Method for recovering ruthenium from amorphous ruthenium sulfide slag

Abstract

The invention belongs to the technical field of precious metal recovery, and discloses a method for recovering ruthenium from amorphous ruthenium sulfide slag, the amorphous ruthenium sulfide slag contains ammonium chloride, and the method comprises the following steps: step 1, adding the amorphous ruthenium sulfide slag into water for washing and stirring, then dropwise adding sulfide to adjust the pH value to 7-8, and carrying out reaction and separation to obtain a precipitate; 2, heating the precipitate to 350-400 DEG C in an inert gas atmosphere, and carrying out primary calcination to obtain primary calcined slag; 3, the primary calcined slag is heated to 550-600 DEG C in the inert gas atmosphere for secondary calcination, and secondary calcined slag is obtained; 4, the secondary calcined slag is sequentially subjected to acid pickling and hydrogen reduction treatment, and ruthenium powder is obtained; wherein the calcination time in the step 2 is 30-40 min, and the calcination time in the step 3 is 4-5 h. According to the method, the amorphous ruthenium sulfide slag is further vulcanized, so that the situation that other ruthenium in the amorphous ruthenium sulfide slag cannot be precipitated and separated out is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of precious metal recovery, and in particular to a method for recovering ruthenium from amorphous ruthenium sulfide slag. Background Art

[0002] Ruthenium is one of the six elements of the platinum group metals (PGM). It is widely used due to its high catalytic properties and stability. It is mainly used as a drug complex in medical targeted therapy, as a chemical drug in chemical production, and as a sputtering raw material in target material preparation. In industry, complex ruthenium materials are melted by high-temperature melting method, and after cooling, the ruthenium is completely leached into the liquid phase by water immersion, and then saturated with chlorine gas and heated and distilled to convert it into ruthenium tetroxide. The gaseous ruthenium tetroxide is absorbed by dilute hydrochloric acid solution and then added with saturated ammonium chloride solution to generate a black precipitate (NH4)2RuCl6, which is then reduced to a sponge-like ruthenium element by hydrogen reduction method. When adding saturated ammonium chloride solution to precipitate precious metals, ruthenium waste liquid containing ammonium chloride will inevitably be produced. The waste liquid reacts with excess sodium sulfide to precipitate amorphous low-grade ruthenium sulfide slag; the ruthenium sulfide slag is amorphous Ru2S3·10H2O with the structure of RuS·RuS2·10H2O.

[0003] Due to the complexity of the crystallization behavior of amorphous RuS·RuS2·10H2O, its parameters such as crystallization temperature and crystallization starting temperature are unknown; at the same time, the ruthenium sulfide slag contains ammonium chloride, and the ammonium chloride molecules can overcome the surface tension and transform into gas when heated. The gas molecules diffuse in the air and re-condense into small particles.

[0004] Therefore, it is difficult to recycle this type of ruthenium sulfide slag into high-purity sponge ruthenium.

[0005] Prior art 1: Chinese patent application 202311531150.0 discloses a method for recovering ruthenium from a low-content ruthenium-containing material; the specification of prior art 1 states: "The purpose of the present invention is to provide a method for recovering ruthenium from a low-content ruthenium-containing material with a ruthenium content of less than 2.0%, which has a simple process, few steps, high recovery efficiency and low economic cost, and at the same time effectively solves the problem of resource utilization of chlorine absorption liquid". In order to achieve this purpose, the technical solution provided by prior art 1 is specifically: "A method for recovering ruthenium from a low-content ruthenium-containing material, which is carried out in sequence according to the following steps: A. Stirring and soaking at room temperature: Stirring and soaking the low-content ruthenium-containing material and the chlorine absorption liquid at room temperature, the liquid-solid ratio of the chlorine absorption liquid to the low-content ruthenium-containing material is 1:0.5~10mL / g, stirring and soaking for 4~12h to obtain a solid-liquid mixed soaking liquid; B. Acidification reaction: Add an acid adjustment solution with a pH value of <2 to the solid-liquid mixed soaking liquid obtained in step A pH value, the volume ratio of the solid-liquid mixed soaking liquid to the acid is 1:0.5-5, the reaction time is 0.5-12h, and the solution is strongly acidic after adjustment; C. solid-liquid separation: the strongly acidic solution obtained in step B is subjected to solid-liquid separation, and the solid-liquid separation method adopts static sedimentation to separate the supernatant to obtain separation residue and separation liquid; chlorine gas absorption liquid is added to the separation residue, and steps A and B are repeated 2-5 times, and the ruthenium-containing solution and tailings are separated by solid-liquid separation, and the tailings are washed, and the washing water is combined with the ruthenium-containing solution or treated separately; D. Reduction: Stir and heat the ruthenium-containing solution obtained in step C to 20°C-100°C, add a reducing agent to reduce the ruthenium valence until no obvious reaction occurs; E. Replacement: Add active metal powder or block to the reduced ruthenium-containing solution obtained in step D for replacement until the ruthenium content in the replacement mother liquor is less than 0.005g / L, the replacement temperature is 20°C-100°C, and a ruthenium-containing replacement concentrate and a replacement mother liquor are obtained, and the ruthenium-containing replacement concentrate is subjected to conventional refining treatment.

