A method and apparatus for detecting the content of sulphides and / or sulphates in a mineral

Abstract

The present application provides a kind of mineral sulfide and / or sulfate content detection method and device, it is related to analytical detection technical field.The present application is determined using stage temperature combustion iodometric method, first in low temperature stage (500~700 DEG C) oxidation reaction is carried out, and the sulfide in the mineral to be detected is oxidized into sulfur dioxide;Again in high temperature stage (1150~1350 DEG C) reduction reaction is carried out, and the sulfate in the combustion residue is reduced into sulfur dioxide, and the sulfur dioxide generated in low temperature stage and high temperature stage is titrated respectively by iodometric method, and then the content of sulfide and / or sulfate in the mineral to be detected is calculated, the sulfide, sulfate and total sulfur content in the mineral to be detected can be obtained simultaneously in one detection process, and then the sulfur form distribution information in the mineral to be detected is obtained.Moreover, the method provided by the present application is simple in operation, short in time consumption, low in risk of sulfur form conversion, high in detection accuracy, and suitable for industrial detection application.

Description

Technical Field

[0001] This invention relates to the field of analytical testing technology, specifically to a method and apparatus for detecting the content of sulfides and / or sulfates in minerals. Background Technology

[0002] Sulfur is an important and ubiquitous element in minerals, primarily found in sulfides and sulfates. In mining, sulfides are a major source of acidic mine wastewater, while sulfates are relatively stable. However, in fields such as road construction, sulfates, due to their water absorption and swelling properties, can cause roadbed deformation, thus affecting the normal operation of transportation routes. Therefore, accurately determining the total sulfur content and its speciation in minerals is crucial for geological research, mineral processing, environmental protection, and energy utilization.

[0003] Currently, the main method for sulfur detection is combustion iodometric titration, which involves converting all forms of sulfur into sulfur dioxide at a single high temperature (>1250℃) to determine the total sulfur content. However, combustion iodometric titration only measures the sum of all sulfur forms (total sulfur) and cannot provide information on the distribution of sulfur speciation. Therefore, there is an urgent need for a method that can simultaneously detect the content of sulfides and sulfates in minerals. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a method and apparatus for detecting the content of sulfides and / or sulfates in minerals. The detection method provided by this invention can simultaneously detect the sulfide content and sulfate content in the mineral to be tested, thereby obtaining information on the sulfur speciation distribution of the mineral to be tested.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for detecting the content of sulfides and / or sulfates in minerals, comprising the following steps: The mineral to be tested is mixed with oxygen-containing gas and subjected to an oxidation reaction to obtain the first gas and the residue. The combustion residue and carbon monoxide-containing gas are mixed and subjected to a reduction reaction to obtain a second gas; The sulfur content in the first gas and the second gas was determined by iodometric titration to obtain the contents of sulfide and sulfate, respectively. The oxidation reaction is carried out at a temperature of 500~700℃, and the reduction reaction is carried out at a temperature of 1150~1350℃.

[0006] Preferably, the sulfide includes one or more of ferrous disulfide, zinc sulfide, lead sulfide, copper sulfide, and cuprous sulfide; The sulfates include one or more of barium sulfate, calcium sulfate, ferrous sulfate, and magnesium sulfate.

[0007] Preferably, the ratio of the mass of the mineral to be tested to the flow rate of the oxygen-containing gas is 0.5~1.5g: 200~500mL / min; The ratio of the mass of the mineral to be tested to the flow rate of carbon monoxide gas is 0.5~1.5g:200~500mL / min.

[0008] Preferably, the oxygen-containing gas comprises an oxygen-protective gas mixture; The volume concentration of oxygen in the oxygen-containing gas is 21% to 100%. The carbon monoxide-containing gas includes a mixture of carbon monoxide and a protective gas. The volume concentration of carbon monoxide in the carbon monoxide-containing gas is 10-20%.

[0009] Preferably, the iodometric titration method includes the following steps: The first gas is absorbed by a first starch solution, and the resulting first absorbent is titrated with a first iodine solution to obtain a first titration result; the content of sulfides in the mineral to be tested is calculated based on the first titration result. The second gas is absorbed by a second starch solution, and the resulting second absorbent is titrated with a second iodine solution to obtain a second titration result; the sulfate content in the mineral to be tested is calculated based on the second titration result. The concentrations of the first iodine solution and the second iodine solution are independently 0.001~0.1 mol / L.

[0010] This invention provides an apparatus for the detection method described in the above technical solution, comprising: Reactor 4, wherein a gas passage 6 is provided in the cavity of reactor 4, and a sample inlet 5 is provided in the gas passage 6; Oxygen-containing gas supply component 1, which is connected to gas passage 6; A carbon monoxide gas supply component 2 is connected to a gas passage 6; Iodometric testing system 21, wherein the iodometric testing system 21 is connected to the outlet of gas passage 6; Color analysis component 17.

