Quantitative analysis method for palladium content in waste palladium catalyst

Abstract

The invention discloses a method for quantitatively analyzing the content of palladium in a waste palladium catalyst, which comprises the following steps of: firstly, placing a waste palladium sample to be detected at the temperature of between 80 and 150 DEG C for infrared irradiation for 150 to 200 minutes, and then placing the waste palladium sample at the temperature of between 800 and 850 DEG C for firing for 4 to 5 hours to obtain palladium ash; adding formic acid into the palladium ash, heating at the temperature of 80-120 DEG C until the liquid is evaporated to dryness, adding aqua regia, heating at the low temperature of 80-120 DEG C for melting, cooling to room temperature, diluting with water to a test scale, and uniformly shaking to obtain a solution to be tested; drawing a standard curve of absorbance and concentration, testing the to-be-tested solution by adopting an inductively coupled plasma spectrometer to obtain the absorbance of the to-be-tested solution, and substituting the absorbance into the standard curve to obtain the concentration C of the to-be-tested solution; and substituting the concentration C into the following formula to obtain the palladium content W2: # imgabs0 # in the waste palladium. The method provided by the invention realizes quantitative analysis of the palladium content in the waste palladium catalyst.

Description

Technical Field

[0001] The invention relates to a method for quantitatively analyzing the palladium content in a waste palladium catalyst, belonging to the technical field of physical and chemical analysis. Background Art

[0002] Palladium carbon (Pd / C) is an important catalyst made by attaching palladium compounds on the surface of activated carbon. It is mainly used for catalytic hydrogenation reactions in the chemical, chemical and pharmaceutical industries. It plays a very important catalytic role in the production of C products in our factory. Since palladium is a precious metal with scarce resources, the amount of waste palladium that fails in our factory every year is quite large. Therefore, in terms of cost control, the company needs to recycle the palladium catalyst in the waste palladium. Therefore, the accurate quantitative detection of the palladium content in the waste palladium is the basis for the recovery of the palladium catalyst in the waste palladium.

[0003] At present, the analytical method for determining the palladium content in palladium catalysts is the dimethylglyoxime precipitation method, which requires sample processing, precipitation, filtration, drying, weighing and other operations to convert the mass fraction of palladium in the catalyst according to the dimethylglyoxime palladium conversion factor. The analysis process is cumbersome, the analysis cycle is about 28 hours, and the analysis efficiency is low, which is not conducive to the demand for rapid and green detection methods.

[0004] According to the physical and chemical properties of the palladium content in waste palladium, it is decided to use an instrumental analysis method, namely inductively coupled plasma emission spectrometry, to accurately quantify it. In order to achieve accurate quantitative detection of the palladium content in waste palladium and meet the analysis requirements of inductively coupled plasma emission spectrometry, it is necessary to study a pretreatment method that can achieve quantitative analysis of the palladium content in waste palladium catalysts. Summary of the invention

[0005] The purpose of the present invention is to provide a method for quantitatively analyzing the palladium content in a waste palladium catalyst.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] A method for quantitatively analyzing the palladium content in a waste palladium catalyst of the present invention comprises the following steps:

[0008] 1) Weigh the waste palladium sample to be tested, place it in an infrared oven, irradiate it with infrared rays at 80° C.-150° C. for 150 min-200 min, and then cool it naturally to room temperature;

[0009] 2) Weigh 2 g to 3 g of the waste palladium sample dried in an infrared oven, put it into a high-temperature furnace at room temperature, burn it at 800° C. to 850° C. for 4 h to 5 h, and cool it naturally to room temperature to obtain palladium ash;

[0010] 3) Weigh 0.05 g of palladium ash, add 5 mL-10 mL of formic acid, use an electric ceramic furnace to heat at 80°C-120°C until the liquid evaporates to dryness, then add 10 mL-20 mL of aqua regia, heat at 80°C-120°C to melt, cool to room temperature, dilute with water to the test scale, and shake well to obtain the test solution;

[0011] 4) preparing a set of standard solutions with a concentration gradient from a waste palladium sample with a known content according to the treatment process of steps 1) to 3), testing the absorbance of each standard solution with an inductively coupled plasma spectrometer, and drawing a standard curve of absorbance and concentration;

[0012] 5) The solution to be tested obtained in step 3) is tested by an inductively coupled plasma spectrometer to obtain the absorbance of the solution to be tested, and the absorbance is substituted into the standard curve to obtain the concentration C of the solution to be tested; the concentration C is substituted into the following formula to obtain the palladium content W2 in the waste palladium:

[0013]

[0014] Where:

[0015] C-the concentration of palladium in the test solution to be measured, in mg / L;

[0016] V-volume of the solution to be tested, in L;

[0017] m2-the mass of palladium ash after the dried waste palladium is burned, in g;

[0018] m1-weigh the mass of the waste palladium after drying, in g;

[0019] m0-palladium ash sample weight, in g.