[0006] When recycling materials with a ruthenium content of less than 2.0%, the prior art 1 has the problems of introducing lower-grade ruthenium-containing tailings, replacing waste liquid, and instability of the strong acid acidification production process.

[0007] Based on this, prior art 2: Chinese patent application 202311475808.0 discloses a method for enriching ruthenium from soluble ruthenium slag, comprising the following steps: Step 1: dissolving the soluble ruthenium slag in water to form a solution; Step 2: adding alkali solution to the solution of step 1, and adjusting the pH value of the solution to 4-6; Step 3: heating the solution obtained in step 2 to 45-75°C and stirring, adding sodium sulfide or ammonium sulfide solution during the process until the pH value of the solution is adjusted to 7-8, and then keeping stirring and keeping the reaction for 1-5h; Step 4: vacuum filtration is performed on the solution after the reaction in step 3 for solid-liquid separation to obtain a filter residue; Step 5: The filter residue is successively acid washed, vacuum filtered once, washed with water, and vacuum filtered twice, and then dried to obtain a dried material; Step 6: calcining the dried material at a calcination temperature of 500-750°C for 1-6h under a nitrogen atmosphere to obtain a crude ruthenium powder.

[0008] The technical solution of prior art 2 can effectively avoid the introduction of lower-grade ruthenium-containing tailings to replace waste liquid, the instability of the strong acid acidification production process, etc., but there will be a problem when it is used for ruthenium recovery from amorphous ruthenium sulfide slag, that is, it is difficult to completely recover ruthenium from amorphous RuS·RuS2·10H2O, and ammonium chloride cannot be separated and removed.

[0009] Therefore, the technical problem to be solved by the present invention is: how to process amorphous ruthenium sulfide slag to recover more ruthenium and avoid excessive impurities in the recovered ruthenium. Summary of the invention

[0010] One of the purposes of the present invention is to provide a method for recovering ruthenium from amorphous ruthenium sulfide slag, by which ruthenium can be efficiently recovered, and while avoiding the loss of ruthenium during the recovery process, the purity of ruthenium in the recovered product can be further improved, and ammonium chloride can be removed.

[0011] To achieve the above object, the present invention provides a method for recovering ruthenium from amorphous ruthenium sulfide slag, wherein the amorphous ruthenium sulfide slag contains ammonium chloride, comprising the following steps:

[0012] Step 1: adding amorphous ruthenium sulfide slag into water for washing and stirring, then adding sulfide dropwise to adjust the pH to 7-8, reacting and separating to obtain a precipitate;

[0013] Step 2: heating the precipitate to 350-400° C. in an inert gas atmosphere to perform a first calcination to obtain a primary calcined slag;

[0014] Step 3: heating the primary calcined slag to 550-600° C. in an inert gas atmosphere and performing a second calcination to obtain a secondary calcined slag;

[0015] Step 4: sequentially subjecting the secondary calcined slag to acid washing and hydrogen reduction treatment to obtain ruthenium powder;

[0016] The calcination time of step 2 is 30-40 minutes, and the calcination time of step 3 is 4-5 hours.

[0017] Preferably, the calcination temperature of the first calcination can be selected from 350°C, 360°C, 370°C, 380°C, 390°C, and 400°C.

[0018] Preferably, the calcination temperature of the second calcination can be selected from 550°C, 560°C, 570°C, 580°C, 590°C, and 600°C.

[0019] In actual production, amorphous ruthenium sulfide slag has a tendency to dissolve back, and after dissolution, it becomes ruthenium ions. Direct water washing / acid washing of impurities can easily cause ruthenium loss. Therefore, the present application again uses sulfide to sulfide the ruthenium-containing waste liquid to obtain a precipitate containing solid ruthenium sulfide.