[0011] Preferably, the iodometric testing system 21 includes an absorption component 8 and a titrant supply component 19. The absorption component 8 is connected to the outlet of the gas passage 6, and the titrant supply component 19 is connected to the absorption component 8. A titration pump 13 is also provided in the passage connecting the titration supply component 19 and the absorption component 8. An air pump 10 is also provided on the exhaust passage of the absorption component 8.

[0012] Preferably, the device further includes: An absorbent supply component 20 is provided, which is connected to the absorbent component 8; an absorbent pump 15 is also provided in the passage connecting the absorbent supply component 20 and the absorbent component 8. An intake controller 3 is disposed on the passage connecting the oxygen-containing gas supply component 1 and the carbon monoxide-containing gas supply component 2 with the gas passage 6. The control unit 18 is communicatively connected to the reactor 4, the air inlet controller 3, the color analysis unit 17, the titration pump 13, the absorption liquid pump 15, and the vacuum pump 10.

[0013] Preferably, the oxygen-containing gas supply component 1 is connected to the oxygen-containing gas inlet 24 of the gas passage 6 through the oxygen-containing gas delivery passage 22; The carbon monoxide gas supply component 2 and the carbon monoxide gas inlet 25 of the gas passage 6 are connected through the carbon monoxide gas delivery passage 23. The absorption component 8 is connected to the gas outlet of the gas passage 6 through the gas delivery passage 9; The titrant supply component 19 and the absorption component 8 are connected through the titrant passage 12; The absorbent supply component 20 and the absorbent component 8 are connected through the absorbent passage 14; The absorption component 8 is connected to the air pump 10 through the air extraction passage 11.

[0014] Preferably, the reactor 4 is further provided with a heating element; The bottom of the absorption component 8 is also provided with a drain port 16.

[0015] This invention provides a method for detecting the content of sulfides and / or sulfates in minerals, comprising the following steps: mixing the mineral to be tested with an oxygen-containing gas and performing an oxidation reaction to obtain a first gas and a residue; mixing the residue with a carbon monoxide-containing gas and performing a reduction reaction to obtain a second gas; using iodometric titration to detect the sulfur content in the first gas and the second gas respectively, and obtaining the content of sulfides and sulfates respectively; the oxidation reaction temperature is 500~700℃, and the reduction reaction temperature is 1150~1350℃. This invention employs a staged temperature combustion iodometric method for determination. First, an oxidation reaction is carried out at a low temperature (500-700℃) to oxidize the sulfides in the mineral to be tested into sulfur dioxide gas. Then, the combustion residue undergoes a reduction reaction at a high temperature (1150-1350℃) to reduce the sulfates in the residue into sulfur dioxide gas. The sulfur dioxide generated in the low and high temperature stages is titrated separately using iodometric titration to calculate the content of sulfides and / or sulfates in the mineral to be tested. This allows for the simultaneous determination of sulfide, sulfate, and total sulfur content in the mineral to be tested in a single detection process, thus providing information on the sulfur speciation distribution in the mineral. Furthermore, the detection method provided by this invention is simple to operate, time-efficient, has a low risk of sulfur speciation conversion, and high accuracy, making it suitable for industrial detection applications.

[0016] The device provided by this invention has low cost, small footprint, and high potential for automation integration. Attached Figure Description

[0017] Figure 1 A schematic diagram of the apparatus used in the method for detecting sulfide and / or sulfate content in minerals provided by the present invention; Figure 2 This is a partial connection diagram of the air intake controller 3 and the reactor 4; Figure 3 for Figure 2 The left view; Figure 4 for Figure 2 Top view; Figures 1-4 In this system, 1-Oxygen gas supply component, 2-Carbon monoxide gas supply component, 3-Inlet controller, 4-Reactor, 5-Sample inlet, 6-Gas passage, 7-Sample stage, 8-Absorption component, 9-Gas passage, 10-Pump, 11-Pumping passage, 12-Titrate passage, 13-Titrate pump, 14-Absorption liquid passage, 15-Absorption liquid pump, 16-Drain, 17-Color analysis component, 18-Control component, 19-Titrate supply component, 20-Absorption liquid supply component; 21-Iodometric titration system; 22-Oxygen gas passage, 23-Carbon monoxide gas passage, 24-Oxygen gas inlet, 25-Carbon monoxide gas inlet; Figure 5 This is a flowchart illustrating the detection process for sulfide and / or sulfate content in minerals in Example 1. Detailed Implementation

[0018] This invention provides a method for detecting the content of sulfides and / or sulfates in minerals, comprising the following steps: The mineral to be tested is mixed with oxygen-containing gas and subjected to an oxidation reaction to obtain the first gas and the residue. The combustion residue and carbon monoxide-containing gas are mixed and subjected to a reduction reaction to obtain a second gas; The sulfur content in the first gas and the second gas was determined by iodometric titration to obtain the contents of sulfide and sulfate, respectively. The oxidation reaction is carried out at a temperature of 500~700℃, and the reduction reaction is carried out at a temperature of 1150~1350℃.

