Method for detecting gold content in gold ore

Abstract

The invention provides a method for detecting gold content in gold ore, and belongs to the technical field of resource exploration. The method comprises the following steps: firstly, carrying out X fluorescence detection on ore powder, judging whether the ore contains a gold element or not, and obtaining the semi-quantitative content of gold in the gold ore powder; then the ore powder containing the gold element is roasted, sulfur, arsenic, organic matter and volatile matter are removed, and follow-up interference on gold detection is avoided; according to the method, aqua regia is adopted for digestion, gold in gold ore powder is dissolved, polyurethane foam plastic is added for adsorption, then a thiourea-hydrochloric acid aqueous solution is adopted for releasing, and finally detection is conducted, so that the detection limit can be reduced, and the detection accuracy can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of resource exploration, and in particular relates to a method for detecting the gold content in a gold ore. Background Art

[0002] Gold analysis and testing is an important part of the gold resource exploration process. The general process of gold determination in gold ore is sample decomposition-enrichment-redissolution or elution-on-machine determination. The complete decomposition of gold in gold ore samples is the first important step in the accurate determination of gold. At present, the decomposition methods of gold ore samples are divided into dry method and wet method. The dry method is suitable for fire assay, which requires the use of high-power equipment and has potential environmental pollution problems. The wet method is divided into cold dissolution method and hot dissolution method according to whether it is heated or not. It is divided into bromine water method, chlorine-sodium chloride method, hydrochloric acid-hydrogen peroxide method, and adsorption of Au(III)-diethyldithiocarbamate complex on Amberlite XAD-2000 resin, and then eluted in acetone with 1mol / L nitric acid, analyzed by flame atomic absorption spectrometry, or titrated by hydroquinone volumetric method to measure gold. Since the content of gold in nature is low, the occurrence matrix is ​​relatively complex, and there are many coexisting interfering elements, the sample solution needs to separate and enrich the gold before it can be accurately determined. At present, the main methods for separation and enrichment of gold are: fire assay separation and enrichment, activated carbon separation and enrichment, ion exchange separation and enrichment, foam plastic separation and enrichment. The measurement methods of gold after enrichment usually include: spectrophotometry, atomic absorption spectroscopy, inductively coupled plasma mass spectrometry, etc. The detection limit and accuracy of the current detection method of gold in gold ore are poor. Therefore, a method for detecting the gold content in gold ore with low detection limit and high detection accuracy is urgently needed. Summary of the invention

[0003] The purpose of the present invention is to provide a method for detecting the gold content in gold ore. The detection method provided by the present invention has a low detection limit and high accuracy.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a method for detecting the gold content in a gold ore, comprising the following steps:

[0006] (1) Performing X-ray fluorescence detection on gold ore standard material powders with different gold contents and drawing a standard curve 1;

[0007] (2) performing X-ray fluorescence detection on the ore powder, judging whether the ore powder contains gold element through the standard curve 1 obtained in step (1), and obtaining the semi-quantitative content of gold in the ore powder;

[0008] (3) Performing X-ray fluorescence detection on thiourea-hydrochloric acid aqueous solutions with different gold contents and drawing a standard curve 2;

[0009] (4) roasting the ore powder containing the gold element to obtain roasted gold ore powder;

[0010] (5) mixing the roasted gold ore powder obtained in step (4) with aqua regia and digesting the mixture to obtain a gold solution;

[0011] (6) mixing the gold solution obtained in step (5) with water and polyurethane foam and performing adsorption to obtain polyurethane foam adsorbing gold;

[0012] (7) mixing the gold-adsorbed polyurethane foam obtained in step (6) with a thiourea-hydrochloric acid aqueous solution and releasing the mixture to obtain a gold liquid;

[0013] (8) Performing X-ray fluorescence detection on the gold solution obtained in step (7), and obtaining the gold content in the gold ore powder through the standard curve 2 obtained in step (3).

[0014] Preferably, the calcination in step (4) comprises low-temperature calcination and high-temperature calcination performed sequentially.

[0015] Preferably, the temperature of the low-temperature calcination is 300-500° C., and the time of the low-temperature calcination is 30-90 minutes.

[0016] Preferably, the high temperature calcination temperature is 600-700° C., and the high temperature calcination time is 90-180 min.

[0017] Preferably, the volume ratio of the mass of the ore powder containing gold element in step (4) to the aqua regia in step (5) is (10-20) g: (30-50) mL.

