A method for rapid determination of silver content in gold-loaded carbon

Abstract

The invention discloses a method for rapidly determining the silver content in gold-loaded carbon, which comprises the following steps: weighing 0.1500g of gold-loaded carbon sample and laying it flat on 0.1000g of aluminum foil, then placing the aluminum foil on a refractory board and placing it in a muffle furnace, starting from a low temperature, heating to 660°C, performing oxidation roasting, keeping the temperature for 20min to 30min, taking it out and cooling it; moving the aluminum foil and the sample into a 125mL beaker, wetting it with water, adding hydrochloric acid, nitric acid and perchloric acid, heating it on a hot plate until it emits a lot of smoke (not all of it), taking it out and cooling it to 120°C; adding hydrochloric acid to extract until the solution is clear, taking it out and adding water to about 100mL, shaking it well and cooling it, and using aluminum as an internal standard element on an inductively coupled plasma emission spectrometer to determine it by the internal standard method; calculating the silver content according to the formula. The method of the invention has the advantages of low detection limit, high sensitivity, good accuracy and precision, wide linear range, stable sample solution medium, no need for accurate volume determination, suitable for laboratory mass production, simple operation steps, etc.

Description

Technical Field

[0001] The invention relates to the technical field of trace element determination, in particular to a method for rapidly determining the silver content in gold-loaded carbon. Background Art

[0002] Gold-loaded carbon refers to activated carbon used to adsorb and recover gold and silver in the leaching solution during the gold hydrometallurgical smelting process. Depending on whether the activated carbon is desorbed and regenerated during the smelting process, the activated carbon is divided into gold-loaded carbon, desorption-poor carbon, and regeneration-poor carbon. The quality of adsorption, desorption, and regeneration effects can be measured by the changes in the gold and silver content in the gold-loaded carbon. Therefore, whether it is to investigate the carbon adsorption process indicators or to settle transactions in economic and trade activities, it is of great significance to accurately measure the gold and silver content in the gold-loaded carbon.

[0003] At present, the mainstream analytical methods for the determination of silver in gold-loaded carbon in the industry mainly adopt ① ashing-aqua regia digestion-atomic absorption spectrophotometry, ② direct digestion with sulfuric acid-nitric acid-perchloric acid mixed acid-atomic absorption spectrophotometry. There are several problems with these methods: ① In the ashing-aqua regia digestion-atomic absorption spectrophotometry, during the ashing of gold-loaded carbon with ordinary porcelain boats, some silver is easy to penetrate into the porcelain boat. After ashing, the sample is placed in a beaker for direct digestion, and the silver determination result is low. ② Direct digestion with sulfuric acid-nitric acid-perchloric acid mixed acid-atomic absorption spectrophotometry first uses high-temperature sulfuric acid for carbonization, and then adds perchloric acid, which is risky to operate and has low analysis efficiency. During the digestion process, the perchloric acid is extracted with aqua regia after emitting all the smoke. The determination solution is an aqua regia medium, which has poor long-term stability and must be determined in a short period of time. It is not suitable for large-scale production in the laboratory. The current effective national standard GB / T 29509.2-2013 "Chemical analysis method of gold-loaded carbon Part 2: Determination of silver content by flame atomic absorption spectrometry" has a measurement range of 10.0-2500 g / t, which is too small to cover samples with low or high content. Therefore, it is necessary to provide a method with lower detection limit, higher accuracy and precision, simple operation and higher efficiency for determining the silver content in gold-loaded carbon. Summary of the invention

[0004] In view of the above problems, the present invention provides a method for quickly determining the silver content in gold-loaded carbon. The method of the present invention is aluminum foil ashing-perchloric acid mixed acid digestion-inductively coupled plasma emission spectrometry to determine the silver in gold-loaded carbon. The aluminum foil ashing can prevent the loss of silver during the ashing process; the perchloric acid mixed acid digestion after ashing is safe and not easy to explode, and the digestion efficiency is improved. The perchloric acid smoke is not completely emitted, and the determination solution medium contains perchloric acid, and the medium stability is enhanced; the aluminum internal standard is introduced in the early stage of sample pretreatment, and the change of the determination volume will not affect the quantitative result, and the volume does not need to be accurately determined during the determination, and the detection limit is low, the sensitivity is high, the accuracy and precision are good, and the linear range is wide. At the same time, it is suitable for large-scale production in the laboratory, and the operation steps are relatively simple.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A method for rapidly determining the silver content in gold-loaded carbon comprises the following steps:

[0007] (1) Weigh 0.1500 g of gold-loaded carbon sample and spread it on 0.1000 g of aluminum foil, then place the aluminum foil on a refractory board and put it into a muffle furnace. Start at a low temperature and raise the temperature to 660°C for oxidative roasting. Keep the temperature for 20 min to 30 min, then take it out and cool it down;

[0008] (2) Place the aluminum foil and sample into a 125 mL beaker, moisten with water, add hydrochloric acid, nitric acid, and perchloric acid, heat on a hot plate until smoke appears (not completely), remove and cool to 120°C;

[0009] (3) adding hydrochloric acid to extract until the solution is clear, removing the solution, adding water, shaking and cooling, and determining the solution by the internal standard method using aluminum as the internal standard element on an inductively coupled plasma emission spectrometer;

[0010] (4) Calculate the silver content according to the following formula:

[0011]

[0012] Where:

[0013] m1—the mass of silver in the sample solution obtained from the working curve, μg;

[0014] m0—the mass of silver in the blank test solution obtained from the working curve, μg;

[0015] m s —Gold-loaded carbon sample, g.

[0016] As a further optimization of the scheme of the present invention: the amounts of hydrochloric acid, nitric acid and perchloric acid used in step (2) are 4 mL to 6 mL, 1 mL to 2 mL and 1 mL to 2 mL respectively. The optimal scheme is 6 mL, 2 mL and 2 mL respectively.

[0017] As a further optimization of the scheme of the present invention: the amount of hydrochloric acid used in step (3) is 30mL to 50mL.

[0018] As a further optimization of the scheme of the present invention: the concentration of the hydrochloric acid in step (3) is 5% to 10%.

[0019] As a further optimization of the scheme of the present invention: the heating rate of step (1) is 10°C / min to 20°C / min

[0020] As a further optimization of the solution of the present invention: when the inductively coupled plasma emission spectrometer is used for measurement, the Ag wavelength is 328.0 nm and the Al wavelength is 308.2 nm.

[0021] As a further optimization of the scheme of the present invention: the silver content in the gold-loaded carbon is determined in the range of 4.0 to 5000 g / t by inductively coupled plasma emission spectrometry.

[0022] As a further optimization of the scheme of the present invention: the gold-loaded carbon sample is accurate to ±0.0002g, and the particle size of the gold-loaded carbon sample is ≤97μm

[0023] Compared with the prior art, the advantages and beneficial effects of the present invention include:

[0024] The method of the present invention is aluminum foil ashing-perchloric acid mixed acid digestion-inductively coupled plasma emission spectrometry to determine the silver in gold-loaded carbon. The aluminum foil ashing can prevent the loss of silver in the ashing process; the perchloric acid mixed acid digestion after ashing is safe and not easy to explode, the digestion efficiency is improved, the perchloric acid smoke is not completely exhausted, the determination solution medium contains perchloric acid, and the medium stability is enhanced; the aluminum internal standard is introduced in the early stage of sample pretreatment, the change of the measurement volume will not affect the quantitative result, and the volume does not need to be accurately determined during the measurement, which improves the efficiency of the measurement; the aluminum in the ashing process is used as an internal standard element, and the silver in the gold-loaded carbon is determined by inductively coupled plasma emission spectrometry, interference is eliminated, the detection limit is reduced, the precision is improved, and the measurement range is expanded from the national standard 10.0-2500g / t to 4.0-5000g / t. Therefore, the method has a low detection limit, high sensitivity, good accuracy and precision, and a wide linear range. At the same time, it is suitable for large-scale laboratory production and the operation steps are relatively simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the Ag standard curve diagram using Al as the internal standard in Example 1.

