阅读说明：本技术 一种氯化铵的回收利用装置及方法 (Ammonium chloride recycling device and method ) 是由 白平平 朱刘 王帮琼 陈创武 于 2021-09-08 设计创作，主要内容包括：本发明涉及贵金属精炼技术领域,公开了一种氯化铵的回收利用装置及方法,所述氯化铵的回收利用装置包括加热炉、反应管、设于所述反应管内的煅烧器皿、喷淋吸收塔和循环水槽,所述反应管设于所述加热炉的内部,所述反应管的一端用于连接氮气,另一端与所述喷淋吸收塔的进气口相连通,所述喷淋吸收塔的底部设有排液口,所述喷淋吸收塔的顶部设有排气口,所述喷淋吸收塔的内部设有喷淋装置,所述排液口与所述循环水槽的进料口相连通,所述喷淋装置与所述循环水槽通过输液管相连通,所述输液管上设有出料管。本发明直接将煅烧过程中产生的氨气和HCl转成氯化铵水溶液作为沉钌试剂,使得整个钌粉精馏提纯工艺更加完善,避免了资源浪费及环境污染。(The invention relates to the technical field of precious metal refining, and discloses a device and a method for recycling ammonium chloride. The invention directly converts ammonia gas and HCl generated in the calcining process into ammonium chloride aqueous solution as the ruthenium precipitation reagent, so that the whole ruthenium powder rectification and purification process is more perfect, and resource waste and environmental pollution are avoided.)

1. The utility model provides a recycle device of ammonium chloride which characterized in that: including heating furnace, reaction tube, locate calcining household utensils, spray absorption tower and circulating water groove in the reaction tube, the reaction tube is located the inside of heating furnace, the one end of reaction tube is used for connecting nitrogen gas, the other end with the air inlet that sprays the absorption tower is linked together, the bottom that sprays the absorption tower is equipped with the leakage fluid dram, the top that sprays the absorption tower is equipped with the gas vent, the inside that sprays the absorption tower is equipped with spray set, the leakage fluid dram with circulating water groove's feed inlet is linked together, spray set with circulating water groove passes through the transfer line and is linked together, be equipped with the discharging pipe on the transfer line.

2. The apparatus for recycling ammonium chloride according to claim 1, wherein: the spray absorption tower is characterized in that a packing layer is arranged inside the spray absorption tower, a plurality of air guide holes are uniformly distributed on the packing layer, and the packing layer is made of quartz or borosilicate glass.

3. The apparatus for recycling ammonium chloride according to claim 1, wherein: the infusion tube is provided with a circulating water pump, the circulating water pump is located between the circulating water tank and the discharge tube, the infusion tube is provided with a first valve, and the discharge tube is provided with a second valve.

4. The apparatus for recycling ammonium chloride according to claim 1, wherein: the exhaust port is provided with an exhaust pipe, the other end of the exhaust pipe is used for being connected with a negative pressure device, and the gas flow in the exhaust pipe is 110-130 m³/h。

5. The apparatus for recycling ammonium chloride according to claim 1, wherein: the reaction tube is provided with an air supply pipe, the free end of the air supply pipe penetrates through the exhaust port and extends into the spray absorption tower, the air supply pipe is arranged in an inclined mode towards the horizontal plane, and the included angle a between the central line of the air supply pipe and the horizontal plane is 5-10 degrees.

6. The apparatus for recycling ammonium chloride according to claim 5, wherein: the inner diameter of the spray absorption tower is D, and the length of the air supply pipe extending into the spray absorption tower is 2/3-3/4D.

7. The apparatus for recycling ammonium chloride according to claim 5, wherein: the part of the air supply pipe, which is positioned in the spray absorption tower, is provided with a plurality of groups of exhaust units, each group of exhaust units is provided with a plurality of exhaust holes, the inner diameter of the air supply pipe is d, and the diameter of each exhaust hole is d₁，d₁＝1/4～1/3d。

8. The apparatus for recycling ammonium chloride according to claim 5, wherein: the air inlet is provided with a sleeve, the air supply pipe is inserted in the sleeve, the inner diameter of the sleeve is 1.5-2 times of the inner diameter of the air supply pipe, and the included angle b between the central line of the sleeve and the horizontal plane is 5-15 degrees.