[0018] Preferably, the digestion temperature in step (5) is 180-200° C., and the digestion time is 50-70 min.

[0019] Preferably, the polyurethane foam in step (6) is W-shaped, the size of the polyurethane foam is (50-70) mm*(20-30) mm*(7-8) mm, and the mass ratio of the polyurethane foam to the ore powder containing gold element in step (4) is 1:(30-50).

[0020] Preferably, the mass concentration of the thiourea-hydrochloric acid aqueous solution in step (7) is 0.5-1.5%, and the volume ratio of the mass of the ore powder containing gold element in step (4) to the thiourea-hydrochloric acid aqueous solution in step (7) is 1g: (0.5-2)mL.

[0021] Preferably, the release in step (7) is carried out in a boiling water bath, and the release time is 30 to 60 minutes.

[0022] Preferably, in step (8), the current of X-ray fluorescence detection is 0.3-0.5 mA, the voltage of X-ray fluorescence detection is 40-60 kV, and the time of X-ray fluorescence detection is 280-320 min.

[0023] The invention provides a method for detecting the gold content in a gold ore, comprising the following steps: (1) performing X-ray fluorescence detection on gold ore standard substance powders with different gold contents, and drawing a standard curve 1; (2) performing X-ray fluorescence detection on the ore powder, judging whether the ore powder contains gold elements through the standard curve 1 obtained in the step (1), and obtaining the semi-quantitative content of gold in the ore powder; (3) performing X-ray fluorescence detection on thiourea-hydrochloric acid aqueous solutions with different gold contents, and drawing a standard curve 2; (4) roasting the ore powder containing the gold element to obtain the roasted gold ore powder; (5) mixing the roasted gold ore powder obtained in step (4) with aqua regia and digesting the mixture to obtain a gold solution; (6) mixing the gold solution obtained in step (5) with water and polyurethane foam and adsorbing the mixture to obtain polyurethane foam adsorbing gold; (7) mixing the polyurethane foam adsorbing gold obtained in step (6) with a thiourea-hydrochloric acid aqueous solution and releasing the mixture to obtain a gold solution; (8) performing X-ray fluorescence detection on the gold solution obtained in step (7), and obtaining the gold content in the gold ore powder through the standard curve 2 obtained in step (3). The present invention first performs X-ray fluorescence detection on ore powder to determine whether the ore contains gold elements, and obtains the semi-quantitative content of gold in the gold ore powder; then roasts the ore powder containing gold elements to remove sulfur, arsenic, organic matter and volatile substances to avoid interference with subsequent gold detection; uses aqua regia to digest the roasted gold ore powder to dissolve the gold in the roasted gold ore powder; adds polyurethane foam for adsorption, and then uses thiourea-hydrochloric acid aqueous solution for release to obtain gold liquid; finally, the gold liquid is detected, which can reduce the detection limit and improve the accuracy of detection. The results of the embodiment show that the detection limit of the detection method of the present invention is 0.022g / t, the relative error is 0.02-5.5%, and the relative standard deviation is 1.3-1.9%. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The standard curve drawn for step (1) of Example 1 of the present invention;

[0025] Figure 2 This is the standard curve drawn in step (3) of Example 1 of the present invention. DETAILED DESCRIPTION

[0026] The present invention provides a method for detecting the gold content in a gold ore, comprising the following steps:

[0027] (1) Performing X-ray fluorescence detection on gold ore standard material powders with different gold contents and drawing a standard curve 1;

[0028] (2) performing X-ray fluorescence detection on the ore powder, judging whether the ore powder contains gold element through the standard curve 1 obtained in step (1), and obtaining the semi-quantitative content of gold in the ore powder;

[0029] (3) Performing X-ray fluorescence detection on thiourea-hydrochloric acid aqueous solutions with different gold contents and drawing a standard curve 2;

[0030] (4) roasting the ore powder containing the gold element to obtain roasted gold ore powder;

[0031] (5) mixing the roasted gold ore powder obtained in step (4) with aqua regia and digesting the mixture to obtain a gold solution;

[0032] (6) mixing the gold solution obtained in step (5) with water and polyurethane foam and performing adsorption to obtain polyurethane foam adsorbing gold;

[0033] (7) mixing the gold-adsorbed polyurethane foam obtained in step (6) with a thiourea-hydrochloric acid aqueous solution and releasing the mixture to obtain a gold liquid;

[0034] (8) Performing X-ray fluorescence detection on the gold solution obtained in step (7), and obtaining the gold content in the gold ore powder through the standard curve 2 obtained in step (3).

