Method for the enrichment and purification of platinum and palladium

Abstract

The application provides a method for enriching and purifying platinum and palladium, which comprises the following process steps: (1) sulfidizing and depositing platinum and palladium; (2) high-temperature calcining and chlorination; (3) precipitating platinum and palladium; (4) gold and silver replacement; (5) separating platinum and palladium; (6) extracting platinum from ammonia complex solution; (7) purifying crude palladium powder; (8) sponge palladium; (9) purifying ammonium chloroplatinate; and (10) sponge platinum. The technology separates platinum and palladium from platinum and palladium concentrates by the method of chlorination, reduces the influence of other impurities, extracts platinum and palladium in the solution by adding potassium permanganate and ammonium chloride, reduces the influence of gold and silver, separates platinum and palladium by adding ammonia water, and then purifies them, so that the enrichment ratio and recovery rate of platinum and palladium are greatly improved, and the subsequent section treatment is also facilitated.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, and specifically relates to a method for enriching and purifying platinum and palladium. Background Technology

[0002] Platinum and palladium, precious metals, are extremely scarce and dispersed in the Earth's crust, making them critically limited mineral resources with a severely insufficient self-sufficiency rate. Their grade is extremely low, and they mainly exist as sulfide ores associated with base metals such as copper and nickel, making mining difficult and exacerbating the supply-demand imbalance. The process of extracting platinum and palladium from platinum-palladium concentrate using physical or chemical methods is called platinum-palladium purification. Platinum and palladium recovery typically employs chemical or electrorefining methods. Chemical methods offer better recovery results but require specific chemical reagents, are complex to operate, costly, and demand highly skilled and safe. Electrorefining methods are low-cost and simple to operate, but have limited recovery purity and rate.

[0003] CN 111850300 B discloses "a method for efficiently enriching platinum and palladium from a low-concentration platinum-palladium nitric acid system solution". The method involves adjusting the pH of the nitric acid system solution, adding a complexing agent A, performing a two-stage temperature-controlled reaction, and then adding an adjusting agent B. After the reaction, a platinum-palladium complex precipitate is obtained. The precipitate is then calcined to remove organic matter, yielding a platinum-palladium concentrate. Platinum and palladium are separated using nitric acid leaching-removal-filtration. NH4Cl and KClO3 are added to the filtrate to obtain a red precipitate. Ammonia is added to the red precipitate to dissolve it, and the solution is filtered. HCl is then added to obtain a yellow precipitate, which is further dissolved in ammonia. A reducing agent is then added to obtain sponge palladium. The platinum concentrate is dissolved in aqua regia, filtered, and NH4Cl is added to the solution to obtain a precipitate. The precipitate is then pulped and reduced to obtain crude platinum powder. This method has obvious drawbacks: the complexing agent A consists of 85%-95% dimethylglyoxime and 5%-15% 2,4-pentanedione dioxime. The agent is toxic, protective clothing must be worn when using it, and the operation is relatively complicated.

[0004] CN 110964918 A discloses a "recovery method for gold and tellurium and enrichment of platinum and palladium from platinum-palladium concentrate," specifically implemented according to the following steps: Step 1, acid leaching of platinum-palladium concentrate to obtain acid leaching solution and acid leaching residue; Step 2, reduction of the acid leaching solution in Step 1 to obtain crude tellurium powder; and sequentially subjecting the acid leaching residue to pulping, heating, and chlorination; Step 3, adjusting the pH of the chlorinated solution after pulping, heating, and chlorination in Step 2 to 1-2, and filtering it to obtain a hydrolysate; Step 4, gold precipitation of the hydrolysate in Step 3 to obtain crude gold powder and gold precipitation solution; Step 5, heating the gold precipitation solution in Step 4 and adding sodium sulfite to precipitate platinum and palladium, continuing to heat and maintain the temperature, and filtering to obtain crude platinum and palladium. This method has a significant drawback: the solution after acid leaching requires further processing, increasing production costs. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for the enrichment and purification of platinum and palladium.

