CN1044823C

CN1044823C - Method and apparatus for activating and dissolving sulfide ores containing gold

Info

Publication number: CN1044823C
Application number: CN96118246A
Authority: CN
Inventors: 赵中伟; 李洪桂; 赵天从; 孙培梅; 李运姣; 苏鹏抟; 刘茂盛
Original assignee: Central South University
Current assignee: Central South University
Priority date: 1996-07-05
Filing date: 1996-07-05
Publication date: 1999-08-25
Anticipated expiration: 2016-07-05
Also published as: CN1170043A

Abstract

The present invention relates to a method and a device for activating and leaching sulfide ore containing gold, which belongs to the field of wet metallurgy. Ore and acidic solution or alkaline solution are together added into a designed activating reactor, and the ore is finely ground and activated through the rotation or vibration of a cylinder or the rotation of a screw rod type crank shaft in a spiral stirring device. Simultaneously, the reaction temperature is controlled to be from 20 to 100 DEG C, and oxygen gas is led in to react for 1 to 5 hours under the oxygen partial pressure of 0.02 to 0.1MPa. After discharge and filtration, filter residues are cyanided for gold leaching. The present invention has the advantages of simple technical process, easy device operation, high metal recovery rate and low dosage of acid and alkali, and the procedures of post treatment are reduced.

Description

Activation leaching method for gold-bearing sulfide ore

The present invention relates to a gold extraction method, particularly to a method for extracting gold from gold-bearing sulfide ores by means of wet process.

For refractory gold-containing sulfide ores, gold is often embedded in the ore body or encapsulated in the form of solid solution or submicron gold, resulting in a low direct leaching rate of gold, making it difficult to dissociate gold even if the ore is finely ground. For such ores, gold-bearing ores are usually destroyed chemically, i.e. gold-bearing sulphide ores are oxidatively dissociated in an acidic or basic medium. Because the chemical property of the gold-containing sulfide minerals is very stable, harsh means such as high temperature, high pressure, strong oxidant and the like are required in production practice. For example, in the acid oxygen pressure cooking method, the dissociation can be achieved by decomposing for 1-3 hours at the high temperature of 170-225 ℃, the total pressure of 2.5-3.2 MPa and the oxygen partial pressure of 0.35-0.7 MPa; if a strong oxidant with the concentration as high as 4mol/L is used as the catalyst, the process condition can be improved to a certain extent, but the dissociation still needs to be carried out under the conditions of the temperature of 80-100 ℃ and the oxygen pressure of 0.4-0.8 MPa. The alkaline oxygen pressure cooking method also requires a temperature of 100 ℃ and an oxygen pressure of 0.28 to 0.8 MPa. The above treatment process is based on external factors, and realizes mineral decomposition by enhancing the external conditions of decomposition, so the treatment process is long and complicated, and requires high temperature and pressure.

Aiming at the existing problems, the invention aims to start from the internal factors of the minerals, and organically combines the mechanical activation and the leaching process to realize the effective separation of the gold-containing minerals; meanwhile, processing equipment which is adaptive to the process requirement is designed.

The invention is directed to refractory gold-bearing sulfide ores, including gold-bearing pyrite (FeS)₂) And arsenopyrite (FeAsS). Mixing gold-containing mineral with granularity less than 1 mm with acidOr the alkaline solution is put into a designed activation reactor together, the mechanical activation is combined with the chemical reaction of acid or alkali, the gold-containing sulphide ore is decomposed under the conditions of normal temperature, normal pressure and oxygen enrichment, and the leaching rate is high. If in an acidic solution, the main reaction process is as follows:

if in alkaline solution, the main reaction process is as follows:

mechanical activation and chemical reaction are combined, so that the kinetic and thermodynamic conditions of the decomposition process are greatly improved, the reaction is accelerated, and the passivation phenomenon in the process of separating the mechanical activation and the leaching process can be avoided. Since the mechanically activated minerals lose their activity if stored for a certain period of time, they are completely deactivated. Practice proves that: the pyrite after mechanical activation has extremely high passivation speed within 20 minutes, and is stored for 5.5 hours at room temperature compared with 20 minutes in HNO₃-H₂SO₄The leaching rate in the solution decreases by 20%, i.e. the leaching rate in the solution after activation is inversely proportional to the time, so that the two are operated separately, and the passivation phenomenon is inevitable.

