Method for determining trace gold, palladium and platinum in carbonylation copper-nickel alloy leaching solution

Abstract

The invention discloses a method for measuring trace gold, palladium and platinum in carbonylation copper-nickel alloy leachate, which comprises the following steps of: enriching trace precious metal elements in the carbonylation alloy leachate by utilizing the principle that gold, palladium and platinum and tellurium form coprecipitation, leaving a large amount of matrixes such as nickel, copper and the like in the solution, filtering and washing the precipitate so as to separate the precipitate from a large amount of copper-nickel matrixes, and measuring the content of gold, palladium and platinum in the carbonylation copper-nickel alloy leachate. According to the method, the influence of a matrix effect generated by a high-copper-nickel matrix on an analysis result is solved, trace precious metal elements can be enriched from the nickel-copper matrix which is more than about 200g / L, the detection conditions of ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry) are met, the accurate analysis of Au, Pd and Pt in the carbonylation alloy leachate is realized, the requirements of production on the accuracy and stability of the analysis result are met, and the method is suitable for industrial production. Therefore, operation parameters can be adjusted in time, and loss of precious metal elements is avoided.

Description

Technical Field

[0001] The invention belongs to the field of chemical analysis, and in particular relates to a method for determining trace amounts of gold, palladium and platinum in a carbonylation copper-nickel alloy leaching solution. Background Art

[0002] Carbonyl copper-nickel alloy is a product of the smelting process of nickel sulfide ore, which is enriched with a large number of precious metal elements and is an important source of raw materials for the development of the precious metal industry. In the process of precious metal smelting, the precious metals in the carbonyl copper-nickel alloy are enriched in the slag through chlorination leaching, and a large number of non-precious metal elements such as nickel and copper separated are enriched in the leachate. As an important material for monitoring the loss of precious metals, the leachate has high requirements for the accuracy of precious metal detection and analysis. The matrix composition is complex, the nickel and copper content is high (>200g / L), and the content of precious metal elements Au, Pd, and Pt are all below 0.00Xg / L or even 0.000Xg / L. The content of the matrix differs from the concentration of the precious metal elements to be measured by more than 10 million times, making the various interference factors such as spectrum, specific gravity, and atomization efficiency of the ICP spectrometer analysis and detection process complex, and the matrix effect is obvious, resulting in the accuracy of the analysis results cannot be controlled. Therefore, it is urgent to study a new detection method to eliminate the influence of high nickel and copper matrix effect on the determination of precious metal content. Summary of the invention

[0003] The purpose of the present invention is to solve the above technical problems existing in the existing analytical technology and to provide a method for separating the matrix and accurately determining the trace amount of gold, palladium and platinum in the carbonylation copper-nickel alloy leachate.

[0004] To achieve the above object, the present invention adopts the following technical solution: A method for determining trace amounts of gold, palladium and platinum in a carbonyl copper-nickel alloy leachate, characterized in that it comprises the following steps: (1) Sample pretreatment 50 mL of carbonyl copper-nickel alloy leachate was transferred into a glass container, and 50 mL of hydrochloric acid and 5 mL of hydrogen peroxide were added in sequence, and the container was heated and evaporated to dryness on a hot plate; 50 mL of hydrochloric acid was added to the evaporated product, and the inner wall of the container was washed with water, and then heated and evaporated again; (2) Coprecipitation Continue to add 100 mL of hydrochloric acid and 200 mL of water into the glass container in step (1), place it on a hot plate and heat it to a slight boil, add 1 mL of tellurium solution, heat it again to a slight boil, add stannous chloride solution until precipitation is complete, continue heating until the precipitation condenses, add 1 mol / L stannous chloride solution, and observe whether there is precipitation. If precipitation is generated, continue to add stannous chloride solution until no precipitation is generated and the excess is 2 mL. If no precipitation is generated, add 2 ml of stannous chloride solution. Finally, keep it at a slight boil for 30-40 minutes; (3) Filtering The precipitate produced in step (2) was removed and filtered using a 0.45 μm filter membrane on a sand core filter device. The glass container and the precipitate were washed with (1+9) hydrochloric acid and water for 5 times each, and the precipitate was transferred to a glass container; (4) Fixed volume Add 10 mL of aqua regia to a glass container to dissolve the precipitate, and evaporate it on a hot plate until it is 2-3 mL. Add 10 mL of hydrochloric acid and 1 mL of hydrogen peroxide, heat and boil until it is dissolved and clear, transfer to a 50 mL volumetric flask, and dilute to volume with water to obtain the sample solution to be tested; (5) Drawing of working curve A series of mixed standard solutions of Au, Pd and Pt in a (1+9) hydrochloric acid medium are prepared, and the series of mixed standard solutions are measured in sequence on an ICP-AES according to set working conditions, and a working curve is drawn with the concentration of gold, palladium and platinum as the abscissa and the absorbance intensity as the ordinate; (6) Sample measurement The sample solution prepared in step (4) is measured on ICP-AES using the same working conditions as in step (5), and then the content of gold, palladium and platinum in the sample solution can be calculated based on the working curve drawn in step (5).

