A dynamic optimization method for the acid-to-ore ratio in the high-pressure leaching of laterite nickel ore

Abstract

The present invention discloses a method for dynamically optimizing the acid-to-ore ratio in the high-pressure leaching of laterite nickel ore, which includes obtaining the ore composition, pulp concentration, pulp flow rate, leaching temperature, and residence time of the pulp in the autoclave, and setting the target leaching rate of nickel; setting the flow rate of sulfuric acid; obtaining the hydrogen ion concentration in the solution; obtaining the theoretical leaching rate of nickel when the leaching time reaches the residence time of the pulp in the autoclave at the current sulfuric acid flow rate; and comparing the size of the theoretical leaching rate of nickel with the target leaching rate of nickel. The beneficial effects of the technical solution proposed by the present invention are: providing a high-pressure acid leaching mathematical model for the leaching of laterite nickel ore and an optimal acid-to-ore ratio calculation method. By inputting the real-time ore composition into this high-pressure acid leaching mathematical model, the optimal acid-to-ore ratio can be calculated, so that the sulfuric acid addition flow rate in the high-pressure leaching link of laterite nickel ore can be dynamically adjusted according to the ore composition, making the high-pressure acid leaching process always in the dynamically optimal state of the optimal acid-to-ore ratio.

Description

Technical Field

[0001] The present invention relates to the technical field of high-pressure leaching of laterite nickel ore, and in particular to a method for dynamically optimizing the acid-to-ore ratio in the high-pressure leaching of laterite nickel ore. Background Art

[0002] The hydrometallurgical process mainly includes atmospheric leaching and pressure leaching. The process of the pressure leaching process is generally to first make the ore into pulp, then preheat the pulp, carry out pressure acid leaching of the preheated pulp in an autoclave, and then cool down, reduce pressure, neutralize, separate the leaching slurry and purify the leaching solution.

[0003] During the pressure leaching process, the acid-to-ore ratio is an important control parameter. An excessively low acid-to-ore ratio will cause the leaching of Ni, Co, and Mn metal ions in the laterite nickel ore to be too slow, resulting in a reduction in production efficiency; while an excessively high acid-to-ore ratio will cause the residual acid content after leaching to be too high, which will result in more use of neutralizing agents and precipitants in the subsequent pre-neutralization and iron-aluminum precipitation processes, and the sulfuric acid consumption in the raw materials is too large, resulting in unnecessary cost increases. Therefore, during the high-pressure acid leaching of laterite nickel ore, there is an optimal acid-to-ore ratio, which can ensure the leaching rate of Ni, Co, and Mn metal ions while avoiding unnecessary acid waste.

[0004] For the determination of the optimal acid-to-ore ratio, it is currently mainly carried out through small-scale laboratory experiments. However, due to the differences in mass transfer and heat transfer processes between the small-scale test device and the large-scale autoclave, the optimal acid-to-ore ratio determined by the small-scale test device is also different from the optimal acid-to-ore ratio in the large-scale autoclave, and it is impossible to completely infer the optimal acid-to-ore ratio under the operating conditions of the large-scale autoclave through the experimental data of the small-scale test device. In addition, the acid consumption during the leaching process of different metals is different, and the optimal acid-to-ore ratio is also a variable value that fluctuates with the ore composition and pulp concentration. At present, the high-pressure acid leaching process often uses a fixed acid-to-ore ratio or only adjusts it based on human judgment, resulting in an excessively high or low acid-to-ore ratio during the actual operation process, leading to unnecessary cost increases or production efficiency reduction technical problems. Summary of the Invention

[0005] In view of this, it is necessary to provide a method for dynamically optimizing the acid-to-ore ratio in the high-pressure leaching of laterite nickel ore to solve the technical problems that the current high-pressure acid leaching process often uses a fixed acid-to-ore ratio or only adjusts it based on human judgment, resulting in an excessively high or low acid-to-ore ratio during the actual operation process, leading to unnecessary cost increases or production efficiency reduction.

[0006] To achieve the above object, the present invention provides a method for dynamically optimizing the acid-to-ore ratio in the high-pressure leaching of laterite nickel ore, including:

[0007] Obtain the ore composition, pulp concentration, pulp flow rate, leaching temperature, and residence time of the pulp in the autoclave, and set the target leaching rate of nickel;

[0008] Set the flow rate of sulfuric acid;

[0009] Based on the set value of the sulfuric acid flow rate, the ore composition, the pulp concentration, the pulp flow rate, and the leaching temperature, obtain the variation relationship of the hydrogen ion concentration in the solution with the reaction time;

[0010] Based on the variation relationship of the hydrogen ion concentration in the solution with the reaction time, the ore composition, the pulp concentration, the pulp flow rate, the leaching temperature, and the residence time of the pulp in the autoclave, obtain the theoretical leaching rate of nickel when the leaching time reaches the residence time of the pulp in the autoclave at the current sulfuric acid flow rate;

[0011] Compare the size of the theoretical leaching rate of nickel and the target leaching rate of nickel. If they are not equal, adjust the set value of the sulfuric acid flow rate, and repeat the above steps until the theoretical leaching rate of nickel is equal to the target leaching rate of nickel. At this time, output the current sulfuric acid flow rate as the optimal sulfuric acid flow rate, and calculate the corresponding optimal acid-to-ore ratio;

[0012] According to the optimal acid-to-ore ratio, adjust the opening of the sulfuric acid flow regulating valve in the autoclave so that the actual high-pressure acid leaching process is always carried out under the condition of the optimal acid-to-ore ratio.