[0019] Unless otherwise specified, the materials and equipment used in this invention are all commercially available products in the field.

[0020] The present invention mixes the mineral to be tested with oxygen-containing gas and carries out an oxidation reaction to obtain a first gas and a combustion residue.

[0021] In this invention, the oxygen-containing gas may include an oxygen-protective gas mixture; the protective gas in the oxygen-protective gas mixture may include nitrogen and / or an inert gas; the volume concentration of oxygen in the oxygen-containing gas may be 21% to 100%, specifically 21%, 30%, 40%, 60%, 80%, or 100%. In this invention, when the oxygen-containing gas is air, the air may be further treated sequentially by a copper sulfate solution gas washing bottle, a potassium permanganate solution gas washing bottle, and a concentrated sulfuric acid gas washing bottle before use. In this invention, the mineral to be tested may include sulfur-containing rocks. In this invention, the mineral to be tested may be further subjected to sequential washing, drying, and crushing before use; the particle size of the powder obtained by grinding may be ≤200 mesh. In this invention, the ratio of the mass of the mineral to be tested to the flow rate of the oxygen-containing gas can be 0.5~1.5g:200~500mL / min, specifically 0.5g:500mL / min, 0.5g:300mL / min, 0.5g:200mL / min, 1g:300mL / min, or 1.5g:300mL / min. In this invention, the temperature of the oxidation reaction is 500~700℃, and can also be 550~650℃, specifically 580℃, 600℃, or 630℃.

[0022] In this invention, the reaction formula for the oxidation reaction is: MS + O2 → MO + SO2, where MS is a sulfide and M is a cation.

[0023] After obtaining the combustion residue, the present invention mixes the combustion residue with a carbon monoxide-containing gas and carries out a reduction reaction to obtain a second gas.

[0024] In this invention, the carbon monoxide-containing gas may include a carbon monoxide-protective gas mixture; the protective gas in the carbon monoxide-protective gas mixture may include nitrogen and / or an inert gas; the volume concentration of carbon monoxide in the carbon monoxide-containing gas may be 10-20%, specifically 10%, 12%, 15%, 18%, or 20%. This invention, by controlling the volume concentration of carbon monoxide in the carbon monoxide-containing gas to 10-20%, avoids side reactions caused by excessively high carbon monoxide concentrations, reduces background interference, and significantly reduces the risks of combustion, explosion, and toxicity.

[0025] In this invention, the ratio of the mass of the mineral to be detected to the flow rate of carbon monoxide-containing gas can be 0.5~1.5g:200~500mL / min, specifically 0.5g:500mL / min, 0.5g:300mL / min, 0.5g:200mL / min, 1g:300mL / min, or 1.5g:300mL / min. In this invention, the temperature of the reduction reaction is 1150~1350℃, and can also be 1200~1300℃, specifically 1225℃, 1250℃, or 1275℃.

[0026] In this invention, the reaction formula for the reduction reaction is: MSO4 + CO → MO + SO2 + CO2, where MSO4 is a sulfate and M is a cation.

[0027] After obtaining the first gas and the second gas, the present invention uses iodometric titration to detect the S content in the first gas and the second gas respectively, and obtains the contents of sulfide and sulfate respectively.

[0028] In this invention, the iodometric titration method may include the following steps: The first gas is absorbed by a first starch solution, and the resulting first absorbent is titrated with a first iodine solution to obtain a first titration result; the content of sulfides in the mineral to be tested is calculated based on the first titration result. The second gas is absorbed by a second starch solution, and the resulting second absorbent is titrated with a second iodine solution to obtain a second titration result; the sulfate content in the mineral to be tested is calculated based on the second titration result.

[0029] In this invention, the first gas is absorbed by a first starch solution, and the resulting first absorbent is titrated with a first iodine solution to obtain a first titration result; the content of sulfides in the mineral to be tested is calculated based on the first titration result.

[0030] In this invention, the sulfide may include one or more of ferrous disulfide, zinc sulfide, lead sulfide, copper sulfide, and cuprous sulfide.

[0031] In this invention, the starch in the first starch solution is soluble starch; the mass concentration of the first starch solution can be 0.5~0.1%, specifically 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%.

[0032] In this invention, the concentration of iodine in the first iodine solution can be 0.001~0.1 mol / L, specifically 0.001 mol / L, 0.005 mol / L, 0.01 mol / L, 0.05 mol / L or 0.1 mol / L; the first iodine solution can be an iodine-potassium iodide aqueous solution.

