CN111036932B - A kind of method for preparing metal rhenium by liquid phase reduction - Google Patents

Abstract

The invention relates to the field of metal material preparation, in particular to a method for preparing metal rhenium by liquid phase reduction. The method includes the following steps: 1) Preparation of a precursor liquid: dissolving a rhenium precursor in water to prepare a solution, adding polyvinylpyrrolidone and/or polyethylene glycol, and adding lye to adjust the pH value of the solution to obtain a precursor liquid; 2 ) Preparation of reducing solution: Dissolving the reducing agent in water to prepare a reducing solution; 3) Reduction reaction: Slowly add the prepared reducing solution dropwise into the precursor liquid through a funnel, and leave it to stand at a constant temperature after it is completely added, and then stand at a constant temperature for reaction After completion, filter to obtain metal rhenium powder. The preparation process of the invention is simple and efficient, easy to popularize and use; the yield of metal rhenium powder is high, and the waste of raw materials is less; the preparation is carried out at medium and low temperature, which is safer, and some materials can be recycled.

Description

A kind of liquid phase reduction prepares the method for metallic rhenium

technical field

The invention relates to the field of metal material preparation, in particular to a method for preparing rhenium metal by liquid phase reduction.

Background technique

Rhenium and rhenium alloys have become indispensable materials in the aerospace industry due to their special properties such as high melting point, high strength, good plasticity and excellent mechanical stability. The rhenium content of single crystal superalloys is the "intergenerational mark" of aero-engine materials. For example, the rhenium content of the fourth-generation single crystal superalloy blades reaches 4.5-6%. Therefore, it can be considered that metal rhenium is the key to alleviating China's "power heart disease". Blindly the right medicine.

However, rhenium, as an extremely important strategic metal, is extremely rare in the earth's crust. In particular, the world's largest rhenium producer, Molybdenum Metals Corporation of the United States, monopolizes most of the rhenium in Chile, Mexico, and Kazakhstan in the form of long-term contracts. By retaining production technology in the United States, all local products And a considerable part of imported products are reserved, resulting in expensive rhenium metal.

Research on the extraction of rhenium started relatively late in my country. At present, ammonium rhenate is only recovered and extracted from molybdenum smelting soot and copper smelting flue gas purification sewage acid. The industry mainly adopts the high-temperature hydrogen reduction method to prepare metal rhenium. The process has problems such as high temperature, high energy consumption, and low efficiency, so there are very few metal rhenium production enterprises. In recent years, the international market of ammonium rhenate has been unsalable and the price has begun to drop, but the price of metal rhenium has remained high. Therefore, the research and development of high-efficiency and low-energy rhenium metal preparation technology is extremely important to promote the development of my country's rhenium industry and even the aerospace industry.

Since metal rhenium is a refractory metal, its subsequent processing is generally carried out by powder metallurgy, so the preparation of metal rhenium powder is the basis for the production of rhenium alloys. At present, ammonium rhenate is generally used as raw material to produce powder metal rhenium through multiple high-temperature hydrogen reductions. However, due to the volatility of rhenium oxide, its preparation process is relatively complicated.

On March 15, 2017, the Chinese Patent Office disclosed an invention patent application for a method for preparing metal rhenium, and the application announcement number is CN106498194A. The method uses ammonium perrhenate as a raw material to prepare high-purity metal rhenium powder through a two-step method. The first step is to prepare high-purity ultrafine ammonium perrhenate by ultrasonic-assisted crystallization and vacuum drying, and the second step is to reduce ammonium perrhenate to Reduction into high-purity metal rhenium powder. The invention has strong adaptability to raw materials, improves the utilization rate of raw materials, and can prepare high-purity metal rhenium powder through the combined process of ultrasonic crystallization and hydrogen reduction. However, this invention also uses a high-temperature hydrogen reduction process, which still has problems such as high energy consumption and low efficiency in the process, and oxides volatilize during the high-temperature hydrogen reduction process, resulting in a decrease in yield.