[0006] The technical solution of this invention is achieved as follows: a method for enriching and purifying platinum and palladium, comprising the following process steps:

[0007] (1) Sulfide precipitation of platinum and palladium: The black gold powder produced by silver electrolysis is subjected to nitric acid leaching and aqua regia gold removal processes to obtain nitric acid leaching solution and aqua regia solution. The nitric acid leaching solution is used for silver precipitation, and the aqua regia solution is used for reduction. The silver precipitation solution and the reduction solution are all put into the sulfidation kettle, and sodium sulfide is added to precipitate platinum and palladium. The amount of sodium sulfide added is 50-100g / L, and sodium sulfide slag is produced, which is platinum and palladium concentrate.

[0008] (2) High-temperature calcination and chlorination: After drying the platinum-palladium concentrate, calcination is carried out until no more white smoke is produced. The calcination temperature is not higher than 200℃. After calcination, the roasted residue is transferred to the chlorination process. 10% to 15% dilute hydrochloric acid is added to carry out the chlorination reaction. The liquid-solid ratio is 4 to 6:1. The temperature is raised to 60℃. 10% to 15% hydrogen peroxide is slowly added while stirring. The temperature is maintained above 80℃. The reaction is stirred for 3 hours to dissolve the platinum and palladium in the sulfide residue into the liquid phase. The platinum and palladium content in the chlorinated residue is tested. When the platinum and palladium content is above 200g / t, the chlorinated residue is repeated in this step until the platinum and palladium content drops below 200g / t. Solid and liquid are separated. The chlorinated liquid is transferred to the next process to extract platinum and palladium. The chlorinated residue is transferred to the fire method process for treatment.

[0009] (3) Precipitation of platinum and palladium: Potassium permanganate and ammonium chloride are added to the chlorination solution. The amount of potassium permanganate added is 10-50 g / L and the amount of ammonium chloride added is 100-200 g / L until no more precipitation is produced. The platinum and palladium in the liquid phase are precipitated out in the form of ammonium chloroplatinate and ammonium chloropalladate. After solid-liquid separation, the platinum and palladium residue is enriched into crude palladium powder, and the filtrate is transferred to the displacement tank to recover gold and silver.

[0010] (4) Gold and silver replacement: Iron powder is added to the replacement kettle for gold and silver replacement. After the sample is qualified, it is placed in the tank for pressure filtration. The filter residue is used to extract gold and silver, and the filtrate is discharged into the waste liquid treatment process.

[0011] (5) Platinum-palladium separation: After the platinum-palladium slag produced in step 3 is slurried with water, ammonia water is added to adjust the pH to 8, the temperature is raised to 70℃, the reaction is carried out for 0.5h, and then filtered. Taking advantage of the property that ammonium chloropalladate is soluble in ammonia water and ammonium chloroplatinate is insoluble in ammonia water, the platinum and palladium are separated. After solid-liquid separation, the ammonia complex slag is left for platinum extraction, and the ammonia complex solution is used for palladium extraction.

[0012] (6) Ammonia complex solution palladium extraction: Cool the ammonia complex solution to below 40°C, add hydrochloric acid to make the pH=1, so that the palladium ions in the solution precipitate out in the form of diammonium chloride palladium sulfide. After solid-liquid separation, the filtrate is discharged into the waste liquid treatment process, and the filter residue is used to reduce crude palladium powder. Diammonium chloride palladium sulfide is slurried with water, heated to above 60°C, hydrazine hydrate is added, and the pH is adjusted to 8-9. The reaction is carried out for 0.5 hours, and the crude palladium powder is obtained by filtration. The crude palladium powder is added to hydrochloric acid and sodium chlorate for palladium dissolution. The amount of hydrochloric acid added is 10-20 mL / g, and the amount of sodium chlorate added is 1%-3%. After palladium dissolution, nitric acid is added for boiling. The amount of nitric acid added is 20-30 mL / g. Then ammonium chloride is added to precipitate palladium. The amount of ammonium chloride added is 50-100 g / L. The nitric acid boiling and palladium precipitation steps are repeated 4 times to purify the crude palladium powder repeatedly.