[0033] In this invention, the method for determining the titration endpoint is as follows: when the color of the absorbent changes from colorless to blue and does not fade, the titration endpoint is considered reached. This invention utilizes a starch solution to absorb sulfur dioxide produced in the reaction, and then titrates it with an iodine solution. When the iodine solution is added to the starch solution, the starch combines with the iodine, resulting in a blue color. After the starch solution absorbs sulfur dioxide, the sulfur dioxide reacts with the iodine, disrupting the combination of iodine and starch, causing the blue color to fade. Continue adding iodine solution until a faint blue color appears and remains briefly, at which point the reaction endpoint can be considered reached.

[0034] In this invention, the reaction that occurs during the titration process is: I₂ + SO₂ + 2H₂O → 2I - +SO4 2- +4H + .

[0035] In this invention, the second gas is absorbed by a second starch solution, and the resulting second absorbent is titrated with a second iodine solution to obtain a second titration result; the sulfate content in the mineral to be tested is calculated based on the second titration result.

[0036] In this invention, the sulfate may include one or more of barium sulfate, calcium sulfate, ferrous sulfate, and magnesium sulfate. In this invention, the parameters and preparation methods of the second starch solution and the second iodine solution are preferably independently the same as those of the first starch solution and the first iodine solution, and will not be repeated here. In this invention, the method for determining the titration endpoint and the reactions occurring during the titration process are preferably the same as described above, and will not be repeated here.

[0037] This invention provides an apparatus for the method described in the above technical solution, comprising: Reactor 4, wherein a gas passage 6 is provided in the cavity of reactor 4, and a sample inlet 5 is provided in the gas passage 6; Oxygen-containing gas supply component 1, which is connected to the sample inlet 5; A carbon monoxide gas supply component 2 is connected to the sample inlet 5; Absorption component 8, which is connected to the outlet of gas passage 6; Titration solution supply component 19, which is connected to absorption component 8; Color analysis component 17.

[0038] Figure 1 A schematic diagram of the apparatus used in the method for detecting sulfide and / or sulfate content in minerals provided by the present invention; Figure 2 This is a partial connection diagram of the air intake controller 3 and the reactor 4; Figure 3 for Figure 2 The left view; Figure 4 for Figure 2 The top view, combined with the following Figures 1-4 The apparatus provided by the present invention will be described in detail.

[0039] The device provided by the present invention includes a reactor 4, wherein a gas passage 6 is provided in the cavity of the reactor 4, and a sample inlet 5 is provided in the gas passage 6.

[0040] In this invention, the reactor 4 may also be equipped with a heating element; the reactor 4 may specifically be a tubular furnace. This invention heats the reactor 4 using the heating element to achieve and maintain the temperatures required for the oxidation and reduction reactions.

[0041] In this invention, the gas passage 6 can be a high-temperature resistant ceramic tube; a sample stage 7 can be inserted into the gas passage 6 through the sample inlet 5. Specifically, the sample stage 7 can be a ceramic boat. The mineral to be tested is held in the sample stage 7, and during the testing process, the mineral can be introduced into the isothermal zone inside the gas passage 6 through the sample inlet 5 for reaction.

[0042] In this invention, the injection port 5 can be located at one end of the gas passage 6 (one side port of the gas passage 6); the injection port 5 can be an openable / closable injection port. This invention, by employing an openable / closable injection port, allows the injection port 5 to open during the injection process and close during the reaction process.

[0043] In this invention, the gas passage 6 may also be provided with an oxygen gas inlet 24 and a carbon monoxide gas inlet 25; the distance between the oxygen gas inlet 24 and the sample inlet 5 may be 1 cm; the distance between the carbon monoxide gas inlet 25 and the sample inlet 5 may be 2 cm.

[0044] The device provided by this invention includes an oxygen-containing gas supply component 1, which is connected to a gas passage 6. In this invention, the oxygen-containing gas supply component 1 and the oxygen-containing gas inlet 24 of the gas passage 6 can be connected via an oxygen-containing gas delivery passage 22. In this invention, the oxygen-containing gas supply component 1 can be an oxygen-containing gas cylinder; the oxygen-containing gas delivery passage 22 can be an oxygen-containing gas delivery pipe. This invention provides an oxidizing environment through the oxygen-containing gas supply component 1, causing sulfides to undergo an oxidation reaction to generate sulfur dioxide.