[0020] Beneficial Effects

[0021] The method of the present invention realizes the quantitative analysis of the palladium content in the waste palladium catalyst, and has the advantages of simple sample processing operation, short analysis cycle, rapid and accurate detection, etc. The rapid and accurate detection of waste palladium also has important positive significance for the recovery plan of palladium in the waste palladium of the production line. DETAILED DESCRIPTION

[0022] The present invention will be further described below by way of examples.

[0023] The specific equipment used in each embodiment is: Taiyuan Shentuo HW-100 infrared safety oven, DC-B11 intelligent box-type high-temperature furnace, Guangdong Shunde Zhongchen LC-EA6S electric ceramic furnace, PerkinElmer Avio200 inductively coupled plasma spectrometer.

[0024] Example 1

[0025] 1) Drying in an infrared oven: Use a weighing bottle with constant weight to weigh 3.6009 g of sample, place it in an oven, dry it at 120°C for 150 min, take it out and place it in a desiccator to cool, and weigh it.

[0026] Result calculation: The content of water and volatile matter in the sample is calculated according to the following formula:

[0027]

[0028] Where:

[0029] C-water and volatile content, in %;

[0030] m1—total mass of the sample plus the weighing bottle before drying, in g;

[0031] m2—total mass of the sample and weighing bottle after drying, in g;

[0032] 2) Use a high-temperature furnace to burn into palladium ash: weigh 2.9167g of the dried sample, put it into a porcelain crucible with constant weight, put it into a high-temperature furnace at room temperature, start timing when the temperature stabilizes at 800℃~850℃, burn for 4 hours, burn into palladium ash, and weigh it after cooling.

[0033] 3) Wet decomposition method for palladium ash treatment: Weigh 0.05017g palladium ash into a 250mL beaker, add 5mL formic acid, cover with a watch glass, use an electric ceramic furnace to heat at low temperature until dry, then add 10mL aqua regia, heat at low temperature to melt, remove and cool. Transfer to a 100mL volumetric flask, dilute to scale with water, and shake well. Take 50mL of the solution and transfer it to another 100mL volumetric flask, dilute to volume with water, and shake well to obtain the solution to be tested.

[0034] 4) preparing a set of standard solutions with a concentration gradient from a waste palladium sample with a known content according to the treatment process of steps 1) to 3), testing the absorbance of each standard solution with an inductively coupled plasma spectrometer, and drawing a standard curve of absorbance and concentration;

[0035] 5) The solution to be tested obtained in step 3) is tested by an inductively coupled plasma spectrometer to obtain the absorbance of the solution to be tested, which is substituted into the standard curve to obtain the concentration C of the solution to be tested; the palladium content W2 in the waste palladium, expressed in %, is calculated as follows:

[0036]

[0037] Where:

[0038] C-the concentration of palladium in the test solution to be measured, in mg / L;

[0039] V-volume of the solution to be tested, in L:

[0040] m2-the mass of palladium ash after the dried waste palladium is burned, in g;

[0041] m1-weigh the mass of the waste palladium after drying, in g;

[0042] m0-palladium ash sample weight, in g.

[0043] The measured data are shown in the following table:

[0044] Absorbance 3869380.7 Concentration C (mg / L) 9.821 content(%) 4.68

[0045] Example 2

[0046] 1) Drying in an infrared oven: Use a weighing bottle with constant weight to weigh 3.6752 g of sample, place it in an oven, dry it at 120°C for 150 min, take it out and place it in a desiccator to cool, and weigh it.

[0047] 2) Burn into palladium ash in a high-temperature furnace: Weigh 3.0249 g of the dried sample, put it into a porcelain crucible with constant weight, put it into a high-temperature furnace at room temperature, start timing when the temperature stabilizes at 800°C~850°C, burn for 4 hours, burn into palladium ash, and weigh it after cooling.

[0048] 3) Wet decomposition method for palladium ash treatment: Weigh 0.05006g palladium ash into a 250mL beaker, add 5mL formic acid, cover with a watch glass, use an electric ceramic furnace to heat at low temperature until dry, then add 10mL aqua regia, heat at low temperature to melt, remove and cool. Transfer to a 100mL volumetric flask, dilute to scale with water, and shake well. Take 50mL of the solution and transfer it to another 100mL volumetric flask, dilute to volume with water, and shake well to obtain the solution to be tested.