[0013] In some embodiments, based on the set value of the sulfuric acid flow rate, the ore composition, the pulp concentration, the pulp flow rate, and the leaching temperature, obtaining the variation relationship of the hydrogen ion concentration in the solution with the reaction time specifically includes:

[0014] Set the hydrogen ion concentration in the solution under the current time and the current sulfuric acid flow rate condition;

[0015] Based on the ore composition, the pulp concentration, the pulp flow rate, the set value of the sulfuric acid flow rate, and the set value of the hydrogen ion concentration in the solution, obtain the leaching rates of nickel ions, cobalt ions, aluminum ions, and iron ions in the solution at the current time;

[0016] Based on the leaching rates of aluminum ions and iron ions in the solution, obtain the hydrolysis precipitation amounts of aluminum ions and iron ions at the current time;

[0017] Based on the hydrolysis precipitation amounts of aluminum ions and iron ions at the current time and the current sulfuric acid flow rate set value, obtain the first sulfate concentration in the solution at the current time;

[0018] Based on the concentrations of nickel ions, cobalt ions, aluminum ions, iron ions, and hydrogen sulfate ions in the solution at the current time, obtain the second sulfate concentration in the solution at the current time;

[0019] Compare the magnitudes of the first sulfate ion concentration and the second sulfate ion concentration. If they are not equal, correct the set value of the hydrogen ion concentration in the solution, and repeat the above steps until the first sulfate ion concentration is equal to the second sulfate ion concentration. At this time, output the set value of the hydrogen ion concentration in the current solution as the actual concentration of hydrogen ions.

[0020] In some embodiments, based on the ore composition, pulp concentration, pulp flow rate, set value of sulfuric acid flow rate, and set value of hydrogen ion concentration in the solution, obtain the leaching rates of nickel ions, cobalt ions, aluminum ions, and iron ions in the solution at the current time. Among them, the specific calculation formula for the leaching rate of nickel ions in the solution at the current time is:

[0021]

[0022] where R is the gas constant, T is the leaching temperature, is the set value of the hydrogen ion concentration in the solution, t is the current time, is the leaching rate of nickel ions in the solution at the current time, is the maximum leaching rate of nickel ions in the solution, which can be calculated from the ore composition, pulp concentration, and pulp flow rate.

[0023] In some embodiments, the specific calculation formula for the leaching rate of cobalt ions in the solution at the current time is:

[0024]

[0025] where R is the gas constant, T is the leaching temperature, is the current set value of the hydrogen ion concentration in the solution, t is the current time, is the leaching rate of cobalt ions in the solution at the current time, is the maximum leaching rate of cobalt ions in the solution, which can be calculated from the ore composition, pulp concentration, and pulp flow rate.

[0026] In some embodiments, the specific calculation formula for the leaching rate of aluminum ions in the solution at the current time is:

[0027]

[0028] where R is the gas constant, T is the leaching temperature, is the set value of the hydrogen ion concentration in the solution, t is the current time, is the leaching rate of aluminum ions in the solution at the current time, is the maximum leaching rate of aluminum ions in the solution, which can be calculated from the ore composition, pulp concentration, and pulp flow rate.

[0029] In some embodiments, the specific calculation formula for the leaching rate of iron ions in the solution at the current time is:

[0030]

[0031] Among them, R is the gas constant, T is the leaching temperature, is the set value of the hydrogen ion concentration in the solution, t is the current time, is the leaching rate of iron ions in the solution at the current time, is the maximum leaching rate of iron ions in the solution, which can be calculated from the ore composition, pulp concentration, and pulp flow rate.

[0032] In some embodiments, according to the leaching rates of aluminum ions and iron ions in the solution, the hydrolysis precipitation amounts of aluminum ions and iron ions at the current time are obtained. Among them, the specific calculation formula for the hydrolysis precipitation amount of aluminum ions at the current time is:

[0033]

[0034]

[0035]

[0036]

[0037]

[0038] Among them, T is the leaching temperature, t is the current time, is the hydrolysis precipitation amount of aluminum ions at the current time, is the current set value of the hydrogen ion concentration in the solution, is the saturation of aluminum ions in the solution, is the leaching rate of aluminum ions in the solution, is the Al concentration in the pulp, which can be calculated from the ore composition, pulp concentration, and pulp flow rate, is the solubility of aluminum sulfate in the solution, is the first sulfate ion concentration in the solution at the current time, is the concentration of aluminum ions in the solution, which can be calculated from the ore composition, pulp concentration, and pulp flow rate, is the concentration of hydrogen sulfate ions in the solution, is ionic strength.

[0039] In some embodiments, the specific calculation formula for the hydrolysis precipitation amount of iron ions at the current time is:

[0040]

[0041]

[0042]

[0043]

[0044]

[0045] Among them, T is the leaching temperature, is the hydrolysis precipitation amount of ferric ions at the current time, is the current set value of the hydrogen ion concentration in the solution, is the saturation of ferric ions in the solution, is the leaching rate of nickel ions in the solution, is the solubility of ferric sulfate in the solution, is the maximum leaching rate of nickel ions in the solution, is the concentration of the first sulfate radical in the solution at the current time, is the concentration of ferric ions in the solution, which can be obtained by calculating the ore composition, pulp concentration, and pulp flow rate, is the concentration of hydrogen sulfate ions in the solution, is ionic strength.

[0046] In some embodiments, according to the hydrolysis precipitation amounts of aluminum ions and ferric ions at the current time and the current set value of sulfuric acid flow rate, the concentration of the first sulfate radical in the solution at the current time is obtained, specifically including:

[0047] Obtain the total sulfate radical concentration according to the current set value of sulfuric acid flow rate;

[0048] According to the hydrolysis precipitation amounts of aluminum ions and ferric ions at the current time, obtain the sulfate radical content in the hydrolysis precipitation;

[0049] According to the total sulfate radical concentration and the sulfate radical content in the hydrolysis precipitation, obtain the concentration of the first sulfate radical in the solution at the current time.