The embodiments of the present invention can be organized into one of the following three technical solutions according to respective conditions.

One is an acid method treatment process, wherein gold-containing sulphide ore and water are mixed according to the mass ratio of ore to water =1 to (1-10), and HNO with the concentration of less than 0.5mol/L is contained in mixed liquid₃And 0.35-0.8 mol/L of H₂SO₄Feeding the mixture into an activation reactor, controlling the temperature to be 20-100 ℃, starting the activation reactor and introducing oxygen to react for 1-5 hours under the condition that the oxygen partial pressure is 0.02-0.1 MPa, then discharging and filtering, feeding filter residues into a cyaniding working section to cyanide and extract gold, wherein the cyaniding leaching rate of gold in the residues can reach 94-96% generally, and the leaching rate is less than that of the untreated goldThe direct cyanidation leaching rate of the raw ore gold is 7.17-16.27%, and is improved by 12-13 times.

And secondly, an alkaline treatment process, wherein basic operation and technical conditions are substantially the same as those of the acid treatment process, namely, firstly, adding 0.4-0.7 time of NaOH in the theoretical required amount into the ore and water according to the mass ratio of the ore to the water = 1: 1 (1-10), sending the ore and the water into an activation reactor through a feeding port, controlling the temperature to be 20-100 ℃ and the oxygen partial pressure to be 0.02-0.1 MPa, starting the activation reactor, introducing oxygen into the activation reactor to react for 1-5 hours, then discharging and filtering the mixture, sending filter residues to a cyaniding working section to cyanide and extract gold, wherein the gold cyaniding rate in the residues can reach 87-95% generally, and is improved by 6-12 times compared with the direct cyaniding leaching rate of untreated raw gold ore, which is 7.17-16.27%.

The third is activation-then-oxidation treatment process, namely, mineral activation and oxidation reaction are respectively carried out in two different devices, firstly, the mineral and water are mixed according to the mass ratio of mineral to water = 1: 1 (1-10), and HNO with the concentration of less than 0.5mol/L is contained in mixed liquid₃0.35 to 0.8mol/L of H₂SO₄Or adding 0.4-0.7 time of NaOH of the theoretical required amount into the activation reactor, activating the minerals for 1-2 hours, pumping the activated mineral slurry into a started conventional stirrer, introducing oxygen at the oxygen partial pressure of 0.02-0.1 MPa, continuously performing oxidation reaction for 1-2 hours at the temperature of 20-100 ℃, discharging and filtering, and delivering filter residues to a cyanidation working section for cyanidation and extraction of gold, wherein the cyanidation leaching rate of gold in the residues can reach 90-95% generally, and is 6-12 times higher than that of untreated raw ore gold, namely the leaching rate of direct cyanidation of 7.17-16.27%. Although the method adds stirring equipment, the method shortens the oxidation time and reduces the consumption of oxygen.

In the above embodiment, the temperature is preferably controlled to be in the range of 40 to 60 ℃.