[0013] (7) Purification of crude palladium powder: After the crude palladium powder purified by boiling in step 6 is slurried with water, ammonia water is added to adjust the pH to 8, the temperature is raised to 70℃, the reaction is carried out for 0.5h, filtered, the obtained ammonia complex solution is cooled to below 40℃, hydrochloric acid is added to it to make the pH to 1, so that the palladium ions in the solution are precipitated in the form of diammonium chloride palladium complex. The ammonia complex acidification step is repeated 4 times. After solid-liquid separation, the crude palladium powder is further purified.

[0014] (8) Sponge palladium: After the crude palladium powder obtained from step 7 is purified, water is added to slurry, ammonia is added to adjust the pH to 8, the temperature is raised to 70°C, the reaction is carried out for 0.5 h, and then filtered. The filtrate is heated to above 60°C, hydrazine hydrate is added, the pH is adjusted to 8-9, the reaction is carried out for 0.5 h, and then filtered to obtain sponge palladium. The purity of sponge palladium is above 95%.

[0015] (9) Purification of ammonium chloroplatinate: After drying the ammonia residue produced in step 5, it is roasted at 400°C and then leached with aqua regia. The solution is heated and evaporated to remove nitrogen oxides. 1% hydrochloric acid is added and boiled. After filtration, a platinum-containing filtrate is obtained. The platinum-containing filtrate is heated to above 90°C and 50-100 g / L ammonium chloride and 10%-15% hydrogen peroxide are added to precipitate the platinum ions in the solution as ammonium chloroplatinate. The ammonium chloroplatinate is purified by the above aqua regia leaching to high temperature platinum precipitation process. This process is repeated 5-6 times.

[0016] (10) Sponge platinum: The purified ammonium chloroplatinate is calcined at 600-1000℃ to obtain sponge platinum, the purity of sponge platinum is above 95%;

[0017] The preferred chemical reactions that mainly occur are as follows:

[0018] 3Pt+2NaClO3+18HCl=3H2PtCl6+2NaCl+6H2O

[0019] H2PtCl6+2NH4Cl=(NH4)2PtCl6↓+2HCl

[0020] 2Pd + 2H₂O₂ + 4HCl = 2PdCl₂ + 4H₂O

[0021] PdCl₂ + 2NH₄Cl = (NH₄)₂PdCl₄

[0022] 2NH4Cl+H2PtCl6=(NH4)2PtCl6↓+2HCl.

[0023] The beneficial effects of this invention are as follows: This invention first chlorinates the platinum-palladium concentrate, effectively separating platinum and palladium from the concentrate and reducing the influence of other impurities. It then uses potassium permanganate and ammonium chloride to extract platinum and palladium from the solution, reducing the influence of gold and silver. Finally, it adds ammonia water to separate platinum and palladium for purification, which greatly improves the enrichment ratio and recovery rate of platinum and palladium, and also facilitates subsequent processing. Attached image description:

[0024] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0025] To better understand and implement this invention, the following description, in conjunction with the accompanying drawings, further illustrates the invention:

[0026] Example 1: A method for enriching and purifying platinum and palladium, comprising the following process steps:

[0027] (1) Sulfide precipitation of platinum and palladium: The black gold powder produced by the silver electrolysis process is leached with nitric acid and reduced with aqua regia to obtain nitric acid leaching solution and aqua regia solution. The nitric acid leaching solution is used to precipitate silver, and the aqua regia solution is used to reduce it. The precipitated silver solution and the reduced solution are all put into the sulfidation kettle, and sodium sulfide is added to precipitate platinum and palladium. The amount of sodium sulfide added is 50g / L, and sulfidation slag is produced, which is platinum and palladium concentrate.

[0028] (2) High-temperature calcination and chlorination: After drying the platinum-palladium concentrate, calcination is carried out until no more white smoke is produced. The calcination temperature is not higher than 200℃. After calcination, the roasted residue is transferred to the chlorination process. 10% dilute hydrochloric acid is added to carry out the chlorination reaction. The liquid-solid ratio is 4:1. The temperature is raised to 60℃. 10% hydrogen peroxide is slowly added while stirring. The temperature is maintained above 80℃. The reaction is stirred for 3 hours to dissolve the platinum and palladium in the sulfide residue into the liquid phase. The platinum and palladium content in the chlorinated residue is tested. When the platinum and palladium content is above 200g / t, the chlorinated residue is repeated in this step until the platinum and palladium content drops below 200g / t. Solid and liquid are separated. The chlorinated liquid is transferred to the next process to extract platinum and palladium. The chlorinated residue is transferred to the fire method process for treatment.