[0035] Unless otherwise specified, the present invention has no particular limitation on the sources of the raw materials, and commercially available products or products from conventional sources known to those skilled in the art may be used.

[0036] The present invention performs X-ray fluorescence detection on gold ore standard material powders with different gold contents to draw a standard curve 1.

[0037] In the present invention, the gold contents in the gold ore standard substance powders with different gold contents are preferably 1.1 g / t, 3.3 g / t, 5.72 g / t, 10.4 g / t, 18.4 g / t, 31.9 g / t and 51.8 g / t, respectively. In the present invention, the particle size of the gold ore standard substance powders with different gold contents is preferably ≤0.074 mm.

[0038] In the present invention, the current of the X-ray fluorescence detection is preferably 0.3-0.5 mA, more preferably 0.4 mA; the voltage of the X-ray fluorescence detection is preferably 40-60 kV, more preferably 50 kV; the time of the X-ray fluorescence detection is preferably 280-320 min, more preferably 300 min. In the present invention, the X-ray fluorescence detection equipment is preferably: Suzhou Jiapu Efind M300 portable X-ray fluorescence spectrometer, volume 0.04m3 , net weight 25kg.

[0039] The present invention preferably performs linear fitting based on the measured X-ray fluorescence intensity of gold ore standard substance powders with different gold contents and the gold content in the gold ore standard substance powders to draw a standard curve 1.

[0040] In the present invention, the horizontal coordinate of the standard curve 1 is the gold content, and the vertical coordinate is the X-ray fluorescence intensity.

[0041] After obtaining the standard curve 1, the present invention performs X-ray fluorescence detection on the ore powder, and judges whether the ore powder contains gold element through the standard curve 1, and obtains the semi-quantitative content of gold in the ore powder. The present invention obtains the gold content in the ore powder through the standard curve 1 according to the X-ray fluorescence intensity of the ore powder.

[0042] In the present invention, the particle size of the ore powder is preferably ≤0.074 mm. The present invention limits the particle size of the ore powder to the above range, which can further improve the detection accuracy.

[0043] When the particle size of the ore powder is not within the above range, the present invention preferably performs coarse crushing, medium crushing and fine crushing on the ore in sequence to obtain the ore powder.

[0044] In the present invention, the particle size of the ore after coarse crushing is preferably ≤10mm; the particle size of the ore after medium crushing is preferably ≤2mm; the particle size of the ore powder after fine crushing is preferably ≤0.074mm. The present invention has no special restrictions on the operations of coarse crushing, medium crushing and fine crushing, and adopts the crushing technical scheme well known to those skilled in the art to ensure that the particle size after crushing is within the above range.

[0045] In the present invention, the current of the X-ray fluorescence detection is preferably 0.3-0.5 mA, more preferably 0.4 mA; the voltage of the X-ray fluorescence detection is preferably 40-60 kV, more preferably 50 kV; the time of the X-ray fluorescence detection is preferably 280-320 min, more preferably 300 min. In the present invention, the X-ray fluorescence detection equipment is preferably: Suzhou Jiapu Efind M300 portable X-ray fluorescence spectrometer, volume 0.04m 3 , net weight 25kg. The present invention limits the parameters of X-ray fluorescence detection within the above range, which can further improve the accuracy of detection. The present invention adopts solid powder sampling, can quickly obtain analysis results, and has good correctness and precision.

[0046] The present invention performs X-ray fluorescence detection on thiourea-hydrochloric acid aqueous solutions with different gold contents and draws a standard curve 2.

[0047] In the present invention, the gold contents in the thiourea-hydrochloric acid aqueous solutions with different gold contents are preferably 0 μg / mL, 1 μg / mL, 5 μg / mL, 10 μg / mL and 20 μg / mL, respectively.

[0048] The invention preferably absorbs 10mL of Au national standard solution (1000 μg / mL) into a 100mL volumetric flask, and dilutes the solution with deionized water to obtain a 100 μg / mL gold standard stock solution; and respectively absorbs 0mL, 0.1mL, 0.5mL, 1mL and 2mL of the gold standard stock solution (100 μg / mL) into a 10mL colorimetric tube, and then dilutes the solution with a thiourea-hydrochloric acid aqueous solution (mass concentration 1%) to obtain thiourea-hydrochloric acid aqueous solutions with gold contents of 0.00 μg / mL, 1.00 μg / mL, 5.00 μg / mL, 10.0 μg / mL and 20.0 μg / mL, respectively.