The Chinese Patent Office also disclosed a patent application for a preparation method of high-purity rhenium powder on November 17, 2004, and the authorized announcement number is CN1175951C. It uses high-purity ammonium rhenate solution to heat and concentrate to a supersaturated state, then cools to room temperature, stirs continuously during the cooling process, filters and dries to make ammonium rhenate powder, and puts it in hydrogen at (400-600) °C Reduced to high-purity rhenium powder. The invention does not require grinding and sieving procedures and adopts a lower reduction temperature in the hydrogen reduction process, which can reduce the content of impurity elements in the rhenium powder, and can meet the requirements of aerospace, electronics and other industries for the purity of rhenium powder. Although the energy consumption of this method is lower than that of ordinary hydrogen thermal reduction, there is still a situation in which oxides volatilize during the hydrogen reduction process, resulting in a decrease in yield.

The Chinese Patent Office also published an invention patent application for a method for preparing metal rhenium by hydrothermal hydrogen liquid phase reduction on February 19, 2019, with the application publication number CN109351985A. The preparation steps include: 1) preparing a precursor solution and concentrating it to a supersaturated state; 2) inducing and regulating self-assembly in the supersaturated precursor solution, controlling the polymer type, reaction temperature, reaction time and Molar ratio and other conditions, the intermediate is prepared; 3) The intermediate is directly subjected to hydrothermal hydrogen reduction to obtain the nano-rhenium powder slurry; 4) The nano-rhenium powder slurry is aged, separated and dried, and depolymerized matter, to obtain rhenium metal. This technical scheme can realize the preparation of metal rhenium powder with low energy consumption, but it still has the problems of relatively cumbersome process, long overall preparation process and low production efficiency, and in this technical scheme, the hydrothermal hydrogen reduction process has certain safety Hidden danger.

SUMMARY OF THE INVENTION

In order to solve the problems that the existing metal rhenium preparation method requires high-temperature hydrogen reduction, there are potential safety hazards, and the overall process is cumbersome, high energy consumption, low efficiency, and production decline caused by volatilization of oxides, etc., the present invention provides a liquid-phase Reduction method for preparing rhenium metal. The main goals to be achieved include: 1. Simplify the preparation process of metal rhenium powder and improve the preparation efficiency; 2. Ensure good preparation effect and improve the yield of product metal rhenium powder; 3. Avoid high-temperature hydrogen reduction and achieve medium and low temperature in the whole process The metal rhenium powder is prepared by reaction, which improves the safety of preparation and saves energy consumption, reduces the demand for equipment and enables large-scale industrial production.

In order to achieve the above object, the present invention adopts the following technical solutions.

A method for preparing rhenium metal by liquid phase reduction, said method comprising the following steps:

1) Preparation of precursor body fluid: dissolving the rhenium precursor in water to prepare a solution, adding polyvinylpyrrolidone and/or polyethylene glycol, and adding lye to adjust the pH value of the solution to obtain the precursor body fluid;

2) Prepare the reducing solution: dissolve the reducing agent in water to prepare the reducing solution;

3) Reduction reaction: Slowly drop the prepared reducing solution into the precursor body liquid through a funnel, wait until it is completely added, and then stand at a constant temperature. After the reaction is completed at a constant temperature, filter to obtain metal rhenium powder.

In the technical solution of the present invention, the rhenium precursor is first dissolved in water to prepare a solution, and at least one of polyvinylpyrrolidone and polyethylene glycol is added to protect and disperse the rhenium precursor. Rhenium precursors, especially rhenate substances, have poor solubility and stability in water, and are prone to problems such as precipitation and agglomeration. After adding polyvinylpyrrolidone and/or polyethylene glycol, their agglomeration and precipitation can be avoided. And promote its uniform dispersion, so as to avoid the single-point reaction in the subsequent reduction process to release too much heat and cause safety hazards, and the single-point reaction is easy to form too large granular metal rhenium and introduce impurities; in the subsequent reduction process, slow drop The method of adding reducing solution makes the high-valent rhenium slowly reduce to zero-valent metal rhenium. The reaction process is highly controllable and can be stopped at any time to ensure the safety of the metal rhenium powder preparation process. It does not need to be heated to High temperature, more energy saving, realize the whole process of medium and low temperature reaction, and the prepared metal rhenium powder has higher purity.

Preferably, the rhenium precursor in step 1) includes soluble rhenate, rhenic acid and perrhenic acid; the rhenium precursor concentration in the precursor liquid is 0.12-0.16 mol/L.

