Method for separating and recovering iridium from waste titanium anode

Abstract

This invention discloses a method for separating and recovering iridium from waste titanium anodes, comprising the following steps: Immersing the waste titanium anode in an alkaline solution, heating to 650-750℃, and reacting at high temperature for 3-4 hours to separate the coating and titanium plate / mesh; drying the coating material, grinding it, and dispersing it in a primary pickling solution for a primary pickling to separate the base metal from the coating; wherein the primary pickling temperature is 70-85℃, and the pickling duration is 6-8 hours per cycle; dispersing the filter residue after the primary pickling in a secondary pickling solution for a secondary pickling, obtaining iridium salt as the filter residue; wherein the pickling temperature is 110-130℃, and the secondary pickling duration is 2-4 hours per cycle; drying the filter residue after the secondary pickling, and reducing it with hydrogen gas at 850-950℃ for 2-3 hours to obtain purified iridium powder. The method for separating and recovering iridium from waste titanium anodes provided by this invention effectively separates and recovers iridium while effectively reducing iridium loss, lowering equipment requirements, simplifying the process, and reducing investment costs.

Description

Technical Field

[0001] This invention relates to the field of precious metal recycling technology, specifically to a method for separating and recovering iridium from waste titanium anodes. Background Technology

[0002] In the copper foil industry, iridium and its compounds are primarily used as the main materials for copper foil titanium anodes. Waste anode plates (mesh) can be utilized as a highly valuable secondary resource of iridium.

[0003] Iridium is one of the rarest elements in the Earth's crust, with an average mass fraction of only 0.001 parts per million. The efficient and low-cost recovery of iridium from titanium anodes has significant commercial value.

[0004] Currently, the main method for iridium recovery is the wet process, which also requires the use of chlorine gas as an oxidant. The method mainly includes the following steps: first, the iridium-containing material is treated by induction melting; then, it undergoes processes such as alkali melting, acid leaching to form a solution, roasting, microwave treatment, reduction, and metal fragmentation; finally, it is purified by extraction and ion exchange. These methods require high-temperature processing, place high demands on equipment, involve complex subsequent processes, consume large amounts of chemical reagents, and result in high equipment investment.

[0005] How to effectively separate and recover iridium from waste titanium anode plates (mesh), while reducing iridium loss, lowering equipment requirements, simplifying processes, and reducing investment costs, has become an urgent problem to be solved. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for separating and recovering iridium from waste titanium anodes, which can effectively separate and recover iridium while effectively reducing iridium loss, lowering equipment requirements, simplifying the process, and reducing investment costs.

[0007] The technical solution of the present invention is as follows:

[0008] A method for separating and recovering iridium from waste titanium anodes includes the following steps:

[0009] Step S1: Immerse the waste titanium anode in an alkaline solution and heat to 650-750℃. React at high temperature for 3-4 hours to separate the coating and titanium plate / mesh. Repeat the water washing of the coating with ultrapure water. The heating temperature can be 650℃, 680℃, 700℃, 720℃ or 750℃, or other values ​​within this range. After high-temperature melting, use a brushing solution to clean the coating material.

[0010] Step S2 involves drying and grinding the coating material, then dispersing it in a primary pickling solution for primary pickling to separate base metals such as potassium, iron, copper, tin, bismuth, and lead from the coating. The primary pickling temperature is 70-85℃, the pickling duration is 6-8 hours per cycle, and the number of pickling cycles is 4-6. Specifically, the primary pickling temperature can be 70℃, 75℃, 80℃, or 85℃, or other values ​​within this range. The pickling time for each cycle can be 6 hours, 7 hours, or 8 hours, or other values ​​within this range.

[0011] Step S3: The filter residue after the first pickling is dispersed in a second pickling solution for a second pickling to separate titanium, lead, and tantalum. The obtained filter residue is iridium salt. The pickling temperature is 110-130℃, the second pickling duration is 2-4 hours per cycle, and the number of second pickling cycles is 2-3. Specifically, the second pickling temperature can be 110℃, 120℃, or 130℃, or other values ​​within this range. The pickling time for each cycle can be 2 hours, 3 hours, or 4 hours, or other values ​​within this range.

[0012] Step S4: Dry the filter residue after secondary acid washing, and reduce it with hydrogen gas at 850-950℃ for 2-3 hours to obtain purified iridium powder. The oxidation-reduction temperature can be 850℃, 880℃, 900℃, 920℃, or 950℃, or other temperatures within this range; the oxidation-reduction reaction time can be 2 hours, 2.5 hours, or 3 hours, or other values ​​within this range.

[0013] Furthermore, in step S1, the alkaline solution used to soak the titanium anode is 4 mol / L potassium hydroxide or sodium hydroxide.

[0014] Furthermore, in step S2, the first pickling solution is a mixture of nitric acid and hydrofluoric acid, wherein the mass concentration of nitric acid is 15-30% and the mass concentration of hydrofluoric acid is 2-4%.