[0049] In the present invention, the mass concentration of the thiourea-hydrochloric acid aqueous solution is preferably 0.5-1.5%, more preferably 1%. In the present invention, the preparation method of the thiourea-hydrochloric acid aqueous solution is preferably: weigh thiourea, dilute with (1+9) hydrochloric acid to obtain the thiourea-hydrochloric acid aqueous solution.

[0050] In the present invention, the current of the X-ray fluorescence detection is preferably 0.3-0.5 mA, more preferably 0.4 mA; the voltage of the X-ray fluorescence detection is preferably 40-60 kV, more preferably 50 kV; the time of the X-ray fluorescence detection is preferably 280-320 min, more preferably 300 min. In the present invention, the X-ray fluorescence detection equipment is preferably: Suzhou Jiapu Efind M300 portable X-ray fluorescence spectrometer, volume 0.04m 3 The present invention limits the parameters of X-ray fluorescence detection within the above range, which can further improve the accuracy of detection.

[0051] The present invention preferably performs linear fitting based on the measured X-ray fluorescence intensity of the thiourea-hydrochloric acid aqueous solution with different gold contents and the gold content in the thiourea-hydrochloric acid aqueous solution with different gold contents to draw a standard curve 2.

[0052] In the present invention, the horizontal coordinate of the standard curve 2 is the gold content, and the vertical coordinate is the X-ray fluorescence intensity.

[0053] The invention roasts the ore powder containing gold element to obtain roasted gold ore powder.

[0054] In the present invention, the calcination preferably includes low-temperature calcination and high-temperature calcination performed sequentially.

[0055] In the present invention, the temperature of the low-temperature calcination is preferably 300-500° C., more preferably 400° C.; the time of the low-temperature calcination is preferably 30-90 min, more preferably 60 min.

[0056] In the present invention, the temperature of the high temperature roasting is preferably 600-700°C, more preferably 650-700°C, and further preferably 680°C; the time of the high temperature roasting is preferably 90-180 minutes, and more preferably 120 minutes. In the present invention, the roasting is used to remove sulfur, arsenic, organic matter and volatile substances in the ore to avoid subsequent interference with gold detection. The present invention limits the roasting temperature and time within the above range, which can fully remove interfering substances and improve the accuracy of detection.

[0057] After the roasting is completed, the present invention preferably cools the roasted product to obtain roasted gold ore powder.

[0058] The present invention has no special limitation on the cooling operation, and cooling to room temperature may be performed using cooling technical solutions well known to those skilled in the art.

[0059] After obtaining the roasted gold ore powder, the present invention mixes the roasted gold ore powder with aqua regia and digests the mixture to obtain a gold solution.

[0060] In the present invention, the aqua regia is preferably (1+1) aqua regia, that is, the volume ratio of concentrated hydrochloric acid and concentrated nitric acid in the aqua regia is 3:1, and the volume ratio of the total volume of concentrated hydrochloric acid and concentrated nitric acid to water is 1:1.

[0061] In the present invention, the mass ratio of the ore powder containing gold element to the volume ratio of aqua regia is preferably (10-20) g: (30-50) mL. The present invention limits the mass ratio of the ore powder containing gold element to the volume ratio of aqua regia within the above range, which can fully dissolve the gold in the ore powder and improve the detection accuracy.

[0062] In the present invention, the digestion temperature is preferably 180-200°C, more preferably 190°C; the digestion time is preferably 50-70min, more preferably 60min; the digestion is preferably performed on a hot plate. In the present invention, oscillation is preferably performed during the digestion process. The present invention has no special limitation on the number of oscillations, and the number of oscillations familiar to those skilled in the art can be used. In the present invention, the oscillation is more conducive to the dissolution of gold in the ore. In the present invention, gold is dissolved in the ore powder during the digestion process. The present invention uses aqua regia for digestion, and controls each parameter within the above range, which can fully dissolve the gold and avoid interference from other substances, thereby further improving the accuracy of detection.

[0063] After the digestion is completed, the present invention preferably cools the digested product to obtain a gold solution.