Rhenate, rhenic acid and perrhenic acid can increase the rhenium source. Controlling the concentration of rhenium in the precursor liquid at a low level can ensure that the rhenium precursor remains stable in the solution without precipitation, and can avoid explosive reduction in the subsequent reduction of rhenium metal powder, further improving safety.

Preferably, the amount of polyvinylpyrrolidone and/or polyethylene glycol added to the precursor liquid in step 1) is 5-15 wt% of the total mass of the rhenium precursor.

Polyvinylpyrrolidone and/or polyethylene glycol with too low concentration cannot achieve good protection and dispersion effects, while too high a concentration will cause a decrease in rhenium concentration and a slow reduction process, resulting in a decrease in rhenium yield. to achieve the best preparation results.

Preferably, the lye in step 1) is ammonia water; the process of adjusting the pH value adjusts the pH value of the precursor body liquid to 5-11.

Ammonia water is relatively stable when adjusting the pH value, it is not easy to introduce impurities, and no precipitation of rhenium compounds will occur. Absorb a large amount of heat released by the subsequent reduction reaction, and release ammonia gas after absorption, which can be collected for repeated recycling, saving more materials.

Preferably, the reducing agent in step 2) includes hydrazine hydrate and/or sodium borohydride.

Both hydrazine hydrate and sodium borohydride are relatively efficient strong reducing agents, which produce nitrogen or boric acid after reduction; in the present invention, the reducing agent is preferably hydrazine hydrate, which has stronger reducibility, more rapid reaction, and produces harmless Nitrogen can be discharged directly.

Preferably, the reducing agent concentration in the reducing solution in step 2) is 0.18-0.28 mol/L.

If the concentration of reducing agent is too high, the reaction process will be too violent; if the concentration is too low, the reduction process will be slow and the yield of metal rhenium powder will be low.

Preferably, the volume ratio of the reducing solution used in step 3) to the precursor solution is 1: (4.5-6).

Controlling the concentration of the reducing agent in the reducing solution so that the two have an appropriate volume ratio can avoid the occurrence of violent reactions and the continuous dilution of the precursor liquid during the dropwise addition of the reducing solution, resulting in the problem that the concentration of rhenium decreases and is difficult to restore.

As a preference, the constant temperature standing in step 3) is carried out under the condition of 20-80°C.

In this temperature range, rapid and stable reduction can be achieved to prepare metal rhenium powder, and this temperature range is at a medium and low temperature, with lower energy consumption and safer.

The beneficial effects of the present invention are:

1) The preparation process is simple and efficient, easy to popularize and use;

2) The yield of metal rhenium powder is high, and the utilization rate of raw materials is high;

3) The preparation is carried out at medium and low temperature, which is safer, and some materials can be recycled and reused.

Detailed ways

The present invention will be further clearly and detailedly described in conjunction with specific embodiments below. Those skilled in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention referred to in the following description are generally only some embodiments of the present invention, not all of them. Therefore, based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Unless otherwise specified, the raw materials used in the examples of the present invention are commercially available or available to those skilled in the art; unless otherwise specified, the methods used in the examples of the present invention are all methods mastered by those skilled in the art.

Example 1

A method for preparing rhenium metal by liquid phase reduction, said method comprising the following steps:

1) Preparation of precursor body fluid: dissolving rhenic acid in water to prepare a solution, adding polyvinylpyrrolidone and 5 wt% of the total mass of rhenic acid, and adding ammonia water to adjust the pH value of the solution to 6 to obtain a precursor body liquid, in which rhenic acid The initial concentration is 0.12mol/L;

2) Preparation of reducing solution: dissolving hydrazine hydrate in water to prepare a reducing solution of 0.18mol/L;

3) Reduction reaction: According to the volume ratio of the reducing solution to the precursor body liquid of 1:5.5, slowly drop the prepared reducing solution into the precursor body liquid through the funnel, and drop 5% of the total volume of the reducing solution per minute during the dropping process. %, after being completely added, place it under the condition of 60°C for 30 minutes at a constant temperature, and after the reaction is completed at a constant temperature, filter to obtain metal rhenium powder, and carry out XRD analysis on the metal rhenium powder;

4) Heat treatment: place the obtained metal rhenium powder in an inert gas, heat up to 100°C at a rate of 6°C/min and keep it for 1h, then raise the temperature to 200°C at a rate of 6°C/min and keep it for 3h, then cool with the furnace Obtain heat-treated rhenium powder;

5) Carry out XRD analysis on the heat-treated rhenium powder.