[0045] The device provided by this invention includes a carbon monoxide gas supply component 2, which is connected to a gas passage 6. In this invention, the carbon monoxide gas supply component 2 and the carbon monoxide gas inlet 25 of the gas passage 6 are connected via a carbon monoxide gas delivery passage 23. In this invention, the carbon monoxide gas supply component 2 can be a carbon monoxide gas cylinder; the carbon monoxide gas delivery passage 23 can be a carbon monoxide gas pipe. This invention provides a reducing environment through the carbon monoxide gas supply component 2, causing sulfate to undergo a reduction reaction to generate sulfur dioxide. The device provided by this invention may further include an intake controller 3, which is disposed on the passage connecting the oxygen-containing gas supply component 1 and the carbon monoxide-containing gas supply component 2 to the gas passage 6. In this invention, the intake controller 3 may be disposed on the gas passage 6 near the sample inlet 5 and is communicatively connected to both the oxygen-containing gas inlet 24 and the carbon monoxide-containing gas inlet 25. This invention controls the opening and closing of the oxygen-containing gas inlet 24 and the carbon monoxide-containing gas inlet 25 by controlling the intake controller 3, thereby controlling the type and flow rate of gas entering the gas passage 6.

[0046] The device provided by the present invention includes an iodometric testing system 21, which is connected to the outlet of the gas passage 6.

[0047] In this invention, the iodometric titration system 21 may include an absorption component 8 and a titrant supply component 19; the absorption component 8 may be connected to the outlet of the gas passage 6; the titrant supply component 19 may be connected to the absorption component 8. In this invention, the absorption component 8 may be an absorption bottle; the titrant supply component 19 may be a titrant storage bottle.

[0048] In this invention, the absorption component 8 and the outlet of the gas passage 6 can be connected via a gas delivery passage 9. In this invention, the gas delivery passage 9 can be a gas pipe. This invention uses the absorption component 8 to absorb sulfur dioxide from the first and second gases.

[0049] In this invention, a drain port 16 may also be provided at the bottom of the absorption component 8. The drain port 16 is used to discharge waste liquid when titration is complete or when there is excessive solution in the absorption component 8.

[0050] In this invention, a vacuum pump 10 may also be provided on the exhaust passage of the absorption component 8; the absorption component 8 and the vacuum pump 10 can be connected through a vacuum passage 11. In this invention, the vacuum passage 11 can be a vacuum pipe. This invention provides a stable negative pressure through the vacuum pump 10, ensuring that the gas generated in the gas passage 6 can be transported to the absorption component 8 through the gas delivery passage 9.

[0051] In this invention, the titrant supply component 19 and the absorption component 8 can be connected via a titrant passage 12; a titrant pump 13 can also be provided on the passage connecting the titrant supply component 19 and the absorption component 8. In this invention, the titrant passage 12 can be a burette; the titrant pump 13 can be a peristaltic pump. In this invention, the titrant (iodine solution) in the titrant supply component 19 is transported to the absorption component 8 along the titrant passage 12 via the titrant pump 13.

[0052] The apparatus provided by this invention may further include an absorbent supply component 20, which is connected to the absorption component 8. In this invention, the absorbent supply component 20 may be an absorbent storage bottle. In this invention, the absorbent supply component 20 and the absorption component 8 may be connected via an absorbent passage 14; an absorbent pump 15 may also be installed on the passage connecting the absorbent supply component 20 and the absorption component 8. In this invention, the absorbent passage 14 may be an absorbent tube. This invention uses the absorbent pump 15 to transport the absorbent (starch solution) from the absorbent supply component 20 to the absorption component 8 along the absorbent passage 14 to replenish the absorbent.

[0053] The device provided by this invention includes a color analysis component 17. In this invention, the color analysis component 17 can be a color analyzer, specifically an RGB-1002 analyzer. This invention uses the color analysis component 17 to monitor the real-time changes in the absorbent liquid in the absorbent component 8.

[0054] The apparatus provided by this invention may further include a control component 18, which is communicatively connected to the reactor 4, the air inlet controller 3, the color analysis component 17, the titrant pump 13, the absorbent pump 15, and the vacuum pump 10. This invention controls the switching of the air inlet controller 3 via the control component 18, thereby controlling the opening and closing of the oxygen-containing gas supply component 1 and the carbon monoxide-containing gas supply component 2; it controls the opening and closing of the titrant pump 13 and the absorbent pump 15 via the control component 18, and automatically records the volume of titrant consumed; it controls the vacuum pump 10 to perform vacuuming via the control component 18; it receives color signal feedback from the color analysis component 17 via the control component 18; and it controls the reactor 4 to heat and maintain the reaction temperature via the control component 18.