[0015] Further, in step S2, the coating material is ground to 200 mesh.

[0016] Furthermore, in step S3, the secondary pickling solution is hydrofluoric acid with a mass concentration of 2-4%.

[0017] Furthermore, the redox reaction in step S4 is carried out in a tube furnace.

[0018] Furthermore, the primary pickling process in step S2 and the secondary pickling process in step S3 are carried out under stirring conditions.

[0019] Compared with existing technologies, the method for separating and recovering iridium from waste titanium anodes provided by this invention has the following advantages:

[0020] I. The method for separating and recovering iridium from waste titanium anodes provided by this invention utilizes the characteristic that metallic iridium is insoluble in acid at low temperatures for recovery. Compared with existing technologies for recovering precious metal iridium, it does not employ repeated roasting and leaching processes for purification, thus reducing the dispersion loss of precious metal iridium. At the same time, the equipment is less corrosive, has low investment costs, a short process, and a high iridium recovery rate, which can reach over 95.1%, and the purity of the obtained iridium powder can reach over 99.95%. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, and to make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be further described below.

[0022] It should be noted that the descriptions of these embodiments are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0023] Example 1

[0024] A method for separating and recovering iridium from waste titanium anodes includes the following steps:

[0025] Step S1: Take the waste titanium anode and immerse it in a 4 mol / L potassium hydroxide solution, heat it to 650℃, react it under high temperature conditions for 4 hours, and separate the coating and titanium plate / mesh. The coating is repeatedly washed with ultrapure water.

[0026] Step S2: After drying the coating material, grind it to 200 mesh and disperse it in a primary pickling solution for primary pickling to separate base metals such as potassium, iron, copper, tin, bismuth, and lead from the coating. The primary pickling solution is a 15wt% nitric acid + 2wt% hydrofluoric acid solution. The primary pickling temperature is 70℃, the pickling duration is 6-8 hours per pickling cycle, and the primary pickling cycle is repeated 6 times. The material is continuously stirred during the pickling process.

[0027] Step S3: The filter residue after the first pickling is dispersed in the second pickling solution for a second pickling to separate titanium, lead and tantalum. The obtained filter residue is iridium salt. The second pickling solution is a 4 wt% hydrofluoric acid solution, the pickling temperature is 110℃, the second pickling duration is 2h / time, the second pickling is repeated 2 times, and the mixture is continuously stirred during the pickling process.

[0028] Step S4: Dry the filter residue after secondary acid washing, place it in a tube furnace, and reduce it with hydrogen at 900°C for 2 hours to obtain purified iridium powder.

[0029] Testing revealed an iridium recovery rate of 95.10% and an iridium powder purity of 99.95%.

[0030] In this embodiment, taking 200g of iridium slag as an example, the first acid washing requires 400ml of nitric acid and 100ml of hydrofluoric acid; the second acid washing requires approximately 150ml of hydrofluoric acid; totaling 400ml of nitric acid and 250ml of hydrofluoric acid. Traditional methods require acid washing, crushing and melting, dissolving in aqua regia, removing nitrates, precipitating iridium, and reduction, generally requiring approximately 300ml of hydrochloric acid, 400ml of nitric acid, and 160ml of hydrofluoric acid. Compared to traditional methods, the recovery process of this invention significantly reduces reagent usage. Note: All reagents mentioned above are of analytical grade.

[0031] Example 2

[0032] A method for separating and recovering iridium from waste titanium anodes includes the following steps:

[0033] Step S1: Take the waste titanium anode and immerse it in a 4 mol / L potassium hydroxide solution, heat it to 750℃, react it under high temperature conditions for 3 hours, and separate the coating and titanium plate / mesh. The coating is repeatedly washed with ultrapure water.

[0034] Step S2: After drying the coating material, grind it to 200 mesh and disperse it in a primary pickling solution for primary pickling to separate the base metal in the coating; wherein the primary pickling solution is a 15wt% nitric acid + 4wt% hydrofluoric acid solution, the primary pickling temperature is 85℃, the pickling duration is 6h / time, the primary pickling is repeated 6 times, and the mixture is continuously stirred during the pickling process.

[0035] Step S3: Disperse the filter residue after the first pickling in the second pickling solution for a second pickling, and the obtained filter residue is iridium salt; wherein the second pickling solution is a 4 wt% hydrofluoric acid solution, the pickling temperature is 110℃, the second pickling duration is 2h / time, the second pickling is repeated 2 times, and the mixture is continuously stirred during the pickling process.

[0036] Step S4: Dry the filter residue after secondary acid washing, place it in a tube furnace, and reduce it with hydrogen at 900°C for 2 hours to obtain purified iridium powder.

[0037] Testing revealed an iridium recovery rate of 95.12% and an iridium powder purity of 99.96%.