[0050] In some embodiments, compare the magnitudes of the first sulfate radical concentration and the second sulfate radical concentration. If they are not equal, then correct the set value of the hydrogen ion concentration in the solution, and repeat the above steps until the first sulfate radical concentration and the second sulfate radical concentration are equal. At this time, output the set value of the hydrogen ion concentration in the current solution as the actual concentration of hydrogen ions. Among them, the specific formula for correcting the set value of the hydrogen ion concentration in the solution is:

[0051] = (Before correction) + k )

[0052] Among them, is the set value of the hydrogen ion concentration after correction, (Before correction) is the set value of the current hydrogen ion concentration, is the first sulfate concentration, is the second sulfate concentration, and k is the proportionality coefficient.

[0053] In some embodiments, based on the variation relationship of the hydrogen ion concentration in the solution with the reaction time, the ore composition, the pulp concentration, the pulp flow rate, the leaching temperature, and the residence time of the pulp in the autoclave, the theoretical leaching rate of nickel at the current sulfuric acid flow rate when the leaching time reaches the residence time of the pulp in the autoclave is obtained. The specific calculation formula is:

[0054]

[0055] where R is the gas constant, T is the leaching temperature, is the value of the hydrogen ion concentration in the solution at time t, t is the current time, is the leaching rate of nickel ions in the solution at the current time, is the maximum leaching rate of nickel ions in the solution, which can be calculated from the ore composition, the pulp concentration, and the pulp flow rate.

[0056] In some embodiments, the theoretical leaching rate of nickel is compared with the target leaching rate of nickel. If they are not equal, the set value of the sulfuric acid flow rate is adjusted, and the above steps are repeated until the theoretical leaching rate of nickel is equal to the target leaching rate of nickel. Specifically:

[0057] If the theoretical leaching rate of nickel is greater than the target leaching rate of nickel, the set value of the sulfuric acid flow rate is decreased;

[0058] If the theoretical leaching rate of nickel is less than the target leaching rate of nickel, the set value of the sulfuric acid flow rate is increased.

[0059] Compared with the prior art, the beneficial effect of the technical solution proposed by the present invention is: a high-pressure acid leaching mathematical model for laterite nickel ore leaching and an optimal acid-ore ratio calculation method are provided. By inputting the real-time ore composition into the high-pressure acid leaching mathematical model, the optimal acid-ore ratio can be calculated, so that the sulfuric acid addition flow rate in the high-pressure leaching process of laterite nickel ore can be dynamically adjusted according to the ore composition, making the high-pressure acid leaching process always in the dynamic optimal state of the optimal acid-ore ratio. Compared with the traditional method of optimizing the acid-ore ratio through small-scale experiments, this method has the advantages of fast response speed and accurate optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 is a schematic flow chart of an embodiment of the dynamic optimization method for the acid-ore ratio of high-pressure leaching of laterite nickel ore provided by the present invention;

[0061] Figure 2 is an algorithm flow chart of the dynamic optimization method for the acid-ore ratio of high-pressure leaching of laterite nickel ore provided by the present invention;

[0062] Figure 3 is Figure 1 The schematic flow chart of step S3 in

[0063] Figure 4 is Figure 3 The schematic flow chart of step S34 in

[0064] Figure 5 It is the experimental result of parallel experiments under various acid - ore ratios through a bench - scale device. Specific embodiments

[0065] The preferred embodiments of the present invention will be specifically described below with reference to the accompanying drawings. The accompanying drawings form a part of this application and are used together with the embodiments of the present invention to explain the principle of the present invention, rather than to limit the scope of the present invention.

[0066] Please refer to Figure 1 and Figure 2 The present invention provides a method for dynamically optimizing the acid - ore ratio in the high - pressure leaching of laterite nickel ore, including the following steps:

[0067] S1. Obtain the ore composition, pulp concentration, pulp flow rate, leaching temperature, and residence time of the pulp in the autoclave, and set the target leaching rate of nickel.

[0068] S2. Set the flow rate of sulfuric acid.

[0069] S3. According to the set value of the sulfuric acid flow rate, ore composition, pulp concentration, pulp flow rate, and leaching temperature, obtain the relationship between the hydrogen ion concentration in the solution and the reaction time (the solution mentioned in the present invention refers to the solution in the autoclave); the hydrogen ion concentration in the solution has an important influence on the leaching of nickel, cobalt, aluminum, and iron. However, the hydrogen ion concentration in the solution cannot be directly obtained from the sulfuric acid flow rate. In the present invention, the hydrogen ion concentration in the solution is obtained by the following method.

[0070] Please refer to Figure 2 and Figure 3 The specific method for obtaining the hydrogen ion concentration in the solution includes the following steps:

[0071] S31. Set the hydrogen ion concentration in the solution under the current time and current sulfuric acid flow rate conditions.

[0072] S32. According to the ore composition, pulp concentration, pulp flow rate, set value of the sulfuric acid flow rate, and set value of the hydrogen ion concentration in the solution, obtain the leaching rates of nickel ions, cobalt ions, aluminum ions, and iron ions in the solution at the current time.

[0073] Among them, the specific calculation formula for the leaching rate of nickel ions in the solution at the current time is:

[0074]

[0075] Among them, R is the gas constant, T is the leaching temperature, is the set value of hydrogen ion concentration in the solution, t is the current time, is the leaching rate of nickel ions in the solution at the current time, is the maximum leaching rate of nickel ions in the solution, which can be calculated from the ore composition, pulp concentration, and pulp flow rate.

[0076] The specific calculation formula for the leaching rate of cobalt ions in the solution at the current time is:

[0077]

[0078] Among them, R is the gas constant, T is the leaching temperature, is the current set value of hydrogen ion concentration in the solution, t is the current time, is the leaching rate of cobalt ions in the solution at the current time, is the maximum leaching rate of cobalt ions in the solution, which can be calculated from the ore composition, pulp concentration, and pulp flow rate.

