to claim 1, characterized in that: In the step S1, the water slurry washing is performed twice.

3. A method for removing selenium impurities from carbonyl alloy-enriched precious metal materials according to claim 1, characterized in that: In the step S2, a 60kw oxidation furnace is used.

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