阅读说明：本技术 一种超声强化低浓度臭氧高效预氧化硫化金精矿的方法 (Method for efficiently pre-oxidizing gold sulfide concentrate by using low-concentration ozone through ultrasonic enhancement ) 是由 张利波 贵琪皓 王仕兴 胡玉婷 于 2021-09-13 设计创作，主要内容包括：本发明涉及一种超声强化低浓度臭氧高效预氧化硫化金精矿的方法,属于金精矿处理技术领域。本发明将硫化金精矿粉、氢氧化钠和水混合均匀得到金矿矿浆；在超声波和机械搅拌条件下,往金矿矿浆中通入含臭氧的空气并进行超声强化预氧化处理,固液分离,固体经洗涤、烘干得到预处理金矿矿粉；其中含臭氧的空气中臭氧体积浓度为5.5～10.5％,臭氧的通入速率为1.7～5.1g/h。预处理金矿矿粉和氰化钠加入到水中混合均匀,通入空气,在搅拌条件下进行超声波强化浸出得到金浸出液和浸出渣。本发明利用臭氧的氧化作用及超声波的机械和空化作用促进臭氧分解,产生具有高氧化性的自由基,提高臭氧利用率,同时破坏难处理金矿硫化物包裹层(黄铁矿),提高金浸出过程中金浸出率。(The invention relates to a method for pre-oxidizing gold sulfide concentrate by using low-concentration ozone under ultrasonic reinforcement, belonging to the technical field of gold concentrate treatment. The gold sulfide concentrate powder, sodium hydroxide and water are uniformly mixed to obtain gold ore pulp; under the conditions of ultrasonic wave and mechanical stirring, introducing air containing ozone into the gold ore pulp, carrying out ultrasonic enhanced pre-oxidation treatment, carrying out solid-liquid separation, and washing and drying solids to obtain pretreated gold ore powder; wherein the volume concentration of ozone in the air containing ozone is 5.5-10.5%, and the ozone introducing speed is 1.7-5.1 g/h. Adding pretreated gold ore powder and sodium cyanide into water, uniformly mixing, introducing air, and carrying out ultrasonic enhanced leaching under the stirring condition to obtain gold leaching solution and leaching residues. The invention utilizes the oxidation of ozone and the mechanical and cavitation of ultrasonic waves to promote the decomposition of ozone, generates free radicals with high oxidability, improves the utilization rate of ozone, destroys sulfide wrapping layers (pyrite) of refractory gold ores, and improves the gold leaching rate in the gold leaching process.)

1. A method for carrying out ultrasonic strengthening on low-concentration ozone and efficiently pre-oxidizing gold sulfide concentrate is characterized by comprising the following specific steps:

(1) finely grinding the gold sulfide concentrate to-150 meshes which account for more than 95% to obtain gold sulfide concentrate powder;

(2) uniformly mixing gold sulfide concentrate powder, sodium hydroxide and water to obtain gold ore pulp;

(3) under the conditions of ultrasonic wave and mechanical stirring, introducing air containing ozone into the gold ore pulp, carrying out ultrasonic enhanced pre-oxidation treatment, carrying out solid-liquid separation, and washing and drying solids to obtain pretreated gold ore powder; wherein the volume concentration of ozone in the air containing ozone is 5.5-10.5%, and the ozone introducing speed is 1.7-5.1 g/h;

(4) adding pretreated gold ore powder and sodium cyanide into water, uniformly mixing, introducing air, and carrying out ultrasonic enhanced leaching under the stirring condition to obtain gold leaching solution and leaching residues.

2. The method for ultrasonically enhancing the low-concentration ozone high-efficiency pre-oxidation gold sulfide concentrate according to claim 1, wherein the method comprises the following steps: the solid-liquid ratio g/mL of the gold sulfide concentrate powder to water in the step (2) is 1: 1-1: 5, and the concentration of sodium hydroxide in the gold ore pulp is 0.5-5 mol/L.