[0029] (3) Precipitation of platinum and palladium: Potassium permanganate and ammonium chloride are added to the chlorination solution. The amount of potassium permanganate added is 10 g / L and the amount of ammonium chloride added is 100 g / L until no more precipitation is produced. The platinum and palladium in the liquid phase are precipitated in the form of ammonium chloroplatinate and ammonium chloropalladate. After solid-liquid separation, the platinum and palladium residue is enriched into crude palladium powder, and the filtrate is transferred to the displacement tank to recover gold and silver.

[0030] (4) Gold and silver replacement: Iron powder is added to the replacement kettle for gold and silver replacement. After the sample is qualified, it is placed in the tank for pressure filtration. The filter residue is used to extract gold and silver, and the filtrate is discharged into the waste liquid treatment process.

[0031] (5) Platinum-palladium separation: After the platinum-palladium slag produced in step 3 is slurried with water, ammonia water is added to adjust the pH to 8, the temperature is raised to 70℃, the reaction is carried out for 0.5h, and then filtered. Taking advantage of the property that ammonium chloropalladate is soluble in ammonia water and ammonium chloroplatinate is insoluble in ammonia water, the platinum and palladium are separated. After solid-liquid separation, the ammonia complex slag is left for platinum extraction, and the ammonia complex solution is used for palladium extraction.

[0032] (6) Ammonia complex solution palladium extraction: Cool the ammonia complex solution to below 40°C, add hydrochloric acid to make the pH=1, so that the palladium ions in the solution are precipitated in the form of diammonium chloride palladium sulfide. After solid-liquid separation, the filtrate is discharged into the waste liquid treatment process, and the filter residue is used to reduce crude palladium powder; diammonium chloride palladium sulfide is slurried with water, heated to above 60°C, hydrazine hydrate is added, the pH is adjusted to 8, the reaction is carried out for 0.5 h, and crude palladium powder is obtained by filtration. The crude palladium powder is added to hydrochloric acid and sodium chlorate for palladium dissolution. The amount of hydrochloric acid added is 10 mL / g, and the amount of sodium chlorate added is 1%. After palladium dissolution, nitric acid is added for boiling. The amount of nitric acid added is 20 mL / g. Then ammonium chloride is added to precipitate palladium. The amount of ammonium chloride added is 50 g / L. The nitric acid boiling and palladium precipitation step is repeated 4 times to purify the crude palladium powder repeatedly.

[0033] (7) Purification of crude palladium powder: After the crude palladium powder purified by boiling in step 6 is slurried with water, ammonia water is added to adjust the pH to 8, the temperature is raised to 70℃, the reaction is carried out for 0.5h, filtered, the obtained ammonia complex solution is cooled to below 40℃, hydrochloric acid is added to it to make the pH to 1, so that the palladium ions in the solution are precipitated in the form of diammonium chloride palladium complex. The ammonia complex acidification step is repeated 4 times. After solid-liquid separation, the crude palladium powder is further purified.

[0034] (8) Sponge palladium: After the crude palladium powder obtained from step 7 is purified, water is added to slurry, ammonia is added to adjust the pH to 8, the temperature is raised to 70°C, the reaction is carried out for 0.5 h, the mixture is filtered, the filtrate is heated to above 60°C, hydrazine hydrate is added, the pH is adjusted to 8-9, the reaction is carried out for 0.5 h, and the sponge palladium is obtained by filtration.

[0035] (9) Purification of ammonium chloroplatinate: After drying the ammonia residue produced in step 5, it is roasted at 400°C and then leached with aqua regia. The solution is heated and evaporated to remove nitrogen oxides. 1% hydrochloric acid is added and boiled. After filtration, a platinum-containing filtrate is obtained. The platinum-containing filtrate is heated to above 90°C and 50g / L ammonium chloride and 10% hydrogen peroxide are added to precipitate the platinum ions in the solution as ammonium chloroplatinate. The ammonium chloroplatinate is purified by the above aqua regia leaching to high temperature platinum precipitation process again. This process is repeated 5-6 times.