[0064] The present invention has no special limitation on the cooling method and end point. A cooling method well known to those skilled in the art may be used to cool the mixture to an operable temperature.

[0065] After obtaining the gold solution, the present invention mixes the gold solution with water and polyurethane foam and then performs adsorption to obtain the polyurethane foam adsorbing gold.

[0066] In the present invention, the volume of the mixed system obtained by mixing the gold solution and water is preferably 70 to 150 mL, and more preferably 90 to 120 mL.

[0067] In the present invention, the polyurethane foam is preferably W-shaped; the size of the polyurethane foam is preferably (50-70) mm*(20-30) mm*(7-8) mm, more preferably 60 mm*25 mm*7.5 mm; the mass ratio of the polyurethane foam to the ore powder containing the gold element is preferably 1:(30-50), more preferably 1:40. The W-shaped polyurethane foam used in the present invention can increase its specific surface area, thereby increasing the adsorption rate. The mass ratio of the polyurethane foam to the ore powder containing the gold element is limited to the above range in the present invention, which can fully adsorb the gold in the solution and improve the detection accuracy.

[0068] In the present invention, the polyurethane foam is preferably washed with water and then soaked before use. The present invention has no special limitation on the operation of washing with water, and the polyurethane foam can be cleaned by using a water washing technical solution well known to those skilled in the art. The present invention washes the polyurethane foam with water to remove impurities therein, thereby avoiding interference with subsequent gold detection.

[0069] In the present invention, the polyurethane foam is preferably subjected to blank spike recovery rate acceptance before use to ensure that the polyurethane foam is clean and free of pollution. In the present invention, the blank spike recovery rate of the polyurethane foam is preferably ≥98%.

[0070] In the present invention, the adsorption is preferably vibration adsorption; the adsorption time is preferably 20 to 50 minutes, more preferably 40 minutes. The present invention limits the adsorption time to the above range, so that gold can be fully adsorbed.

[0071] After the adsorption is completed, the polyurethane foam is preferably taken out, washed with water and squeezed dry.

[0072] The present invention has no particular limitation on the operations of taking out the polyurethane foam, washing with water and squeezing out the water, and operations well known to those skilled in the art may be adopted.

[0073] After obtaining the polyurethane foam plastic that absorbs gold, the present invention mixes the polyurethane foam plastic that absorbs gold with a thiourea-hydrochloric acid aqueous solution and then releases the mixture to obtain a gold liquid.

[0074] In the present invention, the mass concentration of the thiourea-hydrochloric acid aqueous solution is preferably 0.5-1.5%, more preferably 1%; the volume ratio of the mass of the ore powder containing gold elements to the thiourea-hydrochloric acid aqueous solution is preferably 1g: (0.5-2)mL, more preferably 1g: 1mL. The present invention limits the volume ratio of the mass of the ore powder containing gold elements to the thiourea-hydrochloric acid aqueous solution to the above range, which can fully release the gold in the polyurethane foam that adsorbs gold, and further improve the detection accuracy.

[0075] In the present invention, the method for preparing the thiourea-hydrochloric acid aqueous solution is preferably: weighing thiourea, diluting it with (1+9) hydrochloric acid, to obtain the thiourea-hydrochloric acid aqueous solution.

[0076] In the present invention, the release is preferably carried out in a boiling water bath. The present invention has no special limitation on the temperature of the boiling water bath, and the boiling water bath temperature familiar to those skilled in the art can be used. In the present invention, the release time is preferably 30 to 60 minutes, more preferably 30 to 40 minutes. In the present invention, a glass rod is preferably used to squeeze the polyurethane foam during the release process to fully dissolve the adsorbed gold. In the present invention, the gold adsorbed in the polyurethane foam is dissolved during the release process. The present invention limits the various parameters of the release within the above range, which can make the gold fully dissolved and further improve the detection accuracy.

[0077] After the release is completed, the present invention preferably takes out the released polyurethane foam while it is hot.

[0078] The present invention has no particular limitation on the operation of taking out the liberated polyurethane foam, and the polyurethane foam can be taken out by the operation well known to those skilled in the art.

[0079] After obtaining the gold liquid, the present invention performs X-ray fluorescence detection on the gold liquid, and obtains the gold content in the gold ore powder through the standard curve 2. The present invention obtains the gold content in the ore powder through the standard curve 2 according to the X-ray fluorescence intensity of the gold liquid.

