Method for synergistically and co-extracting platinum and iridium by using composite extracting agent

Abstract

The invention belongs to the technical field of synergistic extraction, and particularly relates to a method for synergistically and co-extracting platinum and iridium by using a composite extracting agent. According to the method, an amino-containing extraction agent and a phosphorus-containing extraction agent are innovatively compounded to obtain the synergistic extraction agent, and the volume ratio of the amino-containing extraction agent in an organic phase is controlled to be 1-62%, and the volume ratio of the phosphorus-containing extraction agent in the organic phase is controlled to be 1-62%. According to the method, two extractants are used for extracting platinum and iridium, so that the two extractants play a synergistic role to the greatest extent, then the synergistic extractant is used for extracting a solution containing platinum and iridium, finally, the platinum and the iridium are separated from the extractants through reverse extraction, and finally a mixture only containing a platinum compound and an iridium compound is obtained. The platinum and the iridium in the mixture can be subsequently separated according to needs. By adopting the method disclosed by the invention, platinum and iridium can be effectively recovered from a mixture of various substances, and the recovery rate of platinum and iridium is greater than 99.5%.

Description

Technical Field

[0001] The invention belongs to the technical field of synergistic extraction, and in particular relates to a method for synergistically extracting platinum and iridium by using a composite extractant. Background Art

[0002] Platinum group metals and their compounds are widely used in the production of industrial catalysts due to their unique electronic structure and are valued by all walks of life. High-purity precious metal iridium has a high melting point and density, and has the characteristics of good high-temperature mechanical properties, catalytic activity, stable chemical properties, and strong corrosion resistance. Therefore, it has extremely important uses in aerospace, catalysts, military, weapons, high-energy physics and other fields. However, iridium reserves are scarce and expensive. Recycling iridium from secondary resources can achieve resource recycling and alleviate the contradiction between supply and demand. Metal platinum is widely used in catalysts, sensors, anti-cancer drugs, petroleum refining, electronic equipment manufacturing and other fields. For example, it is used in the production of computer hard drives to increase the storage capacity of multilayer ceramic capacitors and hybrid integrated circuits; to produce glass for the manufacture of liquid crystal displays; and as a tooth restoration material.

[0003] The traditional precipitation-based platinum group metal extraction process is lengthy, with low yield, high cost and complicated operation. Since the solvent extraction process has shown its superiority, the use of this method to extract and purify platinum group metals has attracted great attention. The solvent extraction process has the advantages of simplified process, good separation effect, high yield of precious metals, greater applicability and flexibility to various materials, large processing capacity, and easy automation. It is recognized by domestic and foreign scholars as a high-tech for separating and extracting platinum group metals.

[0004] In a solvent extraction system, if there are two or more extractants or extraction solvents, it is called a binary or multi-component extraction system. In a binary or multi-component extraction system, when the distribution ratio of the metal ion is D 协 Significantly greater than the sum of the distribution ratios of each extractant when used alone under the same experimental conditions D 加和 When the extraction rate of the system with synergistic effect is significantly improved, it is called a synergistic extraction system.

[0005] There are few patent studies on the synergistic extraction system of co-extracting platinum and iridium. Invention CN114438321A discloses a method of heating a platinum-iridium-containing liquid, adding an oxidant, controlling the oxidation potential, and controlling the acidity of the liquid [H +], let stand; step 2, mix the feed liquid after the reaction in step 1 with the composite extractant, extract; step 3, wash the organic phase loaded after extraction in step 2 with acid, then use an acidic stripping agent containing a reducing agent to strip iridium, and an alkaline stripping agent to strip platinum, respectively, to obtain iridium stripping solution and platinum stripping solution; step 4, the iridium stripping solution and the platinum stripping solution are concentrated, acidified, oxidized and precipitated, and hydrogen reduced to obtain iridium and platinum, respectively. This patent requires the use of controlled potential oxidation to oxidize the feed liquid, and the feed liquid needs to be heated, which is not only costly, but also has a cumbersome process. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention provides a method for synergistically extracting platinum and iridium using a composite extractant, and the present invention specifically includes the following contents:

[0007] A method for co-extracting platinum and iridium using a composite extractant comprises the following steps:

[0008] S1, preparing an organic phase: mixing an amine-containing extractant, a phosphorus-containing extractant, a modifier and a diluent to obtain an organic phase, wherein the volume proportion of the amine-containing extractant, the volume proportion of the phosphorus-containing extractant, the volume proportion of the modifier, and the volume proportion of the diluent in the organic phase are controlled to be 1-62%, 1-62%, 2-8%, and 35-85% respectively;

[0009] S2, adjusting the acidity of the aqueous phase containing platinum and iridium so that the concentration of H+ therein is within the range of 3-5 mol / L;

[0010] S3, mixed extraction: the organic phase and the aqueous phase are mixed in a ratio of 1:(1-10), and extraction is performed to obtain an organic phase containing platinum and iridium after the extraction is completed;

[0011] S4, stripping: stripping the organic phase containing platinum and iridium using an alkaline stripping solution having a mass concentration of 6-12% to obtain a stripping solution;

[0012] S5, post-treating the stripping solution to obtain a platinum- and iridium-containing compound.

[0013] Furthermore, the amine-containing extractant in step S1 is one or more of N235, TOA, N263, and N1633; and / or the phosphorus-containing extractant is one or more of TBP, TOPO, TRPO, and TAPO.

[0014] Furthermore, in step S1, the modifier is isooctyl alcohol; and / or the diluent is n-dodecane.

[0015] Furthermore, in the aqueous phase containing platinum and iridium in step S2, the concentration of platinum is 2-10 g / L, and the concentration of iridium is 0.08-17.05 g / L.

[0016] Furthermore, the acidic solution used in step S2 to adjust the acidity of the aqueous phase containing platinum and iridium is one or more of sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid.

[0017] Furthermore, the alkaline stripping solution in step S4 is one of Na2CO3 and NaOH or a mixture of the two.

[0018] Furthermore, the post-treatment in step S5 includes: concentrating the stripping solution, then adding ammonium chloride to carry out precipitation reaction to obtain a mixture of ammonium chloroiridate and ammonium chloroplatinate, and finally separating platinum and iridium by the method in the prior art.

[0019] Furthermore, the recovery rates of platinum and iridium are greater than 99.5%.

[0020] Beneficial effects of the present invention:

[0021] The method disclosed in the present invention for synergistically extracting platinum and iridium with a composite extractant innovatively compounds an amine-containing extractant and a phosphorus-containing extractant to obtain a synergistic extractant, and controls the volume proportion of the amine-containing extractant in the organic phase to be 1-62%, and the volume proportion of the phosphorus-containing extractant to be 1-62%. The present invention maximizes the synergistic effect of the two extractants by designing the composition and content of the synergistic extractant, and then uses the synergistic extractant of the present invention to extract a solution containing platinum and iridium, and finally separates platinum and iridium from the extractant by back extraction, and finally obtains a mixture containing only platinum compounds and iridium compounds, and the platinum and iridium in the mixture can be separated later as needed. The method disclosed in the present invention can effectively recover platinum and iridium from a mixture of multiple substances, and the recovery rate of platinum and iridium is greater than 99.5%. DETAILED DESCRIPTION

[0022] The present invention is described in detail below in conjunction with specific embodiments. The embodiments shown below do not limit the invention content described in the claims. In addition, the entire contents of the structures represented by the following embodiments are not limited to those necessary as solutions to the invention described in the claims.