[0036] (10) Sponge Platinum: The purified ammonium chloroplatinate was calcined at 600℃ to obtain sponge platinum. The test results are shown in Table 1.

[0037] Example 2: A method for enriching and purifying platinum and palladium, comprising the following process steps:

[0038] (1) Sulfide precipitation of platinum and palladium: The black gold powder produced by the silver electrolysis process is leached with nitric acid and reduced with aqua regia to obtain nitric acid leaching solution and aqua regia solution. The nitric acid leaching solution is used to precipitate silver, and the aqua regia solution is used to reduce it. The precipitated silver solution and the reduced solution are all put into the sulfidation kettle, and sodium sulfide is added to precipitate platinum and palladium. The amount of sodium sulfide added is 100g / L, and sulfidation slag is produced, which is platinum and palladium concentrate.

[0039] (2) High-temperature calcination and chlorination: After drying the platinum-palladium concentrate, calcination is carried out until no more white smoke is produced. The calcination temperature is not higher than 200℃. After calcination, the roasted residue is transferred to the chlorination process. 15% dilute hydrochloric acid is added to carry out the chlorination reaction. The liquid-solid ratio is 6:1. The temperature is raised to 60℃. 15% hydrogen peroxide is slowly added while stirring. The temperature is maintained above 80℃. The reaction is stirred for 3 hours to dissolve the platinum and palladium in the sulfide residue into the liquid phase. The platinum and palladium content in the chlorinated residue is tested. When the platinum and palladium content is above 200g / t, the chlorinated residue is repeated in this step until the platinum and palladium content drops below 200g / t. Solid and liquid are separated. The chlorinated liquid is transferred to the next process to extract platinum and palladium. The chlorinated residue is transferred to the fire process for treatment.

[0040] (3) Precipitation of platinum and palladium: Potassium permanganate and ammonium chloride are added to the chlorination solution. The amount of potassium permanganate added is 50 g / L and the amount of ammonium chloride added is 200 g / L until no more precipitation is produced. The platinum and palladium in the liquid phase are precipitated out in the form of ammonium chloroplatinate and ammonium chloropalladate. After solid-liquid separation, the platinum and palladium residue is enriched into crude palladium powder, and the filtrate is transferred to the displacement tank to recover gold and silver.

[0041] (4) Gold and silver replacement: Iron powder is added to the replacement kettle for gold and silver replacement. After the sample is qualified, it is placed in the tank for pressure filtration. The filter residue is used to extract gold and silver, and the filtrate is discharged into the waste liquid treatment process.

[0042] (5) Platinum-palladium separation: After the platinum-palladium slag produced in step 3 is slurried with water, ammonia water is added to adjust the pH to 8, the temperature is raised to 70℃, the reaction is carried out for 0.5h, and then filtered. Taking advantage of the property that ammonium chloropalladate is soluble in ammonia water and ammonium chloroplatinate is insoluble in ammonia water, the platinum and palladium are separated. After solid-liquid separation, the ammonia complex slag is left for platinum extraction, and the ammonia complex solution is used for palladium extraction.

[0043] (6) Ammonia complex solution for palladium extraction: The ammonia complex solution is cooled to below 40°C, and hydrochloric acid is added to make the pH = 1, so that the palladium ions in the solution are precipitated in the form of diammonium chloride palladium sulfide. After solid-liquid separation, the filtrate is discharged into the waste liquid treatment process, and the filter residue is used to reduce crude palladium powder. Diammonium chloride palladium sulfide is slurried with water, heated to above 60°C, hydrazine hydrate is added, the pH is adjusted to 9, the reaction is carried out for 0.5 h, and crude palladium powder is obtained by filtration. The crude palladium powder is added to hydrochloric acid and sodium chlorate for palladium dissolution. The amount of hydrochloric acid added is 20 mL / g, and the amount of sodium chlorate added is 1%. After palladium dissolution, nitric acid is added for boiling. The amount of nitric acid added is 30 mL / g. Then ammonium chloride is added to precipitate palladium. The amount of ammonium chloride added is 100 g / L. The nitric acid boiling and palladium precipitation steps are repeated 4 times to purify the crude palladium powder repeatedly.

