A method for precisely regulating pH by adding sodium carbonate in a tungsten tailings flotation process

Abstract

The present application belongs to the technical field of pH regulation for flotation of wolframite and scheelite from tungsten tailings, and particularly relates to a method for accurate pH regulation by adding sodium carbonate in the process of flotation of wolframite and scheelite from tungsten tailings, which is suitable for accurate pH regulation of the pulp when wolframite and scheelite are recovered by flotation from tungsten tailings. The method establishes a calibration fitting curve and a fitting curve formula of the mass-volume percentage concentration of sodium carbonate in the pulp and the concentration of hydroxyl ions, accurately calculates the amount of sodium carbonate and the amount of its aqueous solution according to the mass of the actual tungsten tailings and the concentration of the pulp and other parameters, and combines the target pH value for efficient and accurate regulation of the pH value of the pulp, solving the problems of slow adjustment process, late results, and low accuracy of conventional regulation methods, significantly improving the accuracy and efficiency of pH regulation, and reducing the consumption of reagents and the risk of equipment corrosion.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of pH regulation of scheelite tailings flotation of wolframite and scheelite, and particularly relates to a method for precisely regulating pH by adding sodium carbonate in the process of scheelite tailings flotation. BACKGROUND

[0002] Flotation of wolframite and scheelite is usually operated in an alkaline environment, and conventional agents such as sodium hydroxide, lime, sodium carbonate and sodium silicate are used to regulate the pH value of the ore slurry. Sodium hydroxide has a fast adjustment speed, and the pH value can be adjusted to 14, which is suitable for scenarios requiring high pH value and fast adjustment, but the cost is high, and the equipment requires high corrosion resistance. It is generally suitable for laboratory tests, and is not commonly used in industrial sites. Sodium carbonate is a strong base and weak acid salt, and the pH value can be adjusted to 7-12, with strong buffering capacity. The carbonate ion can remove metal cations in the ore slurry, and has little effect on the viscosity of the ore slurry, which is suitable for flotation systems sensitive to metal cations. Sodium silicate is a strong base and weak acid salt, which is a depressant for gangue minerals and a dispersant for ore slurry. The hydrolyzed ions of sodium silicate can be adsorbed on the surface of silicate gangue to form a hydrophilic film, which can inhibit the combination of gangue and collector, and effectively improve the flotation index.

[0003] The principle of the conventional pH regulation method is as follows: a water solution of a certain mass-volume percentage concentration (for example, 1%, 2%) of an alkali regulating agent (for example, lime, sodium carbonate, etc.) is prepared, the alkali regulating agent water solution is added to the roughing operation section of the flotation, and a pH meter or an advanced online pH meter is used to test and record the pH value. If the pH value is too high, the amount of alkali regulating agent water solution added is reduced, and if the pH value is too low, the amount of alkali regulating agent water solution added is increased, until the target pH value is reached. The pH value is then regularly monitored, and if there is a deviation from the target pH value, the same regulation procedure is repeated. If the pH value needs to be regulated in the cleaning and scavenging operation section, the regulation steps are similar to those in the roughing operation section.

[0004] When wolframite and scheelite are recovered by flotation from scheelite tailings, there are many dissolved metal cations in the ore slurry, such as iron ions (Fe 2+ , Fe 3+ ), copper ions (Cu 2+ ), calcium ions (Ca 2+ ), magnesium ions (Mg 2+ ) and the like, and there are also many gangue minerals, such as hematite, sphalerite, chalcopyrite, pyrite, kaolinite, calcite, dolomite, quartz and the like. After adding the alkali regulating agent, the metal cations and gangue mineral particles will adsorb the anions (such as CO3 2- ) dissociated from the alkali regulating agent, and will also adsorb OH - generated by hydrolysis or directly dissociated from the alkali regulating agent. The adsorption of anions (such as CO3 2- ) and OH- The behavior of the metal cations and the gangue mineral particles adsorbed anions (such as CO3 2- ) and OH - is not accurately measurable and depends entirely on the properties of the tungsten tailings, so the conventional pH control method can only be feedback control, that is, after adding the alkali adjusting agent to the ore slurry, the pH is measured, and if it is too high or too low, the amount of the alkali adjusting agent is reduced or increased for corresponding adjustment. Therefore, this conventional pH control method has the disadvantages of slow adjustment process, late result, and low accuracy. SUMMARY

[0005] To solve the above technical defects, the present application provides a method for precisely controlling pH by adding sodium carbonate in the process of tungsten tailings flotation, which improves the precision and efficiency of controlling the pH of the ore slurry by adding sodium carbonate in the process of tungsten tailings flotation, and can accurately and efficiently control the pH value.

