Quantitative analysis method for sulfur-containing ions in thiosulfate leaching system

Abstract

The invention discloses a quantitative analysis method for sulfur-containing ions in a thiosulfate leaching system. The quantitative analysis method for the sulfur-containing ions in the thiosulfate leaching system comprises the following steps: obtaining a plurality of isopyknic solutions to be detected; carrying out pretreatment and iodine titration on each part of the to-be-detected solution to obtain the titration volume of each part of the to-be-detected solution; and calculating the concentration of each sulfur-containing ion in the to-be-detected liquid according to the titration volume of each part of the to-be-detected liquid. The quantitative analysis method for the sulfur-containing ions in the thiosulfate leaching system provided by the invention is simple and convenient to operate, has wide applicability and can be used in laboratories and industrial sites; the method is accurate in determination and small in error (+ / -0.2%).

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrometallurgy, in particular, to a quantitative analysis method of sulfur-containing ions in a thiosulfate leaching system. BACKGROUND

[0002] Gold has many unique properties and is an important strategic reserve metal in China. The traditional cyanide leaching process cannot meet the current environmental production requirements because of the use of highly toxic cyanide. In recent years, people have developed a variety of alternative leaching agents for cyanide (such as thiosulfate, thiourea, thiocyanate, halide, microorganisms, and synthetic leaching agents), among which thiosulfate has high leaching efficiency, high adaptability to ores, perfect basic theory research, and green environmental protection. It has been used in industrial applications in Barrick Gold. However, thiosulfate (S2O3 2- ) is prone to redox reactions with Cu(II), O2 and other substances to generate SO3 2- , S 2- , S3O6 2- , S4O6 2- , S5O6 2- and other sulfur-containing substances, resulting in excessive consumption of thiosulfate, usually more than 25 kg / t of ore, sometimes more than 100 kg / t of ore.

[0003] In order to promote the large-scale industrial application of thiosulfate leaching system, accurate determination of the ion concentration of thiosulfate decomposition products is crucial for exploring the consumption reduction method of thiosulfate. The commonly used determination method in the laboratory is chromatography-ultraviolet detection method, which has high sensitivity and can quickly and accurately determine the concentration of sulfur-containing ions. However, this method is usually only suitable for laboratory research and is difficult to be directly applied to industrial sites, and depends on professional technicians. Therefore, it is particularly important to develop an analysis method that is not limited by location and personnel and can accurately determine the concentration of each sulfur-containing ion. SUMMARY

[0004] In order to solve the technical problem of the quantitative analysis method of sulfur-containing ions in the thiosulfate leaching system that the faceplate is prone to deformation under environmental stress and misoperation, the present application provides a quantitative analysis method of sulfur-containing ions in a thiosulfate leaching system, which is simple and convenient to operate, has wide applicability, and can be used in laboratories and industrial sites. The method is accurate and has small error (±0.2%).

[0005] The present application provides a quantitative analysis method of sulfur-containing ions in a thiosulfate leaching system, comprising the following steps:

[0006] Obtain multiple aliquots of the test solution;

[0007] Each sample of the test solution was pretreated and titrated using the iodine titration method to obtain the titration volume of each sample of the test solution;

[0008] The concentration of each sulfur-containing ion in the test solution is calculated based on the titration volume of each test solution.

[0009] In a preferred embodiment of the quantitative analysis method for sulfur-containing ions in the thiosulfate leaching system provided by the present invention, the pretreatment includes masking, precipitation separation and ion conversion.

[0010] In a preferred embodiment of the quantitative analysis method for sulfur-containing ions in the thiosulfate leaching system provided by the present invention, the masking operation is as follows: adding excess formaldehyde solution to the test solution to mask SO3 in the test solution. 2- .

[0011] In a preferred embodiment of the quantitative analysis method for sulfur-containing ions in the thiosulfate leaching system provided by the present invention, the precipitation separation operation is as follows: adding excess zinc acetate solution to the test solution to remove sulfur ions from the test solution. 2- Then filter to remove the precipitate.