[0044] (7) Purification of crude palladium powder: After the crude palladium powder purified by boiling in step 6 is slurried with water, ammonia water is added to adjust the pH to 8, the temperature is raised to 70℃, the reaction is carried out for 0.5h, filtered, the obtained ammonia complex solution is cooled to below 40℃, hydrochloric acid is added to it to make the pH to 1, so that the palladium ions in the solution are precipitated in the form of diammonium chloride palladium complex. The ammonia complex acidification step is repeated 4 times. After solid-liquid separation, the crude palladium powder is further purified.

[0045] (8) Sponge palladium: After the crude palladium powder obtained from step 7 is purified, water is added to slurry, ammonia is added to adjust the pH to 8, the temperature is raised to 70°C, the reaction is carried out for 0.5 h, the mixture is filtered, the filtrate is heated to above 60°C, hydrazine hydrate is added, the pH is adjusted to 8-9, the reaction is carried out for 0.5 h, and the sponge palladium is obtained by filtration.

[0046] (9) Purification of ammonium chloroplatinate: After drying the ammonia residue produced in step 5, it is roasted at 400°C and then leached with aqua regia. The solution is heated and evaporated to remove nitrogen oxides. 1% hydrochloric acid is added and boiled. After filtration, a platinum-containing filtrate is obtained. The platinum-containing filtrate is heated to above 90°C and 100g / L ammonium chloride and 15% hydrogen peroxide are added to precipitate the platinum ions in the solution as ammonium chloroplatinate. The ammonium chloroplatinate is purified by the above aqua regia leaching to high temperature platinum precipitation process again. This process is repeated 5-6 times.

[0047] (10) Sponge platinum: The purified ammonium chloroplatinate was calcined at 1000℃ to obtain sponge platinum. The test results are shown in Table 1.

[0048] Table 1. Laboratory analysis results (mg / L)

[0049]