[0005] As a further preferred embodiment of the technical solution of the present invention, in step (1), the composition and content of the carbonyl copper-nickel alloy leaching solution are Ni: 20-130 g / L, Cu: 20-180 g / L, Au<0.1 g / L, Pd<0.1 g / L, Pt<0.1 g / L.

[0006] Furthermore, in step (2), the concentration of the tellurium solution is 2.5 g / L.

[0007] Furthermore, in step (2), the concentration of the stannous chloride solution is 200 g / L.

[0008] Furthermore, in step (3), the washing times of hydrochloric acid and water are both 5 times.

[0009] Furthermore, in step (5), the concentrations of the series of mixed standard solutions are 0.00 mg / L, 0.10 mg / L, 0.50 mg / L, 1.00 mg / L, and 5.00 mg / L, respectively.

[0010] Furthermore, in step (5), the ICP-AES working conditions are shown in the following table.

[0011] By adopting the above technical solution, the beneficial effects of the present invention are: The present invention forms a co-precipitation of trace gold, palladium, platinum and tellurium in a carbonylation copper-nickel alloy leachate, nickel and copper still exist in the solution, and the precipitate is separated from a large amount of copper-nickel matrix through filtration and washing, thereby eliminating matrix interference generated by nickel and copper in an ICP-AES measurement process, and the precipitate generated by gold, palladium, platinum and tellurium is redissolved in aqua regia, and gold, palladium, and platinum can be accurately measured on ICP-AES, thereby truly reflecting the concentration of precious metal elements in the leachate, timely adjusting operating parameters, and preventing the loss of precious metal elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a process flow chart of the present invention; Figure 2-Figure 4 This is the working curve of the method of the present invention. DETAILED DESCRIPTION

[0013] The method of the present invention is described in detail below in conjunction with specific embodiments through the accompanying drawings.

[0014] Reference Figure 1 The present invention discloses a method for determining trace amounts of gold, palladium and platinum in a carbonylation copper-nickel alloy leachate, and its ICP-AES working conditions are as follows.

[0015] Working curve drawing: prepare a series of mixed standard solutions of Au, Pd, and Pt in (1+9) hydrochloric acid medium, with concentrations of 0.00 mg / L, 0.10 mg / L, 0.50 mg / L, 1.00 mg / L, and 5.00 mg / L, respectively. Determine the series of mixed standard solutions in sequence on ICP-AES under the above working conditions, and draw a working curve with the concentration of gold, palladium, and platinum as the horizontal axis and the absorbance intensity as the vertical axis. Figure 2-4 shown.

[0016] The tellurium solution is an aqueous solution of tellurium with a concentration of 2.5 g / L. The stannous chloride solution is an aqueous solution of tellurium with a concentration of 200 g / L.

[0017] During the chlorination leaching of copper-nickel from the carbonyl alloy rich in precious metals, a small amount of gold, palladium and platinum will be dissolved in the solution. In order to control the loss of precious metals, the gold, palladium and platinum in the carbonyl copper-nickel alloy leaching solution obtained need to be accurately detected. The methodological verification experiment of the determination method of the present invention is as follows: 1. Detection limit and determination limit of the method Under the above ICP-AES working conditions, the blank solution was used for continuous determination 11 times, and 3 times the standard deviation of the determination results was taken as the detection limit, and 10 times the standard deviation was taken as the determination lower limit of the method. The decomposition results are shown in Table 1.

[0018] The results in Table 1 show that the detection limit and determination lower limit of the method of the present invention meet the requirements of the analytical method.

[0019] 2. Precision test After the analysis conditions were determined, in order to verify the stability of the analysis method, seven parallel tests were carried out on the carbonyl alloy leaching solution samples. The experimental results are shown in Table 2.

[0020] The results in Table 2 show that the relative standard deviations of Au, Pd, and Pt in this test are all <5%, meeting the precision requirements.

