A method for enriching and recovering rhodium from waste rhodium Parker catalyst

Abstract

The present invention discloses a method for enriching and recovering rhodium from waste rhodium Parker catalyst, comprising the following steps: (1) inert atmosphere roasting: placing the waste rhodium Parker catalyst in a closed reactor, introducing an inert gas into the reactor, and roasting at a certain temperature to obtain a rhodium-containing solid. (2) oxidative roasting: adding solid sodium carbonate to the rhodium-containing solid obtained in step (1) according to a certain mass ratio, oxidative roasting at a certain temperature for a period of time, so that the phosphorus-containing component generates sodium phosphate. (3) water leaching: leaching the roasted product obtained in step (2) with water, filtering, and obtaining a rhodium enriched product. The present invention adopts high-temperature roasting in an inert atmosphere, which improves the recovery rate of rhodium, does not produce toxic and harmful substances, and is environmentally friendly.

Description

Technical Field

[0001] The invention belongs to the field of secondary resource recovery of precious metals and relates to a method for enriching and recovering rhodium from waste rhodium Parker catalyst. Background Art

[0002] The commonly used rhodium-phosphine complex catalyst for the production of butyl octanol by propylene low-pressure carbonyl synthesis is triphenylphosphine carbonyl acetylacetonate rhodium (I)

[0003] [Rh(C5H7O2)(CO)(PPh3)], trade name is Rhodium Parker. Rhodium Parker catalyst is often deactivated due to various high-boiling point by-products produced during the reaction and the presence of impurities in the raw materials. The waste Rhodium Parker catalyst is usually in liquid form, containing a large amount of organic matter, such as triphenylphosphine, triphenylphosphine oxide, high-boiling point by-products of carbonyl synthesis and condensation products of butyraldehyde. Rhodium resources are scarce, and mining and extraction are difficult and expensive. Therefore, recovering rhodium from waste catalysts has important social and economic significance.

[0004] Currently, the methods for recovering rhodium-containing waste catalysts include regeneration, precipitation, incineration, extraction, adsorption, etc.

[0005] US Patent No. 4,363,765 discloses a method for internal regeneration of a deactivated rhodium catalyst, wherein the catalyst is treated with oxygen and then, under hydroformylation conditions, 70% of its activity is restored and returned to its hydroformylation reaction system for continued use.

[0006] Chinese patent CN107021983A mentions a method for recycling rhodium-containing waste liquid from a butanol plant. The rhodium is replaced from the triphenylphosphine ligand by resin mixed exchange adsorption, and a rhodium-containing solution is obtained by desorption. Rhodium chloride is obtained after separation and purification. The mother liquor after rhodium removal is treated to obtain triphenylphosphine, and rhodium trichloride and triphenylphosphine are used to prepare a new rhodium Parker catalyst. The mixed solvent evaporated during the treatment process is incinerated, and the tail gas is discharged after desulfurization and denitration.

[0007] German patent DE4326076A1 discloses a method for recovering rhodium catalyst, wherein an organic solution of an organic phosphorus compound containing rhodium is added with an alkaline compound, and then burned at a controlled temperature below 1000°C and burnt into ash. After ashing, a cleaning liquid containing a reducing agent is used to remove soluble salts from elements other than rhodium in the ash, thereby recovering rhodium with high efficiency and high proportion.

[0008] German patent DE2438847A1 discloses an immersion combustion method for recovering rhodium catalysts. The waste rhodium catalyst residue is sent into an immersion combustion chamber together with air, and the combustion gas is absorbed by water. The rhodium remains in the water in a suspended state and is obtained after filtration. The recovery rate of rhodium is about 94%.

[0009] Chinese patent CN102925699A discloses a method for recovering rhodium by treating waste rhodium-containing catalysts in hydroformylation reaction with hydrogen peroxide. The method comprises the following steps: firstly treating waste rhodium liquid with hydrogen peroxide, recovering nearly 90% of the rhodium therein in the form of precipitation, and then concentrating the remaining rhodium solution containing about 10% of the rhodium to obtain rhodium slag. The rhodium slag is then incinerated in an electric furnace, and the residual carbon deposits in the ash are removed to obtain rhodium metal containing other metal impurities. Finally, the rhodium metals obtained in the two steps are combined and processed to prepare hydrated rhodium trichloride, a raw material for preparing a rhodium-phosphine complex catalyst.

[0010] Chinese patent CN111848674A discloses a method for step-by-step recovery of effective components of waste rhodium Parker catalyst, the method is as follows: waste rhodium Parker catalyst is subjected to atmospheric distillation to remove light components, vacuum distillation, the top distilled components and the heavy rhodium-containing tar residue are incinerated and the tail gas is treated to become ammonium phosphate fertilizer, the incineration residue is activated at high temperature, liquid is made, and rhodium powder is reduced and refined to obtain rhodium powder.