[0055] In this invention, the method for detecting the sulfide and / or sulfate content in minerals using the apparatus provided by this invention includes the following steps: Starch solution is added to absorption unit 8 and absorption liquid supply unit 20, and iodine solution is added to titrant supply unit 19. The mineral to be tested is placed on sample stage 7. Control unit 18 is turned on to preheat reactor 4 to the oxidation reaction temperature. Sample stage 7 containing the mineral to be tested is placed into gas passage 6 through inlet 5. Inlet 5 is closed, and oxygen-containing gas is supplied to gas passage 6 through oxygen-containing gas supply unit 1 to carry out the oxidation reaction. First, 1-2 drops of iodine solution are added to starch solution in absorption unit 8. Vacuum pump 10 is turned on, and the obtained first gas is transported to absorption unit 8 along gas delivery passage 9. The blue color in absorption unit 8 fades, and the color change is fed back to control unit 18 by color analysis unit 17, causing control unit 18 to start titration pump 13 to continuously supply iodine solution to absorption unit 8 along titrant passage 12. When the solution turns blue and remains unchanged, the titration endpoint is reached, and the first volume of iodine solution consumed is recorded. The sulfide content in the mineral to be tested is calculated based on the first volume. The control unit 18 controls the intake controller 3 to switch the gas path, shuts off the oxygen-containing gas supply unit 1, and turns on the carbon monoxide-containing gas supply unit 2, supplying carbon monoxide-containing gas into the gas passage 6, heating the reactor 4 to the temperature of the reduction reaction, and carrying out the reduction reaction; first, 1-2 drops of iodine solution are added to the starch solution in the absorption unit 8, and the resulting second gas is transported to the absorption unit 8 along the gas delivery passage 9. The blue color in the absorption unit 8 fades, and the color change is fed back to the control unit 18 by the color analysis unit 17, causing the control unit 18 to start the titration pump 13, continuously supplying the iodine solution to the absorption unit 8 along the titrant passage 12. When the solution turns blue and remains unchanged, it is determined that the titration endpoint has been reached, and the second volume of the consumed iodine solution is recorded; the sulfate content in the mineral to be tested is calculated based on the second volume.

[0056] In this invention, the RGB values ​​of the solution at the titration endpoint can be: 0 < R < 50, 0 < G < 100, 50 < B < 150.

[0057] In this invention, when there is too much absorbent liquid in the absorption component 8 or when the next sample needs to be tested, the drain port 16 can be opened to discharge the waste liquid. Then, the absorbent starch solution in the absorbent supply component 20 is transported to the absorption component 8 through the absorbent liquid passage 14 by the absorbent liquid pump 15. After replenishing the new absorbent liquid, the next test can be performed.

[0058] To further illustrate the present invention, the solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0059] In all embodiments of the present invention, reactor 4 is a tubular furnace, gas passage 6 is a high-temperature resistant ceramic tube, sample stage 7 is a ceramic boat, inlet 5 is an openable inlet, oxygen gas supply component 1 is an oxygen cylinder, carbon monoxide gas supply component 2 is a carbon monoxide cylinder, absorption component 8 is an absorption bottle, titrant supply component 19 is a titrant storage bottle, gas delivery passage 9 is a gas delivery pipe, extraction passage 11 is an extraction pipe, titrant passage 12 is a titrant pipe, absorption liquid supply component 20 is an absorption liquid storage bottle, absorption liquid passage 14 is an absorption liquid pipe, color analysis component 17 is an RGB-1002 analyzer, oxygen gas delivery passage 22 is an oxygen gas delivery pipe, and carbon monoxide gas delivery passage 23 is a carbon monoxide gas delivery pipe.

[0060] The reagents used in the examples are: Iodine-potassium iodide aqueous solution, product number BWZ8349-2016, was purchased from Guangzhou Rongman Biotechnology Co., Ltd., with a purchased concentration of 0.1 mol / L. After calibration, the actual concentration was 0.09 mol / L. Starch solution, product number BWZ6044-2016, with a mass concentration of 0.5%.

[0061] Example 1 Figure 1 A schematic diagram of the apparatus used in the method for detecting sulfide and / or sulfate content in minerals provided by the present invention; Figure 2 This is a partial connection diagram of the air intake controller 3 and the reactor 4; Figure 3 for Figure 2 The left view; Figure 4 for Figure 2 Top view.

[0062] Figure 5 This is a flowchart illustrating the detection process for sulfide and / or sulfate content in minerals in Example 1. The specific detection steps are as follows: Fresh, unweathered sulfur-containing rock samples were selected, cleaned, and dried. The dried samples were then ground to a particle size of less than 200 mesh using a grinder. The minerals to be tested were selected in three batches and labeled as rock sample 1, rock sample 2, and rock sample 3, respectively. XRD analysis was performed on each sample, and the results are shown in Table 1.