[0026] Figure 2 This is the Ag standard curve diagram of Example 1 without internal standard.

[0027] Figure 3 This is the Ag standard curve diagram of Example 2 using Al as the internal standard.

[0028] Figure 4 This is the Ag standard curve diagram of Example 2 without internal standard.

[0029] Figure 5 This is the Ag standard curve diagram of Example 3 using Al as the internal standard.

[0030] Figure 6 This is the Ag standard curve diagram of Example 3 without internal standard.

[0031] Figure 7 This is the Ag standard curve diagram of Example 4 using Al as the internal standard.

[0032] Figure 8 This is the Ag standard curve diagram of Example 4 without internal standard. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] Example 1

[0035] A method for rapidly determining the silver content in gold-loaded carbon comprises the following steps:

[0036] (1) Weigh 0.1500 g of gold-loaded carbon sample and spread it on 0.1000 g of aluminum foil, then place the aluminum foil on a refractory board and put it into a muffle furnace, heat it to 660 ° C at 20 ° C / min, perform oxidative roasting, keep it at this temperature for 25 min, and take it out to cool;

[0037] (2) Place the aluminum foil and sample into a 125 mL beaker, moisten with water, add 6 mL of hydrochloric acid, 2 mL of nitric acid, and 2 mL of perchloric acid, and place on a hot plate until smoke (not all smoke) is emitted. Remove the beaker and cool to 120°C.

[0038] (3) Add 40 mL of 5% hydrochloric acid to extract until the solution is clear, remove and add water to 100 mL, shake and cool to obtain the sample solution;

[0039] (4) Internal standard correction: select Al wavelength 308.2nm as the internal standard element analysis line, select Ag wavelength 328.0nm as the element analysis line to be measured, and perform internal standard correction;

[0040] (5) External standard calibration: select Ag wavelength 328.0 nm as the element analysis line to be measured and perform external standard calibration;

[0041] (6) The blank test solution, analytical test solution and working curve are measured on an inductively coupled plasma emission spectrometer according to the measurement conditions.

[0042] (7) Calculate the silver content according to the following formula:

[0043] Where:

[0044] m1—the mass of silver in the sample solution obtained from the working curve, μg;

[0045] m0—the mass of silver in the blank test solution obtained from the working curve, μg;

[0046] m s —Sample mass, g.

[0047] Weigh 0.1500g of sample A, accurate to 0.0002g. The particle size of the sample should be less than 97μm.

[0048] Two independent measurements were performed and the average value was taken.

[0049] Carry out 8 blank tests along with the test material, and the reagents used should be taken from the same bottle of reagents, of which 2 are sample blanks and 6 are used to prepare the standard series.

[0050] According to the above steps, the spectral intensity values ​​of the standard series, blank sample and sample A were measured and obtained, see Table 1.

[0051] Table 1 Spectral intensity of Ag in gold-loaded carbon determined by ICP-OES

[0052] Agμg Ag strength value Al strength value Ag strength value / Al strength value Standard Series-0 10.01 105840 0.0000945767 Standard Series-50 452.3 98765 0.004579558 Standard Series-100 900.7 94681 0.009512996 Standard Series-200 1666 85774 0.019423135 Standard Series-500 5029 102346 0.04913724 Standard Series-750 6182 83228 0.074277887 Blank 1 9.652 104633 0.0000922462 Blank 2 10.68 108894 0.000098077 Sample A1 5564 88708 0.062722641 Sample A2 5990 95331 0.062833706

[0053] According to Table 1, curve fitting is performed to obtain Figure 1 , Figure 2 , calculate the results of sample A, and the relevant parameters are shown in Table 2.

[0054] Table 2 Related parameters for determination of Ag in gold-loaded carbon by ICP-OES

[0055]

[0056]

[0057] From the results in Table 2, it can be seen that the standard curve of the internal standard method has R2 = 0.9999, and the standard curve of the external standard method has R2 = 0.983. Compared with the two, the standard curve of the internal standard method has better linearity. The RSD of the parallel samples of sample A determined by the internal standard method is 0.09%, and the RSD of the parallel samples of sample A determined by the external standard method is 3.69%. The internal standard method has better precision.