Example 2

A method for preparing rhenium metal by liquid phase reduction, said method comprising the following steps:

1) Preparation of precursor body fluid: dissolving perrhenic acid in water to prepare a solution, adding polyethylene glycol with a total mass of rhenium precursor of 11wt%, adding ammonia water to adjust the pH value of the solution to 7, and obtaining a precursor body fluid, in which high The initial concentration of rhenic acid is 0.15mol/L;

2) Preparation of reducing solution: dissolving sodium borohydride in water to prepare a reducing solution of 0.28mol/L;

3) Reduction reaction: According to the volume ratio of the reducing solution to the precursor body liquid of 1:4.5, slowly drop the prepared reducing solution into the precursor body liquid through the funnel, and drop 3% of the total volume of the reducing solution per minute during the dropping process. %, after being completely added, place it under the condition of 80°C for 35 minutes at a constant temperature, and after the reaction is completed at a constant temperature, filter to obtain metal rhenium powder, and carry out XRD analysis on the metal rhenium powder;

4) Heat treatment: place the obtained metal rhenium powder in an inert gas, raise the temperature to 100°C at a rate of 5°C/min and keep it for 1h, then raise the temperature to 200°C at a rate of 6°C/min and keep it for 3h, then cool with the furnace Obtain heat-treated rhenium powder;

5) Carry out XRD analysis on the heat-treated rhenium powder.

Example 3

A method for preparing rhenium metal by liquid phase reduction, said method comprising the following steps:

1) Preparation of precursor fluid: dissolving ammonium rhenate in water to prepare a solution, adding a mixture of polyvinylpyrrolidone and polyethylene glycol with a total mass of ammonium rhenate of 15 wt%, and the mass ratio of polyvinylpyrrolidone and polyethylene glycol in the mixture 1:1, adding ammonia water to adjust the pH value of the solution to 11 to obtain a precursor body fluid, the concentration of ammonium rhenate in the precursor body fluid is 0.16mol/L;

2) Preparation of reducing solution: dissolving hydrazine hydrate in water to prepare a reducing solution of 0.28mol/L;

3) Reduction reaction: According to the volume ratio of the reducing solution to the precursor body liquid of 1:5, slowly drop the prepared reducing solution into the precursor body liquid through the funnel, and drop 5% of the total volume of the reducing solution per minute during the dropping process. %, after being completely added, place it under the condition of 20°C for 40 minutes at a constant temperature, and after the reaction is completed at a constant temperature, filter to obtain metal rhenium powder, and carry out XRD analysis on the metal rhenium powder;

4) Heat treatment: place the obtained metal rhenium powder in an inert gas, heat up to 100°C at a rate of 6°C/min and keep it for 1h, then raise the temperature to 200°C at a rate of 6°C/min and keep it for 3h, then cool with the furnace Obtain heat-treated rhenium powder;

5) Carry out XRD analysis on the heat-treated rhenium powder.

Example 4

A method for preparing rhenium metal by liquid phase reduction, said method comprising the following steps:

1) Preparation of precursor body fluid: dissolving ammonium rhenate in water to prepare a solution, adding polyvinylpyrrolidone and polyethylene glycol with a total mass of ammonium rhenate of 10 wt%, and the mass ratio of polyvinylpyrrolidone and polyethylene glycol in the mixture is 1:4, add ammonia water to adjust the pH value of the solution to 9 to obtain a precursor body fluid, the concentration of ammonium rhenate in the precursor body fluid is 0.14mol/L;

2) Preparation of reducing solution: dissolving hydrazine hydrate or sodium borohydride in water to prepare a reducing solution of 0.28mol/L;

3) Reduction reaction: According to the volume ratio of the reducing solution to the precursor liquid of 1:6, slowly drop the prepared reducing solution into the precursor liquid through the funnel, and drop 5% of the total volume of the reducing solution per minute during the dropping process. %, after being completely added, place it under the condition of 60°C for 30 minutes at a constant temperature, and after the reaction is completed at a constant temperature, filter to obtain metal rhenium powder, and carry out XRD analysis on the metal rhenium powder;

4) Heat treatment: place the obtained metal rhenium powder in an inert gas, heat up to 100°C at a rate of 6°C/min and keep it for 1h, then raise the temperature to 200°C at a rate of 6°C/min and keep it for 3h, then cool with the furnace Obtain heat-treated rhenium powder;

5) Carry out XRD analysis on the heat-treated rhenium powder.