9. The apparatus for recycling ammonium chloride according to claim 1, wherein: the inner diameter of the spraying absorption tower is D, the spraying device is a spraying pipe, and the diameter of the spraying pipe is D₂，d₂1/4 ~ 1/3D, the upside of shower is equipped with the multiunit and sprays the unit, and every group spray the unit and all include a plurality of spray holes, the length of shower is 3/4 ~ 4/5D, spray the diameter in hole and be 1/10 ~ 1/8D₂。

10. A method for recycling ammonium chloride is characterized by comprising the following steps: the method comprises the following steps:

(1) placing the noble metal ammonium salt in a calcining vessel in a reaction tube for calcining;

(2) opening the first valve and closing the second valve;

(3) starting a circulating water pump and a negative pressure device;

(4) sampling and detecting the mass fraction of ammonium chloride in the circulating water tank;

(5) when the mass fraction of the ammonium chloride in the circulating water tank reaches 20-30%, closing the first valve, opening the second valve, and transferring the ammonium chloride solution in the circulating water tank;

(6) supplementing new water into the circulating water tank;

wherein, the calcination of the noble metal ammonium salt is carried out in three steps:

firstly, setting a target temperature to be 300-400 ℃, and keeping the temperature for 2-4 h;

secondly, setting the target temperature to be 500-600 ℃, and keeping the temperature for 4-8 hours;

and thirdly, setting the target temperature to be 900-1000 ℃ and keeping the temperature for 4-8 h.

Technical Field

The invention relates to the technical field of precious metal refining, in particular to recycling of byproducts in the field of precious metal refining, and particularly relates to a device and a method for recycling ammonium chloride.

Background

When the precious metals Ru, Pt and Pd are refined and purified by the hydrometallurgical process, the materials containing Ru, Pt and Pd are mostly converted into the materials containing Cl^-And NH4⁺Salt, and calcining the noble metal salt at high temperature to obtain high purity Ru, Pt, Pd and by-product ammonium chloride (NH) in powder or sponge form₃And HCl gas). The specific preparation is that (NH) is prepared first₄)₂RuCl₆And calcining the precursor in a certain atmosphere to obtain high-purity ruthenium powder and other byproducts. Ruthenium is used as an example for the following description.

Preparation of (NH) from acidic systems containing ruthenium₄)₂RuCl₆In the precursor, ammonium chloride aqueous solution is mostly used as a ruthenium precipitation reagent, (NH)₄)₂RuCl₆The alloy contains 28.87 percent of Ru and the balance of ammonium and chloride ions. (NH)₄)₂RuCl₆After calcination, ammonia, HCl and Cl are by-products in addition to the main product Ru powder₂. The ammonia gas and the HCl are easy to react to generate ammonium chloride, the purity of the ammonia gas and the HCl gas generated by calcining is high, and the ammonium chloride generated by the reaction of the ammonia gas and the HCl gas can be directly used as a ruthenium precipitation reagent. If the part of ammonium chloride can be recycled, the generation of ammonium chloride waste in the process can be reduced, and the closed cycle of the ammonium chloride in the system can be realized, so that the utilization rate of auxiliary materials is maximized.

Disclosure of Invention

In order to solve the technical problems, the invention provides a device and a method for recycling ammonium chloride, which directly treat ammonia gas and HCl gas generated in the calcining process to finally generate an ammonium chloride aqueous solution, and the concentration of the ammonium chloride aqueous solution is controlled to ensure that the formed ammonium chloride aqueous solution can be directly used as a ruthenium precipitation reagent, so that the whole ruthenium powder rectification and purification process is more complete, and resource waste and environmental pollution are avoided.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the utility model provides an ammonium chloride's recycle device, includes heating furnace, reaction tube, locates calcining household utensils, spray absorption tower and circulating water groove in the reaction tube, the reaction tube is located the inside of heating furnace, the one end of reaction tube is used for connecting nitrogen gas, the other end with the air inlet that sprays the absorption tower is linked together, the bottom that sprays the absorption tower is equipped with the leakage fluid dram, the top that sprays the absorption tower is equipped with the gas vent, the inside that sprays the absorption tower is equipped with spray set, the leakage fluid dram with circulating water groove's feed inlet is linked together, spray set with circulating water groove is linked together through the transfer line, be equipped with the discharging pipe on the transfer line.

Preferably, a packing layer is arranged inside the spraying absorption tower, a plurality of air guide holes are uniformly distributed on the packing layer, and the packing layer is made of quartz or borosilicate glass.

Preferably, a circulating water pump is arranged on the infusion tube and located between the circulating water tank and the discharge tube, a first valve is arranged on the infusion tube, and a second valve is arranged on the discharge tube.