[0063] Table 1. Composition and relative content percentage of the minerals to be tested (%)

[0064] Starch solution is added to absorption unit 8 and absorption liquid supply unit 20. Iodine solution (concentration meter: C mol / L) is added to titrant supply unit 19. A certain amount of the mineral to be tested is placed on sample stage 7. Control unit 18 is turned on to preheat reactor 4 to 600°C. Sample stage 7 containing the mineral to be tested is placed into gas passage 6 through inlet 5. Inlet 5 is closed. Oxygen gas is supplied to gas passage 6 through oxygen gas supply unit 1 at a flow rate of 200 mL / min for oxidation reaction. First, 1-2 drops of iodine solution are added to the starch solution in absorption unit 8. Vacuum pump 10 is turned on to obtain the gas... The solution is transported along the gas delivery path 9 to the absorption component 8. The blue color in the absorption component 8 fades, and the color change is fed back to the control component 18 via the color analysis component 17. This causes the control component 18 to start the titration pump 13, which continuously delivers the iodine solution to the absorption component 8 along the titrant path 12. When the solution turns blue (RGB values: 0 < R < 50, 0 < G < 100, 50 < B < 150) and remains unchanged, the titration endpoint is reached. The volume of iodine solution consumed is recorded as V1. The content of sulfides in the mineral to be tested is then calculated. The gas path is switched by the gas inlet controller 3 controlled by the control unit 18, the oxygen gas supply unit 1 is closed, and the carbon monoxide gas supply unit 2 is turned on. Carbon monoxide gas is delivered into the gas passage 6 at a flow rate of 200 mL / min. The reactor 4 is heated to 1250℃ to carry out the reduction reaction. First, 1~2 drops of iodine solution are added to the starch solution in the absorption unit 8. The obtained gas is delivered to the absorption unit 8 along the gas delivery passage 9. The blue color in the absorption unit 8 fades. The color change is fed back to the control unit 18 by the color analysis unit 17, which causes the control unit 18 to start the titration pump 13. The iodine solution is continuously delivered to the absorption unit 8 along the titration liquid passage 12. When the solution is blue (RGB value: 0 < R < 50, 0 < G < 100, 50 < B < 150) and remains unchanged, the titration endpoint is determined to be reached. The volume of iodine solution consumed is recorded as V2. The sulfate content in the mineral to be tested is calculated.

[0065] The formula for calculating the sulfide content in the mineral to be tested is shown in Equation 1: Formula 1.

[0066] Wherein, S1 is the sulfide content in the mineral to be tested (g / kg); C is the concentration of iodine solution (mol / L); V1 is the volume of iodine solution consumed by the gas generated in the oxidation reaction (mL); 32.06 is the molar mass of sulfur (g / mol) multiplied by the conversion factor; m is the mass of the mineral to be tested (g); and G is the empirical correction constant (1.05).

[0067] The empirical correction constant G is obtained by using the empirical correction constant in the People's Republic of China Forestry Industry Standard: Determination of Total Sulfur in Forest Soils (LY / T 1255—1999).

[0068] The formula for calculating the sulfate content in the mineral to be tested is shown in Formula 2: Equation 2.

[0069] Where S2 is the sulfate content in the mineral to be tested (g / kg); C is the concentration of iodine solution (mol / L); V2 is the volume of iodine solution consumed by the gas generated in the reduction reaction (mL); 32.06 is the molar mass of sulfur (g / mol) multiplied by the conversion factor; m is the mass of the mineral to be tested (g); and G is the empirical correction constant (1.05).

[0070] The formula for calculating the total sulfur content in the mineral to be tested is: Total sulfur content S total =S1+S2.

[0071] Table 2. Results of sulfur speciation tests in the minerals to be tested.

[0072] Table 2 shows the test results of sulfur speciation in the minerals to be tested. As can be seen from Table 2, the detection method provided by this invention has small error, high accuracy, and short detection time.

[0073] Comparative Example 1 The total sulfur content in the minerals to be tested was determined using the combustion iodometric method in the Forestry Industry Standard of the People's Republic of China: Determination of Total Sulfur in Forest Soils (LY / T 1255—1999).

[0074] The formula for calculating the total sulfur content in the mineral to be tested is shown in Equation 3: Formula 3.

[0075] Where S is the total sulfur content in the mineral to be tested (g / kg); C is the concentration of iodine solution (mol / L); V is the volume of iodine solution consumed by the oxidation reaction to generate gas (mL); 32.06 is the molar mass of sulfur (g / mol) multiplied by the conversion factor; m is the mass of the mineral to be tested (g); and G is the empirical correction constant (1.05).

[0076] Table 3. Results of Total Sulfur Determination in Minerals by Traditional Combustion Iodometric Method

[0077] Table 3 shows the test results of total sulfur in the tested minerals using the traditional combustion iodometric method. As shown in Tables 2 and 3, compared with the traditional combustion iodometric method, the detection method provided by this invention reduces the detection error by up to approximately 64%. Ignoring the preliminary preparation stage and assuming skilled operation, the traditional combustion iodometric method takes approximately 30 minutes per sample, while the detection method provided by this invention takes approximately 20 minutes per sample, improving detection efficiency by about 30%. By using the detection device and method provided by this invention, the accuracy and efficiency of the detection results are significantly improved, enabling accurate differentiation of the sulfide and sulfate content (sulfur speciation) of the tested minerals in a very short time.