[0011] Chinese patent CN111996386A discloses a method for recovering rhodium from homogeneous waste catalyst containing rhodium. The method adopts the recovery method of acidification oxidation-complexation precipitation-sulfurization precipitation. The recovery rate of rhodium reaches 95.23% in one step. The main body of rhodium in the waste catalyst is recovered in one step, which effectively reduces the dispersion of rhodium and improves the recovery rate of rhodium. In the acidification-oxidation process step, a small part of rhodium will be directly oxidized to Rh 3+ This part is recovered by sulfide precipitation method, and the final recovery rate of rhodium combined in the two stages can reach more than 97%.

[0012] Chinese patent CN113462900A discloses a method for recovering rhodium from waste rhodium Parker catalyst. The waste rhodium Parker catalyst is subjected to oxidative extraction to obtain an oil phase and an aqueous phase respectively. The rhodium-containing aqueous phase is precipitated and purified by DETA or other rhodium compounds are produced. The residual rhodium in the oil phase is incinerated, slag smelting, captured, dissolved, separated and purified by rhodium molecule recognition resin, and reduced with hydrazine hydrate to obtain a product rhodium powder. The recovery rate of rhodium is greater than or equal to 96%.

[0013] In summary, the current research on the process of recovering rhodium from waste rhodium catalysts at home and abroad mainly includes pyrolysis and hydrolysis. Direct oxidation incineration results in large metal losses and low rhodium recovery rates, while the hydrolysis involves the reaction of organic matter and strong oxidants, which is violent, flammable and explosive, and has prominent safety issues. Summary of the invention

[0014] In order to overcome the deficiencies of the above technologies, the present invention proposes a method for enriching rhodium from waste rhodium Parker catalyst.

[0015] The present invention is mainly achieved through the following technical solutions:

[0016] A method for enriching and recovering rhodium from waste rhodium Parker catalyst comprises the following steps:

[0017] (1) Calcination in an inert atmosphere: The waste rhodium Parker catalyst is placed in a quartz boat and placed in a tube furnace. Nitrogen, argon or helium is introduced at a flow rate of 30 to 100 mL / min. The catalyst is calcined at 600 to 800°C for 2 to 5 hours to convert the macromolecular organic matter such as triphenylphosphine into gaseous and solid components with smaller molecular weights, and rhodium and phosphorus enter the solid components to obtain a rhodium-containing solid. The calcined tail gas is oxidized and burned at high temperature to meet emission standards.

[0018] (2) Oxidative calcination: mixing the rhodium-containing solid obtained in step (1) with solid sodium carbonate in a mass ratio of 1:0.1-0.5, and calcining at a temperature of 500-600° C. for 1-2 h;

[0019] (3) Water leaching: The roasted product obtained in step (2) is leached with water at room temperature for 0.5 to 1 hour to leach water-soluble sodium phosphate and the like, and then filtered to obtain a rhodium-enriched product.

[0020] Furthermore, in step 1, activated carbon powder or starch-rich plant powder is added to the waste rhodium Parker catalyst in a mass ratio of 1:0.1-0.5, mixed and then roasted.

[0021] Furthermore, the starch-rich plant powder includes wheat flour and / or corn flour.

[0022] Mechanism of the Invention

[0023] The present invention roasts the liquid waste rhodium Parker catalyst in an inert atmosphere. Under high-temperature conditions without oxygen, macromolecular organic substances such as triphenylphosphine are cracked and converted into gaseous substances with smaller molecular weights and solid carbon through the combined effects of decomposition and condensation. During the roasting in the inert atmosphere, rhodium and phosphorus in the waste catalyst generate rhodium phosphide or remain in the solid component in the form of a single substance. Sodium carbonate is added to the obtained rhodium-containing solid for oxidative roasting, so that the carbon therein is burned and the phosphorus-containing phase is converted into sodium phosphate, while the rhodium-containing component does not react and is retained in the roasting slag. The oxidative roasting product is leached with water to obtain water-soluble sodium phosphate, and the rhodium-containing component enters the filter residue, thereby achieving rhodium enrichment.

[0024] The beneficial effects of the present invention include:

[0025] (1) Compared with the traditional oxidation incineration method, the present invention calcines the waste rhodium Parker catalyst in an inert atmosphere at high temperature, without causing high-temperature oxidation reaction and producing no toxic or harmful substances; the solid carbon produced or added by calcination adsorbs rhodium, thereby improving the recovery rate of rhodium; the gaseous components with smaller molecular weight produced by the breaking of carbon chains in macromolecular organic substances such as triphenylphosphine are oxidized, burned, and absorbed before being discharged in compliance with emission standards, which is environmentally friendly.