Preferably, the exhaust port is provided with an exhaust pipe, the other end of the exhaust pipe is used for being connected with a negative pressure device, and the gas flow in the exhaust pipe is 110-130 m³/h。

Preferably, the reaction pipe is provided with an air supply pipe, the free end of the air supply pipe penetrates through the exhaust port and extends into the spray absorption tower, the air supply pipe is inclined towards the horizontal plane, and the included angle a between the central line and the horizontal plane is 5-10 degrees.

Preferably, the inner diameter of the spray absorption tower is D, and the length of the air supply pipe extending into the spray absorption tower is 2/3-3/4D.

Preferably, a plurality of groups of exhaust units are arranged on the part of the air supply pipe in the spray absorption tower, each group of exhaust units is provided with a plurality of exhaust holes, and the inner diameter of the air supply pipeD, the diameter of the vent hole is d₁，d₁＝1/4～1/3d。

Preferably, the air inlet is provided with a sleeve, the air supply pipe is inserted into the sleeve, the inner diameter of the sleeve is 1.5-2 times of the inner diameter of the air supply pipe, and an included angle b between the central line of the sleeve and the horizontal plane is 5-15 degrees.

Preferably, the inner diameter of the spray absorption tower is D, the spray device is a spray pipe, and the diameter of the spray pipe is D₂，d₂1/4 ~ 1/3D, the upside of shower is equipped with the multiunit and sprays the unit, and every group spray the unit and all include a plurality of spray holes, the length of shower is 3/4 ~ 4/5D, spray the diameter in hole and be 1/10 ~ 1/8D₂。

A method for recycling ammonium chloride comprises the following steps:

(1) placing the noble metal ammonium salt in a calcining vessel in a reaction tube for calcining;

(2) opening the first valve and closing the second valve;

(3) starting a circulating water pump and a negative pressure device;

(4) sampling and detecting the mass fraction of ammonium chloride in the circulating water tank;

(5) when the mass fraction of the ammonium chloride in the circulating water tank reaches 20-30%, closing the first valve, opening the second valve, and transferring the ammonium chloride solution in the circulating water tank;

(6) supplementing new water into the circulating water tank;

wherein, the calcination of the noble metal ammonium salt is carried out in three steps:

firstly, setting a target temperature to be 300-400 ℃, and keeping the temperature for 2-4 h;

secondly, setting the target temperature to be 500-600 ℃, and keeping the temperature for 4-8 hours;

and thirdly, setting the target temperature to be 900-1000 ℃ and keeping the temperature for 4-8 h.

Compared with the prior art, the ammonium chloride recycling device and method provided by the embodiment of the invention have the beneficial effects that: the spraying absorption tower is connected with the reaction tube through the arrangement, the liquid outlet of the spraying absorption tower is communicated with the feed inlet of the circulating water tank, the spraying device is communicated with the circulating water tank through a liquid conveying tube, a discharging tube is arranged on the liquid conveying tube, precious metal ammonium salt is placed in the reaction tube to be calcined during reaction, ammonium chloride produced by reaction of ammonia gas and HCl gas is sprayed in the spraying absorption tower to form ammonium chloride solution, the ammonium chloride solution flows into the circulating water tank, the ammonium chloride solution in the circulating water tank can be transferred to an ammonium chloride concentrated solution storage tank of the working procedure through the discharging tube to be used as ruthenium precipitating reagent when the mass fraction of the ammonium chloride in the circulating water tank meets the requirement of the working procedure, the whole ruthenium powder rectification and purification process is more complete, and resource waste and environmental pollution are avoided. The invention has simple structure, good use effect and easy popularization and use.

Drawings

FIG. 1 is a schematic structural diagram of an apparatus and a method for recycling ammonium chloride according to the present invention.

FIG. 2 is a schematic view of the structure of a reaction tube of the present invention.

Fig. 3 is a schematic structural view of the spray absorption tower of the present invention.

Wherein: 1-heating furnace, 2-reaction tube, 3-calcining vessel, 4-spray absorption tower, 5-circulating water tank, 6-liquid conveying tube, 7-discharging tube, 8-packing layer, 9-circulating water pump, 10-first valve, 11-second valve, 12-gas supply tube, 13-sleeve, 14-spray tube and 15-exhaust tube.

Detailed Description

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

The invention can be used for noble metal ammonium salts: the preparation of noble metal powders such as Ru, Pd, Pt, etc. with a chlorine content of less than 100ppm by calcination decomposition of ammonium chlororuthenate, ammonium chloropalladate, ammonium chloroplatinate, etc. in this embodiment, Ru is taken as an example for illustration, and the preparation methods of the other noble metals are the same, which is not repeated herein.