The activation reactor for carrying out the above three methods is any one of a drum type vibration device, a drum type rotation device and a drum type rotational flow stirring device. The activation reactors are composed of a reaction cylinder 1, an activation medium 2, a heating device 3, a temperature measuring device 4, an oxygen supply device 5, a motor 6 and a transmission mechanism 7 of a transmission system and the like. Wherein the motor 6 of the cylinder type vibration device is a plurality of vibration motors, the inner side of the cylinder body of the cylinder type rotational flow stirring device is carved with a rotational flow groove 8 from bottom to top and in the counterclockwise direction, and the center of the cylinder body is provided with a rotatable screw type crankshaft 9 so as to drive the activation medium 2 to rotate from bottom to top. The features, functions and operation modes of the common components of the three activation reactors are summarized as follows:

1. reaction cylinder and activation medium part: the reaction cylinder 1 is a cylinder made of high carbon steel, manganese steel or stainless steel, the upper end and the lower end of the cylinder are sealed by a cover, and an activation reaction container is formed by lining acid-resistant glue or epoxy resin, and belongs to a common reaction container because the operation is carried out under the conditions of normal temperature and normal pressure; the container is filled with spherical or rod-shaped activating medium, and is filled with proper amount of activating medium to activate and further grind the mineral, and the activating medium 2 is moved by the rotation or vibration of the cylinder 1 or the rotation of the screw crankshaft 9 in the spiral stirring device to impact the mineral grains and apply mechanical force to the mineral grains to grind and activate the mineral grains. The filling rate of the activating medium 2 in the container is about 40-60%; the driving part of the activation reactor, except the vibration container, is composed of a common motor, a speed reducer and a linkage device, which make the cylinder body generate rotary motion or vibration.

2. Feeding and discharging devices: the feeding part is designed as a closed controllable screw feeder 10 which can feed continuously or intermittently; the discharge part is designed as a flow-controllable device 11, which can discharge continuously or intermittently during the reaction. The loading and unloading devices are installed at positions respectively designated by 10 and 11 according to the difference of three types of activation reactors.

3. Oxygen supply apparatus: oxygen is fed into the activation reactor by an oxygen supply device 5 extending into the cylinder according to a rated oxygen pressure to oxidize the sulfide ore.

4. The heating mode is as follows: the method of the present invention can be operated in the range of normal temperature to 100 ℃, so any heating mode of common induction, resistance, steam or coal gas can be adopted, and when the steam is used for heating, a direct or indirect heating mode can be adopted.

5. Temperature measuring device: a thermocouple or a common thermometer can be used to extend the sealing tube 4 into the activation reactor for temperature measurement and temperature control adjustment.

The invention has the advantages that the mechanical activation (ore grinding) of the minerals is tightly combined with acid leaching or alkali leaching, thereby greatly improving the dynamics and thermodynamics conditions of the mineral decomposition process, accelerating the reaction rate, and leading the reaction to be rapidly carried out under the conditions of normal temperature and normal pressure, thereby reducing the requirements on equipment; the mineral decomposition rate is high and is improved by 6-13 times compared with the decomposition rate of a raw mineral direct cyanidation method; the use amount of acid and alkali is small, and the post-treatment process is reduced; the process flow is simple, the equipment is easy to operate, and the recovery rate of main metal is high, so that the method is a new technology with low investment, low energy consumption, low cost and high benefit.

FIG. 1 is a schematic diagram of a vibrating activation reactor;

FIG. 2 is a schematic view of a rotary activation reactor;

FIG. 3 is a schematic view of a swirl-stirring type activation reactor;

fig. 4 is a partial sectional view of the swirl-stirring type activation reactor cylinder 1.

In order to fully implement the present invention, the technical solution of the present invention will now be further described with reference to the accompanying drawings and examples; the nominal values of the conditions listed in the examples are not necessarily the optimum values, but the solution according to the invention can be realized.

Example (b):

1. the components of a certain concentrate are as follows: 75.6g/t of Au, 22.35 percent of S, 18.87 percent of As, 30.55 percent of Fe, and 16.27 percent of direct gold cyanide leaching rate; according to the technical scheme of the invention, 100g of the concentrate and 500g of water are taken, and the H content in the mixed liquor is controlled₂SO₄0.37mol/L、HNO₃0.30mol/L, simultaneously sending into a rotary activation reactor, introducing oxygen with the pressure of 0.03MPa after the activation reactor is started, keeping the process temperature at 30 ℃, continuously and mechanically activating for 3 hours, then filtering, wherein the arsenic removal rate reaches 93.06%, and the filter residue is sent to a cyanidation working section for treatment, and the gold cyanidation leaching rate reaches 95.41%.