[0012] In a preferred embodiment of the quantitative analysis method for sulfur-containing ions in the thiosulfate leaching system provided by the present invention, the ion conversion operation is as follows: adding excess SO3 to the test solution. 2- or CN - or S 2- The S3O6 in the test solution 2- S4O6 2- S5O6 2- S2O3 that can be determined by ion conversion to iodine titration 2- SO3 2- ion.

[0013] In a preferred embodiment of the quantitative analysis method for sulfur ions in the thiosulfate leaching system provided by the present invention, the pretreatment and iodine titration of each sample of the test solution to obtain the titration volume of each sample of the test solution includes:

[0014] Take one portion of the test solution and perform iodine titration directly to obtain the titration volume V1.

[0015] Take one portion of the test solution, perform a masking operation, and then perform iodine titration to obtain the titration volume V2.

[0016] Take one portion of the test solution, perform precipitation separation, and then perform iodine titration to obtain titration volume V3.

[0017] Take one portion of the test solution and add excess SO3.2- After ion conversion, excessive formaldehyde solution is added for masking, and then iodine titration is performed to obtain a titration volume V4;

[0018] Take one of the said to be measured liquid, and add excessive CN - After ion conversion under boiling conditions, iodine titration is performed to obtain a titration volume V5;

[0019] Take one of the said to be measured liquid, and add excessive S 2- After ion conversion, excessive zinc acetate solution is added for precipitation separation, and then iodine titration is performed to obtain a titration volume V6.

[0020] In a preferred embodiment of the quantitative analysis method for sulfur-containing ions in the thiosulfate leaching system provided by the application, the concentration calculation formula of each sulfur-containing ion in the to-be-measured liquid is as follows:

[0021] c(S2O3 2- )=2c(I2)(V3+V2-V1) / V;

[0022] c(SO3 2- )=c(I2)(V1-V2) / V;

[0023] c(S 2- )=c(I2)(V1-V3) / V;

[0024] c(S3O6 2- )=2c(I2)(V5+V3-V1-V6) / V;

[0025] c(S4O6 2- )=2c(I2)(4V6-4V3-2V5-V4+2V1+V2) / V;

[0026] c(S5O6 2- )=2c(I2)(V4+2V3+V5-2V6-V2-V1) / V;

[0027] Wherein, c(I2) is the concentration of iodine solution used in the iodine titration, and V is the volume of the to-be-measured liquid.

[0028] Compared with the prior art, the quantitative analysis method for sulfur-containing ions in the thiosulfate leaching system provided by the application has the following beneficial effects: the quantitative analysis method for sulfur-containing ions in the thiosulfate leaching system proposed by the application is simple and convenient to operate, has wide applicability, and can be used in laboratories and industrial sites; the method is accurate and has a small error (±0.2%). BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments description. Obviously, the drawings in the following description only constitute some of the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0030] Figure 1 is the quantitative analysis principle diagram of the quantitative analysis method of the sulfur-containing ions in the thiosulfate leaching system provided by the present application;

[0031] Figure 2 is the quantitative analysis operation flowchart of the quantitative analysis method of the sulfur-containing ions in the thiosulfate leaching system provided by the present application. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments only constitute some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without any creative effort are within the scope of protection of the present application.

[0033] Please refer to Figure 1 and Figure 2 , wherein, Figure 1 is the quantitative analysis principle diagram of the quantitative analysis method of the sulfur-containing ions in the thiosulfate leaching system provided by the present application; Figure 2 is the quantitative analysis operation flowchart of the quantitative analysis method of the sulfur-containing ions in the thiosulfate leaching system provided by the present application.

[0034] The quantitative analysis method of the sulfur-containing ions in the thiosulfate leaching system provided by the present application involves three processes of pretreatment, titration and calculation, and the titration operation of each portion of the to-be-tested liquid can be carried out in parallel without any operation sequence.