As shown in fig. 1, the apparatus for recycling ammonium chloride according to the preferred embodiment of the present invention includes a heating furnace 1, a reaction tube 2, a calcination vessel 3 disposed in the reaction tube 2, a spray absorption tower 4, and a circulating water tank 5, wherein the heating furnace 1 is a tubular heating furnace, and the heating temperature zones are three and respectively correspond to three stages during calcination. The calcining vessel 3 can be selected from alumina, quartz glass or common ceramic boat, etc. The reaction tube 2 is arranged in the heating furnace 1, one end of the reaction tube 2 is used for connecting nitrogen, and noble metal powder obtained by calcining and decomposing noble metal ammonium salt is prevented from being oxidized. The other end of the reaction tube 2 is communicated with an air inlet of the spray absorption tower 4, a liquid discharge port is arranged at the bottom of the spray absorption tower 4, an air exhaust port is arranged at the top of the spray absorption tower 4, a spray device is arranged inside the spray absorption tower 4, the liquid discharge port is communicated with a feed inlet of the circulating water tank 5, the spray device is communicated with the circulating water tank 5 through a liquid conveying pipe 6, and a discharge pipe 7 is arranged on the liquid conveying pipe 6.

The ammonium chloride recycling device based on the technical characteristics is characterized in that a spray absorption tower 4 is arranged to be connected with a reaction tube 2, a liquid outlet of the spray absorption tower 4 is communicated with a feed inlet of a circulating water tank 5, the spray device is communicated with the circulating water tank 5 through a liquid conveying tube 6, a discharge tube 7 is arranged on the liquid conveying tube 6, a noble metal ammonium salt is placed in the reaction tube 2 to be calcined during reaction, ammonium chloride produced by reaction of generated ammonia gas and HCl gas is sprayed in the spray absorption tower 4 to form an ammonium chloride solution, the ammonium chloride solution flows into the circulating water tank 5, when the mass fraction of the ammonium chloride in the circulating water tank 5 meets the requirement of the process, the ammonium chloride solution in the circulating water tank 5 can be transferred to an ammonium chloride concentrated solution storage tank of the process through the discharge tube 7 to be used as a ruthenium precipitation reagent, and the whole ruthenium powder rectification and purification process is more complete, and resource waste and environmental pollution are avoided. The invention has simple structure, good use effect and easy popularization and use.

In this embodiment, a packing layer 8 is disposed inside the spray absorption tower 4, a plurality of air holes are uniformly distributed on the packing layer 8, and the packing layer 8 is set to increase mass transfer between water flow and gas, so that rising gas and falling water flow are fully mixed, and the generated ammonia gas and HCl gas are ensured to completely react to produce ammonium chloride. Meanwhile, because the temperature of the gas coming out of the reaction tube 2 is high, the material of the packing layer 8 is selected from quartz or borosilicate glass, the stability of the equipment is ensured, meanwhile, the ammonium chloride is prevented from being polluted, and the purity of the ammonium chloride is ensured.

In this embodiment, the infusion tube 6 is provided with a circulating water pump 9, the circulating water pump 9 is located between the circulating water tank 5 and the discharge tube 7, the infusion tube 6 is provided with a first valve 10, and the discharge tube 7 is provided with a second valve 11. When spraying, the first valve 10 is opened, the second valve 11 is closed, when the mass fraction of the ammonium chloride in the circulating water tank 5 easily reaches the concentration requirement, the first valve 10 is closed, and the second valve 11 is opened to transfer the ammonium chloride solution. After the circulation, new water needs to be added to the circulation water tank 5, and therefore a water filling port needs to be provided in the circulation water tank 5.

In this embodiment, in order to ensure that all NH3, HCl gas and the like generated in the production process enter the spray absorption tower 4, the exhaust port is provided with an exhaust pipe 15, and the other end of the exhaust pipe 15 is used for connecting a negative pressure device. In practical application, the negative pressure device can directly adopt a plant tail gas spray tower, so that negative pressure in the spray absorption tower 4 can be ensured, other tail gases can be treated, and other negative pressure equipment is not required to be added. However, in order to keep the spray absorption tower 4 in a normal operation state, a proper circulating water pump 9 needs to be selected to make the flow rate of water reach a required range, and if the flow rate of circulating water is too small, gas absorption is insufficient; if the circulating water flow is too large, the pressure in the spraying device is increased, and the risk of breakage of a circulating water outlet is increased. Preferably, the flow rate of the circulating water pump 9 is 5-8m³/h。