3. The method for ultrasonically enhancing the low-concentration ozone high-efficiency pre-oxidation gold sulfide concentrate according to claim 1, wherein the method comprises the following steps: and (3) controlling the ultrasonic frequency to be 20-40 kHz, controlling the ultrasonic power to be 0.5-1.5 kW, controlling the temperature of the ultrasonic strengthening pre-oxidation treatment to be 20-50 ℃ and controlling the time to be 2-4 hours.

4. The method for ultrasonically enhancing the low-concentration ozone high-efficiency pre-oxidation gold sulfide concentrate according to claim 1, wherein the method comprises the following steps: the addition amount of the sodium cyanide in the step (4) is 2-10 kg/t calculated by the pretreated gold ore powder; the solid-liquid ratio g/mL of the pretreated gold ore powder to water is 1: 2-1: 4, the temperature of ultrasonic enhanced leaching is 20-50 ℃, the time is 4-18 h, the ultrasonic frequency is 20-40 kHz, the ultrasonic power is 0.25-1.0 kW, the air introduction rate is 50-200L/h, and the pH value is 10.5-11.5.

Technical Field

The invention relates to a method for pre-oxidizing gold sulfide concentrate by using low-concentration ozone under ultrasonic reinforcement, belonging to the technical field of gold concentrate treatment.

Background

At present, the pre-oxidation-cyanidation gold extraction process is mainly adopted in the industry. The coated mineral of gold-sulfide is oxidized by adopting pre-oxidation to form a porous material, so that the contact chance and the surface area of cyanide and fine-grain and micro-fine-grain gold are increased; and remove the harmful impurities such as arsenic, antimony, carbon and the like which hinder cyaniding and leaching and reduce the recovery rate, or change the physical and chemical properties of the harmful impurities. The existing various pretreatment processes can improve the recovery rate of gold by utilizing respective advantages aiming at different gold ores which are difficult to treat, but the pretreatment processes such as roasting, pressure oxidation and the like can directly increase the production cost and the investment of fixed assets, and the cost is too high to cause the failure of the whole extraction process; the ideal pretreatment effect is difficult to achieve by adopting the conventional chemical oxidation due to the mild operation condition.

Disclosure of Invention

The invention provides a method for pre-oxidizing gold sulfide concentrate by using ultrasonic-enhanced low-concentration ozone with high efficiency, aiming at solving the problem of gold extraction in gold sulfide concentrate in the prior art, namely, the low-concentration ozone is enhanced by using ultrasonic, so that the oxidation effect of a pyrite inclusion is improved, the ultrasonic cavitation promotes the reaction of the low-concentration ozone dissolved in a solution and water to generate a high-oxidizing intermediate product (OH), the mass transfer efficiency of the solution is improved by using the mechanical effect of ultrasonic, the inclusion is damaged, the granularity of ore is reduced, and the subsequent leaching efficiency is improved.

A method for efficiently pre-oxidizing gold sulfide concentrate by using low-concentration ozone through ultrasonic reinforcement comprises the following specific steps:

(1) finely grinding the gold sulfide concentrate to-150 meshes which account for more than 95% to obtain gold sulfide concentrate powder;

(2) uniformly mixing gold sulfide concentrate powder, sodium hydroxide and water to obtain gold ore pulp;

(3) under the conditions of ultrasonic wave and mechanical stirring, introducing air containing ozone into the gold ore pulp, carrying out ultrasonic enhanced pre-oxidation treatment, carrying out solid-liquid separation, and washing and drying solids to obtain pretreated gold ore powder; wherein the volume concentration of ozone in the air containing ozone is 5.5-10.5%, and the ozone introducing speed is 1.7-5.1 g/h;