[0079] The specific calculation formula for the leaching rate of aluminum ions in the solution at the current time is:

[0080]

[0081] Among them, R is the gas constant, T is the leaching temperature, is the set value of hydrogen ion concentration in the solution, t is the current time, is the leaching rate of aluminum ions in the solution at the current time, is the maximum leaching rate of aluminum ions in the solution, which can be calculated from the ore composition, pulp concentration, and pulp flow rate.

[0082] The specific calculation formula for the leaching rate of iron ions in the solution at the current time is:

[0083]

[0084] Among them, R is the gas constant, T is the leaching temperature, is the set value of hydrogen ion concentration in the solution, t is the current time, is the leaching rate of iron ions in the solution at the current time, is the maximum leaching rate of iron ions in the solution, which can be calculated from the ore composition, pulp concentration, and pulp flow rate.

[0085] S33. Obtain the hydrolysis precipitation amounts of aluminum ions and iron ions at the current time according to the leaching rates of aluminum ions and iron ions in the solution;

[0086] Among them, the specific calculation formula for the hydrolysis precipitation amount of aluminum ions at the current time is:

[0087]

[0088]

[0089]

[0090]

[0091]

[0092] wherein, T is the leaching temperature, t is the current time, is the hydrolysis precipitation amount of aluminum ions at the current time, is the current set value of the hydrogen ion concentration in the solution, is the saturation degree of aluminum ions in the solution, is the leaching rate of aluminum ions in the solution, is the Al concentration in the pulp, which can be calculated from the ore composition, pulp concentration, and pulp flow rate, is the solubility of aluminum sulfate in the solution, is the concentration of the first sulfate radical in the solution at the current time, is the concentration of aluminum ions in the solution, which can be calculated from the ore composition, pulp concentration, and pulp flow rate, is the concentration of hydrogen sulfate ions in the solution, is ionic strength.,

[0093] The specific calculation formula for the hydrolysis precipitation amount of iron ions at the current time is:

[0094]

[0095]

[0096]

[0097]

[0098]

[0099] wherein, T is the leaching temperature, is the hydrolysis precipitation amount of iron ions at the current time, is the current set value of the hydrogen ion concentration in the solution, is the saturation degree of iron ions in the solution, is the leaching rate of nickel ions in the solution, is the solubility of iron sulfate in the solution, is the maximum leaching rate of nickel ions in the solution, is the concentration of the first sulfate radical in the solution at the current time, is the concentration of iron ions in the solution, which can be calculated from the ore composition, pulp concentration, and pulp flow rate, is the concentration of hydrogen sulfate ions in the solution, is ionic strength.

[0100] S34. Obtain the concentration of the first sulfate radical in the solution at the current time according to the hydrolysis precipitation amounts of aluminum ions and iron ions at the current time and the set value of the current sulfuric acid flow rate;

[0101] Please refer to Figure 4 , and step S34 specifically includes:

[0102] S341. Obtain the total sulfate radical concentration according to the set value of the current sulfuric acid flow rate;

[0103] S342. Obtain the sulfate radical content in the hydrolysis precipitation according to the hydrolysis precipitation amounts of aluminum ions and iron ions at the current time;

[0104] S343. Obtain the concentration of the first sulfate radical in the solution at the current time according to the total sulfate radical concentration and the sulfate radical content in the hydrolysis precipitation. Specifically, the concentration of the first sulfate radical in the solution at the current time is the difference between the total sulfate radical concentration and the sulfate radical content in the hydrolysis precipitation.

[0105] The principle of the calculation process of steps S341 - S343 is: the total sulfate radical concentration can be obtained from the amount of sulfuric acid added. For the sulfuric acid added to the solution, a part forms sulfate ions in the solution, and another part of the sulfate radical will precipitate out as precipitation through the hydrolysis of aluminum ions and iron ions. Therefore, the actual sulfate radical concentration in the solution can be obtained by subtracting the sulfate radical content in the hydrolysis precipitation of aluminum ions and iron ions from the total sulfate radical concentration.

[0106] S35. Obtain the concentration of the second sulfate radical in the solution at the current time according to the concentrations of nickel ions, cobalt ions, aluminum ions, iron ions, and hydrogen sulfate ions in the solution at the current time;

[0107] The principle of step S35 is: the charges of anions and cations in the solution are conserved. The main anions in the solution are sulfate ions, and the main cations in the solution are nickel ions, cobalt ions, aluminum ions, and iron ions. By calculating the total positive charge concentration of hydrogen ions, nickel ions, cobalt ions, aluminum ions, and iron ions, the concentration of sulfate ions in the solution can be obtained. It should be noted that since it is generally considered that H 2 SO 4 will only ionize into H + and HSO 4 - , and will not directly ionize SO 4 2-, H + and HSO 4 - The positive and negative charges cancel each other out. Therefore, when calculating the cations in the solution, H ions are not considered.

[0108] S36. Compare the magnitudes of the first sulfate concentration and the second sulfate concentration. If they are not equal, correct the set value of the hydrogen ion concentration in the solution, and repeat the above steps until the first sulfate concentration is equal to the second sulfate concentration. At this time, output the set value of the hydrogen ion concentration in the current solution as the actual concentration of hydrogen ions.

[0109] Among them, the specific formula for correcting the set value of the hydrogen ion concentration in the solution is:

[0110] = (Before correction) + k )

[0111] Among them, is the set value of the hydrogen ion concentration after correction, (Before correction) is the current set value of the hydrogen ion concentration, is the first sulfate concentration, is the second sulfate concentration, and k is the proportionality coefficient.

[0112] The principle of step S36 is: The first sulfate concentration obtained by subtracting the sulfate content in the hydrolysis precipitates of aluminum ions and iron ions from the total sulfate concentration should be equal to the second sulfate concentration calculated by charge conservation. If they are not equal, it means that the value of the hydrogen ion concentration in the solution under the current time and current sulfuric acid flow conditions set in step S31 is inaccurate. Therefore, the hydrogen ion concentration needs to be reset until they are equal, which indicates that the currently set hydrogen ion concentration is the accurate value. Therefore, the real-time hydrogen ion concentration can be calculated through the above method, providing a basis for calculating the theoretical leaching rate of nickel subsequently.