Claims

1. A method for the enrichment purification of platinum-palladium characterized in that The process comprises the following steps: (1) Sulfidation of platinum and palladium: The black gold powder produced by silver electrolysis process is subjected to nitric acid leaching and aqua regia gold separation processes to obtain nitric acid leaching solution and aqua regia solution. The nitric acid leaching solution is subjected to silver deposition, and the aqua regia solution is subjected to reduction. The solution after silver deposition and the solution after reduction are all introduced into a sulfidation kettle, sodium sulfide is added for sulfidation of platinum and palladium, the amount of sodium sulfide added is 50-100 g / L, and sulfidation slag, i.e. platinum and palladium concentrate, is produced; (2) High-temperature calcination and chlorination: The platinum and palladium concentrate is dried and then calcined until no white smoke is generated, the calcination temperature is not higher than 200℃, and the calcined residue is transferred to a chlorination process, 10%-15% dilute hydrochloric acid is added for chlorination reaction, the liquid-solid ratio is 4-6:1, the temperature is raised to 60℃, 10%-15% hydrogen peroxide is slowly added while stirring, the temperature is maintained above 80℃, and stirring reaction is performed for 3h. Platinum and palladium in the sulfidation slag are dissolved into the liquid phase, solid-liquid separation is performed, the chlorination liquid is transferred to the next process for platinum and palladium extraction, and the chlorination residue is transferred to a fire process for treatment; (3) Precipitation of platinum and palladium: Potassium permanganate and ammonium chloride are added to the chlorination liquid, the amount of potassium permanganate added is 10-50 g / L, the amount of ammonium chloride added is 100-200 g / L, platinum and palladium in the liquid phase are precipitated in the form of ammonium chloroplatinate and ammonium chloropalladate, solid-liquid separation is performed, platinum and palladium residue is subjected to enrichment of crude palladium powder, and the filtrate is transferred to a displacement kettle for recovery of gold and silver; (4) Gold and silver displacement: Iron powder is added to the displacement kettle for gold and silver displacement, after sampling and passing the quality inspection, the displacement kettle is discharged for pressure filtration, the filter residue is subjected to extraction of gold and silver, and the filtrate is discharged into a waste liquid treatment process; (5) Platinum and palladium separation: The platinum and palladium residue produced in step 3 is slurried after water is added, ammonia water is added to adjust the pH to 8, the temperature is raised to 70℃, reaction is performed for 0.5h, filtration is performed, platinum and palladium are separated by taking advantage of the property that ammonium chloropalladate is soluble in ammonia water while ammonium chloroplatinate is insoluble in ammonia water, and solid-liquid separation is performed. After the solid-liquid separation, the ammonia complex residue is left for platinum extraction, and the ammonia complex liquid is subjected to palladium extraction; (6) Palladium extraction from ammonia complex liquid: The ammonia complex liquid is cooled to below 40℃, hydrochloric acid is added to the ammonia complex liquid to make the pH equal to 1, palladium ions in the solution are precipitated in the form of dichloro diammonium complex palladium, solid-liquid separation is performed, the filtrate is discharged into a waste liquid treatment process, and the filter residue is subjected to reduction of crude palladium powder; the dichloro diammonium complex palladium is slurried after water is added, the temperature is raised to above 60℃, hydrazine hydrate is added, the pH is adjusted to 8-9, reaction is performed for 0.5h, filtration is performed, crude palladium powder is produced, the crude palladium powder is subjected to large chlorination for palladium dissolution by adding hydrochloric acid and sodium chlorate, the amount of hydrochloric acid added is 10-20 mL / g, the amount of sodium chlorate added is 1%-3%, after palladium dissolution, nitric acid is added for water boiling, the amount of nitric acid added is 20-30 mL / g, ammonium chloride is then added for palladium precipitation, the amount of ammonium chloride added is 50-100 g / L, and the step of water boiling with nitric acid for palladium precipitation is repeated 4 times. The crude palladium powder is repeatedly subjected to purification; (7) Purification of crude palladium powder: The crude palladium powder purified by water boiling in step 6 is slurried after water is added, ammonia water is added to adjust the pH to 8, the temperature is raised to 70℃, reaction is performed for 0.5h, filtration is performed, the obtained ammonia complex liquid is cooled to below 40℃, hydrochloric acid is added to the ammonia complex liquid to make the pH equal to 1, palladium ions in the solution are precipitated in the form of dichloro diammonium complex palladium, the step of acidification of the ammonia complex is repeated 4 times, solid-liquid separation is performed, and further purified crude palladium powder is obtained. (8) Sponge palladium: the crude palladium powder purified in step 7 is slurried with water, then ammonia is added to adjust the pH to 8, and the mixture is heated to 70°C and reacted for 0.5 h. The mixture is filtered, and the filtrate is heated to above 60°C, then hydrazine hydrate is added to adjust the pH to 8-9, and the mixture is reacted for 0.5 h. The sponge palladium is obtained by filtration, and the purity of the sponge palladium is above 95%; (9) Ammonium chloroplatinate purification: the ammonia complex residue produced in step 5 is dried, then calcined at 400°C, and then immersed in aqua regia. Nitrogen oxide is removed by heating and evaporation of the solution. 1% hydrochloric acid is added and boiled, and then filtered to obtain a filtrate containing platinum. The filtrate is heated to above 90°C, and 50-100 g / L of ammonium chloride and 10%-15% hydrogen peroxide are added to precipitate platinum ions in the form of ammonium chloroplatinate. The ammonium chloroplatinate is purified by repeating the above aqua regia immersion and high-temperature platinum precipitation process for 5-6 times; (10) Sponge platinum: the purified ammonium chloroplatinate is calcined at 600-1000°C to obtain sponge platinum, and the purity of the sponge platinum is above 95%.

2. A process for the enrichment and purification of platinum-palladium as claimed in claim 1, characterized in that The main chemical reactions are as follows: 3Pt+2NaClO3+18HCl=3H2PtCl6+2NaCl+6H2O H2PtCl6+2NH4Cl=(NH4)2PtCl6↓+2HCl 2Pd+2H2O2+4HCl=2PdCl2+4H2O PdCl2+2NH4Cl=(NH4)2PdCl4 2NH4Cl+H2PtCl6=(NH4)2PtCl6↓+2HCl.

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