(4) adding pretreated gold ore powder and sodium cyanide into water, uniformly mixing, introducing air, and carrying out ultrasonic enhanced leaching under the stirring condition to obtain gold leaching solution and leaching residues;

the solid-liquid ratio g/mL of the gold sulfide concentrate powder to water in the step (2) is 1: 1-1: 5, and the concentration of sodium hydroxide in the gold ore pulp is 0.5-5 mol/L;

the ultrasonic frequency in the step (3) is 20-40 kHz, the ultrasonic power is 100-800W, the temperature of ultrasonic enhanced pre-oxidation treatment is 20-50 ℃, and the time is 2-4 h; the stirring speed is 300-700 rpm;

the addition amount of the sodium cyanide in the step (4) is 2-10 kg/t calculated by the pretreated gold ore powder; the solid-liquid ratio g/mL of the pretreated gold ore powder to water is 1: 2-1: 4, the temperature of ultrasonic enhanced leaching is 20-50 ℃, the time is 4-18 h, the ultrasonic frequency is 20-40 kHz, the ultrasonic power is 200-1000W, the air introduction rate is 50-200L/h, the pH value is 10.5-11.5, and the stirring rate is 300-700 rpm.

The principle of ultrasonic strengthening of low-concentration ozone efficient preoxidation gold sulfide concentrate is as follows: ultrasonically strengthening the low-concentration ozone oxidation process, destroying the structure of a gold inclusion (pyrite) and exposing the wrapped gold

The ozone is decomposed to generate new ecological oxygen atoms, a group with strong oxidation effect-hydroxyl free radical can be formed in water, most simple substances and compounds in the water solution can be oxidized to the highest oxidation state at a lower temperature, and in the ultrasonic and low-concentration ozone synergistic leaching process, bubbles of the low-concentration ozone are crushed into smaller micro-bubbles through the dispersing and shearing action of the ultrasonic, so that the contact area with minerals is increased, the mixing degree is increased, the mass transfer rate of the ozone is improved, the reaction of the ozone and the minerals is strengthened, and the oxidation capability of the ozone is enhanced.

The invention has the beneficial effects that:

(1) according to the invention, low-concentration ozone is introduced into the ore pulp obtained by fully mixing the mineral powder, sodium hydroxide and water, and oxidation-reduction reaction is carried out by utilizing the synergistic effect of the low-concentration ozone, ultrasound and sodium hydroxide, the reaction temperature is low, and the reaction can be carried out at normal temperature and normal pressure, so that the energy can be saved, and the material requirement on equipment is reduced;

(2) the invention uses ultrasonic strengthening low-concentration ozone to pretreat the gold sulfide concentrate, can shorten the subsequent leaching time, improve the pretreatment and leaching effects on the gold ore, crush the ore in the ultrasonic process, expose the coated gold, and reduce the granularity of the ore by 20-50 percent compared with that before ultrasonic treatment; meanwhile, the ultrasonic wave can promote the low-concentration ozone to be decomposed into free radicals with stronger oxidability, promote the oxidation reaction, improve the utilization rate of the ozone and reduce the ozone consumption.

Drawings

FIG. 1 is SEM images of gold sulfide concentrate before and after treatment in example 1;

FIG. 2 is the leaching rate of gold ore treated by ultrasonic-enhanced low-concentration ozone pre-oxidation in example 1;

FIG. 3 is the leaching rate of gold ore treated by ultrasonic-enhanced low-concentration ozone pre-oxidation in example 2;

FIG. 4 is the leaching rate of gold ore treated by ultrasonic-enhanced low-concentration ozone pre-oxidation in example 3;

FIG. 5 shows the leaching rate of gold ore treated by ultrasonic-enhanced low-concentration ozone pre-oxidation in example 4;

FIG. 6 is a graph of particle size change after different pretreatments of example 1.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments, but the scope of the present invention is not limited to the description.

Example 1: in the gold concentrate of the embodiment, the gold grade is 3.23g/t, the silver grade is 24.5g/t, the leaching rate of gold by conventional direct cyanidation leaching is only 49.1 percent, the leaching rate of silver is 9.8 percent, and the average particle size is 33.75 mu m;

a method for efficiently pre-oxidizing gold sulfide concentrate by using low-concentration ozone through ultrasonic reinforcement comprises the following specific steps:

(1) finely grinding the gold sulfide concentrate to-150 meshes which account for more than 95% to obtain gold sulfide concentrate powder;