2. 100g of the concentrate, 50g of NaOH and 300g of water in example 1 are taken and simultaneously fed into a vibration type activation reactor, oxygen with the pressure of 0.04MPa is introduced after the activation reactor is started, the process temperature is kept at 25 ℃, continuous mechanical activation is carried out for 3 hours, then filtration is carried out, filter residue is fed into a cyanidation working section for treatment, and the gold cyanidation leaching rate is 89.54%.

3. 50g of the concentrate and 250g of water in example 1 are taken and activated in a cyclone stirring type activation reactor for 40 minutes, and then HNO is added₃0.15mol/L、H₂SO₄200ml of each 0.8mol/L solution, introducing oxygen with the pressure of 0.05MPa, keeping the process temperature at 55 ℃, continuously activating for 90 minutes, filtering, and sending filter residues to a cyanidation section for treatment, wherein the gold cyanidation leaching rate is 91.6%.

4. According to the technical scheme of the invention, 100g of concentrate, 75g of NaOH and 500g of water are taken and simultaneously added into a vibration type activation reactor, the process temperature is kept at 30 ℃ for continuous reaction for 2 hours, then the concentrate is pumped intoa conventional stirrer, oxygen with the pressure of 0.04MPa is introduced for further reaction for 60 minutes and then is filtered, filter residues are sent to a cyaniding working section for treatment, the gold cyaniding leaching rate is 94.83%, and the silver leaching rate is 63.15%.

5. Taking 100g of the concentrate and 600g of water in example 4, and controlling the HNO content in the mixed solution₃0.25mol/L、H₂SO₄0.5mol/L, and simultaneously adding the mixture into a rotary activation reactor, keeping the process temperature at 25 ℃ for continuous reaction for 2 hours, pumping the mixture into a conventional stirrer, introducing oxygen with the pressure of 0.05MPa, reacting for 50 minutes, filtering, and sending filter residues to a cyanidation section for treatment, wherein the gold cyanidation leaching rate is 95.43%, and the silver leaching rate is 64.18%.

Claims

1. An activation leaching method for gold-bearing sulfide ore comprises acid or alkali oxygen-enriched leaching and filtering of materials, and is characterized in that: controlling the content of HNO less than 0.5mol/L in the mixed solution under the conditions that the mass ratio of ore water is 1 to (1-10) and the temperature is controlled to be 20-100 DEG C₃And 0.35 ℃0.8mol/L of H₂SO₄Or adding NaOH with 0.4-0.7 time of theoretical required amount, respectively introducing oxygen with the pressure of 0.02-0.1 MPa, grinding or activating and leaching by screw stirring for 1-5 hours, then discharging and filtering, and sending filter residues to a cyanidation working section for cyanidation and extraction of gold.

2. An activation leaching method for gold-bearing sulfide ore comprises acidor alkali oxygen-enriched leaching and filtering of materials, and is characterized in that: controlling the content of HNO less than 0.5mol/L in the mixed solution under the conditions that the mass ratio of ore water is 1 to (1-10) and the temperature is controlled to be 20-100 DEG C₃And 0.35-0.8 mol/L of H₂SO₄Or adding NaOH with the theoretical required amount of 0.4-0.7 time, carrying out activation leaching for 1-2 hours by grinding or screw stirring, introducing oxygen with the pressure of 0.02-0.1 MPa into a stirrer for carrying out oxidation reaction for 1-2 hours, then discharging and filtering, and sending filter residues to a cyanidation working section for cyanidation and extraction of gold.

3. The leaching process according to claim 1 or 2, wherein: the reaction temperature in the process is 40-60 ℃.