[0006] A method for precisely controlling pH by adding sodium carbonate in the process of tungsten tailings flotation, comprising the following steps:

[0007] S1: establishing a calibration fitting curve of the mass percentage concentration of sodium carbonate and the OH - concentration after adding the alkali adjusting agent sodium carbonate aqueous solution to tungsten tailings with different concentrations through experiments;

[0008] S2: determining a target pH value to be reached for a specific concentration of flotation ore slurry, selecting the calibration fitting curve corresponding to the concentration of the ore slurry, and calculating the mass percentage concentration of sodium carbonate;

[0009] S3: converting the mass percentage concentration of sodium carbonate into the amount of alkali adjusting agent sodium carbonate and the amount of aqueous solution.

[0010] Further, step S1 specifically comprises the following steps:

[0011] S1.1: preparing tungsten tailings flotation ore slurry and preparing alkali adjusting agent sodium carbonate aqueous solution;

[0012] S1.2: adding sodium carbonate aqueous solution to the tungsten tailings flotation ore slurry to control the pH value of the ore slurry, obtaining the relationship between the amount of sodium carbonate aqueous solution and the pH value of the ore slurry; converting the amount of sodium carbonate aqueous solution into the mass percentage concentration of sodium carbonate in the ore slurry, and converting the pH value into the OH - concentration of the ore slurry, that is, the relationship between the amount of sodium carbonate aqueous solution and the pH value of the ore slurry can be converted into the relationship between the mass percentage concentration of sodium carbonate and the OH - concentration, and a relationship curve is established;

[0013] S1.3: fitting the mass-volume percentage concentration of sodium carbonate and OH - concentration curve, and the calibration fitting relationship curve and the fitting relationship curve formula are obtained, the horizontal axis X of the fitting curve is the mass-volume percentage concentration of sodium carbonate, and the vertical axis Y is the OH - concentration.

[0014] Further, step S2 specifically includes the following steps:

[0015] S2.1: measuring and calculating the specific concentration of the tungsten tailings flotation slurry;

[0016] S2.2: selecting the calibration fitting relationship curve corresponding to the slurry concentration, determining the target pH value to be reached, and converting the target pH value to the target OH - concentration, substituting the OH - concentration into the fitting relationship curve formula, and calling the calculate function in Python3.8 program to calculate the mass-volume percentage concentration of sodium carbonate.

[0017] Further, step S3 specifically includes the following steps:

[0018] S3.1: calculating the amount of sodium carbonate alkali adjusting agent according to formula 1;

[0019] S3.2: calculating the amount of sodium carbonate aqueous solution according to formula 2.

[0020] Further, the slurry concentration range in step S1.1 is 20-30%, and the mass-volume percentage concentration of sodium carbonate aqueous solution is 1-6%.

[0021] Further, the method for measuring and calculating the tungsten tailings slurry concentration in step S2.1 can be determined by the concentration kettle method in industrial field, while the laboratory test can be directly calculated.

[0022] Further, formula 1 in step S3.1 is: , wherein: M T — the amount of sodium carbonate / g; C T — the mass-volume percentage concentration of sodium carbonate / %; M S — the mass of tungsten tailings / g; C S — the concentration of tungsten tailings slurry / %, (wherein: M L — the liquid mass of the slurry / g).

[0023] Further, formula 2 in step S3.2 is: , wherein: V T — the amount of sodium carbonate aqueous solution / ml; c T — the mass-volume percentage concentration of sodium carbonate aqueous solution / %.