[0058] Example 2

[0059] A method for rapidly determining the silver content in gold-loaded carbon comprises the following steps:

[0060] (1) Weigh 0.1500 g of gold-loaded carbon sample and spread it on 0.1000 g of aluminum foil, then place the aluminum foil on a refractory board and put it into a muffle furnace, heat it to 660 ° C at 20 ° C / min, perform oxidative roasting, keep it at this temperature for 25 min, and take it out to cool;

[0061] (2) Place the aluminum foil and sample into a 125 mL beaker, moisten with water, add 6 mL of hydrochloric acid, 2 mL of nitric acid, and 2 mL of perchloric acid, and place on a hot plate until smoke (not all smoke) is emitted. Remove the beaker and cool to 120°C.

[0062] (3) Add 50 mL of 5% hydrochloric acid to extract until the solution is clear, remove and add water to 100 mL, shake and cool to obtain the sample solution;

[0063] (4) Internal standard correction: select Al wavelength 308.2nm as the internal standard element analysis line, select Ag wavelength 328.0nm as the element analysis line to be measured, and perform internal standard correction;

[0064] (5) External standard calibration: select Ag wavelength 328.0 nm as the element analysis line to be measured and perform external standard calibration;

[0065] (6) The blank test solution, analytical test solution and working curve are measured on an inductively coupled plasma emission spectrometer according to the measurement conditions.

[0066] (7) Calculate the silver content according to the following formula:

[0067] Where:

[0068] m1—the mass of silver in the sample solution obtained from the working curve, μg;

[0069] m0—the mass of silver in the blank test solution obtained from the working curve, μg;

[0070] m s —Sample mass, g.

[0071] Weigh 0.1500g of sample B, accurate to 0.0002g. The particle size of the sample should be less than 97μm.

[0072] Two independent measurements were performed and the average value was taken.

[0073] Carry out 8 blank tests along with the test material, and the reagents used should be taken from the same bottle of reagents, of which 2 are sample blanks and 6 are used to prepare the standard series.

[0074] According to the above steps, the spectral intensity values ​​of the standard series, blank sample and sample B were measured and obtained, see Table 3.

[0075] Table 3 Spectral intensity of Ag in gold-loaded carbon determined by ICP-OES

[0076] Agμg Ag strength value Al strength value Ag strength value / Al strength value Standard Series-0 12.87 116879 0.000110114 Standard Series-50 459.6 95362 0.00481953 Standard Series-100 884.3 94789 0.009329142 Standard Series-200 1698 89600 0.018950893 Standard Series-500 4761 98947 0.048116669 Standard Series-750 6395 90633 0.070559289 Blank 1 11.25 112278 0.000100198 Blank 2 10.77 105975 0.000101628 Sample B1 3389 95723 0.035404239 Sample B2 3074 88398 0.034774542

[0077] According to Table 3, curve fitting is performed and the Figure 3 , Figure 4 , calculate the results of sample B, and the relevant parameters are shown in Table 4.

[0078] Table 4 Relevant parameters for determination of Ag in gold-loaded carbon by ICP-OES

[0079]

[0080]

[0081] From the results in Table 4, we can see that the internal standard method standard curve R 2 =0.9998, external standard method standard curve R 2 =0.9949, compared with the two, the standard curve of the internal standard method is more linear. The RSD of the parallel samples of sample B determined by the internal standard method is 0.90%, and the RSD of the parallel samples of sample B determined by the external standard method is 4.89%, and the internal standard method has better precision.