(2) uniformly mixing gold sulfide concentrate powder, sodium hydroxide and water to obtain gold ore pulp; wherein the solid-to-liquid ratio g/mL of the gold sulfide concentrate powder to water is 1:4, and the concentration of sodium hydroxide in the gold ore pulp is 0.5 mol/L;

(3) under the conditions of ultrasonic wave and mechanical stirring, introducing air containing ozone into the gold ore pulp, carrying out ultrasonic enhanced pre-oxidation treatment, carrying out solid-liquid separation, and washing and drying solids to obtain pretreated gold ore powder; wherein the volume concentration of ozone in the air containing ozone is 5.7 percent, and the introduction rate of the ozone is 2.0 g/h; the solid-liquid ratio g to mL is 1: 4; the ultrasonic frequency is 20kHz, the ultrasonic power is 240W, 360W, 480W, 600W and 720W respectively, the temperature of ultrasonic strengthening pre-oxidation treatment is 30 ℃, and the time is 3 h; the stirring speed is 300 rpm;

SEM pictures before and after the gold sulfide concentrate treatment are shown in figure 1, (1) is the SEM picture of the gold sulfide concentrate before the treatment, and (2) is the SEM picture of the gold sulfide concentrate after the treatment, as can be seen from figure 1, sulfide inclusion bodies before the pretreatment have complete structures and smooth surfaces, obvious holes and cracks are generated on the sulfide inclusion bodies after the ultrasonic ozone pretreatment, the particle size is reduced, and the gold leaching is facilitated;

the particle size change chart after different pretreatments is shown in fig. 6, and it can be seen from fig. 6 that the average particle size of the untreated gold sulfide concentrate powder is 33.75 μm, because iron oxide is coated on the surface of sulfide after conventional ozone oxidation to form secondary coating and agglomerate, the average particle size of the gold sulfide concentrate powder subjected to conventional ozone pretreatment (conventional ozone concentration) is 49.67 μm, and the average particle size of the gold sulfide concentrate powder subjected to ultrasonic strengthening low-concentration ozone pretreatment is 18.69 μm;

(4) adding pretreated gold ore powder and sodium cyanide into water, uniformly mixing, introducing air, and carrying out ultrasonic enhanced leaching for 5 hours under the stirring condition to obtain gold leaching solution and leaching residues; the addition amount of sodium cyanide is 3kg/t based on the pretreated gold ore powder; the solid-liquid ratio g: mL of the pretreated gold ore powder to water is 1:2, the temperature of ultrasonic enhanced leaching is 25 ℃, the ultrasonic frequency is 28kHz, the ultrasonic power is 0.5kW, the air introducing speed is 150L/h, the pH value is 11 +/-0.5, and the stirring speed is 500 rpm;

the leaching rate of gold ore subjected to ultrasonic-enhanced low-concentration ozone pre-oxidation treatment is shown in figure 2 along with the change of ultrasonic power in the ultrasonic-enhanced pre-oxidation treatment, and as can be seen from figure 2, the leaching rates of gold and silver are improved along with the improvement of the ultrasonic power, the gold leaching rate is highest when 720W is used, the leaching rate is 87.23%, and the silver leaching rate is highest when 480W is used, and is 46.84%.

Example 2: in the gold grade and the silver grade of the gold sulfide concentrate of the embodiment, the gold leaching rate is only 49.1 percent, the silver leaching rate is 9.8 percent and the average particle size is 39.77 mu m, wherein the gold grade and the silver grade are respectively 27.5g/t and 107.4g/t, and the gold leaching rate is directly obtained by the conventional cyanidation leaching process;

a method for efficiently pre-oxidizing gold sulfide concentrate by using low-concentration ozone through ultrasonic reinforcement comprises the following specific steps:

(1) finely grinding the gold sulfide concentrate until the gold sulfide concentrate is-250 meshes and accounts for more than 95 percent to obtain gold sulfide concentrate powder;

(2) uniformly mixing gold sulfide concentrate powder, sodium hydroxide and water to obtain gold ore pulp; wherein the solid-to-liquid ratio g/mL of the gold sulfide concentrate powder to water is 1:5, and the concentration of sodium hydroxide in the gold ore pulp is 4 mol/L;