[0113] S4. According to the variation relationship of the hydrogen ion concentration in the solution with the reaction time, the ore composition, the pulp concentration, the pulp flow rate, the leaching temperature, and the residence time of the pulp in the autoclave, obtain the theoretical leaching rate of nickel when the leaching time reaches the residence time of the pulp in the autoclave under the current sulfuric acid flow rate;

[0114] The specific calculation formula is:

[0115]

[0116] Among them, R is the gas constant, T is the leaching temperature, is the value of the hydrogen ion concentration in the solution at time t, t is the current time, is the leaching rate of nickel ions in the solution at the current time, is the maximum leaching rate of nickel ions in the solution, which can be calculated from the ore composition, pulp concentration, and pulp flow rate.

[0117] S5. Compare the theoretical leaching rate of nickel with the target leaching rate of nickel. If they are not equal, adjust the set value of the sulfuric acid flow rate, and repeat the above steps until the theoretical leaching rate of nickel is equal to the target leaching rate of nickel. At this time, output the current sulfuric acid flow rate as the optimal sulfuric acid flow rate, and calculate the corresponding optimal acid-to-ore ratio;

[0118] Specifically, if the theoretical leaching rate of nickel is greater than the target leaching rate of nickel, decrease the set value of the sulfuric acid flow rate; if the theoretical leaching rate of nickel is less than the target leaching rate of nickel, increase the set value of the sulfuric acid flow rate.

[0119] S6. According to the optimal acid-to-ore ratio, adjust the opening of the sulfuric acid flow rate regulating valve in the autoclave so that the actual high-pressure acid leaching process is always carried out under the condition of the optimal acid-to-ore ratio. This control process can be directly controlled by a program without manual operation.

[0120] In summary, the beneficial effects of the technical solution provided by the present invention include: providing a mathematical model for high-pressure acid leaching of laterite nickel ore and a calculation method for the optimal acid-to-ore ratio. By inputting the real-time ore composition into the mathematical model of high-pressure acid leaching, the optimal acid-to-ore ratio can be calculated, so that the sulfuric acid addition flow rate in the high-pressure leaching link of laterite nickel ore can be dynamically adjusted according to the ore composition, making the high-pressure acid leaching process always in the dynamic optimal state of the optimal acid-to-ore ratio. Compared with the traditional method of optimizing the acid-to-ore ratio through small-scale experiments, this method has the advantages of fast response speed and accurate optimization.

[0121] The following is the program code for the autoclave acid leaching process involved in this technical solution:

[0122] clear all

[0123] clc

[0124] global t H Xmax1 Xmax2 Xmax3 T

[0125] T=input('Please enter the temperature K');

[0126] rho=input('Please enter the pulp density g / cm3');

[0127] c=input('Please enter the pulp solid content %');

[0128] V=input('Please enter the pulp flow rate m3 / h');

[0129] CNiin=input('Please enter the Ni content in the ore %');

[0130] CCoin = input('Please enter the Co content % in the ore');

[0131] CAlin = input('Please enter the Al content % in the ore');

[0132] CFein = input('Please enter the Fe content % in the ore');

[0133] CMgin = input('Please enter the Mg content % in the ore');

[0134] CMnin = input('Please enter the Mn content % in the ore');

[0135] ratio = [];

[0136] Fepre = [];

[0137] Alpre = [];

[0138] Hreal = [];

[0139] treal = [];

[0140] Nireal = [];

[0141] Coreal = [];

[0142] treal = [];

[0143] SO4real = [];

[0144] Alreal = [];

[0145] Fereal = [];

[0146] Mnreal = [];

[0147] H2SO4real = [];

[0148] Treal = [];

[0149] Mgreal = [];

[0150] M0real = [];

[0151] ratiotest = [];

[0152] Aldissolution = [];

[0153] Fedissolution = [];

[0154] lcreal = [];

[0155] Alconv = [];

[0156] Treal = [];

[0157] deltat = 1;

[0158] M1 = 0.01;

[0159] tmax = 50 / V * 60;

[0160] for j = 1:0.01:4

[0161] H2SO4 = rho * c * V * j;

[0162] for i = 1:1:tmax

[0163] t = i * deltat;

[0164] R = 8.314;

[0165] Xmax1 = 0.95;

[0166] Xmax2 = 0.99;

[0167] Xmax3 = 0.99;

[0168] k = 0.1;

[0169] cAlin = 1000 * c * rho / 100 * CAlin * V / 100 / 27 / (V + H2SO4in / 1.84);

[0170] SO4a = 0.18;

[0171] SO4b = 0.05;

[0172] SO4c = 0.05;

[0173] CinNi = 1000 * c * rho / 100 * CNiin / 100 / 58.69 * V / (V + H2SO4in / 1.84);

[0174] CinCo = 1000 * c * rho / 100 * CCoin / 100 / 58.93 * V / (V + H2SO4in / 1.84);

[0175] CinMg = 1000 * c * rho / 100 * CAlin / 100 / 24.3 * V / (V + H2SO4in / 1.84);

[0176] CinMn = 1000 * c * rho / 100 * CMnin / 100 / 54.94 * V / (V + H2SO4in / 1.84);

[0177] CinFe = 1000 * c * rho / 100 * CFein / 100 / 55.845 * V / (V + H2SO4in / 1.84);

[0178] err = 2;

[0179] Al = 0.1;

[0180] Fe = 0.1;

[0181] H = 0.56;

[0182] CMgin = 0.2829;

[0183] while err > 0.0001

[0184] HSO4 = H;

[0185] if t <= 15

[0186] Mg = CMgin * t ^ 0.5 / 15 ^ 0.5;