[0024] The beneficial effect is that: the present application can realize efficient and accurate control of the pH value of the ore slurry by establishing the calibration fitting relationship curve of the mass percentage concentration of sodium carbonate and the concentration of hydroxyl ions, regulating the target pH value, combining the calibration fitting relationship curve and the fitting relationship curve formula, and accurately calculating the dosage of sodium carbonate and the dosage of aqueous solution according to the mass and pulp concentration of the actual tungsten tailings, solving the problems of slow adjustment process, late result and low accuracy of the conventional control method, and significantly improving the accuracy and efficiency of pH adjustment. According to the same logical thinking as above, if sodium hydroxide, lime or sodium silicate is used to regulate the pH value of the ore slurry, the same can also be done by first establishing the calibration fitting relationship curve and the fitting relationship curve formula of the mass percentage concentration of the reagent and the concentration of hydroxyl ions, and then accurately calculating the dosage of the reagent and the dosage of aqueous solution, which can also realize efficient and accurate control of the pH value of the ore slurry. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 For the tungsten tailings flotation ore slurry with a concentration of 0%, 20%, and 30%, the calibration fitting relationship curve and the fitting relationship curve formula of the mass percentage concentration of sodium carbonate and the concentration of OH - The calibration fitting relationship curve and the fitting relationship curve formula of the mass percentage concentration of sodium carbonate and the concentration of OH DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0027] Embodiment 1

[0028] The pH value of the tungsten tailings flotation ore slurry in a tungsten ore dressing plant is accurately controlled by the method of the present application. The main chemical composition of the tungsten tailings is as follows in mass percentage: WO3 0.350%, SiO2 64.840%, Al2O3 13.860%, CaO 2.620%, MgO 2.260%; the particle size composition is as follows: less than 0.038mm accounts for 72.080%, less than 0.074mm accounts for 91.500%.

[0029] S1.1: prepare tungsten tailings flotation ore slurry with a mass concentration of 20%, and prepare aqueous solution of sodium carbonate with a mass percentage concentration of 5%;

[0030] S1.2: Add an aqueous solution of sodium carbonate to the tungsten tailings flotation slurry, adjust the pH value of the slurry, establish the relationship between the amount of aqueous sodium carbonate solution and the pH value of the slurry, and convert the calculation to obtain the mass-volume percentage concentration of sodium carbonate and the OH - concentration relationship, establish the relationship curve (Y2 = 6.907e-2 * X6 - 1.861e-1 * X5 + 1.918e-1 * X4 - 9.092e-2 * X3 + 1.690e-2 * X2 + 1.160e-3 * X - 7.964e-6) Figure 1 );

[0031] S1.3: Fit the relationship curve to obtain the calibration fitting relationship curve and fitting relationship curve formula of the mass-volume percentage concentration of sodium carbonate and OH - concentration at 20% concentration.

[0032] The fitting relationship curve formula is: Y2 = 6.907e-2 * X6 - 1.861e-1 * X5 + 1.918e-1 * X4 - 9.092e-2 * X3 + 1.690e-2 * X2 + 1.160e-3 * X - 7.964e-6 -2 X 6 -1.861e-1 * X5 + 1.918e-1 * X4 - 9.092e-2 * X3 + 1.690e-2 * X2 + 1.160e-3 * X - 7.964e-6 -1 X 5 + 1.918e-1 * X4 - 9.092e-2 * X3 + 1.690e-2 * X2 + 1.160e-3 * X - 7.964e-6 -1 X 4 - 9.092e-2 * X3 + 1.690e-2 * X2 + 1.160e-3 * X - 7.964e-6 -2 X 3 + 1.690e-2 * X2 + 1.160e-3 * X - 7.964e-6 -2 X 2 + 1.160e-3 * X - 7.964e-6 -3 X - 7.964e-6 −6 .

[0033] S2.1: In the laboratory test, the tungsten tailings are 200g and the pure water is 800mL, so C S = 200 / (200 + 800) = 20.000%, the mass concentration of the tungsten tailings flotation slurry is calculated to be 20.000%;

[0034] S2.2: The target pH value is determined to be 10.53, the target OH - concentration is Y2 = 3.388e-1 * X6 - 1.861e-1 * X5 + 1.918e-1 * X4 - 9.092e-2 * X3 + 1.690e-2 * X2 + 1.160e-3 * X - 7.964e-6 -4 mol / L, the mass-volume percentage concentration of sodium carbonate C T = 0.157% is calculated by calling the calculate function in the Python3.8 program, and the program code is as follows:

[0035] def calculate_Y(x):

[0036] return 6.907e-2 * x**6 - 1.861e-1 * x**5 + 1.918e-1 * x**4 - 9.092e-2 * x**3 + 1.690e-2 * x**2 + 1.160e-3 * x - 7.964e-6

[0037] def find_root():

[0038] target = 3.388e-4

[0039] left, right = 0.0, 0.8

[0040] epsilon = 1e-6

[0041] while right - left > epsilon:

[0042] mid = (left + right) / 2

[0043] mid_value = calculate_Y(mid)

[0044] if mid_value < target:

[0045] left = mid

[0046] else:

[0047] right = mid

[0048] return (left + right) / 2

[0049] root = find_root()

[0050] print(f"Na2CO3 mass-volume percentage concentration is {root:.3g}%")

[0051] S3.1: According to the formula , where: M T — the amount of sodium carbonate / g; C T — the mass-volume percentage concentration of sodium carbonate / %; M S — the mass of tungsten tailings selected / g; C S — the concentration of tungsten tailings slurry / %, (where: M L — the liquid mass of the slurry / g). The amount of sodium carbonate M T = 1.256g;

[0052] S3.2: According to the formula , where: V T — the amount of sodium carbonate solution / ml, c T — the mass-volume percentage concentration of sodium carbonate solution / %, the amount of sodium carbonate solution V T = 25.120mL.

[0053] In practice, the target pH value is 10.53, the added mass of sodium carbonate is 1.250 g, and the amount of sodium carbonate solution used for adjusting the alkaline agent is 25 mL, and the error with the calculation results in steps S3.1 and S3.2 is 0.480%.

[0054] Example 2

[0055] The method of the present application is used to accurately control the pH value of the tailings flotation slurry of a tungsten ore dressing plant. The main chemical composition and particle size composition of the tungsten tailings are consistent with those of Example 1.

[0056] S1.1: Prepare a tungsten tailings flotation slurry with a mass concentration of 30%, and prepare a 5% sodium carbonate aqueous solution with a mass percentage concentration;

[0057] S1.2: Add the sodium carbonate aqueous solution to the tungsten tailings flotation slurry to control the pH value of the slurry, establish the relationship between the amount of sodium carbonate aqueous solution and the pH value of the slurry, and convert the calculation to obtain the mass percentage concentration of sodium carbonate and the OH - concentration relationship, and establish a relationship curve ( Figure 1 );

[0058] S1.3: Fit the relationship curve to obtain the calibrated fitting relationship curve and fitting relationship curve formula of the mass percentage concentration of sodium carbonate and OH - concentration at a concentration of 30%.

[0059] The fitting relationship curve formula is: Y3=5.313×10 -2 X 6 -1.385×10 -1 X 5 +1.436×10 -1 X 4 -7.312×10 -2 X 3 +1.672×10 -2 X 2 +2.522×10 -4 X-4.394×10 −6 .

[0060] S2.1: In the laboratory test, the tungsten tailings are 342.857 g and the pure water is 800 mL, therefore, C S = 342.857 / (342.857 + 800) = 30.000%, and the mass concentration of the tungsten tailings flotation slurry is calculated to be 30.000%;

[0061] S2.2: The target pH value is determined to be 10.25, and the target OH - concentration is converted to Y3=1.778×10 -4mol / L, the same calculation method as in Example 1, and the calculate function in Python 3.8 program is used to calculate the mass percentage concentration C of sodium carbonate T = 0.126%.

[0062] S3.1: According to the formula , wherein: M T - the amount of sodium carbonate / g; C T - the mass percentage concentration of sodium carbonate / %; M S - the mass of selected tungsten tailings / g; C S - the concentration of selected tungsten tailings slurry / %, (wherein: M L - the mass of the liquid of the slurry / g). The amount M T = 1.008 g.

[0063] S3.2: According to the formula , wherein: V T - the amount of sodium carbonate aqueous solution / ml, c T - the mass percentage concentration of sodium carbonate aqueous solution / %, the amount V T = 20.160 mL.

[0064] In practice, the target pH value is 10.25, the added mass of sodium carbonate is 1.000 g, and the amount of sodium carbonate solution used in the alkali adjusting agent is 20 mL, and the error of the calculation results in steps S3.1 and S3.2 is 0.800%.