[0020] Theoretically, when sulfide is added dropwise in step 1 to sulfidize the soluble ruthenium and soluble metals in the amorphous ruthenium sulfide slag to form ruthenium sulfide and other metal sulfide precipitates, since ammonium chloride is easily soluble in water, ammonium chloride should exist in the form of an aqueous solution, and the precipitate should not contain ammonium chloride. However, in the technical solution of the present invention, it is found that ammonium chloride crystals are still present in the precipitate obtained in step 1. It is speculated that the excessive amount of ammonium chloride causes the solution to be saturated and ammonium chloride crystals to precipitate and be adsorbed in the precipitate.

[0021] The calcination temperature of the first calcination in the present invention can effectively convert ammonium chloride into gaseous small molecules for volatilization, and this temperature will not decompose other substances in the precipitate, especially amorphous RuS, so that a highly efficient impurity removal effect can be achieved.

[0022] The second calcination can then decompose RuS in the precipitate into ruthenium element and gaseous sulfur, and decompose ruthenium hydroxide that may exist in the precipitate into ruthenium oxide.

[0023] The present invention utilizes the physical and chemical properties of RuS in the precipitate that it is soluble in acid and easily decomposes at high temperature, and completely calcines and decomposes RuS into elemental ruthenium and gaseous sulfur, thereby preventing ruthenium from being dissolved into the liquid phase in step 5, leaving all ruthenium metal in the solid phase, thereby improving the enrichment effect of ruthenium and avoiding the loss of ruthenium.

[0024] Furthermore, the specific operation of step 1 is: adding amorphous ruthenium sulfide slag to water, keeping warm and stirring at 40-50°C for 30-60 minutes, the mass ratio of the amorphous ruthenium sulfide slag to water is 1:5-10; then adding sulfide solution dropwise to a pH of 7-8, stirring the reaction for 60-90 minutes, and separating to obtain a precipitate; the sulfide solution is one of a sodium sulfide solution, an ammonium sulfide solution, and a zinc sulfide solution.

[0025] Preferably, as described in the technical solution of the present invention, the sulfide solution is preferably a sodium sulfide solution, wherein the content of sodium sulfide in the sodium sulfide solution is 5-10wt%.

[0026] Preferably, inert gas is continuously introduced during the calcination process of step 2 and step 3, and the flow rate of the inert gas is 2-5 L / min.

[0027] Furthermore, the pickling operation in step 4 is specifically as follows: adding 1-2 mol / L of acid to the secondary calcined slag, stirring and reacting for 60-70 minutes, and then separating to obtain filter residue; the mass ratio of the secondary calcined slag to the acid is 1:10.

[0028] Preferably, the acid used in step 4 is a dilute acid solution, preferably hydrochloric acid.

[0029] Furthermore, the hydrogen reduction operation in step 4 is specifically as follows: heating the filter residue to 470-500° C. in a hydrogen atmosphere and keeping the temperature for 1-2 hours to obtain ruthenium powder.

[0030] Furthermore, the precipitate obtained in step 1, the primary calcined slag obtained in step 2, the secondary calcined slag obtained in step 3, and the filter residue obtained after acid washing and separation are all dried at 90° C. and ground through a 100-mesh sieve.

[0031] Beneficial Effects

[0032] Compared with the prior art, the present invention provides a method for recovering ruthenium from amorphous ruthenium sulfide slag, which has the following advantages:

[0033] (1) further sulfiding the amorphous ruthenium sulfide slag to prevent other ruthenium from failing to precipitate and separate from the amorphous ruthenium sulfide slag;

[0034] (2) The ammonium chloride crystals attached to the precipitate are converted into gaseous small molecules and volatilized by the first calcination, and this temperature does not decompose other substances in the precipitate, especially amorphous RuS, so that a highly efficient impurity removal effect can be achieved;

[0035] (3) The second calcination can decompose RuS in the precipitate into ruthenium element and gaseous sulfur, and at the same time, decompose ruthenium hydroxide that may exist in the precipitate into ruthenium oxide;

[0036] (4) In the second calcination process, the RuS in the precipitate is soluble in acid and easily decomposed at high temperature, and the RuS is completely calcined and decomposed into elemental ruthenium and gaseous sulfur, thereby preventing the ruthenium from being dissolved into the liquid phase in step 5, and leaving all the ruthenium metal in the solid phase, thereby improving the enrichment effect of ruthenium and avoiding the loss of ruthenium;

[0037] (5) RuS is first decomposed by the second calcination, thereby avoiding the need to use too much hydrogen to reduce RuS in the subsequent hydrogen reduction treatment step 5, effectively saving energy and reducing the recovery cost of ruthenium. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present invention is further described below in conjunction with the accompanying drawings and embodiments;

[0039] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0040] The present invention will be further described below in conjunction with the embodiments, but it does not constitute any limitation to the present invention. Any limited number of modifications made within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0041] In order to explain the technical content of the present invention in detail, further description is given below in conjunction with the implementation modes.