[0035] The quantitative analysis method of the sulfur-containing ions in the thiosulfate leaching system comprises the following steps:

[0036] Obtaining multiple portions of to-be-tested liquid with equal volume;

[0037] Pretreating and titrating each portion of the to-be-tested liquid by iodine titration to obtain the titration volume of each portion of the to-be-tested liquid;

[0038] Calculating the concentration of each sulfur-containing ion in the to-be-tested liquid according to the titration volume of each portion of the to-be-tested liquid.

[0039] Specifically, the pretreatment comprises masking operation, precipitation separation operation and ion conversion operation.

[0040] The masking operation is adding excessive formaldehyde solution into the to-be-tested liquid to mask SO3 in the to-be-tested liquid 2- The reaction formula of the masking operation is:

[0041] SO3 2- +HCHO+H2O→CH2OH·SO3 - +OH -

[0042] The precipitation separation operation is adding excessive zinc acetate solution into the to-be-tested liquid to remove S in the to-be-tested liquid 2- , and then removing the precipitate by filtration; the reaction formula of the precipitation separation operation is:

[0043] S 2- +Zn(CH3COO)2→ZnS↓+2CH3COO -

[0044] The ion conversion operation is adding excessive SO3 2- or CN - or S 2- into the to-be-tested liquid, and converting S3O6 2- , S4O6 2- , S5O6 2- ions in the to-be-tested liquid into S2O3 2- , SO3 2- ions which can be determined by iodine titration; in the ion conversion operation, the reaction formulas after adding SO3 2- , CN - , S 2- are respectively:

[0045] 2S2O3 2- +I2→S4O6 2- +2I -

[0046] SO3 2- +I2+H2O→SO4 2- +2I - +2H +

[0047] S 2- +I2→S 0 +2I -

[0048] S4O6 2- +SO3 2- →S3O6 2- +S2O3 2-

[0049] S5O6 2-+ 2SO3 2- → S3O6 2- + 2S2O3 2-

[0050]

[0051] S3O6 2- + S 2- → 2S2O3 2-

[0052] S4O6 2- + S 2- → 2S2O3 2- + S 0

[0053] S5O6 2- + S 2- → 2S2O3 2- + 2S 0

[0054] Further, the pre-treatment and iodine titration method are used to titrate each of the test liquids to obtain a titration volume of each of the test liquids, which comprises:

[0055] One of the test liquids is directly titrated by the iodine titration method to obtain a titration volume V1;

[0056] One of the test liquids is subjected to a masking operation and then titrated by the iodine titration method to obtain a titration volume V2;

[0057] One of the test liquids is subjected to a precipitation separation operation and then titrated by the iodine titration method to obtain a titration volume V3;

[0058] One of the test liquids is added with excess SO3 2- and then subjected to an ion conversion operation, added with excess formaldehyde solution for a masking operation, and then titrated by the iodine titration method to obtain a titration volume V4;

[0059] One of the test liquids is added with excess CN - and then subjected to an ion conversion operation under boiling conditions and then titrated by the iodine titration method to obtain a titration volume V5;

[0060] One of the test liquids is added with excess S 2- and then subjected to an ion conversion operation, added with excess zinc acetate solution for a precipitation separation operation, and then titrated by the iodine titration method to obtain a titration volume V6.

[0061] Further, a calculation formula of the concentration of each sulfur ion in the test liquid is:

[0062] c(S2O3 2-) = 2c(I2)(V3+V2-V1) / V;

[0063] c(SO3 2- ) = c(I2)(V1-V2) / V;

[0064] c(S 2- ) = c(I2)(V1-V3) / V;

[0065] c(S3O6 2- ) = 2c(I2)(V5+V3-V1-V6) / V;

[0066] c(S4O6 2- ) = 2c(I2)(4V6-4V3-2V5-V4+2V1+V2) / V;

[0067] c(S5O6 2- ) = 2c(I2)(V4+2V3+V5-2V6-V2-V1) / V;

[0068] Wherein, c(I2) is the iodine titration method using iodine solution concentration, V is the volume of the liquid to be measured.

