Rapid preparation method of rhodium nitrate

Abstract

The invention discloses a rapid preparation method of rhodium nitrate, which comprises the following steps: S1, rhodium trichloride hydrate is dissolved in water to form an aqueous solution of rhodium trichloride, and the mass ratio of rhodium trichloride hydrate to water is 1: (2-6); s2, silver nitrate is added into the rhodium trichloride aqueous solution obtained in the step S1, then the temperature is increased to 70-80 DEG C, microwave radiation is carried out, a reaction is carried out for 60-80 min, solid-liquid separation is carried out after the reaction, and the molar ratio of the rhodium trichloride aqueous solution to the silver nitrate is 1: (3-5); and S3, evaporating the filtrate obtained in the step S2 to dryness by using an evaporator to obtain rhodium nitrate.

Description

Technical Field

[0001] The present invention relates to the technical field of noble metal synthesis, and particularly relates to a rapid preparation method of rhodium nitrate. Background Art

[0002] Due to the unique and excellent physical and chemical properties of noble metals, such as unique catalytic action, high-temperature oxidation resistance, chemical corrosion resistance, thermoelectric stability, and excellent biological activity, they have been widely used in various fields such as aerospace, fine chemicals, catalytic environmental protection, biomedicine, high-tech, and military technology. Currently, most of the noble metal functional materials, information materials, catalytic materials, and biological materials used are processed from noble metal compounds as starting materials or precursors through a series of chemical reaction processes. For example, rhodium nitrate (Rhodium nitrate solution) is usually prepared by the reaction of rhodium and nitric acid, and reacts with alkali to form a lemon-yellow precipitate of rhodium sesquioxide pentahydrate. It is a red or yellow deliquescent crystal and can be used as an important precursor for automotive exhaust catalysts and is widely used in industry. In addition, it is also often used as an oxidant.

[0003] The traditional preparation process of rhodium nitrate needs to go through processes such as rhodium powder grinding, activation and dissolution, impurity removal, rhodium precipitation, and dissolution in sequence to prepare rhodium nitrate, which has many deficiencies such as a long process flow, high operation difficulty, and unstable rhodium yield. Summary of the Invention

[0004] In view of the above technical problems, the present invention provides a rapid preparation method of rhodium nitrate.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows: A rapid preparation method of rhodium nitrate includes the following steps: S1. Dissolve hydrated rhodium trichloride in water to form an aqueous solution of rhodium trichloride, wherein the mass ratio of hydrated rhodium trichloride to water is 1:2 - 6; S2. Add silver nitrate to the aqueous solution of rhodium trichloride obtained in step S1, then heat to 70 - 80 °C and carry out microwave radiation for 60 - 80 min. After the reaction, perform solid-liquid separation, wherein the molar ratio of the aqueous solution of rhodium trichloride to silver nitrate is 1:3 - 5; S3. Evaporate the filtrate obtained in step S2 to dryness using an evaporator to obtain rhodium nitrate.

[0006] Wherein, in step S1, the water is deionized water.

[0007] Wherein, in step S2, the conditions of microwave irradiation are: the microwave frequency is 1500 - 2500 MHz, and the microwave power is 80 - 200 W.

[0008] Among them, in the step S3, the evaporation temperature is 100-110°C.

[0009] Among them, in the step S2, the filter residue obtained by solid-liquid separation is reduced and recovered with one, two or more of iron powder, copper powder, and zinc powder to recover silver therein.