[0038] Example 3

[0039] A method for separating and recovering iridium from waste titanium anodes includes the following steps:

[0040] Step S1: Take the waste titanium anode and immerse it in a 4 mol / L sodium hydroxide solution, heat it to 700℃, react it under high temperature conditions for 3 hours, separate the coating and titanium plate / mesh, and repeatedly wash the coating with ultrapure water.

[0041] Step S2: After drying the coating material, grind it to 200 mesh and disperse it in a primary pickling solution for primary pickling to separate the base metal in the coating; wherein the primary pickling solution is a 30wt% nitric acid + 2wt% hydrofluoric acid solution, the primary pickling temperature is 85℃, the pickling duration is 6h / time, the primary pickling is repeated 5 times, and the mixture is continuously stirred during the pickling process.

[0042] Step S3: Disperse the filter residue after the first pickling in the second pickling solution for a second pickling, and the obtained filter residue is iridium salt; wherein the second pickling solution is a 4 wt% hydrofluoric acid solution, the pickling temperature is 110℃, the second pickling duration is 2h / time, the second pickling is repeated 2 times, and the mixture is continuously stirred during the pickling process.

[0043] Step S4: Dry the filter residue after secondary acid washing, place it in a tube furnace, and reduce it with hydrogen at 900°C for 2 hours to obtain purified iridium powder.

[0044] Testing revealed an iridium recovery rate of 95.2% and an iridium powder purity of 99.95%.

[0045] Example 4

[0046] A method for separating and recovering iridium from waste titanium anodes includes the following steps:

[0047] Step S1: Take the waste titanium anode and immerse it in a 4 mol / L sodium hydroxide solution, heat it to 680℃, react it under high temperature conditions for 4 hours, and separate the coating and titanium plate / mesh. The coating is repeatedly washed with ultrapure water.

[0048] Step S2: After drying the coating material, grind it to 200 mesh and disperse it in a primary pickling solution for primary pickling to separate the base metal in the coating; wherein the primary pickling solution is a 30wt% nitric acid + 4wt% hydrofluoric acid solution, the primary pickling temperature is 85℃, the pickling duration is 6h / time, the primary pickling is 4 times, and the mixture is continuously stirred during the pickling process.

[0049] Step S3: Disperse the filter residue after the first pickling in the second pickling solution for a second pickling, and the obtained filter residue is iridium salt; wherein the second pickling solution is a 4 wt% hydrofluoric acid solution, the pickling temperature is 130℃, the second pickling duration is 2h / time, the second pickling is repeated 2 times, and the mixture is continuously stirred during the pickling process.

[0050] Step S4: Dry the filter residue after secondary acid washing, place it in a tube furnace, and reduce it with hydrogen at 900°C for 2 hours to obtain purified iridium powder.

[0051] Testing revealed an iridium recovery rate of 95.32% and an iridium powder purity of 99.97%.

[0052] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and spirit of the present invention still fall within the protection scope of the present invention.

Claims

1. A method for separating and recovering iridium from waste titanium anodes, characterized in that, Includes the following steps: Step S1: Take the waste titanium anode and immerse it in an alkaline solution, heat it to 650-750℃, react it under high temperature conditions for 3-4 hours, separate the coating and titanium plate / mesh, and repeatedly wash the coating with ultrapure water. Step S2: After drying the coating material, grind it and disperse it in a primary pickling solution for primary pickling to separate the base metals from the coating; the primary pickling temperature is 70-85℃, the pickling duration is 6-8 hours / time, and the primary pickling is repeated 4-6 times; the primary pickling solution is a mixture of nitric acid and hydrofluoric acid, wherein the mass concentration of nitric acid is 15-30% and the mass concentration of hydrofluoric acid is 2-4%; Step S3: The filter residue after the first pickling is dispersed in a second pickling solution for a second pickling, and the obtained filter residue is iridium salt; wherein the pickling temperature is 110-130℃, the second pickling duration is 2-4 hours / time, and the second pickling is repeated 2-3 times; the second pickling solution is hydrofluoric acid with a mass concentration of 2-4%; Step S4: Dry the filter residue after secondary acid washing, and reduce it with hydrogen at 850-950 ℃ for 2-3 hours to obtain purified iridium powder.

2. The method for separating and recovering iridium from waste titanium anodes according to claim 1, characterized in that, In step S1, the alkaline solution used to soak the titanium anode is 4 mol / L potassium hydroxide or sodium hydroxide.

3. The method for separating and recovering iridium from waste titanium anodes according to claim 1, characterized in that, In step S2, the coating material is ground to 200 mesh.

4. The method for separating and recovering iridium from waste titanium anodes according to claim 1, characterized in that, The redox reaction in step S4 is carried out in a tube furnace.

5. The method for separating and recovering iridium from waste titanium anodes according to any one of claims 1-4, characterized in that, The primary pickling process in step S2 and the secondary pickling process in step S3 are carried out under stirring conditions.