(3) under the conditions of ultrasonic wave and mechanical stirring, introducing air containing ozone into the gold ore pulp, carrying out ultrasonic enhanced pre-oxidation treatment, carrying out solid-liquid separation, and washing and drying solids to obtain pretreated gold ore powder; wherein the volume concentration of ozone in the air containing ozone is 8.2 percent, and the introduction rate of ozone is 4.3 g/h; the ultrasonic frequency is 20kHz, the ultrasonic power is 480kW, the temperature of the ultrasonic strengthening pre-oxidation treatment is 15 ℃, 30 ℃, 50 ℃, 65 ℃ and 85 ℃ respectively, and the time is 4 hours; the stirring speed is 500 rpm;

the average particle size of the pretreated gold ore powder in the embodiment is 14.47 μm;

(4) adding pretreated gold ore powder and sodium cyanide into water, uniformly mixing, introducing air, and carrying out ultrasonic enhanced leaching for 8 hours under the stirring condition to obtain gold leaching solution and leaching residues; the addition amount of sodium cyanide is 10kg/t based on the pretreated gold ore powder; the solid-liquid ratio g: mL of the pretreated gold ore powder to water is 1:2, the temperature of ultrasonic enhanced leaching is 25 ℃, the ultrasonic frequency is 28kHz, the ultrasonic power is 0.5kW, the air introducing speed is 200L/h, the pH value is 11 +/-0.5, and the stirring speed is 500 rpm;

the leaching rate of gold ore subjected to ultrasonic-enhanced low-concentration ozone pre-oxidation treatment is shown in figure 3 along with the change of the ultrasonic temperature in the ultrasonic-enhanced pre-oxidation treatment, and as can be seen from figure 3, the leaching rates of gold and silver are improved along with the improvement of the temperature, the leaching rate of gold can reach the best value at 50 ℃, and the leaching rate is 89.32%; the leaching rate of silver reaches the highest at 65 ℃, and the leaching rate is 61.24%.

Example 3: in the gold grade and the silver grade of the gold sulfide concentrate of the embodiment, the gold leaching rate is 35.2g/t, the silver leaching rate is 73.42g/t, and the gold leaching rate obtained by the direct conventional cyanidation leaching process is only 32.53 percent, the silver leaching rate is 17.24 percent, and the average particle size is 41.34 mu m;

a method for efficiently pre-oxidizing gold sulfide concentrate by using low-concentration ozone through ultrasonic reinforcement comprises the following specific steps:

(1) finely grinding the gold sulfide concentrate to-200 meshes which account for more than 95 percent to obtain gold sulfide concentrate powder;

(2) uniformly mixing gold sulfide concentrate powder, sodium hydroxide and water to obtain gold ore pulp; wherein the solid-to-liquid ratio g/mL of the gold sulfide concentrate powder to water is 1:4, and the concentration of sodium hydroxide in the gold ore pulp is 3 mol/L;

(3) under the conditions of ultrasonic wave and mechanical stirring, introducing air containing ozone into the gold ore pulp, carrying out ultrasonic enhanced pre-oxidation treatment, carrying out solid-liquid separation, and washing and drying solids to obtain pretreated gold ore powder; wherein the volume concentration of ozone in the air containing ozone is 8.0 percent, and the introduction rates of the ozone are 1.7g/h, 2.4g/h, 3.2g/h, 4.1g/h and 5.1g/h respectively; the ultrasonic frequency is 30kHz, the ultrasonic power is 800W, the temperature of ultrasonic strengthening pre-oxidation treatment is 50 ℃, and the time is 5 h; the stirring speed is 500 rpm;

the average granularity of the pretreated gold ore powder in the embodiment is 18.25 mu m;