[0023] A method for co-extracting platinum and iridium using a composite extractant comprises the following steps:

[0024] S1, preparing an organic phase: mixing an amine-containing extractant, a phosphorus-containing extractant, a modifier and a diluent to obtain an organic phase, wherein the volume proportion of the amine-containing extractant, the volume proportion of the phosphorus-containing extractant, the volume proportion of the modifier, and the volume proportion of the diluent in the organic phase are controlled to be 1-62%, 1-62%, 2-8%, and 35-85%; the amine-containing extractant is one or more of N235, TOA, N263, and N1633; the phosphorus-containing extractant is one or more of TBP, TOPO, TRPO, and TAPO; the modifier is isooctyl alcohol; and the diluent is n-dodecane;

[0025] S2, add one or more of sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid to the aqueous phase containing platinum and iridium to adjust the acidity of the aqueous phase so that H + The concentration is in the range of 3-5 mol / L; in the aqueous phase containing platinum and iridium, the concentration of platinum is 2-10 g / L and the concentration of iridium is 0.08-17.05 g / L;

[0026] S3, mixed extraction: the organic phase and the aqueous phase are mixed in a ratio of 1:(1-10), and extraction is performed to obtain an organic phase containing platinum and iridium after the extraction is completed;

[0027] S4, stripping: using an alkaline stripping solution with a mass concentration of 6-12% to strip the organic phase containing platinum and iridium to obtain a stripping solution; the alkaline stripping solution is Na 2 CO 3 , NaOH or a mixture of the two;

[0028] S5, concentrating the stripping solution, then adding ammonium chloride to carry out precipitation reaction to obtain a mixture of ammonium chloroiridate and ammonium chloroplatinate, and finally separating platinum and iridium by the method in the prior art.

[0029] By adopting the method of the present invention, the recovery rate of platinum and iridium is greater than 99.5%.

[0030] Example 1

[0031] A method for co-extracting platinum and iridium using a composite extractant comprises the following steps:

[0032] S1, measure 10% by volume of extractant N235, 30% by volume of extractant TBP, 5% by volume of modifier isooctyl alcohol, and 55% by volume of n-dodecane for later use.

[0033] S2, prepare the raw material to be extracted with an aqueous phase acidity of 3 mol, a platinum concentration of 2 g / L, and an iridium concentration of 0.08 g / L.

[0034] S3, add the organic phase feed liquid and the aqueous phase feed liquid into a separatory funnel in a ratio of 1:1, shake, and let stand for 30 seconds to 5 minutes before separation.

[0035] S4, the organic phase after separation is back-extracted with 6% NaOH.

[0036] S5, collecting the stripping solution, concentrating it by rotary evaporation, and precipitating it with ammonium chloride to obtain ammonium chloroiridate and ammonium chloroplatinate, which are then separated and refined by chemical methods. Using the method described in this embodiment, the recovery rate of platinum and iridium is 99.7%.

[0037] Example 2

[0038] S1, measure 20% by volume of extractant N235, 40% by volume of extractant TBP, 5% by volume of modifier isooctyl alcohol, and 35% by volume of n-dodecane for later use.

[0039] S2, prepare the raw material to be extracted with an aqueous phase acidity of 4 mol, a platinum concentration of 5 g / L, and an iridium concentration of 9.2 g / L.

[0040] S3, add the organic phase liquid and the aqueous phase liquid into a separatory funnel in a ratio of 1:2, shake, and let stand for 30s-5min before separating.

[0041] S4, the organic phase after separation is back-extracted with 10% NaOH.

[0042] S5, collecting the stripping solution, concentrating it by rotary evaporation, and precipitating it with ammonium chloride to obtain ammonium chloroiridate and ammonium chloroplatinate, which are then separated and refined by chemical methods. Using the method described in this embodiment, the recovery rate of platinum and iridium is 99.6%.

[0043] Example 3

[0044] A method for co-extracting platinum and iridium using a composite extractant comprises the following steps:

[0045] S1, measure 30% by volume of extractant N235, 50% by volume of extractant TBP, 5% by volume of modifier isooctyl alcohol, and 15% by volume of n-dodecane for later use.

[0046] S2, prepare the raw material to be extracted with an aqueous phase acidity of 5 mol, a platinum concentration of 10 g / L, and an iridium concentration of 17.05 g / L.

[0047] S3, add the organic phase feed liquid and the aqueous phase feed liquid into a separatory funnel at a ratio of 1:5, shake, and let stand for 30s-5min before separating.

[0048] S4, the organic phase after separation is back-extracted with 12% NaOH.