[0080] In the present invention, the current of the X-ray fluorescence detection is preferably 0.3-0.5 mA, more preferably 0.4 mA; the voltage of the X-ray fluorescence detection is preferably 40-60 kV, more preferably 50 kV; the time of the X-ray fluorescence detection is preferably 280-320 min, more preferably 300 min. In the present invention, the X-ray fluorescence detection equipment is preferably: Suzhou Jiapu Efind M300 portable X-ray fluorescence spectrometer, volume 0.04m 3The present invention limits the parameters of X-ray fluorescence detection within the above range, which can further improve the accuracy of detection.

[0081] The invention firstly performs X-ray fluorescence detection on ore powder to judge whether the ore contains gold element and obtains the semi-quantitative content of gold in the gold ore powder; then roasts the ore powder containing the gold element to remove sulfur, arsenic, organic matter and volatile substances to avoid interference with subsequent gold detection; aqua regia is used to digest the ore powder containing the gold element to dissolve the gold in the gold ore powder, polyurethane foam is added for adsorption, thiourea solution is used for release to obtain gold liquid, and finally the gold liquid is detected, and various process parameters are controlled to reduce the detection limit and improve the accuracy of detection.

[0082] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0083] Example 1

[0084] (1) A group of gold ore standard material powders (≤0.074 mm) with gold contents ranging from low to high were selected, namely GBW07807a, GBW07808b, GBW07300a, GBW07809a, GBW07297a, GBW07298a and GBW07299a, with gold contents of 1.1 g / t, 3.3 g / t, 5.72 g / t, 10.4 g / t, 18.4 g / t, 31.9 g / t and 51.8 g / t, respectively. They were directly placed in a sample box for X-ray fluorescence detection (detection equipment: Suzhou Jiapu Efind M300 portable X-ray fluorescence spectrometer, volume 0.04 m 3 , net weight 25kg, current 0.4mA, voltage 50kV, detection time 300min), linear fitting was performed based on the measured X-ray fluorescence intensity and the gold content in the standard substance to draw a standard curve, the curve equation was y=3.4806x-1.2018, and the linear correlation coefficient was 0.9977;

[0085] (2) The gold ore is crushed coarsely (≤10 mm), medium (≤2 mm) and finely to obtain gold ore powder with a particle size of ≤0.074 mm, which is directly placed in a sample box for X-ray fluorescence detection (detection equipment: Suzhou Jiapu Efind M300 portable X-ray fluorescence spectrometer, volume 0.04m 3, net weight 25kg, current 0.4mA, voltage 50kV, detection time 300min), according to the standard curve drawn in step (1), measure the gold content in the gold ore powder;

[0086] (3) Accurately pipette 10 mL of Au national standard solution (1000 μg / mL) into a 100 mL volumetric flask, dilute with deionized water to obtain Au standard stock solution (100 μg / mL), and accurately pipette 0 mL, 0.1 mL, 0.5 mL, 1 mL and 2.0 mL of Au standard stock solution (100 μg / mL) into 10 mL colorimetric tubes, respectively, and then dilute with thiourea-hydrochloric acid aqueous solution (mass concentration 1%). The gold concentrations are 0.00, 1.00, 5.00, 10.0 and 20.0 μg / mL, respectively, and X-ray fluorescence detection is performed (detection equipment: Suzhou Jiapu Efind M300 portable X-ray fluorescence spectrometer, volume 0.04 m 3 , net weight 25kg, current 0.4mA, voltage 50kV, detection time 300min), a standard curve was drawn based on the relationship between gold concentration and X-ray fluorescence intensity, the curve equation was y=3.3736x+0.2403, and the linear correlation coefficient was 0.9991;

[0087] (4) Weigh 20 g of gold ore powder (≤0.074 mm) sample, accurate to 0.01 g, place in a porcelain crucible for roasting, keep at 400 °C for 1 h, keep at 680 °C for 2 h, take out and cool, pour the sample into a conical flask, add 40 mL (1+1) aqua regia (the mass ratio of gold ore powder to aqua regia is 10 g: 20 mL), heat on a hot plate to dissolve, digest at 190 °C for 60 min, oscillate twice during the digestion process, cool, and obtain 10 mL of gold solution; add 90 mL of deionized water (the volume of the mixed system obtained by mixing the gold solution and water is 100 mL) to the gold solution. L), add a piece of polyurethane foam (W-shaped, 60mm*25mm*7.5mm, the mass ratio of polyurethane foam to ore powder containing gold element is 1:40), shake and adsorb for 40 minutes, then take out the polyurethane foam, wash it and squeeze out the water, put it into a 25mL colorimetric tube, add 20mL thiourea-hydrochloric acid aqueous solution (mass concentration 1%, the volume ratio of the mass of ore powder containing gold element to thiourea-hydrochloric acid aqueous solution is 1g:1mL), put it into a boiling water bath to release for 40 minutes, during which time the foam is squeezed with a glass rod, and the foam is taken out while hot to obtain gold liquid;