[0042] In the following examples and comparative examples, the precipitate obtained in step 1, the primary calcined slag obtained in step 2, the secondary calcined slag obtained in step 3, and the filter residue obtained after acid washing and separation were dried at 90° C. and ground through a 100-mesh sieve.

[0043] In the following examples and comparative examples, the ruthenium content was measured by ICP-MS.

[0044] Example 1

[0045] like Figure 1 As shown, a method for recovering ruthenium from amorphous ruthenium sulfide slag comprises the following steps:

[0046] Step 1: Add 50 g of amorphous ruthenium sulfide slag containing 2.7 g of ruthenium into 250 ml of water, keep warm and stir at 45° C. for 30 min, then dropwise add a sodium sulfide solution with a sodium sulfide content of 5 wt% until the pH is 7.5, then stir and react for 60 min, and separate the solid and liquid to obtain a precipitate;

[0047] Step 2: The precipitate is placed in a nitrogen atmosphere and nitrogen is continuously introduced at a flow rate of 2 L / min, and the temperature is raised to 350° C. for a first calcination for 30 min to obtain a primary calcined slag;

[0048] Step 3: The primary calcined slag was heated to 550°C for a second calcination for 4 h under a nitrogen atmosphere and nitrogen was continuously introduced at a flow rate of 2 L / min to obtain 23.8 g of secondary calcined slag. The components of the secondary calcined slag were detected by XRD and contained Ru, RuO2, and RuS2;

[0049] Step 4: Add 238 ml of 1 mol / L hydrochloric acid to the secondary calcined slag, stir and react for 60 minutes, then separate the filter residue, heat the filter residue to 470°C in a hydrogen atmosphere and keep the temperature for 1 hour to obtain 3.1 g of ruthenium powder; the ruthenium content in the ruthenium powder is 85%, that is, the weight of the recovered ruthenium is 2.635 g.

[0050] Example 2

[0051] A method for recovering ruthenium from amorphous ruthenium sulfide slag comprises the following steps:

[0052] Step 1: Add 50 g of amorphous ruthenium sulfide slag containing 2.35 g of ruthenium into 250 ml of water, keep warm and stir at 45° C. for 30 min, then dropwise add a sodium sulfide solution with a sodium sulfide content of 5 wt% until the pH is 7.5, then stir and react for 60 min, and separate the solid and liquid to obtain a precipitate;

[0053] Step 2: The precipitate was placed in a nitrogen atmosphere and nitrogen was continuously introduced at a flow rate of 2 L / min, and the temperature was raised to 400° C. for a first calcination for 30 min to obtain a primary calcined slag;

[0054] Step 3: The primary calcined slag was heated to 600°C for a second calcination for 4 h under a nitrogen atmosphere while nitrogen was continuously introduced at a flow rate of 2 L / min to obtain 24.1 g of secondary calcined slag. The components of the secondary calcined slag were detected by XRD and found to contain Ru, RuO2, and RuS2;

[0055] Step 4: Add 241 ml of 1 mol / L hydrochloric acid to the secondary calcined slag, stir and react for 60 minutes, then separate the filter residue, heat the filter residue to 470°C in a hydrogen atmosphere and keep the temperature for 1 hour to obtain 2.6 g of ruthenium powder; the ruthenium content in the ruthenium powder is 88%, that is, the weight of the recovered ruthenium is 2.29 g.