[0010] The beneficial effects of the present invention are as follows: The present invention has the advantages of short process flow, simple operation, easy process control, environmental protection and no pollution, high resource utilization rate, etc. The present invention solves many deficiencies existing in the traditional rhodium nitrate process, such as long process flow, difficult operation, unstable rhodium recovery rate, etc., and has the advantages of short process flow, simple operation, easy process control, environmental protection and no pollution, high resource utilization rate, etc. Among them, the present invention passes through Step 1: Hydrated rhodium trichloride and deionized water are mixed at a mass ratio of 1:2-6 to prepare an aqueous solution of rhodium trichloride. Using the rhodium trichloride solution as the raw material for preparing rhodium nitrate can solve the defects such as low solubility, long activation and impurity removal treatment process, and unstable rhodium recovery rate when preparing rhodium nitrate from rhodium powder. Through Steps 2 and 3: The rhodium trichloride solution and silver nitrate are mixed at a molar ratio of rhodium trichloride to silver nitrate of 1:3-5 and reacted under microwave radiation to generate rhodium nitrate and a silver-containing precipitate. Then, the silver-containing precipitate is filtered off, and the filtrate is evaporated to prepare rhodium nitrate crystals. Microwave radiation can induce the interaction of different substances in the solution and change the dissolution characteristics of compounds. At the same time, microwave oscillation can improve the reaction efficiency, the conversion efficiency of rhodium nitrate and the utilization rate of rhodium. Through Step 2: Using silver nitrate to convert rhodium nitrate, after forming a silver-containing precipitate, the silver therein can be recovered by reduction, avoiding the loss of valuable metals. At the same time, the silver-containing precipitate is accompanied by chloride ions, which can effectively remove the chloride ion inclusion in rhodium nitrate, effectively ensure the product purity of rhodium nitrate and improve the application effect. Specific embodiments

[0011] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that these descriptions are exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0012] Example 1 A rapid preparation method of rhodium nitrate includes the following steps: S1. Dissolve hydrated rhodium trichloride in water to form an aqueous solution of rhodium trichloride, wherein the mass ratio of hydrated rhodium trichloride to water is 1:2; S2. Add silver nitrate to the rhodium trichloride aqueous solution obtained in step S1, heat it to 70°C and perform microwave radiation, react for 60 min, and perform solid-liquid separation after the reaction, wherein the molar ratio of the rhodium trichloride aqueous solution to silver nitrate is 1:3; S3. Evaporate the filtrate obtained in step S2 to dryness using an evaporator to obtain rhodium nitrate.

[0013] Among them, in step S1, the water is deionized water.

[0014] Among them, in step S2, the conditions of microwave irradiation are: the microwave frequency is 1500 MHz and the microwave power is 80 W.

[0015] Among them, in step S3, the evaporation temperature is 100 °C.

[0016] Among them, in step S2, the filter residue obtained by solid-liquid separation is reduced and recycled for silver therein by one, two or more of iron powder, copper powder, and zinc powder.

[0017] Example 2 A rapid preparation method of rhodium nitrate, comprising the following steps: S1. Dissolve rhodium trichloride trihydrate in water to form an aqueous solution of rhodium trichloride, wherein the mass ratio of rhodium trichloride trihydrate to water is 1:6; S2. Add silver nitrate to the aqueous solution of rhodium trichloride obtained in step S1, heat it to 80 °C and perform microwave radiation for 80 min, and perform solid-liquid separation after the reaction, wherein the molar ratio of the aqueous solution of rhodium trichloride to silver nitrate is 1:5; S3. Evaporate the filtrate obtained in step S2 to dryness using an evaporator to obtain rhodium nitrate.

[0018] Among them, in step S1, the water is deionized water.

[0019] Among them, in step S2, the conditions of microwave irradiation are: the microwave frequency is 2500 MHz and the microwave power is 200 W.

[0020] Among them, in step S3, the evaporation temperature is 110 °C.

[0021] Among them, in step S2, the filter residue obtained by solid-liquid separation is reduced and recycled for silver therein by one, two or more of iron powder, copper powder, and zinc powder.

[0022] Example 3 A rapid preparation method of rhodium nitrate, comprising the following steps: Step 1: Dissolve 96 g of rhodium trichloride trihydrate in 196 mL of water to form an aqueous solution of rhodium trichloride, and the rhodium content in the rhodium trichloride trihydrate is 39%; Step 2: Add 216 g of silver nitrate to the aqueous solution of rhodium trichloride obtained in step 1, heat it to 70 °C and perform microwave radiation for 65 min, the microwave frequency is 1500 MHz and the microwave power is 80 W, and perform solid-liquid separation after the reaction to obtain a filtrate and a filter residue; Step 3: The filtrate obtained in Step 2 is evaporated to dryness at 105°C using an evaporator to obtain 246 g of rhodium nitrate.