[0187] end

[0188] if t > 15

[0189] Mg = CMgin;

[0190] end

[0191] lc3 = 0.5 * (Mg * 4 + SO4c * 4);

[0192] Mgsol = 5 * H ^ 2 / 10 ^ (-1312 / T - 9.369 + 34.62 * lc3 ^ 0.5 / (1 + 1.6 * lc3 ^ 0.5) - 1.484 * lc3);

[0193] if Mg > Mgsol

[0194] Mg = Mg - 0.5 * (Mg - Mgsol);

[0195] end

[0196] fun1 = @untitled6;

[0197] XAL = fsolve(fun1, 0.1);

[0198] if XAL > 0.95

[0199] XAL = 0.95;

[0200] end

[0201] Aldis = cAlin * XAL;

[0202] lc1 = 0.5 * (9 * (0.5 * Aldis + 0.5 * Al) + 4 * SO4c);

[0203] ALsol = ((H * HSO4)^2.5 / 10^(-4464 / T + 3.774 + 4.373 + 14.21 * lc1^0.5 / (1 + 1.6 * lc1^0.5) - 1.667 * lc1))^(2 / 3);

[0204] SAL = Al / (2 * ALsol);

[0205] M0 = 0.408 * H * (SAL - 1) * M1 * deltat;

[0206] Al = Aldis - M1 * 3;

[0207] if Al > Aldis

[0208] Al = Aldis;

[0209] end

[0210] XCO = Xmax1 * (1 - (1 - (0.303 * exp(-3179 / R / T) * H * t)^0.5)^3);

[0211] if XCO > 1

[0212] XCO = 1;

[0213] end

[0214] fun2 = @untitled8;

[0215] XNI = fsolve(fun2, 0.1);

[0216] if XNI > Xmax3

[0217] XNI = Xmax3;

[0218] end

[0219] Ni = CinNi * XNI;

[0220] Co = CinCo * XCO;

[0221] lc2 = 0.5 * (Fe * 9 + (SO4c) * 4);

[0222] Fesol = (H * HSO4) / 10^(-2740 / T + 10.72 - 9.905 * lc2^0.5 / (1 + 1.6 * lc2^0.5) + 0.0294 * lc2)^0.5;

[0223] SFe = 6.21 - 5.11 * XNI / Xmax2;

[0224] Fedis = Fesol * SFe;

[0225] M2 = Fedis * (0.01 * SFe^2 - 0.24 * SFe + 1.23);

[0226] Mn = 0.05 * SO4b;

[0227] Cr = Mn / 1.5;

[0228] Fe = Fedis;

[0229] H2SO4free = SO4b + Cr - 0.5 * (3 * Fe + 3 * Al + 2 * Mg + 2 * Ni + 2 * Co);

[0230] Mnsol = 9.82 * 0.001 * exp(4.91 * H2SO4free);

[0231] SO4a = H2SO4 - M1 * 3;

[0232] HSO4 = H - Cr;

[0233] SO4b = HSO4 + 1.6 * (Ni + Co + Mg + Mn) + 1.5 * (Al + Fe);

[0234] SO4c = SO4b - HSO4;

[0235] err = abs(SO4a - SO4b);

[0236] H = H + k * (SO4a - SO4b);

[0237] r = M2 * 2 * 55.845 / (M1 * 27 * 3 + M2 * 2 * 55.845);

[0238] Mn = 0.05 * SO4b;

[0239] NiM = Ni * 58.69;

[0240] CoM = Co * 58.93;

[0241] AlM = Al * 27;

[0242] MgM = Mg * 24.3;

[0243] FeM = Fe * 55.845;

[0244] MnM = Mn * 54.94;

[0245] Nire = real(NiM);

[0246] Core = real(CoM);

[0247] Alre = real(AlM);

[0248] Mgre = real(MgM);

[0249] Fere = real(FeM);

[0250] Mnre = real(MnM);

[0251] end

[0252] M1 = M1 + M0;

[0253] deltaT = 541.72 * M1 * 55 / (3 * 4.2 * 50);

[0254] ratio(i) = r;

[0255] treal(i) = t;

[0256] Fepre(i) = M2 * 55.845;

[0257] Alpre(i) = M1 * 27;

[0258] Hreal(i) = H;

[0259] Nireal(i) = Ni;

[0260] Coreal(i) = Co;

[0261] SO4real(i) = SO4a;

[0262] Alreal(i) = Al;

[0263] Fereal(i) = Fe * 10;

[0264] Fe = Fe * 10;

[0265] Mnreal(i) = Mn;

[0266] H2SO4real(i) = H2SO4free;

[0267] Treal(i) = T;

[0268] Mgreal(i) = Mg;

[0269] M0real(i) = M1;

[0270] Aldissolution(i) = ALsol;

[0271] Fedissolution(i) = Fedis;

[0272] lcreal(i) = lc1;

[0273] Alconv(i) = XAL;

[0274] SAl(i) = SAL;

[0275] Treal(i) = T;

[0276] if Ni >= Nidef

[0277] disp('Optimal acid-to-ore ratio');

[0278] disp(j);

[0279] disp('Ni content in the leachate after high-pressure acid leaching, g / L');

[0280] disp(Nire);

[0281] disp('Co content in the leachate after high-pressure acid leaching, g / L');

[0282] disp(Core);

[0283] disp('Fe content in the leachate after high-pressure acid leaching, g / L');

[0284] disp(Fere);

[0285] disp('Al content in the leachate after high-pressure acid leaching, g / L');

[0286] disp(Alre);

[0287] disp('Mg content in the leachate after high-pressure acid leaching, g / L');

[0288] disp(Mgre);

[0289] disp('Mn content in the leachate after high-pressure acid leaching, g / L');

[0290] disp(Mnre);

[0291] end

[0292] Technical solution verification experiment

[0293] To verify the reliability of the above calculation model, a verification experiment on the optimization of the acid-to-ore ratio was carried out using a laboratory-scale test device. The optimal acid-to-ore ratio obtained by inputting the reaction process parameters of the test device into the above calculation program was 0.27.