[0056] Comparative Example 1

[0057] A method for recovering ruthenium from amorphous ruthenium sulfide slag comprises the following steps:

[0058] Step 1: Add 50 g of amorphous ruthenium sulfide slag containing 2.7 g of ruthenium into 250 ml of water, keep warm and stir at 45° C. for 30 min, then dropwise add a sodium sulfide solution with a sodium sulfide content of 5 wt% until the pH is 7.5, then stir and react for 60 min, and separate the solid and liquid to obtain a precipitate;

[0059] Step 2: The precipitate is placed in a nitrogen atmosphere and nitrogen is continuously introduced at a flow rate of 2 L / min, and the temperature is raised to 550°C for calcination for 4.5 hours to obtain 22.3 g of calcined slag. During this process, ammonium chloride volatilization occurred many times, blocking the tail gas outlet, causing desulfurization safety hazards, and multiple treatments were required. XRD detection showed that the components of the calcined slag contained Ru, RuS, RuO2, and RuS2.

[0060] Step 3: Add 223 ml of 1 mol / L hydrochloric acid to the calcined slag, stir and react for 60 minutes, then separate and obtain a filter residue, heat the filter residue to 470° C. in a hydrogen atmosphere and keep the temperature for 1 hour to obtain 3.37 g of ruthenium powder; the ruthenium content in the ruthenium powder is 77.4%, that is, the weight of the recovered ruthenium is 2.61 g.

[0061] Comparative Example 2

[0062] A method for recovering ruthenium from amorphous ruthenium sulfide slag comprises the following steps:

[0063] Step 1: Add 50 g of amorphous ruthenium sulfide slag containing 2.7 g of ruthenium into 250 ml of water, keep warm and stir at 45° C. for 30 min, then dropwise add a sodium sulfide solution with a sodium sulfide content of 5 wt% until the pH is 7.5, then stir and react for 60 min, and separate the solid and liquid to obtain a precipitate;

[0064] Step 2: The precipitate was heated to 350°C and calcined for 4.5 h under a nitrogen atmosphere at a flow rate of 2 L / min to obtain 33.6 g of calcined slag. The XRD detection showed that the calcined slag contained Ru, RuS, RuO2, and RuS2;

[0065] Step 3: Add 336 ml of 1 mol / L hydrochloric acid to the calcined slag, stir and react for 60 minutes, then separate and obtain a filter residue, heat the filter residue to 470° C. in a hydrogen atmosphere and keep the temperature for 1 hour to obtain 4.08 g of ruthenium powder; the ruthenium content in the ruthenium powder is 62%, that is, the weight of the recovered ruthenium is 2.53 g.

[0066] Comparative Example 3

[0067] Step 1: Grind 50 g of amorphous ruthenium sulfide slag containing 2.7 g of ruthenium through a 100-mesh sieve to obtain a powder;

[0068] Step 2: The powder is placed in a nitrogen atmosphere and nitrogen is continuously introduced at a flow rate of 2 L / min, and the temperature is raised to 350° C. for a first calcination for 30 min to obtain a primary calcined slag;

[0069] Step 3: The primary calcined slag was heated to 550°C for a second calcination for 4 h under a nitrogen atmosphere and nitrogen was continuously introduced at a flow rate of 2 L / min to obtain (23) g of secondary calcined slag. The components of the secondary calcined slag were detected by XRD and contained Ru, RuO2, and RuS2;

[0070] Step 4: Add 1 mol / L hydrochloric acid (230) ml to the secondary calcined slag, stir and react for 60 minutes, then separate to obtain a filter residue, the filtrate is tested by ICP-MS to find that the ruthenium content is 115 ppm, and ruthenium-containing waste liquid is produced and needs to be centrally treated; heat the filter residue to 470° C. in a hydrogen atmosphere and keep the temperature for 1 hour to obtain 2.9 g of ruthenium powder; the ruthenium content in the ruthenium powder is 69%, that is, the weight of the recovered ruthenium is 2.00 g.

[0071] According to the ruthenium powder data obtained in Example 1-2 and Comparative Example 1-2, the recovery rate of ruthenium was calculated, as shown in Table 1;

[0072] Table 1 Ruthenium recovery rate of Example 1-2 and Comparative Example 1-2

[0073] Ruthenium recovery rate Example 1 97.59％ Example 2 97.45％ Comparative Example 1 96.67％ Comparative Example 2 93.70％ Comparative Example 3 74.07％

[0074] According to the results in Table 1, we can see that:

[0075] According to the results of Example 1 and Example 2, the present invention can stably and efficiently recover ruthenium by combining further sulfidation of amorphous ruthenium sulfide slag with secondary calcination to remove impurities.