In addition, if the air volume of the exhaust port of the spray absorption tower 4 is too small, the negative pressure in the tower is insufficient, and the generated NH3, HCl gas and the like can not be ensured to enter the spray absorption tower 4 completely, so that the risk of gas leakage is increased; if the air volume of the exhaust port of the spray absorption tower 4 is too large, the negative pressure in the tower is too large, and partial water flow of the circulating water outlet is brought into the tail gas absorption tower due to the negative pressure in the tower, so that the loss of absorption liquid is caused. Preferably, the gas flow rate in the exhaust pipe 15 is 110 to 130m 3/h. The following calculation formula is adopted:

Q＝3.14D²V/4

q is the air volume, and the unit is m³/h；

D is the inner diameter of the spray absorption tower (4), and the unit is m;

v is wind speed, m/s.

In practical applications, the gas flow rate in the exhaust pipe 15 may be set first, and other parameters are determined to ensure that the equipment operates well.

Referring to fig. 2-3, in this embodiment, an air feed pipe 12 is disposed on the reaction pipe 2, a free end of the air feed pipe 12 passes through the exhaust port and extends into the spray absorption tower 4, a plurality of groups of exhaust units are disposed on a portion of the air feed pipe 12 located in the spray absorption tower 4, each group of exhaust units has a plurality of exhaust holes, and each group of exhaust units preferably has 3 to 4 exhaust holes. In the reaction process, NH4Cl crystals are also generated in the gas feed pipe 12, and gas without crystals is discharged from the gas discharge hole, and the reaction is performed in the spray absorption tower 4, and simultaneously, water flows into the gas feed pipe 12 along the gas discharge hole to dissolve NH4Cl crystals, so as to facilitate rapid discharge of water flow and avoid blockage of a gas outlet due to enrichment of ammonium chloride crystals, the gas feed pipe 12 is inclined towards a horizontal plane, and an included angle a between a central line and the horizontal plane is 5 to 10 degrees, such as 6 degrees, 8 degrees, and the like. In addition, in order to ensure the best use effect, tests show that if the inner diameter of the spray absorption tower 4 is D, the length of the air supply pipe 12 extending into the spray absorption tower 4 is selected to be 2/3-3/4D. Meanwhile, if the inner diameter of the air supply pipe 12 is d, the diameter of the exhaust hole is d₁，d₁＝1/4～1/3d。

Meanwhile, in order to facilitate the connection of the air supply pipe 12 and the spray absorption tower 4, the air inlet is provided with a sleeve 13, the air supply pipe 12 is inserted into the sleeve 13, the inner diameter of the sleeve 13 is 1.5-2 times of the inner diameter of the air supply pipe 12, the included angle b between the central line of the sleeve 13 and the horizontal plane is 5-15 degrees, such as 6 degrees, 8 degrees, 10 degrees and the like, and the specific setting angle needs to be matched with the angle of the air supply pipe 12.

In this embodiment, the inner diameter of the spray absorption tower 4 is D, the spray device is a spray pipe 14, and the diameter of the spray pipe 14 is D₂，d₂1/4-1/3D, and the length of the spray pipe 14 is 3/4-4/5D, so that the best spray effect can be achieved. Meanwhile, in order to further ensure the spraying quality, a state similar to 'spraying' is required to be achieved during spraying, a plurality of descending water flows enter the packing layer 8 made of quartz or glass and are contacted and absorbed with ascending NH3 and HCl gas, so that a plurality of groups of spraying units, preferably 3-4 groups, are arranged on the upper side of the spraying pipe 14. Each group of spraying units comprises a plurality of spraying holes, preferably 5-8 spraying holes are formed in each group, and the diameter of each spraying hole is 1/10-1/8 d₂。

In order to solve the technical problem, the invention provides a method for recycling ammonium chloride, which comprises the following steps:

(1) the noble metal ammonium salt is placed in a calcination vessel 3 in the reaction tube to be calcined. In order to avoid the generation of too much NH4Cl due to the massive decomposition of the precious metal ammonium salt in a short time and increase the processing load of the tail gas absorption device, the temperature rise program consists of three stages, the target temperature and the duration of each stage are different, and the temperature rise program is respectively controlled by three heating text areas of the heating furnace, specifically:

in the first stage, the target temperature is 300-400 ℃, the heat preservation time is 2-4 h, the temperature in the stage is maintained at the temperature point at which the noble metal ammonium salt just starts to generate the decomposition reaction, the decomposition rate of the noble metal ammonium salt is low, and the amount of ammonia gas and HCl generated in unit time is small, so that the absorption treatment of a rear-end spray tower is facilitated;

and in the second stage, the target temperature is 500-600 ℃, the heat preservation time is 4-8 hours, the decomposition rate of the noble metal ammonium salt is greatly increased, the noble metal ammonium salt is basically changed into ruthenium powder after the calcination in the stage, and the Cl & lt- & gt ion content in the Ru powder is reduced to about 1000 ppm. In the specific operation, the operation is started when the white smoke in the spray absorber 4 is found to be reduced.

And in the third stage, the target temperature is 900-1000 ℃, the heat preservation time is 4-8 hours, and the Cl-concentration is reduced to be below 100ppm mainly in the stage of deeply removing Cl-in the Ru powder of the calcined product. This step is carried out when the white fumes inside the spray absorber 4 are found to be substantially disappeared.

(2) Opening the first valve 10 and closing the second valve 11;

(3) starting the circulating water pump 9 and the negative pressure device;

(4) sampling and detecting the mass fraction of ammonium chloride in the circulating water tank 5;

(5) when the mass fraction of the ammonium chloride in the circulating water tank 5 reaches 20-30%, closing the first valve, opening the second valve, and transferring the ammonium chloride solution in the circulating water tank 5;

(6) fresh water is supplied to the circulation water tank 5.

The effect of the present invention will be described below with reference to a specific example.

Example one

The reaction tube 2 is made of quartz glass, the inner diameter of the reaction tube 2 is 200mm, the inclination angle of the air feed tube 12 is 5 degrees, the inner diameter is 50mm, the length of the air feed tube 12 extending into the spray absorption tower 4 is 2/3 of the diameter of the spray absorption tower 4, a group of small holes are arranged at the upper end of the air feed tube 12, the aperture of each small hole is 1/3 of the inner diameter of the air feed tube, and the number of the small holes is 4. The calcination vessel 3 containing the precious metal ammonium salt is quartz glass or a 99% alumina crucible.

The spray absorption tower 4 is a borosilicate glass product, and the inner diameter of the spray absorption tower 4 is 200 mm. The spraying device is a borosilicate glass tube, the inner diameter of the borosilicate glass tube is 1/4 (namely 50 mm) of the inner diameter of the spraying absorption tower 4, and the length of the borosilicate glass tube is 3/4 and 150mm of the inner diameter of the spraying absorption tower 4; the upside of shower has 4 groups to spray the hole, sprays the aperture of hole for 1/10 of shower internal diameter, every group spray the hole quantity for 8. The inner diameter of the sleeve 13 is 1.5 times the inner diameter of the air feed pipe 12, and the inclination angle thereof is 5 °.

Opening a tail gas spray tower connected with the top of the spray absorption tower 4 to ensure that the air volume of the spray absorption tower 4 reaches 110m³The circulating water pump is a corrosion-resistant centrifugal pump (Kunshan national treasure GS25-1/2), and the flow of the circulating absorption liquid is 6m³/h。

The precious metal ammonium salt is selected from ammonium chlororuthenate, three quartz calcining vessels 3 are taken, 1kg of ammonium chlororuthenate is filled into each calcining vessel 3, then the calcining vessels 3 are filled into the reaction tube 2, and 3 calcining vessels 3 are placed at the central part of the reaction tube 2 as far as possible. Starting a calcination procedure to calcine ammonium chlororuthenate into ruthenium powder, wherein the specific calcination procedure is as follows:

in the first stage, the target temperature is 400 ℃, and the heat preservation time is 4 hours; the target temperature of the second stage of calcination is 600 ℃, the heat preservation time is 8 hours, the decomposition rate of the noble metal ammonium salt is greatly increased, the noble metal ammonium salt is basically changed into ruthenium powder after the stage of calcination, and the ruthenium powder contains 945ppm Cl after GDMS test; in the third stage, the target temperature is 900 ℃, the heat preservation time is 8 hours, the third stage is mainly used for deeply removing Cl in the Ru powder of the calcined product, and the GDMS tests that the Ru powder contains 83ppm of Cl after calcination. The total amount of ruthenium powder obtained after three-stage calcination was 0.85 kg.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and substitutions can be made without departing from the technical principle of the present invention, and these modifications and substitutions should also be regarded as the protection scope of the present invention.