[0294] Next, parallel experiments were carried out using this test device under various acid-to-ore ratios, and the experimental results are as Figure 5 shown.

[0295] From Figure 5 it can be seen that when the acid-to-ore ratio is 0.26, Ni has the highest leaching rate, and at this acid-to-ore ratio, the leaching amounts of Al and Fe are relatively low, reducing the subsequent separation cost.

[0296] Table 1 Operating conditions, leaching effects, and leaching costs of the high-pressure acid leaching process before and after optimization

[0297]

[0298] Table 1 shows the operating conditions, leaching effects, and leaching costs of the high-pressure acid leaching process before and after optimization. It can be seen from Table 1 that the optimal acid-to-ore ratio obtained by dynamic optimization using this calculation model is basically consistent with the experimental results of the acid-to-ore ratio optimization of the laboratory-scale test device. While ensuring the leaching rates of target metals such as Ni, Co, and Mn, the leaching rates of non-target elements such as Al are restricted. By optimizing the acid-to-ore ratio, the production cost can be saved by 86 $ / h, and the annual cost savings of the device are about 751,300 $. Moreover, unnecessary sulfuric acid waste is saved, promoting the economic efficiency, energy conservation, and consumption reduction of the high-pressure acid leaching process of laterite nickel ore.

[0299] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A dynamic optimization method for the acid-to-ore ratio in the high-pressure leaching of laterite nickel ore, characterized in that, it includes: Obtain the ore composition, pulp concentration, pulp flow rate, leaching temperature, and residence time of the pulp in the autoclave, and set the target leaching rate of nickel; Set the flow rate of sulfuric acid; According to the set value of the sulfuric acid flow rate, ore composition, pulp concentration, pulp flow rate, and leaching temperature, obtain the variation relationship of the hydrogen ion concentration in the solution with the reaction time; According to the variation relationship of the hydrogen ion concentration in the solution with the reaction time, ore composition, pulp concentration, pulp flow rate, leaching temperature, and residence time of the pulp in the autoclave, obtain the theoretical leaching rate of nickel at the current sulfuric acid flow rate when the leaching time reaches the residence time of the pulp in the autoclave; Compare the theoretical leaching rate of nickel with the target leaching rate of nickel. If they are not equal, adjust the set value of the sulfuric acid flow rate, and repeat the above steps until the theoretical leaching rate of nickel is equal to the target leaching rate of nickel. At this time, output the current sulfuric acid flow rate as the optimal sulfuric acid flow rate, and calculate the corresponding optimal acid-to-ore ratio; According to the optimal acid-to-ore ratio, adjust the opening of the sulfuric acid flow regulating valve in the autoclave to make the actual high-pressure acid leaching process always carried out under the condition of the optimal acid-to-ore ratio.

2. The dynamic optimization method for the acid-to-ore ratio in the high-pressure leaching of laterite nickel ore according to claim 1, characterized in that, According to the set value of the sulfuric acid flow rate, ore composition, pulp concentration, pulp flow rate, and leaching temperature, obtain the variation relationship of the hydrogen ion concentration in the solution with the reaction time, specifically including: Set the hydrogen ion concentration in the solution under the current time and current sulfuric acid flow rate conditions; According to the ore composition, pulp concentration, pulp flow rate, set value of the sulfuric acid flow rate, and set value of the hydrogen ion concentration in the solution, obtain the leaching rates of nickel ions, cobalt ions, aluminum ions, and iron ions in the solution at the current time; According to the leaching rates of aluminum ions and iron ions in the solution, obtain the hydrolysis precipitation amounts of aluminum ions and iron ions at the current time; According to the hydrolysis precipitation amounts of aluminum ions and iron ions at the current time and the current sulfuric acid flow rate set value, obtain the first sulfate concentration in the solution at the current time; According to the concentrations of nickel ions, cobalt ions, aluminum ions, iron ions, and hydrogen sulfate ions in the solution at the current time, obtain the second sulfate concentration in the solution at the current time; Compare the magnitudes of the first sulfate concentration and the second sulfate concentration. If they are not equal, correct the set value of the hydrogen ion concentration in the solution, and repeat the above steps until the first sulfate concentration is equal to the second sulfate concentration. At this time, output the set value of the hydrogen ion concentration in the current solution as the actual concentration of hydrogen ions.

3. The dynamic optimization method for the acid-to-ore ratio in the high-pressure leaching of laterite nickel ore according to claim 2, characterized in that, According to the ore composition, pulp concentration, pulp flow rate, sulfuric acid flow rate set value, and set value of the hydrogen ion concentration in the solution, obtain the leaching rates of nickel ions, cobalt ions, aluminum ions, and iron ions in the solution at the current time. Among them, the specific calculation formula for the leaching rate of nickel ions in the solution at the current time is: wherein, R is the gas constant, T is the leaching temperature, is the set value of the hydrogen ion concentration in the solution, t is the current time, is the leaching rate of nickel ions in the solution at the current time, is the maximum leaching rate of nickel ions in the solution, which is calculated from the ore incoming composition, pulp concentration, and pulp flow rate.

4. The dynamic optimization method for the acid-to-ore ratio in the high-pressure leaching of laterite nickel ore according to claim 2, characterized in that, The specific calculation formula for the leaching rate of cobalt ions in the solution at the current time is: where R is the gas constant, T is the leaching temperature, is the current set value of the hydrogen ion concentration in the solution, t is the current time, is the leaching rate of cobalt ions in the solution at the current time, is the maximum leaching rate of cobalt ions in the solution, which is calculated from the ore composition, pulp concentration, and pulp flow rate.