[0082] Example 3

[0083] A method for rapidly determining the silver content in gold-loaded carbon comprises the following steps:

[0084] (1) Weigh 0.1500 g of gold-loaded carbon sample and spread it on 0.1000 g of aluminum foil, then place the aluminum foil on a refractory board and put it into a muffle furnace, heat it to 660 ° C at 20 ° C / min, perform oxidative roasting, keep it at this temperature for 25 min, and take it out to cool;

[0085] (2) Place the aluminum foil and sample into a 125 mL beaker, moisten with water, add 6 mL of hydrochloric acid, 2 mL of nitric acid, and 2 mL of perchloric acid, and place on a hot plate until smoke (not all smoke) is emitted. Remove the beaker and cool to 120°C.

[0086] (3) Add 30 mL of 5% hydrochloric acid to extract until the solution is clear, remove and add water to 100 mL, shake and cool to obtain the sample solution;

[0087] (4) Internal standard correction: select Al wavelength 308.2nm as the internal standard element analysis line, select Ag wavelength 328.0nm as the element analysis line to be measured, and perform internal standard correction;

[0088] (5) External standard calibration: select Ag wavelength 328.0 nm as the element analysis line to be measured and perform external standard calibration;

[0089] (6) The blank test solution, analytical test solution and working curve are measured on an inductively coupled plasma emission spectrometer according to the measurement conditions.

[0090] (7) Calculate the silver content according to the following formula:

[0091] Where:

[0092] m1—the mass of silver in the sample solution obtained from the working curve, μg;

[0093] m0—the mass of silver in the blank test solution obtained from the working curve, μg;

[0094] m s —Sample mass, g.

[0095] Weigh 0.1500g of sample C, accurate to 0.0002g. The particle size of the sample should be less than 97μm.

[0096] Two independent measurements were performed and the average value was taken.

[0097] Carry out 8 blank tests along with the test material, and the reagents used should be taken from the same bottle of reagents, of which 2 are sample blanks and 6 are used to prepare the standard series.

[0098] According to the above steps, the spectral intensity values ​​of the standard series, blank samples, and sample C were measured and obtained, see Table 5.

[0099] Table 5 Spectral intensity of Ag in gold-loaded carbon determined by ICP-OES

[0100]

[0101] According to Table 5, curve fitting is performed and the Figure 5 , Figure 6 , calculate the results of sample C, and the relevant parameters are shown in Table 6.

[0102] Table 6 Relevant parameters for determination of Ag in gold-loaded carbon by ICP-OES

[0103]

[0104] From the results in Table 6, we can see that the internal standard method standard curve R 2 =0.9999, external standard method standard curve R 2=0.9958, compared with the two, the standard curve of the internal standard method is more linear. The RSD of the parallel samples of sample C measured by the internal standard method is 1.55%, and the RSD of the parallel samples of sample C measured by the external standard method is 8.83%. The internal standard method has better precision.

[0105] Example 4

[0106] A method for rapidly determining the silver content in gold-loaded carbon comprises the following steps:

[0107] (1) Weigh 0.1500 g of gold-loaded carbon sample and spread it on 0.1000 g of aluminum foil, then place the aluminum foil on a refractory board and put it into a muffle furnace, heat it to 660 ° C at 20 ° C / min, perform oxidative roasting, keep it at this temperature for 25 min, and take it out to cool;

[0108] (2) Place the aluminum foil and sample into a 125 mL beaker, moisten with water, add 6 mL of hydrochloric acid, 2 mL of nitric acid, and 2 mL of perchloric acid, and place on a hot plate until smoke (not all smoke) is emitted. Remove the beaker and cool to 120°C.

[0109] (3) Add 45 mL of 5% hydrochloric acid to extract until the solution is clear, remove and add water to 100 mL, shake and cool to obtain the sample solution;

[0110] (4) Internal standard correction: select Al wavelength 308.2nm as the internal standard element analysis line, select Ag wavelength 328.0nm as the element analysis line to be measured, and perform internal standard correction;

[0111] (5) External standard calibration: select Ag wavelength 328.0 nm as the element analysis line to be measured and perform external standard calibration;

[0112] (6) The blank test solution, analytical test solution and working curve are measured on an inductively coupled plasma emission spectrometer according to the measurement conditions.