[0076] According to the comparison of the results of Example 1 and Comparative Example 1, if the temperature is directly increased in one step to remove the ammonium chloride and decompose RuS at high temperature, the following problems will occur:

[0077] (1) Due to the high temperature, the volatilization speed of ammonium chloride is accelerated, and a large amount of ammonium chloride gas crystallizes at the tail gas outlet during the discharge process with nitrogen, causing the tail gas outlet to be blocked. Safety hazards have occurred many times during the recovery process, and the blockage needs to be treated by cooling;

[0078] (2) Since a large amount of ammonium chloride gas evaporates quickly, the decomposition of RuS is affected, resulting in the presence of a small amount of RuS in the calcined slag after calcination. Therefore, more hydrogen is needed to reduce RuS to Ru in the subsequent hydrogen reduction process, which increases the cost.

[0079] According to the comparison of the results of Example 1 and Comparative Example 2, if the calcination temperature is insufficient, only the ammonium chloride will be removed, and a large amount of RuS will still exist in the calcined slag. Although the subsequent reduction step can reduce RuS, the reduction efficiency will still be greatly reduced, resulting in a significant decrease in the recovery rate of ruthenium.

[0080] According to the comparison of the results of Example 1 and Comparative Example 3, it can be seen that if the amorphous ruthenium sulfide slag is not subjected to a second sulfide sulfidation treatment, ruthenium loss will occur. The reason is that the amorphous ruthenium sulfide slag is re-dissolved to obtain ruthenium ions. Direct water washing / acid washing of impurities will cause ruthenium loss, resulting in a significant decrease in the recovery rate of ruthenium finally recovered in Comparative Example 3. Based on the results of Comparative Example 3, the present invention has another advantage. By adopting the technical solution of the present invention, due to the excellent ruthenium recovery rate, there is no output of ruthenium-containing waste liquid or ruthenium-containing waste slag, and there are no subsequent industrial problems.

[0081] The embodiments presented herein are only embodiments selected according to the combination of all possible embodiments. The appended claims should not be limited by the embodiments describing the present invention. Some numerical ranges used in the claims include sub-ranges therein, and the changes in these ranges should also be covered by the appended claims.

Claims

1. A method for recovering ruthenium from amorphous ruthenium sulfide slag, wherein the amorphous ruthenium sulfide slag contains ammonium chloride, characterized in that: The steps include: Step 1: adding amorphous ruthenium sulfide slag into water for washing and stirring, then adding sulfide dropwise to adjust the pH to 7-8, reacting and separating to obtain a precipitate; Step 2: heating the precipitate to 350-400° C. in an inert gas atmosphere to perform a first calcination to obtain a primary calcined slag; Step 3: heating the primary calcined slag to 550-600° C. in an inert gas atmosphere and performing a second calcination to obtain a secondary calcined slag; Step 4: sequentially subjecting the secondary calcined slag to acid washing and hydrogen reduction treatment to obtain ruthenium powder; The calcination time of step 2 is 30-40 minutes, and the calcination time of step 3 is 4-5 hours.

2. The method for recovering ruthenium from ruthenium-containing waste liquid according to claim 1, characterized in that: The specific operation of step 1 is: adding amorphous ruthenium sulfide slag into water, keeping warm and stirring for 30-60 minutes at 40-50°C, wherein the mass ratio of the amorphous ruthenium sulfide slag to water is 1:5-10; then adding a sulfide solution dropwise until the pH value is 7-8, stirring and reacting for 60-90 minutes, and separating to obtain a precipitate; the sulfide solution is one of a sodium sulfide solution, an ammonium sulfide solution, and a zinc sulfide solution.

3. The method for recovering ruthenium from ruthenium-containing waste liquid according to claim 2, characterized in that: The content of sodium sulfide in the sodium sulfide solution is 5-10wt%.

4. The method for recovering ruthenium from ruthenium-containing waste liquid according to claim 1, characterized in that: During the calcination process of step 3 and step 4, inert gas is continuously introduced, and the flow rate of the inert gas is 2-5 L / min.

5. The method for recovering ruthenium from ruthenium-containing waste liquid according to claim 1, characterized in that: The acid washing operation in step 5 is specifically as follows: adding 1-2 mol / L of acid to the secondary calcined slag, stirring and reacting for 60-70 minutes, and then separating to obtain filter residue; the mass ratio of the secondary calcined slag to the acid is 1:

10.

6. The method for recovering ruthenium from ruthenium-containing waste liquid according to claim 5, characterized in that: The hydrogen reduction operation in step 5 is specifically as follows: heating the filter residue to 470-500° C. in a hydrogen atmosphere and keeping the temperature for 1-2 hours to obtain ruthenium powder.

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