(4) adding pretreated gold ore powder and sodium cyanide into water, uniformly mixing, introducing air, and carrying out ultrasonic enhanced leaching for 8 hours under the stirring condition to obtain gold leaching solution and leaching residues; the addition amount of sodium cyanide is 10kg/t based on the pretreated gold ore powder; the solid-liquid ratio g: mL of the pretreated gold ore powder to water is 1:5, the temperature of ultrasonic enhanced leaching is 30 ℃, the ultrasonic frequency is 20kHz, the ultrasonic power is 600W, the air introduction rate is 120L/h, the pH value is 11 +/-0.5, and the stirring rate is 400 rpm;

the leaching rate of the gold ore subjected to the ultrasonic-enhanced low-concentration ozone pre-oxidation treatment is shown in figure 4 along with the change of the ultrasonic temperature in the ultrasonic-enhanced pre-oxidation treatment, and as can be seen from figure 4, when the ozone flow is 1.7g/L, the gold leaching rate is 66.74%, and the silver leaching rate is 34.25%; along with the improvement of the ozone flow, the leaching rates of the gold and silver are improved in different degrees; the gold leaching rate reaches the maximum value of 84.24 percent when the ozone concentration reaches 2.4 g/L; the silver leaching rate reached a maximum of 57.74% at 5.1 g/L.

Example 4: in the gold grade and the silver grade of the gold sulfide concentrate of the embodiment, the gold leaching rate is only 27.42%, the silver leaching rate is 7.45% and the average particle size is 52.43 mu m, wherein the gold leaching rate is obtained by directly adopting a conventional cyanidation leaching process and the silver leaching rate is 52.52 g/t;

a method for efficiently pre-oxidizing gold sulfide concentrate by using low-concentration ozone through ultrasonic reinforcement comprises the following specific steps:

(1) finely grinding the gold sulfide concentrate to-150 meshes which account for more than 95% to obtain gold sulfide concentrate powder;

(2) uniformly mixing gold sulfide concentrate powder, sodium hydroxide and water to obtain gold ore pulp; wherein the solid-liquid ratio g: mL of the gold sulfide concentrate powder to water is 1:3, and the concentrations of sodium hydroxide in the gold ore pulp are respectively 0mol/L, 0.5mol/L, 1.5mol/L, 2mol/L, 3mol/L and 4 mol/L;

(3) under the conditions of ultrasonic wave and mechanical stirring, introducing air containing ozone into the gold ore pulp, carrying out ultrasonic enhanced pre-oxidation treatment, carrying out solid-liquid separation, and washing and drying solids to obtain pretreated gold ore powder; wherein the volume concentration of ozone in the air containing ozone is 4.7 percent, and the introduction rate of the ozone is 4.7 g/h; the ultrasonic frequency is 20kHz, the ultrasonic power is 550W, the temperature of ultrasonic strengthening pre-oxidation treatment is 40 ℃, and the time is 5 h; the stirring speed is 600 rpm;

the average particle size of the pretreated gold ore powder in the embodiment is 27.52 μm;

(4) adding pretreated gold ore powder and sodium cyanide into water, uniformly mixing, introducing air, and carrying out ultrasonic enhanced leaching for 6 hours under the stirring condition to obtain gold leaching solution and leaching residues; the addition amount of the sodium cyanide is 7.5kg/t based on the pretreated gold ore powder; the solid-liquid ratio g: mL of the pretreated gold ore powder to water is 1:3, the temperature of ultrasonic enhanced leaching is 40 ℃, the ultrasonic frequency is 20kHz, the ultrasonic power is 700W, the air introduction rate is 180L/h, the pH value is 11 +/-0.5, and the stirring rate is 750 rpm;

the leaching rate of gold ore subjected to ultrasonic-enhanced low-concentration ozone pre-oxidation treatment is shown in figure 5 along with the change of the ultrasonic temperature in the ultrasonic-enhanced pre-oxidation treatment, and as can be seen from figure 5, when the concentration of sodium hydroxide is 0mol/L, the leaching rate of gold is 46.23%, and the leaching rate of silver is 33.25%; when sodium hydroxide is added, the gold leaching rate is increased to more than 80%, and the silver leaching rate is increased to more than 48%. The maximum leaching rates of gold and silver are 90.34% and 50.48% when the concentration of sodium hydroxide is 0.5 mol/L.

While the present invention has been described in detail with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, and various changes can be made without departing from the spirit and scope of the present invention.