[0049] 4) preparing a set of standard solutions with a concentration gradient from a waste palladium sample with a known content according to the treatment process of steps 1) to 3), testing the absorbance of each standard solution with an inductively coupled plasma spectrometer, and drawing a standard curve of absorbance and concentration;

[0050] 5) The solution to be tested obtained in step 3) is tested by an inductively coupled plasma spectrometer to obtain the absorbance of the solution to be tested, which is substituted into the standard curve to obtain the concentration C of the solution to be tested; the palladium content W2 in the waste palladium, expressed in %, is calculated as follows:

[0051]

[0052] Where:

[0053] C-the concentration of palladium in the test solution to be measured, in mg / L;

[0054] V-volume of the solution to be tested, in L:

[0055] m2-the mass of palladium ash after the dried waste palladium is burned, in g;

[0056] m1-weigh the mass of the waste palladium after drying, in g;

[0057] m0-palladium ash sample weight, in g.

[0058] The measured data are shown in the following table:

[0059] Absorbance 3629884.7 Concentration C (mg / L) 9.2141 content(%) 4.52

[0060] Example 3

[0061] 1) Drying in an infrared oven: Use a weighing bottle with constant weight to weigh 3.4753 g of sample, place it in an oven, dry it at 120°C for 150 min, take it out and place it in a desiccator to cool, and weigh it.

[0062] Result calculation: The content of water and volatile matter in the sample is calculated according to the following formula:

[0063] 2) Use a high-temperature furnace to burn into palladium ash: weigh 3.0240g of the dried sample, put it into a porcelain crucible with constant weight, put it into a high-temperature furnace at room temperature, start timing when the temperature stabilizes at 800℃~850℃, burn for 4 hours, burn into palladium ash, and weigh it after cooling.

[0064] 3) Wet decomposition method for palladium ash treatment: Weigh 0.05037g palladium ash into a 250mL beaker, add 5mL formic acid, cover with a watch glass, use an electric ceramic furnace to heat at low temperature until dry, then add 10mL aqua regia, heat at low temperature to melt, remove and cool. Transfer to a 100mL volumetric flask, dilute to scale with water, and shake well. Take 50mL of the solution and transfer it to another 100mL volumetric flask, dilute to volume with water, and shake well to obtain the solution to be tested.

[0065] 4) preparing a set of standard solutions with a concentration gradient from a waste palladium sample with a known content according to the treatment process of steps 1) to 3), testing the absorbance of each standard solution with an inductively coupled plasma spectrometer, and drawing a standard curve of absorbance and concentration;

[0066] 5) The solution to be tested obtained in step 3) is tested by an inductively coupled plasma spectrometer to obtain the absorbance of the solution to be tested, which is substituted into the standard curve to obtain the concentration C of the solution to be tested; the palladium content W2 in the waste palladium, expressed in %, is calculated as follows:

[0067]

[0068] Where:

[0069] C-the concentration of palladium in the test solution to be measured, in mg / L;

[0070] V-volume of the solution to be tested, in L:

[0071] m2-the mass of palladium ash after the dried waste palladium is burned, in g;

[0072] m1-weigh the mass of the waste palladium after drying, in g;

[0073] m0-palladium ash sample weight, in g.

[0074] The measured data are shown in the following table:

[0075] Absorbance 3684277.5 Concentration C (mg / L) 9.352 content(%) 4.56

[0076] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the protection scope of the present invention.

Claims

1. A method for quantitatively analyzing the palladium content in a waste palladium catalyst, characterized in that: The steps include: 1) Weigh the waste palladium sample to be tested, place it in an infrared oven, irradiate it with infrared rays at 80° C.-150° C. for 150 min-200 min, and then cool it naturally to room temperature; 2) Weigh 2 g to 3 g of the waste palladium sample dried in an infrared oven, put it into a high-temperature furnace at room temperature, burn it at 800° C. to 850° C. for 4 h to 5 h, and cool it naturally to room temperature to obtain palladium ash; 3) Weigh 0.05 g of palladium ash, add 5 mL-10 mL of formic acid, use an electric ceramic furnace to heat at 80°C-120°C until the liquid evaporates to dryness, then add 10 mL-20 mL of aqua regia, heat at 80°C-120°C to melt, cool to room temperature, dilute with water to the test scale, and shake well to obtain the test solution; 4) preparing a set of standard solutions with a concentration gradient from a waste palladium sample with a known content according to the treatment process of steps 1) to 3), testing the absorbance of each standard solution with an inductively coupled plasma spectrometer, and drawing a standard curve of absorbance and concentration; 5) The solution to be tested obtained in step 3) is tested by an inductively coupled plasma spectrometer to obtain the absorbance of the solution to be tested, and the absorbance is substituted into the standard curve to obtain the concentration C of the solution to be tested; the concentration C is substituted into the following formula to obtain the palladium content W2 in the waste palladium: Where: C-the concentration of palladium in the test solution to be measured, in mg / L; V-volume of the solution to be tested, in L; m2-the mass of palladium ash after the dried waste palladium is burned, in g; m1-weigh the mass of the waste palladium after drying, in g; m0-palladium ash sample weight, in g.

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