[0021] 3. Spike recovery experiment According to the grade of the elements to be tested in the samples, a spike recovery test was carried out and the analysis results are shown in Table 3.

[0022] The results in Table 3 show that the spike recovery of the method of the present invention is between 98.04% and 112.50%, which meets the requirement of 80% to 120% for the spike recovery of trace analysis.

[0023] The operation process of the method of the present invention is specifically described below by way of examples: Example 1 The sample to be tested in this embodiment is carbonyl alloy leachate No. 1; 50 mL of carbonyl nickel-copper alloy leachate was transferred into a 500 mL beaker, and 50 mL of hydrochloric acid and 5 mL of hydrogen peroxide were added. The solution was heated and evaporated on a hot plate, and then 50 mL of hydrochloric acid was added. A small amount of water was used to wash the beaker wall, and the solution was heated and evaporated again. After cooling, 100 mL of hydrochloric acid and 200 mL of water were added, and the solution was heated to a slight boil on a hot plate. 1 mL of tellurium solution was added, and the solution was heated to a slight boil again. Stannous chloride solution was added until the precipitation was completely precipitated. The solution was heated until the precipitation condensed. 1 mol / L stannous chloride solution was added until no precipitation was generated and the solution was in excess of 2 mL. The solution was then kept in a slight boiling state at a low temperature on the hot plate for 30 min. The generated precipitation was filtered with a 0.45 μm filter membrane on a sand core filter device. The beaker and the precipitation were washed with (1+9) hydrochloric acid for 5 times each, and then washed with water for 5 times. The precipitation was transferred to the original beaker. Add 10mL of aqua regia to the original beaker to dissolve the precipitate, evaporate it on a hot plate to 2mL, add 10mL of hydrochloric acid and 1mL of hydrogen peroxide, heat and boil until it is clear, transfer it to a 50mL volumetric flask, and dilute it with water to obtain the sample solution to be tested. The sample solution to be tested was measured on ICP-AES using the same working conditions as the series of mixed standard solutions, and the analysis results of gold, palladium, and platinum are shown in Table 4.

[0024] Example 2 Carbonylation alloy leachate No. 2, transfer 50mL of carbonylation nickel-copper alloy leachate into a 500mL beaker, add 50mL hydrochloric acid, 5mL hydrogen peroxide, heat on a hot plate to dryness, add 50mL hydrochloric acid, a small amount of water to blow and wash the table and cup wall, and heat again to dryness; after cooling, add 100mL hydrochloric acid, 200mL water and heat on a hot plate to slightly boil, add 1mL tellurium solution, heat again to slightly boil, add stannous chloride solution until precipitation is complete, continue heating until precipitation condenses, add 1mol / L stannous chloride solution until no precipitation is produced and 2mL excess, then keep slightly boiling at the low temperature of the hot plate for 40min, and then keep slightly boiling at the low temperature of the hot plate for 30min; filter the produced precipitate with a 0.45μm filter membrane on a sand core filter device, wash the beaker and precipitate with (1+9) hydrochloric acid 5 times each, then wash with water 5 times, and transfer the precipitate to the original beaker. Add 10mL of aqua regia to the original beaker to dissolve the precipitate, evaporate it on a hot plate to 3mL, add 10mL of hydrochloric acid and 1mL of hydrogen peroxide, heat and boil until it is clear, transfer it to a 50mL volumetric flask, and dilute it with water to obtain the sample solution to be tested. The sample solution to be tested was measured on ICP-AES using the same working conditions as the series of mixed standard solutions, and the analysis results of gold, palladium and platinum are shown in Table 5.

[0025] Example 3 Carbonylation alloy leachate No. 3, transfer 50mL of carbonylation nickel-copper alloy leachate into a 500mL beaker, add 50mL hydrochloric acid, 5mL hydrogen peroxide, heat on a hot plate to dryness, add 50mL hydrochloric acid, a small amount of water to blow and wash the table and cup wall, and heat again to dryness; after cooling, add 100mL hydrochloric acid, 200mL water and heat on a hot plate to slightly boil, add 1mL tellurium solution, heat again to slightly boil, add stannous chloride solution until precipitation is complete, continue heating until precipitation condenses, add 1mol / L stannous chloride solution until no precipitation is produced and 2mL excess, then keep slightly boiling at the low temperature of the hot plate for 35min, and then keep slightly boiling at the low temperature of the hot plate for 30min; filter the produced precipitate with a 0.45μm filter membrane on a sand core filter device, wash the beaker and precipitate with (1+9) hydrochloric acid 5 times each, then wash with water 5 times, and transfer the precipitate to the original beaker. Add 10mL of aqua regia to the original beaker to dissolve the precipitate, evaporate it on a hot plate to 3mL, add 10mL of hydrochloric acid and 1mL of hydrogen peroxide, heat and boil until it is clear, transfer it to a 50mL volumetric flask, and dilute it with water to obtain the sample solution to be tested. The sample solution to be tested was measured on ICP-AES using the same working conditions as the series of mixed standard solutions, and the analysis results of gold, palladium and platinum are shown in Table 6.