[0088] (5) The gold solution obtained in step (4) was subjected to X-ray fluorescence detection (detection equipment: Suzhou Jiapu Efind M300 portable X-ray fluorescence spectrometer, volume 0.04m 3, net weight 25kg, current 0.4mA, voltage 50kV, detection time 300min), according to the standard curve drawn in step (3), the gold content in the gold ore powder is obtained.

[0089] Acceptance of blank spiked recovery rate of polyurethane foam in Example 1: 0.5 μg / mL, 3 μg / mL and 10 μg / mL gold standard solution were added to the blank solution, and a piece of polyurethane foam (W-shaped, 60 mm*25 mm*7.5 mm) was added. The polyurethane foam was adsorbed by shaking for 40 min, and then the polyurethane foam was taken out, washed and squeezed dry, put into a 25 mL colorimetric tube, and thiourea-hydrochloric acid aqueous solution (mass concentration 1%, the volume ratio of sample mass to thiourea-hydrochloric acid aqueous solution was 1 g: 1 mL) was added, and the solution was put into a boiling water bath for 40 min. During this period, the foam was squeezed with a glass rod, and the foam was taken out while hot to obtain gold liquid; the obtained gold liquid was subjected to X-ray fluorescence detection (detection equipment: Suzhou Jiapu Efind M300 portable X-ray fluorescence spectrometer, volume 0.04 m 3 , net weight 25kg, current 0.4mA, voltage 50kV, detection time 300min), according to the standard curve drawn in step (3) of Example 1, the gold content was obtained, and the measurement was repeated twice to calculate the blank spike recovery rate. The results are shown in Table 1.

[0090] Table 1 Blank spike recovery of polyurethane foam

[0091]

[0092]

[0093] As can be seen from Table 1, the blank spike recovery rate is between 98% and 99.24%, and the quality of polyurethane foam and other reagents is qualified.

[0094] The standard curve drawn in step (1) of Example 1 is as follows Figure 1 shown.

[0095] The gold content of the gold ore national standard material GBW07142a was measured 11 times according to the method of steps (1) and (2) of Example 1. The results are shown in Table 2. The detection limit of gold in the gold ore was calculated to be 0.053 g / t.

[0096] Table 2 Detection limits of the detection methods in steps (1) and (2) of Example 1

[0097]

[0098] The gold ore national standard substances GBW07807a, GBW07809a and GBW07298a were directly sampled according to the method of steps (1) and (2) of Example 1, and were measured six times continuously using a portable energy dispersive X-ray fluorescence spectrometer. The substance concentration and relative standard deviation were determined according to the standard curve. The measurement results are shown in Table 3.

[0099] Table 3 Precision and accuracy of the detection methods in steps (1) and (2) of Example 1

[0100]

[0101] As can be seen from Tables 2 to 3, the determination of the gold content of gold ore by solid powder sampling-portable energy dispersive X-ray fluorescence spectrometry in steps (1) and (2) of Example 1 has high accuracy and precision, with relative errors ranging from 1.6 to 2.9% and relative standard deviations ranging from 4.4 to 8.3%.

[0102] The standard curve drawn in step (3) of Example 1 is as follows Figure 2 shown.

[0103] The gold content of the gold ore national standard material GBW07142a was determined 11 times according to the method flow of steps (3) to (5) of Example 1. The results are shown in Table 4. The detection limit of gold in the gold ore was calculated to be 0.022 g / t.

[0104] Table 4 Detection limits of the method in steps (3) to (5) of Example 1

[0105]

[0106] The gold ore national standard materials GBW07807a, GBW07300a and GBW07297a were treated according to steps (3) to (5) of Example 1 and then measured six times in succession using a portable energy dispersive X-ray fluorescence spectrometer. The substance concentration and relative standard deviation were determined based on the standard curve. The measurement results are shown in Table 5.