[0023] Through chemical analysis, the mass content of rhodium in the rhodium nitrate synthesized by the present invention is 15%, and the yield of rhodium nitrate is 98.6%.

[0024] Example 4 A rapid preparation method of rhodium nitrate, comprising the following steps: Step 1: Dissolve 100 g of rhodium trichloride trihydrate in 220 mL of water to form an aqueous solution of rhodium trichloride, and the rhodium content in the rhodium trichloride trihydrate is 39%; Step 2: Add 249 g of silver nitrate to the aqueous solution of rhodium trichloride obtained in Step 1, then heat to 75°C and carry out microwave radiation for 70 min. The microwave frequency is 1800 MHz, and the microwave power is 110 W. After the reaction, carry out solid-liquid separation to obtain a filtrate and a filter residue; Step 3: The filtrate obtained in Step 2 is evaporated to dryness at 110°C using an evaporator to obtain 259.12 g of rhodium nitrate.

[0025] Through chemical analysis, the mass content of rhodium in the rhodium nitrate synthesized by the present invention is 14.87%, and the yield of rhodium nitrate is 98.8%.

[0026] Example 5 A rapid preparation method of rhodium nitrate, comprising the following steps: Step 1: Dissolve 100 g of rhodium trichloride trihydrate in 300 mL of water to form an aqueous solution of rhodium trichloride, and the rhodium content in the rhodium trichloride trihydrate is 39%; Step 2: Add 355 g of silver nitrate to the aqueous solution of rhodium trichloride obtained in Step 1, then heat to 80°C and carry out microwave radiation for 80 min. The microwave frequency is 2000 MHz, and the microwave power is 180 W. After the reaction, carry out solid-liquid separation to obtain a filtrate and a filter residue; Step 3: The filtrate obtained in Step 2 is evaporated to dryness at 105°C using an evaporator to obtain 257.66 g of rhodium nitrate.

[0027] Through chemical analysis, the mass content of rhodium in the rhodium nitrate synthesized by the present invention is 15%, and the yield of rhodium nitrate is 99.1%.

[0028] It should be understood that the above specific embodiments of the present invention are only used for exemplary illustration or explanation of the principle of the present invention, and do not constitute a limitation to the present invention. Therefore, any modifications, equivalent replacements, improvements, etc. made without departing from the spirit and scope of the present invention shall be included within 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 equivalent forms of such scope and boundaries.

Claims

1. A rapid preparation method of rhodium nitrate, characterized in that, It includes the following steps: S1. Dissolve rhodium(III) chloride hydrate in water to form an aqueous solution of rhodium(III) chloride, where the mass ratio of rhodium(III) chloride hydrate to water is 1:2 - 6; S2. Add silver nitrate to the aqueous solution of rhodium(III) chloride obtained in step S1, then heat it to 70 - 80 °C and carry out microwave irradiation for 60 - 80 min. After the reaction, perform solid-liquid separation, where the molar ratio of the aqueous solution of rhodium(III) chloride to silver nitrate is 1:3 - 5; S3. Evaporate the filtrate obtained in step S2 to dryness using an evaporator to obtain rhodium(III) nitrate.

2. The rapid preparation method of rhodium nitrate according to claim 1, characterized in that: In step S1, the water is deionized water.

3. a rapid preparation method of rhodium nitrate according to claim 1, is characterized in that: In step S2, the conditions of microwave irradiation are: the microwave frequency is 1500 - 2500 MHz, and the microwave power is 80 - 200 W.

4. a rapid preparation method of rhodium nitrate according to claim 1, is characterized in that: In step S3, the evaporation temperature is 100 - 110 °C.

5. a rapid preparation method of rhodium nitrate according to claim 1, is characterized in that: In step S2, the silver in the filter residue obtained by solid-liquid separation is recovered by reduction with one, two or more of iron powder, copper powder and zinc powder.