[0069] The quantitative analysis method of sulfur-containing ions in the thiosulfate leaching system provided by the application, through masking, precipitation separation and ion conversion pretreatment operations, using iodine titration method step-by-step measurement of titration volume, using the calculation formula of the concentration of each sulfur-containing ion in the liquid to be measured provided by the application can calculate the accurate concentration of each sulfur-containing ion. The method is simple to operate, has wide applicability, and is not limited by site and personnel; the method is accurate and has small error (±0.2%).

[0070] The quantitative analysis method of sulfur-containing ions in the thiosulfate leaching system provided by the application will be described in detail in combination with the following examples, but they should not be understood as limiting the scope of protection of the application.

[0071] The sulfur-containing ion solution used in the following examples is prepared from commercially available sodium or potassium salt, including Na2S2O3, Na2SO3, Na2S, Na2S3O6, Na2S4O6, Na2S5O6.

[0072] Unless otherwise specified, the volume of the liquid to be measured used in the following examples is 200 mL, and the solutions used for pretreatment are 1 mol / L Na2SO3, NaS, NaCN, HCHO and Zn(CH3COO)2 solutions, which are stored for standby use.

[0073] During the determination, the untreated test solution was titrated using the conventional iodine titration method, and the titration volume was V1; the test solution masked only by adding excess formaldehyde solution was titrated using the iodine titration method, and the titration volume was V2; the test solution masked only by adding excess zinc acetate solution to remove sulfur was titrated using the iodine titration method. 2- The test solution was filtered and then titrated using the iodine titration method. The titration volume was V3. Excess SO3 was added first. 2- An ion conversion operation was performed, followed by iodine titration of the test solution after masking with excess formaldehyde solution. The measured titration volume was V4. For the solution first treated with excess CN... - The ion conversion operation was performed by boiling, and the test solution was then cooled to room temperature for iodine titration. The titration volume was V5. For solutions where excess S was added first... 2- Perform an ion conversion operation, then add excess zinc acetate solution to remove sulfur. 2- The test solution was filtered and then titrated using the iodine titration method. The titration volume was V6. During the above operations, after mixing the liquids, they should be allowed to stand for 5 minutes to allow for complete reaction after thorough stirring. When performing the titration, a starch solution was used as an indicator. The titration endpoint was considered reached when the starch solution turned blue and remained unchanged for three seconds.

[0074] Example 1

[0075] (1) Prepare 200 mL of a mixed solution of Na2S2O3, Na2SO3, Na2S, Na2S3O6, Na2S4O6 and Na2S5O6, each with an ion concentration of 10 mmol / L.

[0076] (2) Take multiple 20 mL aliquots of the test solution and pretreat them;

[0077] (3) Use 0.05 mol / L iodine solution to titrate the pretreated multiple test solutions respectively, and record the titration volume Vx (x = 1 to 6) respectively. Use the calculation formula of the concentration of each sulfur-containing ion in the test solution proposed in this invention to calculate the concentration of each sulfur-containing ion and its error with the standard value.

[0078] During the experiment, the titration volumes of each test solution were recorded as shown in Table 1. Using the calculation formula for the concentration of each sulfur-containing ion given in this invention, the measured values ​​of each sulfur-containing ion were calculated as shown in Table 2.

[0079] Table 1. Titration volumes of each test solution

[0080]

[0081]

[0082] Table 2 Standard values, measured values, and errors of each sulfur-containing ion.

[0083]

[0084] The multiple parallel experiment results obtained by using the above steps are that the concentration of each sulfur ion measured by the quantitative analysis method of the sulfur ion provided by the application is within the allowable error of ±0.2%, and the measured results are accurate and reliable.

[0085] Example 2

[0086] (1) Prepare 200 mL of Na2S2O3, Na2SO3, Na2S, Na2S3O6, Na2S4O6, Na2S5O6 mixed solution with an ion concentration of 50 mmol / L;

[0087] (2) Take multiple portions of the test solution with a volume of 20 mL, respectively, for pretreatment;

[0088] (3) Use 0.05 mol / L iodine solution to titrate the pretreated multiple portions of the test solution, respectively, and record the titration volume Vx (x = 1-6), and use the concentration calculation formula of each sulfur ion in the test solution provided by the application to calculate the concentration of each sulfur ion and the error with the standard value.