[0107] Table 5 Precision and accuracy of the method in steps (3) to (5) of Example 1

[0108]

[0109] As can be seen from Tables 4 to 5, the determination of the gold content of gold ore by foam plastic adsorption-portable energy dispersive X-ray fluorescence spectrometry in steps (3) to (5) of Example 1 has high accuracy and precision, with relative errors ranging from 0.02 to 5.5% and relative standard deviations ranging from 1.3 to 1.9%.

[0110] In summary, the detection method of the present invention has a good detection limit, as well as high accuracy and precision, and plays a guiding role in the determination of gold content in gold ores in the geological industry.

[0111] The method of the present invention is suitable for on-site analysis in field base laboratories. The detection equipment is small in size and easy to carry and transport, and does not require any auxiliary equipment. The error of the rapid determination of standard substances is less than 40%, and the relative deviation of repeated sample determination is less than 20%; the error of the accurate determination of standard substances is less than 5%, and the relative deviation of repeated sample determination is less than 10%. The accurate determination results meet the requirements for gold ore analysis in DZ / T0130.3-2006 "Geological Mineral Laboratory Test Quality Management Standard Part 3: Chemical Composition Analysis of Rock and Mineral Samples". When the sample processing meets the requirements for gold ore analysis and testing, when the sample weight is 10-20g, the detection range of gold in the gold ore is: 0.25μg / g-50.0μg / g.

[0112] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for detecting the gold content in a gold ore, comprising the following steps: (1) Performing X-ray fluorescence detection on gold ore standard material powders with different gold contents and drawing a standard curve 1; (2) performing X-ray fluorescence detection on the ore powder, judging whether the ore powder contains gold element through the standard curve 1 obtained in step (1), and obtaining the semi-quantitative content of gold in the ore powder; (3) Performing X-ray fluorescence detection on thiourea-hydrochloric acid aqueous solutions with different gold contents and drawing a standard curve 2; (4) roasting the ore powder containing the gold element to obtain roasted gold ore powder; (5) mixing the roasted gold ore powder obtained in step (4) with aqua regia and digesting the mixture to obtain a gold solution; (6) mixing the gold solution obtained in step (5) with water and polyurethane foam and performing adsorption to obtain polyurethane foam adsorbing gold; (7) mixing the gold-adsorbed polyurethane foam obtained in step (6) with a thiourea-hydrochloric acid aqueous solution and releasing the mixture to obtain a gold liquid; (8) Performing X-ray fluorescence detection on the gold solution obtained in step (7), and obtaining the gold content in the gold ore powder through the standard curve 2 obtained in step (3).

2. The detection method according to claim 1, characterized in that: The calcination in step (4) includes low-temperature calcination and high-temperature calcination performed sequentially.

3. The detection method according to claim 2, characterized in that: The temperature of the low-temperature roasting is 300-500° C., and the time of the low-temperature roasting is 30-90 minutes.

4. The detection method according to claim 2, characterized in that: The temperature of the high temperature calcination is 600-700° C., and the time of the high temperature calcination is 90-180 minutes.

5. The detection method according to claim 1, characterized in that: The volume ratio of the mass of the ore powder containing gold element in step (4) to the aqua regia in step (5) is (10-20) g: (30-50) mL.

6. The detection method according to claim 1, characterized in that: The digestion temperature in step (5) is 180-200° C., and the digestion time is 50-70 min.

7. The detection method according to claim 1, characterized in that: The polyurethane foam in step (6) is W-shaped, and the size of the polyurethane foam is (50-70) mm*(20-30) mm*(7-8) mm. The mass ratio of the polyurethane foam to the ore powder containing gold element in step (4) is 1:(30-50).

8. The detection method according to claim 1, characterized in that: The mass concentration of the thiourea-hydrochloric acid aqueous solution in step (7) is 0.5-1.5%, and the volume ratio of the mass of the ore powder containing the gold element in step (4) to the thiourea-hydrochloric acid aqueous solution in step (7) is 1g: (0.5-2)mL.

9. The detection method according to claim 1, characterized in that: The release in step (7) is carried out in a boiling water bath, and the release time is 30 to 60 minutes.

10. The detection method according to claim 1, characterized in that: In the step (8), the current of X-ray fluorescence detection is 0.3-0.5 mA, the voltage of X-ray fluorescence detection is 40-60 kV, and the time of X-ray fluorescence detection is 280-320 min.

Images