[0026] (2) The solid product obtained after calcination in an inert atmosphere is oxidatively calcined by adding sodium carbonate, so that the phosphorus and rhodium phosphide therein react with sodium carbonate to form sodium phosphate, and rhodium exists in the form of oxide or elemental substance, thereby avoiding the generation of harmful phosphorus oxide during calcination; the oxidatively calcined product is leached with water to remove water-soluble salts such as sodium phosphate, thereby achieving rhodium enrichment. DETAILED DESCRIPTION

[0027] Example 1

[0028] 1L of waste rhodium Parker catalyst (rhodium content of 800mg / L) viscous liquid was loaded into a quartz boat, the quartz boat was placed in a tubular furnace, nitrogen was introduced, the nitrogen flow rate was controlled at 80mL / min, the tubular furnace was turned on and heated to 600°C, and the temperature was kept and roasted for 3h. After cooling, the roasted slag was mixed with 5g of sodium carbonate, placed in a crucible and oxidized and roasted at 600°C in a muffle furnace for 2h, cooled, and the roasted product was leached with 100mL of water at room temperature for 1h, filtered, and dried to obtain 1.24g of rhodium-containing enriched product, with an analysis of Rh62.58% and a rhodium recovery rate of 97%.

[0029] Example 2

[0030] Mix 1L of waste rhodium Parker catalyst (rhodium content of 800mg / L) viscous liquid with 100g of wheat flour and / or corn flour and put them into a quartz boat, place the quartz boat in a tube furnace, introduce nitrogen, control the nitrogen flow rate to 80mL / min, start the tube furnace and heat to 800°C, keep warm and roast for 4h, cool, mix the roasted slag with 8g of sodium carbonate, place it in a crucible and use a muffle furnace to oxidize and roast at 600°C for 2h, cool, leaching the roasted product with 100mL of water at room temperature for 1h, filter, and dry to obtain 1.19g of rhodium-containing enriched product, with an analysis of Rh 64.67% and a rhodium recovery rate of 96.2%.

[0031] Example 3

[0032] 1L of waste rhodium Parker catalyst (rhodium content of 800mg / L) viscous liquid is mixed with 200g of wheat flour and / or corn flour and put into a quartz boat, the quartz boat is placed in a tube furnace, nitrogen is introduced, and the nitrogen flow rate is controlled to 80mL / min. The tube furnace is turned on and heated to 700°C, and the temperature is kept and roasted for 4h. After cooling, the roasted slag is mixed with 10g of sodium carbonate, placed in a crucible, and oxidatively roasted at 600°C in a muffle furnace for 2h, cooled, and the roasted product is leached with 100mL of water at room temperature for 1h, filtered, and dried to obtain 1.22g of rhodium-containing enriched product, with an analysis of Rh 63.80% and a rhodium recovery rate of 97.3%.

Claims

1. A method for enriching and recovering rhodium from waste rhodium Parker catalyst, characterized in that: The following steps are involved: (1) Calcination in an inert atmosphere: Add activated carbon powder or starch-rich plant powder to the waste rhodium Parker catalyst at a mass ratio of 1:0.1-0.5 and place the mixture in a closed reactor. Inert gas is introduced into the reactor at a flow rate of 30-100 mL / min. The reactor is calcined at a temperature of 600-800°C. Rhodium and phosphorus enter the solid components to obtain a rhodium-containing solid. (2) Oxidative calcination: adding solid sodium carbonate to the rhodium-containing solid obtained in step (1) at a mass ratio of 1:0.1-0.5, and oxidatively calcining at a temperature of 500-600°C for a period of time to convert the phosphorus-containing component into sodium phosphate; (3) Water leaching: The roasted product obtained in step (2) is leached with water and filtered to obtain a rhodium-enriched product.

2. A method for enriching and recovering rhodium from waste rhodium Parker catalyst according to claim 1, characterized in that: The inert gas in step (1) is nitrogen, argon or helium.

3. A method for enriching and recovering rhodium from waste rhodium Parker catalyst according to claim 1, characterized in that: The calcination time in step (1) is 2 to 5 hours.

4. A method for enriching and recovering rhodium from waste rhodium Parker catalyst according to claim 1, characterized in that: The calcination time in step (2) is 1 to 2 h.

5. A method for enriching and recovering rhodium from waste rhodium Parker catalyst according to claim 1, characterized in that: The water immersion conditions in step (3) are leaching at room temperature for 0.5 to 1 hour.

6. A method for enriching and recovering rhodium from waste rhodium Parker catalyst according to claim 1, characterized in that: The starch-rich plant powder includes wheat flour and / or corn flour.

7. A method for enriching and recovering rhodium from waste rhodium Parker catalyst according to any one of claims 1 to 6, characterized in that: The reactor described in step (1) is a tubular furnace.