[0089] During the experiment, the titration volume of each portion of the test solution is recorded as shown in Table 3, and the measured value of each sulfur ion is calculated as shown in Table 4 using the concentration calculation formula of each sulfur ion provided by the application.

[0090] Table 3 Titration volume of each portion of the test solution

[0091]

[0092] Table 4 Standard value, measured value and error of each sulfur ion

[0093]

[0094] The multiple parallel experiment results obtained by using the above steps are that the concentration of each sulfur ion measured by the quantitative analysis method of the sulfur ion provided by the application is within the allowable error of ±0.2%, and the measured results are accurate and reliable.

[0095] Example 3

[0096] (1) Prepare 200 mL of Na2S2O3, Na2SO3, Na2S, Na2S3O6, Na2S4O6, Na2S5O6, Na2S6O6, Na2SO4 mixed solution with an ion concentration of 0.1 mol / L;

[0097] (2) Take multiple portions of the test solution with a volume of 20 mL, respectively, for pretreatment;

[0098] (3) using 0.05 mol / L iodine solution to titrate the pretreated multiple portions of the test solution respectively, recording the titration volume Vx (x = 1-6) respectively, using the concentration calculation formula of each sulfur ion in the test solution proposed by the present application to calculate the concentration of each sulfur ion and the error thereof with the standard value.

[0099] During the experiment, the titration volume of each portion of the test solution recorded is shown in Table 5, and the measured value of each sulfur ion calculated using the concentration calculation formula of each sulfur ion given by the present application is shown in Table 6.

[0100] Table 5 titration volume of each portion of the test solution

[0101]

[0102] Table 6 standard value, measured value and error of each sulfur ion

[0103]

[0104]

[0105] The multiple parallel experimental results obtained by using the above steps are as follows: using the quantitative analysis method of sulfur ions proposed by the present application, the concentration of each sulfur ion measured is within the allowable error of ±0.2%, and the measured results are accurate and reliable.

[0106] Example 4

[0107] (1) preparing 200 mL of Na2S2O3, Na2SO3, Na2S, Na2S3O6, Na2S4O6, Na2S5O6 mixed solution with an ion concentration of 0.5 mol / L;

[0108] (2) taking multiple portions of test solution with a volume of 20 mL respectively, and pretreating;

[0109] (3) using 0.05 mol / L iodine solution to titrate the pretreated multiple portions of the test solution respectively, recording the titration volume Vx (x = 1-6) respectively, using the concentration calculation formula of each sulfur ion in the test solution proposed by the present application to calculate the concentration of each sulfur ion and the error thereof with the standard value.

[0110] During the experiment, the titration volume of each portion of the test solution recorded is shown in Table 5, and the measured value of each sulfur ion calculated using the concentration calculation formula of each sulfur ion given by the present application is shown in Table 6.

[0111] Table 7 titration volume of each portion of the test solution

[0112]

[0113] Table 8 standard value, measured value and error of each sulfur ion

[0114]

[0115]

[0116] The multiple parallel experimental results obtained by using the above steps are as follows: the concentration of each sulfur ion measured by using the quantitative analysis method of the sulfur ion provided by the present application is within the allowable error of ±0.2%, and the measured results are accurate and reliable.

[0117] Example 5

[0118] (1) Prepare a mixed solution of 200 mL containing 500 mmol / L Na2S2O3, 100 mmol / L Na2SO3, 50 mmol / L Na2S, 50 mmol / L Na2S3O6, 30 mmol / L Na2S4O6 and 10 mmol / L Na2S5O6;

[0119] (2) Take multiple portions of the test solution with a volume of 20 mL, respectively, for pretreatment;

[0120] (3) Use 0.05 mol / L iodine solution to titrate the multiple portions of the pretreated test solution, respectively, and record the titration volume Vx (x = 1-6), respectively. The concentration of each sulfur ion in the test solution and the error of the concentration and the standard value are calculated by using the calculation formula of the concentration of each sulfur ion provided by the present application.