[0065] The above two implementation cases show that the results obtained by the method of the present application have an error within ±1% compared with the actual situation, and the method is excellent.

[0066] The above examples are only illustrative of the principles and effects of the present application, and are not intended to limit the present application. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical idea disclosed by the present application should be covered by the claims of the present application.

Claims

1. A method for precise pH control by adding sodium carbonate in a tungsten tailings flotation process, characterized by, The method comprises the following steps: S1: through the experiment to establish different concentrations of selected tungsten tailings, adding sodium carbonate solution after the concentration of sodium carbonate mass percentage and OH - concentration of the calibration fitting curve; S2: for a specific concentration of the flotation slurry, a target pH value reached by regulation is determined, a calibration fitting curve corresponding to the slurry concentration is selected, and the mass-volume percentage concentration of sodium carbonate is obtained by calculation; S3: the mass-volume percentage concentration of sodium carbonate is converted into the dosage of the alkali regulating agent sodium carbonate and the dosage of the aqueous solution.

2. The method for precise pH control by adding sodium carbonate in a process of tungsten tailings flotation according to claim 1, characterized in that, Step S1 specifically comprises the following steps: S1.1: preparing the tungsten tailings flotation slurry and preparing the sodium carbonate aqueous solution of the alkali regulating agent; S1.2: In the selected tungsten tailings flotation slurry, add sodium carbonate aqueous solution, adjust the pH value of the slurry, and the relationship between the amount of sodium carbonate aqueous solution and the pH value of the slurry can be obtained; The amount of sodium carbonate aqueous solution is converted into the concentration of sodium carbonate in the slurry, and the pH value is converted into the OH - concentration of the slurry, that is, the relationship between the amount of sodium carbonate aqueous solution and the pH value of the slurry can be converted into the relationship between the concentration of sodium carbonate and the OH - concentration, and the relationship curve is established; S1.3: fitting the mass-volume percentage concentration of sodium carbonate and OH - concentration curve, obtaining the calibration fitting relationship curve and the fitting relationship curve formula, the horizontal axis X axis of the fitting curve is the mass-volume percentage concentration of sodium carbonate, and the vertical axis Y axis is the OH - concentration.

3. A method for precise pH control by adding sodium carbonate in a process for the flotation of tungsten tailings according to claim 1, characterized in that, Step S2 specifically comprises the following steps: S2.1: measuring and calculating the specific concentration of the tungsten tailings flotation slurry; S2.2: Select the calibration fitting curve corresponding to the pulp concentration, determine the target pH value that needs to be regulated, and convert the target pH value to the target OH - concentration, and substitute the OH - concentration into the fitting curve formula. The calculate function in the Python3.8 program can calculate the mass percentage concentration of sodium carbonate.

4. The method for precise pH control by adding sodium carbonate in a process of tungsten tailings flotation according to claim 1, characterized in that, Step S3 specifically comprises the following steps: S3.1: The dosage of the alkali agent sodium carbonate is calculated according to Formula 1: M = C x V x S T — the dosage of sodium carbonate / g; C T — the mass percentage concentration of sodium carbonate / %; M S — the mass of the selected tungsten tailings / g; C S — the concentration of the selected tungsten tailings slurry / %, (wherein: M L — the mass of the liquid of the slurry / g) S3.2: the amount of sodium carbonate aqueous solution is according to formula 2: The calculation is as follows: in the formula, V T — the amount of sodium carbonate aqueous solution / ml; c T — the mass percentage concentration of sodium carbonate aqueous solution / %.

5. The method for precise pH control by adding sodium carbonate in a process of tungsten tailings flotation according to claim 2, characterized in that, The slurry concentration in step S1.1 ranges from 20% to 30%, and the mass-volume percentage concentration of the sodium carbonate aqueous solution ranges from 1% to 6%.

6. The method for precise pH control by adding sodium carbonate in a process of tungsten tailings flotation according to claim 3, characterized in that, The method for measuring and calculating the concentration of the tungsten tailings slurry in step S2.1 can be the concentration kettle method in the industrial field, and the laboratory test can be directly calculated.

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