[0113] (7) Calculate the silver content according to the following formula:

[0114] Where:

[0115] m1—the mass of silver in the sample solution obtained from the working curve, μg;

[0116] m0—the mass of silver in the blank test solution obtained from the working curve, μg;

[0117] m s —Sample mass, g.

[0118] Weigh 0.1500g of sample D, accurate to 0.0002g. The particle size of the sample should be less than 97μm.

[0119] Two independent measurements were performed and the average value was taken.

[0120] According to the above steps, the spectral intensity values ​​of the standard series, blank samples, and sample D were measured and obtained, see Table 7.

[0121] Table 7 Spectral intensity of Ag in gold-loaded carbon determined by ICP-OES

[0122] Agμg Ag strength value Al strength value Ag strength value / Al strength value Standard Series-0 10.87 110879 0.0000980348 Standard Series-50 402.7 80445 0.005005905 Standard Series-100 1083 98443 0.01100129 Standard Series-200 2347 111883 0.020977271 Standard Series-500 4798 90650 0.052928847 Standard Series-750 7899 98678 0.080048238 Blank 1 10.335 112890 0.0000915493 Blank 2 11.874 109883 0.00010806 Sample D1 20.66 100712 0.000205139 Sample D2 22.35 110461 0.000202334

[0123] According to Table 7, curve fitting is performed and the Figure 7 , Figure 8 , calculate the results of sample D, and the relevant parameters are shown in Table 8.

[0124] Table 8 Related parameters for determination of Ag in gold-loaded carbon by ICP-OES

[0125]

[0126] From the results in Table 8, we can see that the internal standard method standard curve R 2 =0.9999, external standard method standard curve R 2 =0.9946, compared with the two, the standard curve of the internal standard method is more linear. The RSD of the parallel samples of sample D determined by the internal standard method is 1.31%, and the RSD of the parallel samples of sample D determined by the external standard method is 8.13%. The internal standard method has better precision.

[0127] The above contents are further detailed descriptions of the present invention in combination with specific / preferred implementations, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, they can also make several substitutions or modifications to these described embodiments without departing from the concept of the present invention, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for rapidly determining the silver content in gold-loaded carbon, characterized in that: The steps include: (1) Weigh 0.1500 g of gold-loaded carbon sample and spread it on 0.1000 g of aluminum foil. Then place the aluminum foil on a refractory plate and put it into a muffle furnace. Start from a low temperature and raise the temperature to 660°C for oxidative roasting. Keep the temperature for 20 min to 30 min and take it out to cool. (2) Place the aluminum foil and sample into a 125 mL beaker, moisten with water, add hydrochloric acid, nitric acid, and perchloric acid, and heat on a hot plate until smoke starts to come out. Remove the beaker and cool to 120 °C. (3) Add hydrochloric acid to extract until the solution is clear, remove and add water, shake and cool, and measure by internal standard method on inductively coupled plasma emission spectrometer with aluminum as internal standard element; (4) Calculate the silver content according to the following formula: Where: m1—the mass of silver in the sample solution obtained from the working curve, μg; m0—the mass of silver in the blank test solution obtained from the working curve, μg; m s —gold-loaded carbon sample, g; The amounts of hydrochloric acid, nitric acid and perchloric acid used in step (2) are 4 mL to 6 mL, 1 mL to 2 mL and 1 mL to 2 mL respectively; In step (2), the perchloric acid mixture is heated until smoke is emitted, but the smoke should not be completely emitted; The amount of hydrochloric acid used in step (3) is 30 mL to 50 mL; The amount of water added in step (3) is 50 mL to 100 mL; The concentration of the hydrochloric acid in step (3) is 5% to 10%; The heating rate of step (1) is 10°C / min to 20°C / min; When measured by the inductively coupled plasma emission spectrometer, the Ag wavelength is 328.0 nm and the Al wavelength is 308.2 nm; The silver content in the gold-loaded carbon is determined in the range of 4.0 to 5000 g / t by inductively coupled plasma emission spectrometry; The gold-loaded carbon sample is accurate to ±0.0002 g, and the particle size of the gold-loaded carbon sample is ≤97 μm.

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