Example 5

A method for preparing rhenium metal by liquid phase reduction, said method comprising the following steps:

1) Preparation of precursor body fluid: dissolving ammonium rhenate in water to prepare a solution, adding polyvinylpyrrolidone and polyethylene glycol with a total mass of ammonium rhenate of 10 wt%, and the mass ratio of polyvinylpyrrolidone and polyethylene glycol in the mixture is 3:2, add ammonia water to adjust the pH value of the solution to 9.5 to obtain a precursor body fluid, the concentration of ammonium rhenate in the precursor body fluid is 0.15mol/L;

2) Preparation of reducing solution: dissolving hydrazine hydrate or sodium borohydride in water to prepare a reducing solution of 0.28mol/L;

3) Reduction reaction: According to the volume ratio of the reducing solution to the precursor body liquid of 1:5, slowly drop the prepared reducing solution into the precursor body liquid through the funnel, and drop 5% of the total volume of the reducing solution per minute during the dropping process. %, after being completely added, place it under the condition of 65°C for 30 minutes at a constant temperature, and after the reaction is completed at a constant temperature, filter to obtain metal rhenium powder, and carry out XRD analysis on the metal rhenium powder;

4) Heat treatment: place the obtained metal rhenium powder in an inert gas, heat up to 100°C at a rate of 6°C/min and keep it for 1h, then raise the temperature to 200°C at a rate of 6°C/min and keep it for 3h, then cool with the furnace Obtain heat-treated rhenium powder;

5) Carry out XRD analysis on the heat-treated rhenium powder.

The test results after sampling and analysis of Examples 1 to 5 are shown in Table 1 below, and all test results are the average value of the effective values of ten tests.

Table 1 Example 1～5 sampling analysis results.

It can be clearly seen from the above table that the metal rhenium prepared by the method of the present invention has extremely high purity, and the content of impurity elements is low, and the metal rhenium prepared after reduction can further improve its purity after heat treatment and crystallization, and the overall preparation The process is simple and safe.

Claims (3)

1. A method for preparing metallic rhenium by liquid phase reduction, characterized in that the method comprises the following steps:

1) Preparation of precursor liquid: dissolving a rhenium precursor in water to prepare a solution, adding polyvinylpyrrolidone and/or polyethylene glycol, and adding an alkali liquor to adjust the pH value of the solution to obtain a precursor solution;

2) Preparing a reducing solution: dissolving a reducing agent in water to prepare a reducing solution;

3) Reduction reaction: slowly dripping the prepared reducing solution into the precursor solution through a funnel, standing at constant temperature after the reducing solution is completely added, and filtering to obtain metal rhenium powder after the reaction of standing at constant temperature is completed;

step 1) the concentration of a rhenium precursor in the precursor liquid is 0.12-0.16 mol/L;

step 1), the addition amount of polyvinylpyrrolidone and/or polyethylene glycol in the precursor liquid is 5-15 wt% of the total mass of the rhenium precursor;

step 1), the alkali liquor is ammonia water;

step 1) adjusting the pH value of the precursor liquid to 5-11 in the process of adjusting the pH value;

the concentration of the reducing agent in the reducing solution in the step 2) is 0.18-0.28 mol/L;

the volume ratio of the reducing liquid to the precursor liquid used in the step 3) is 1: (4.5 to 6);

and 3) standing at the constant temperature of 20-65 ℃.

2. The method for preparing rhenium metal by liquid-phase reduction according to claim 1, wherein the rhenium precursor in the step 1) comprises soluble rhenate, rhenic acid and perrhenic acid.

3. The method for preparing metallic rhenium through liquid-phase reduction according to claim 1, wherein the reducing agent in the step 2) comprises hydrazine hydrate and/or sodium borohydride.