[0049] S6, collecting the stripping solution, concentrating it by rotary evaporation, and precipitating it with ammonium chloride to obtain ammonium chloroiridate and ammonium chloroplatinate, which are then separated and refined by chemical methods. Using the method described in this embodiment, the recovery rate of platinum and iridium is 99.8%.

[0050] Example 4

[0051] A method for co-extracting platinum and iridium using a composite extractant comprises the following steps:

[0052] S1, preparing an organic phase: mixing a TOA extractant, a TRPO extractant, an isooctyl alcohol modifier and a n-dodecane diluent to obtain an organic phase, wherein the volume proportion of the amine-containing extractant, the volume proportion of the phosphorus-containing extractant, the volume proportion of the modifier, and the volume proportion of the diluent in the organic phase are controlled to be 5%, 55%, 5%, and 35% respectively;

[0053] S2, add sulfuric acid to the aqueous phase containing platinum and iridium to adjust the acidity of the aqueous phase so that H + The concentration is within the range of 3 mol / L; in the aqueous phase containing platinum and iridium, the concentration of platinum is 2 g / L and the concentration of iridium is 17.05 g / L;

[0054] S3, mixed extraction: the organic phase and the aqueous phase are mixed in a ratio of 1:2, and extraction is performed to obtain an organic phase containing platinum and iridium after the extraction is completed;

[0055] S4, stripping: using an alkaline stripping solution with a mass concentration of 6% to strip the organic phase containing platinum and iridium to obtain a stripping solution; the alkaline stripping solution is Na 2 CO 3 , a mixture of NaOH;

[0056] S5, the stripping solution is concentrated, and then ammonium chloride is added to perform precipitation reaction to obtain a mixture of ammonium chloroiridate and ammonium chloroplatinate, and finally platinum and iridium are separated by the method in the prior art. Using the method described in this embodiment, the recovery rate of platinum and iridium is 99.6%.

[0057] Example 5

[0058] A method for co-extracting platinum and iridium using a composite extractant comprises the following steps:

[0059] S1, preparing an organic phase: mixing N1633 extractant, TAPO extractant, isooctyl alcohol modifier and n-dodecane diluent to obtain an organic phase, wherein the volume proportion of the amine-containing extractant, the volume proportion of the phosphorus-containing extractant, the volume proportion of the modifier, and the volume proportion of the diluent in the organic phase is controlled to be 8%, 22%, 6%, and 64% respectively;

[0060] S2, add nitric acid to the aqueous phase containing platinum and iridium to adjust the acidity of the aqueous phase so that H +The concentration is within the range of 5 mol / L; in the aqueous phase containing platinum and iridium, the concentration of platinum is 10 g / L and the concentration of iridium is 0.085 g / L;

[0061] S3, mixed extraction: the organic phase and the aqueous phase are mixed in a ratio of 1:10, and extraction is performed to obtain an organic phase containing platinum and iridium after the extraction is completed;

[0062] S4, stripping: using an alkaline stripping solution with a mass concentration of 12% to strip the organic phase containing platinum and iridium to obtain a stripping solution; the alkaline stripping solution is a NaOH solution;

[0063] S5, the stripping solution is concentrated, and then ammonium chloride is added to perform precipitation reaction to obtain a mixture of ammonium chloroiridate and ammonium chloroplatinate, and finally platinum and iridium are separated by the method in the prior art. Using the method described in this embodiment, the recovery rate of platinum and iridium is 99.8%.

[0064] Example 6

[0065] A method for co-extracting platinum and iridium using a composite extractant comprises the following steps:

[0066] S1, preparing an organic phase: mixing an N235 extractant, a TBP extractant, an isooctyl alcohol modifier and an n-dodecane diluent to obtain an organic phase, wherein the volume proportion of the amine-containing extractant, the volume proportion of the phosphorus-containing extractant, the volume proportion of the modifier, and the volume proportion of the diluent in the organic phase are controlled to be 22%, 8%, 5%, and 65% respectively;