Claims

1. A method for determining trace amounts of gold, palladium and platinum in a carbonyl copper-nickel alloy leachate, characterized in that: The following steps are involved: (1) Sample pretreatment 50 mL of carbonyl copper-nickel alloy leachate was transferred into a glass container, and 50 mL of hydrochloric acid and 5 mL of hydrogen peroxide were added in sequence, and the container was heated and evaporated to dryness on a hot plate; 50 mL of hydrochloric acid was added to the evaporated product, and the inner wall of the container was washed with water, and then heated and evaporated again; (2) Coprecipitation Continue to add 100 mL of hydrochloric acid and 200 mL of water into the glass container in step (1), place it on a hot plate and heat it to a slight boil, add 1 mL of tellurium solution, heat it again to a slight boil, add stannous chloride solution until precipitation is complete, continue heating until the precipitation condenses, add 1 mol / L stannous chloride solution, and observe whether there is precipitation. If precipitation is generated, continue to add stannous chloride solution until no precipitation is generated and the excess is 2 mL. If no precipitation is generated, add 2 ml of stannous chloride solution. Finally, keep it at a slight boil for 30 min-40 min; (3) Filtering The precipitate produced in step (2) was removed and filtered using a 0.45 μm filter membrane on a sand core filter device. The glass container and the precipitate were washed with (1+9) hydrochloric acid and water for 5 times each, and the precipitate was transferred to a glass container; (4) Fixed volume Add 10 mL of aqua regia to a glass container to dissolve the precipitate, and evaporate it on a hot plate until it is 2-3 mL. Add 10 mL of hydrochloric acid and 1 mL of hydrogen peroxide, heat and boil until it is dissolved and clear, transfer to a 50 mL volumetric flask, and dilute to volume with water to obtain the sample solution to be tested; (5) Drawing of working curve A series of mixed standard solutions of Au, Pd and Pt in a (1+9) hydrochloric acid medium are prepared, and the series of mixed standard solutions are measured in sequence on an ICP-AES according to set working conditions, and a working curve is drawn with the concentration of gold, palladium and platinum as the abscissa and the absorbance intensity as the ordinate; Sample determination The sample solution prepared in step (4) is measured on ICP-AES using the same working conditions as in step (5), and then the content of gold, palladium and platinum in the sample solution can be calculated based on the working curve drawn in step (5).

2. The method for determining trace amounts of gold, palladium and platinum in a carbonyl copper-nickel alloy leachate according to claim 1, characterized in that: In step (1), the composition and content of the carbonyl copper-nickel alloy leaching solution are Ni: 20-130 g / L, Cu: 20-180 g / L, Au<0.1 g / L, Pd<0.1 g / L, Pt<0.1 g / L.

3. The method for determining trace amounts of gold, palladium and platinum in a carbonyl copper-nickel alloy leachate according to claim 1, characterized in that: In step (2), the concentration of the tellurium solution is 2.5 g / L.

4. The method for determining trace amounts of gold, palladium and platinum in a carbonyl copper-nickel alloy leachate according to claim 2, characterized in that: In step (2), the concentration of the stannous chloride solution is 200 g / L.

5. The method for determining trace amounts of gold, palladium and platinum in a carbonyl copper-nickel alloy leachate according to any one of claims 1 to 3, characterized in that: In step (3), the washing times of hydrochloric acid and water are both 5 times.

6. The method for treating trace amounts of gold, palladium and platinum in a carbonyl copper-nickel alloy leachate according to any one of claims 1 to 3 The measuring method is characterized in that In step (5), the concentrations of the series of mixed standard solutions are 0.00 mg / L, 0.10 mg / L, 0.50 mg / L, 1.00 mg / L, and 5.00 mg / L, respectively.

7. The method for determining trace amounts of gold, palladium and platinum in a carbonyl copper-nickel alloy leachate according to claim 5, It is characterized in that In step (5), the ICP-AES working conditions are shown in the following table.

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