[0078] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for detecting the content of sulfides and / or sulfates in minerals, characterized in that, Includes the following steps: The mineral to be tested is mixed with oxygen-containing gas and subjected to an oxidation reaction to obtain the first gas and the residue. The combustion residue and carbon monoxide-containing gas are mixed and subjected to a reduction reaction to obtain a second gas; The sulfur content in the first gas and the second gas was determined by iodometric titration to obtain the contents of sulfide and sulfate, respectively. The oxidation reaction is carried out at a temperature of 500~700℃, and the reduction reaction is carried out at a temperature of 1150~1350℃.

2. The detection method according to claim 1, characterized in that, The sulfides include one or more of ferric trisulfide, ferrous sulfide, ferrous disulfide, zinc sulfide, lead sulfide, copper sulfide, and cuprous sulfide; The sulfates include one or more of ferric sulfate, barium sulfate, calcium sulfate, ferrous sulfate, and magnesium sulfate.

3. The detection method according to claim 1 or 2, characterized in that, The ratio of the mass of the mineral to be tested to the flow rate of the oxygen-containing gas is 0.5~1.5g: 200~500mL / min; The ratio of the mass of the mineral to be tested to the flow rate of carbon monoxide gas is 0.5~1.5g:200~500mL / min.

4. The detection method according to claim 3, characterized in that, The oxygen-containing gas includes a mixture of oxygen and protective gas; The volume concentration of oxygen in the oxygen-containing gas is 21% to 100%. The carbon monoxide-containing gas includes a mixture of carbon monoxide and a protective gas. The volume concentration of carbon monoxide in the carbon monoxide-containing gas is 10-20%.

5. The detection method according to claim 1, characterized in that, The iodometric method includes the following steps: The first gas is absorbed by a first starch solution, and the resulting first absorbent is titrated with a first iodine solution to obtain a first titration result; the content of sulfides in the mineral to be tested is calculated based on the first titration result. The second gas is absorbed by a second starch solution, and the resulting second absorbent is titrated with a second iodine solution to obtain a second titration result; the sulfate content in the mineral to be tested is calculated based on the second titration result. The concentrations of the first iodine solution and the second iodine solution are independently 0.001~0.1 mol / L.

6. The apparatus used in the detection method according to any one of claims 1 to 5, characterized in that, include: The reactor (4) has a gas passage (6) inside its cavity and a sample inlet (5) in its gas passage (6). An oxygen-containing gas supply component (1) is connected to a gas passage (6); A carbon monoxide gas supply component (2) is connected to a gas passage (6); Iodometric testing system (21), wherein the iodometric testing system (21) is connected to the outlet of the gas passage (6); Color analysis component (17).

7. The apparatus according to claim 6, characterized in that, The iodometric testing system (21) includes an absorption component (8) and a titrant supply component (19). The absorption component (8) is connected to the outlet of the gas passage (6), and the titrant supply component (19) is connected to the absorption component (8). A titration pump (13) is also provided in the passage connecting the titration supply component (19) and the absorption component (8). An air pump (10) is also provided on the exhaust passage of the absorption component (8).

8. The apparatus according to claim 7, characterized in that, The device further includes: An absorbent supply component (20) is provided, which is connected to the absorbent component (8); an absorbent pump (15) is also provided in the passage connecting the absorbent supply component (20) and the absorbent component (8). An intake controller (3) is provided on the passage connecting the oxygen gas supply component (1) and the carbon monoxide gas supply component (2) with the gas passage (6); The control unit (18) is communicatively connected to the reactor (4), the air inlet controller (3), the color analysis unit (17), the titration pump (13), the absorption pump (15), and the vacuum pump (10).

9. The apparatus according to claim 8, characterized in that, The oxygen-containing gas supply component (1) is connected to the oxygen-containing gas inlet (24) of the gas passage (6) through the oxygen-containing gas delivery passage (22); The carbon monoxide gas supply component (2) and the carbon monoxide gas inlet (25) of the gas passage (6) are connected through the carbon monoxide gas delivery passage (23); The absorption component (8) is connected to the outlet of the gas passage (6) through the gas delivery passage (9); The titrant supply component (19) and the absorption component (8) are connected through the titrant passage (12); The absorbent supply component (20) and the absorbent component (8) are connected through the absorbent passage (14); The absorption component (8) is connected to the air pump (10) through the air extraction passage (11).

10. The apparatus according to claim 7, characterized in that, The reactor (4) is also equipped with a heating element; The bottom of the absorbent component (8) is also provided with a drain port (16).

Images