[0067] S2, add phosphoric acid to the aqueous phase containing platinum and iridium to adjust the acidity of the aqueous phase so that H + The concentration is within the range of 4 mol / L; in the aqueous phase containing platinum and iridium, the concentration of platinum is 80 g / L and the concentration of iridium is 10 / L;

[0068] S3, mixed extraction: the organic phase and the aqueous phase are mixed in a ratio of 1:7, and extraction is performed to obtain an organic phase containing platinum and iridium after the extraction is completed;

[0069] S4, stripping: using an alkaline stripping solution with a mass concentration of 10% to strip the organic phase containing platinum and iridium to obtain a stripping solution; the alkaline stripping solution is a sodium hydroxide solution;

[0070] S5, the stripping solution is concentrated, and then ammonium chloride is added to perform precipitation reaction to obtain a mixture of ammonium chloroiridate and ammonium chloroplatinate, and finally platinum and iridium are separated by the method in the prior art. Using the method described in this embodiment, the recovery rate of platinum and iridium is 99.9%.

[0071] Comparative Example 1

[0072] The difference between this comparative example and Example 6 is that the N235 extractant accounts for 30% in the organic phase, no TBP extractant is added, and other conditions are the same. The recovery rate of platinum and iridium in this comparative example is 89.4%.

[0073] Comparative Example 2

[0074] The difference between this comparative example and Example 6 is that the proportion of TBP extractant in the organic phase is 30%, no N235 extractant is added, and other conditions are the same. The recovery rate of platinum and iridium in this comparative example is 91.8%.

[0075] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for co-extracting platinum and iridium using a composite extractant, characterized in that: The following steps are involved: S1, preparing an organic phase: mixing an amine-containing extractant, a phosphorus-containing extractant, a modifier and a diluent to obtain an organic phase, wherein the volume proportion of the amine-containing extractant, the volume proportion of the phosphorus-containing extractant, the volume proportion of the modifier, and the volume proportion of the diluent in the organic phase are controlled to be 1-62%, 1-62%, 2-8%, and 35-85% respectively; S2, adjust the acidity of the aqueous phase containing platinum and iridium so that H + The concentration is in the range of 3-5 mol / L; S3, mixed extraction: the organic phase and the aqueous phase are mixed in a ratio of 1:(1-10), and extraction is performed to obtain an organic phase containing platinum and iridium after the extraction is completed; S4, stripping: stripping the organic phase containing platinum and iridium using an alkaline stripping solution having a mass concentration of 6-12% to obtain a stripping solution; S5, post-treating the stripping solution to obtain a platinum- and iridium-containing compound.

2. The method for co-extracting platinum and iridium with a composite extractant according to claim 1, characterized in that: In step S1, the amine-containing extractant is one or more of N235, TOA, N263, and N1633; and / or the phosphorus-containing extractant is one or more of TBP, TOPO, TRPO, and TAPO.

3. The method for co-extracting platinum and iridium with a composite extractant according to claim 1, characterized in that: In step S1, the modifying agent is isooctyl alcohol; and / or the diluent is n-dodecane.

4. The method for co-extracting platinum and iridium with a composite extractant according to claim 1, characterized in that: In the aqueous phase containing platinum and iridium in step S2, the concentration of platinum is 2-10 g / L, and the concentration of iridium is 0.08-17.05 g / L.

5. The method for co-extracting platinum and iridium with a composite extractant according to claim 1, characterized in that: The acidic solution used in step S2 to adjust the acidity of the aqueous phase containing platinum and iridium is one or more of sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid.

6. The method for co-extracting platinum and iridium with a composite extractant according to claim 1, characterized in that: The alkaline stripping solution in step S4 is one of Na2CO3 and NaOH or a mixture of the two.

7. The method for co-extracting platinum and iridium with a composite extractant according to claim 1, characterized in that: The post-treatment in step S5 includes: concentrating the stripping solution, and then adding ammonium chloride to perform a precipitation reaction to obtain a mixture of ammonium chloroiridate and ammonium chloroplatinate.

8. The method for co-extracting platinum and iridium with a composite extractant according to any one of claims 1 to 7, characterized in that: The recovery rates of platinum and iridium are >99.5%.