5. The dynamic optimization method for the acid-to-ore ratio in the high-pressure leaching of laterite nickel ore according to claim 2, characterized in that, the specific calculation formula for the leaching rate of aluminum ions in the solution at the current time is: where, R is the gas constant, T is the leaching temperature, is the set value of the hydrogen ion concentration in the solution, t is the current time, is the leaching rate of aluminum ions in the solution at the current time, is the maximum leaching rate of aluminum ions in the solution, which is calculated from the ore composition, pulp concentration, and pulp flow rate.

6. The dynamic optimization method for the acid-to-ore ratio in the high-pressure leaching of laterite nickel ore according to claim 2, characterized in that, the specific calculation formula for the leaching rate of iron ions in the solution at the current time is: where R is the gas constant, T is the leaching temperature, is the set value of the hydrogen ion concentration in the solution, t is the current time, is the leaching rate of iron ions in the solution at the current time, is the maximum leaching rate of iron ions in the solution, which is calculated from the ore composition, pulp concentration, and pulp flow rate.

7. The dynamic optimization method for the acid-to-ore ratio in the high-pressure leaching of laterite nickel ore according to claim 2, characterized in that, based on the leaching rates of aluminum ions and iron ions in the solution, the hydrolysis precipitation amounts of aluminum ions and iron ions at the current time are obtained, wherein the specific calculation formula for the hydrolysis precipitation amount of aluminum ions at the current time is: where T is the leaching temperature, t is the current time, is the hydrolysis precipitation amount of aluminum ions at the current time, is the current set value of the hydrogen ion concentration in the solution, is the saturation of aluminum ions in the solution, is the leaching rate of aluminum ions in the solution, is the Al concentration in the pulp, calculated from the ore composition, pulp concentration, and pulp flow rate, is the solubility of aluminum sulfate in the solution, is the first sulfate ion concentration in the solution at the current time, is the concentration of aluminum ions in the solution, calculated from the ore composition, pulp concentration, and pulp flow rate, is the concentration of hydrogen sulfate ions in the solution, is ionic strength.

8. The dynamic optimization method for the acid-to-ore ratio in the high-pressure leaching of laterite nickel ore according to claim 2, characterized in that, the specific calculation formula for the hydrolysis precipitation amount of iron ions at the current time is: where T is the leaching temperature, is the hydrolysis precipitation amount of ferric ions at the current time, is the current set value of the hydrogen ion concentration in the solution, is the saturation of ferric ions in the solution, is the leaching rate of nickel ions in the solution, is the solubility of ferric sulfate in the solution, is the maximum leaching rate of nickel ions in the solution, is the concentration of the first sulfate radical in the solution at the current time, is the concentration of ferric ions in the solution, which is calculated from the ore composition, pulp concentration, and pulp flow rate, is the concentration of hydrogen sulfate ions in the solution, is the ionic strength.

9. The dynamic optimization method for the acid-to-ore ratio in the high-pressure leaching of laterite nickel ore according to claim 2, characterized in that, based on the hydrolysis precipitation amounts of aluminum ions and iron ions at the current time and the current sulfuric acid flow rate set value, the first sulfate ion concentration in the solution at the current time is obtained, specifically including: obtaining the total sulfate ion concentration according to the current sulfuric acid flow rate set value; obtaining the sulfate ion content in the hydrolysis precipitation based on the hydrolysis precipitation amounts of aluminum ions and iron ions at the current time; obtaining the first sulfate ion concentration in the solution at the current time based on the total sulfate ion concentration and the sulfate ion content in the hydrolysis precipitation.

10. The dynamic optimization method for the acid-to-ore ratio in the high-pressure leaching of laterite nickel ore according to claim 2, characterized in that, comparing the magnitudes of the first sulfate ion concentration and the second sulfate ion concentration, if they are not equal, then correcting the set value of the hydrogen ion concentration in the solution, and repeating the above steps until the first sulfate ion concentration and the second sulfate ion concentration are equal, at which time the set value of the hydrogen ion concentration in the current solution is output as the actual concentration of hydrogen ions, wherein the specific formula for correcting the set value of the hydrogen ion concentration in the solution is: = (Before correction) + k ) Among them, is the set value of the corrected hydrogen ion concentration, (before correction) is the set value of the current hydrogen ion concentration, is the first sulfate ion concentration, is the second sulfate ion concentration, and k is the proportionality coefficient.

11. The dynamic optimization method for the acid-to-ore ratio in the high-pressure leaching of laterite nickel ore according to claim 1, characterized in that, based on the variation relationship of the hydrogen ion concentration in the solution with the reaction time, the ore incoming composition, the pulp concentration, the pulp flow rate, the leaching temperature, and the residence time of the pulp in the autoclave, the theoretical leaching rate of nickel at the current sulfuric acid flow rate when the leaching time reaches the residence time of the pulp in the autoclave is obtained, and the specific calculation formula is: wherein, R is the gas constant, T is the leaching temperature, is the value of the hydrogen ion concentration in the solution at time t, and t is the current time, is the leaching rate of nickel ions in the solution at the current time, is the maximum leaching rate of nickel ions in the solution, which is calculated from the ore composition, pulp concentration, and pulp flow rate.

12. The dynamic optimization method for the acid-to-ore ratio in the high-pressure leaching of laterite nickel ore according to claim 1, characterized in that, comparing the magnitudes of the theoretical leaching rate of nickel and the target leaching rate of nickel, if they are not equal, then adjusting the set value of the sulfuric acid flow rate, and repeating the above steps until the theoretical leaching rate of nickel and the target leaching rate of nickel are equal, specifically: if the theoretical leaching rate of nickel is greater than the target leaching rate of nickel, then reducing the set value of the sulfuric acid flow rate; if the theoretical leaching rate of nickel is less than the target leaching rate of nickel, then increasing the set value of the sulfuric acid flow rate.

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