[0121] During the experiment, the titration volume of each portion of the test solution is recorded as shown in Table 9. The measured value of each sulfur ion is calculated by using the calculation formula of the concentration of each sulfur ion provided by the present application, as shown in Table 10.

[0122] Table 9 titration volume of each portion of the test solution

[0123]

[0124] Table 10 standard value, measured value and error of each sulfur ion

[0125]

[0126]

[0127] The multiple parallel experimental results obtained by using the above steps are as follows: the concentration of each sulfur ion measured by using the quantitative analysis method of the sulfur ion provided by the present application is within the allowable error of ±0.2%, and the measured results are accurate and reliable.

[0128] The above merely illustrates the embodiments of the present application, and is not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process conversion, or direct or indirect application in other related technical fields, which is made according to the content of the present application, shall be included in the patent protection scope of the present application.

Claims

1. A method for quantitative analysis of sulfur ions in a thiosulfate leaching system, characterized in that, Includes the following steps: Obtain multiple equal volumes of the test solution; Each sample of the test solution was pretreated and titrated using the iodine titration method to obtain the titration volume of each sample of the test solution; The concentration of each sulfur-containing ion in the test solution is calculated based on the titration volume of each test solution.

2. The method for quantitative analysis of sulfur ions in the thiosulfate leaching system according to claim 1, characterized in that, The pretreatment includes masking, precipitation separation, and ion conversion.

3. The method for quantitative analysis of sulfur ions in the thiosulfate leaching system according to claim 2, characterized in that, The masking operation is as follows: adding excess formaldehyde solution to the test solution to mask the SO3 in the test solution. 2- .

4. The method for quantitative analysis of sulfur ions in the thiosulfate leaching system according to claim 2, characterized in that, The precipitation separation operation is as follows: An excess of zinc acetate solution is added to the test solution to remove sulfur from the test solution. 2- Then filter to remove the precipitate.

5. The method for quantitative analysis of sulfur ions in the thiosulfate leaching system according to claim 2, characterized in that, The ion conversion operation is as follows: adding excess SO3 to the test solution. 2- or CN - or S 2- The S3O6 in the test solution 2- S4O6 2- S5O6 2- S2O3 that can be determined by ion conversion to iodine titration 2- SO3 2- ion.

6. The method for quantitative analysis of sulfur ions in the thiosulfate leaching system according to claim 2, characterized in that, The pretreatment and iodine titration of each sample of the test solution to obtain the titration volume of each sample of the test solution includes: Take one portion of the test solution and perform iodine titration directly to obtain the titration volume V1. Take one portion of the test solution, perform a masking operation, and then perform iodine titration to obtain the titration volume V2. Take one portion of the test solution, perform precipitation separation, and then perform iodine titration to obtain titration volume V3. Take one portion of the test solution and add excess SO3. 2- An ion conversion operation was performed, followed by the addition of excess formaldehyde solution for masking, and then iodine titration was performed to obtain a titration volume V4. Take one portion of the test solution and add excess CN. - Ion conversion was performed under boiling conditions, followed by iodine titration to obtain titration volume V5. Take one portion of the test solution and add excess S 2- An ion conversion operation was performed, followed by the addition of excess zinc acetate solution for precipitation separation, and then iodine titration was performed to obtain a titration volume V6.

7. The method for quantitative analysis of sulfur ions in the thiosulfate leaching system according to claim 6, characterized in that, The formula for calculating the concentration of each sulfur-containing ion in the test solution is as follows: c(S2O3 2- )=2c(I2)(V3+V2-V1) / V; c(SO3 2- )=c(I2)(V1-V2) / V; c(S 2- )=c(I2)(V1-V3) / V; c(S3O6 2- )=2c(I2)(V5+V3-V1-V6) / V; c(S4O6 2- )=2c(I2)(4V6-4V3-2V5-V4+2V1+V2) / V; c(S5O6 2- )=2c(I2)(V4+2V3+V5-2V6-V2-V1) / V; Wherein, c(I2) is the concentration of the iodine solution used in the iodine titration method, and V is the volume of the test solution.

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