Low temperature plasma modification and enhanced arsenic removal from pyrite beneficiation method

Abstract

The present invention belongs to the technical field of mineral processing, and specifically relates to a beneficiation method for pyrite arsenic removal by low-temperature plasma modification. First, the ore is ground to monomer dissociation, and after slurry adjustment, it is inserted into a plasma reactor, and then the gas is introduced and the current and voltage of the plasma power supply are adjusted to excite the gas to generate plasma to achieve selective modification of the mineral. Finally, under the premise of the absence of arsenic inhibitors, a conventional flotation process is used to obtain a qualified low-arsenic pyrite concentrate product. The beneficiation method for pyrite arsenic removal by low-temperature plasma modification described in the present invention has the advantages of high active particle mass transfer efficiency, fast modification rate, simple maintenance, strong selectivity, low production cost, and environmental friendliness, and is suitable for pyrite beneficiation and arsenic removal with high arsenopyrite content.

Description

Technical Field

[0001] The invention belongs to the technical field of mineral processing, and specifically relates to a pyrite beneficiation method for strengthening arsenic removal by low-temperature plasma modification. Background Art

[0002] Pyrite is an important carrier mineral of gold, which often contains harmful element arsenic in the form of arsenopyrite. The presence of arsenic will not only strongly interfere with the cyanide leaching of gold, but the smelting of arsenic-containing pyrite will also produce a large amount of inorganic arsenic, which is one of the main causes of skin cancer, liver cancer and lung cancer. The green development concept of harmless resources and the market's requirements for product quality have determined that arsenic content has become a key standard for concentrate quality. Only by reducing the harm of arsenic from the source and preventing arsenic from entering metallurgical operations can the application value of pyrite and associated gold be improved.

[0003] Flotation is the most important means of removing arsenic from pyrite. However, when xanthate is used as a collector, arsenopyrite and pyrite show similar flotation responses and electrochemical activities, and the surface hydrophobic products are all dixanthate, which makes xanthate lose its cationic selectivity. Therefore, it is difficult to achieve effective separation of arsenopyrite and pyrite by conventional flotation with added chemicals. Therefore, the development of new and efficient surface regulation technology has become a new way to induce flotation separation of polymetallic sulfide ores.

[0004] Low-temperature plasma is a new pretreatment method for mineral surface regulation. Plasma is formed by gas transformation under high temperature or specific excitation conditions, which contains a large number of active particles that can bombard the mineral surface, causing the old bonds on the mineral surface to break and induce the formation of new bonds, thereby achieving selective modification of minerals.

[0005] Patent CN108246512A discloses a plasma-enhanced low-rank coal slime reverse flotation deashing method, which uses plasma pretreatment-slurry adjustment and dosing-reverse flotation to enhance the recovery of low-rank coal slime, thereby significantly reducing the consumption of low-rank coal reverse flotation inhibitors and improving flotation indicators. However, its modification process is to pass the slurry into a low-temperature plasma reaction chamber, and then pass gas for plasma discharge. Therefore, the plasma survives in the gas phase above the slurry. The rate of surface modification of mineral particles in the slurry depends on the dissolution rate of the plasma into the slurry, which makes its modification rate low. The modification needs to be carried out at a higher output power (100W), and only reduces the amount of reverse flotation inhibitors by more than 10%, and does not achieve inhibitor-free flotation separation.

[0006] Patent CN111408481A discloses a method for plasma flotation deashing and desulfurization of coal slime, firstly, positive flotation deashing - adding water to the sulfur-containing coking coal slime to obtain a first pulp, then the first pulp is subjected to positive flotation deashing to obtain a sulfur-containing flotation clean coal pulp; then the sulfur-containing clean coal pulp is treated with plasma, and finally reverse flotation desulfurization is performed to obtain a low-ash and low-sulfur clean coal product. However, in this method, plasma still uses the form of water surface discharge in the process of mineral surface modification, and its high-voltage electrode is suspended 0.5-1.5cm above the pulp. The way plasma modifies the mineral surface in the pulp still depends on the migration and diffusion of active particles in the gas-liquid interface layer, resulting in a low mass transfer efficiency of active particles. Therefore, a higher processing voltage (50-100V), processing current (1.5-3A) and a longer processing time (1-9min) are required to achieve selective modification.

[0007] Patent CN110508403A discloses a method for strengthening coal slime flotation by combining hydrogen and oxygen plasma, wherein hydrogen plasma is used to selectively treat dry coal slime to achieve modification, oxygen plasma is used to activate conventional collectors after emulsification in aqueous solution, and then conventional flotation methods are used to mix the two to achieve efficient flotation recovery of combustibles. However, this method uses hydrogen plasma to modify dry coal slime, and flotation is carried out in a slurry in a multiphase system. The mineral surface after grinding cannot be dried, which greatly limits the practical application of this method. Summary of the invention

[0008] The purpose of the present invention is to provide a low-temperature plasma modified and enhanced pyrite arsenic removal beneficiation method. The beneficiation method solves the current problems of low-temperature plasma migration on the ore pulp surface, slow diffusion rate, low mass transfer efficiency, slow modification rate, etc., and greatly improves the efficiency of pyrite arsenic removal.

[0009] The low-temperature plasma modified and enhanced pyrite arsenic removal beneficiation method of the present invention comprises the following steps:

[0010] (1) Grinding: Grinding the arsenic pyrite to -0.074 mm accounts for 50% to 95%;

[0011] (2) controlling the slurry concentration of the slurry obtained in step (1) to 10-30%, then transferring it to a slurry reaction chamber, and starting mechanical stirring; inserting a low-temperature plasma generator with a built-in high-voltage electrode and a bubble generator at the bottom into the slurry, introducing gas into the low-temperature plasma generator, adjusting the current and voltage of the low-temperature plasma power supply, exciting the gas to generate plasma, and allowing the plasma to be pushed into the slurry in the form of bubble nuclei through the bubble generator under the impetus of the airflow, and obtaining a modified slurry after the reaction is complete;

[0012] (3) Adding a collector and a frother to the modified slurry for slurry adjustment, and obtaining pyrite concentrate and high-arsenic tailings products after one roughing, multiple cleaning and multiple scavenging.

[0013] in:

[0014] The mass content of arsenic in the arsenic-containing pyrite in step (1) is ≥ 0.5%. Preferably, the mass content of arsenic in the arsenic-containing pyrite is 0.5-10%.

[0015] In step (2), the low-temperature plasma generator is made of quartz or glass; the high-voltage electrode is in the shape of a spiral spring, a rod or a multi-needle rod, and the high-voltage electrode material is stainless steel or tungsten carbon steel; the bubble generator is made of quartz sand, porous ceramic balls or gas disk stone porous media.

[0016] In step (2), the distance between the bottom end of the bubble generator and the bottom of the slurry reaction chamber is 0.5 to 1 cm.

[0017] In step (2), the discharge gas is one of air or oxygen, with a flow rate of 0.3 to 10 L / min; the discharge current is 1 to 1.5 A, the discharge power is 30 to 60 W, and the plasma modification time is 40 s to 5 min.

[0018] In step (3), the amount of collector used in the roughing operation is 50-200 g / t, and the amount of frother used is 20-60 g / t; no collector and frother are added in the concentrating operation; the amount of collector and frother used in the scavenging operation is 1 / 4-1 / 2 of that in the previous operation; the intermediate ore products from the concentrating and scavenging in step (3) are sequentially returned to the previous operation to form a flotation closed circuit.

[0019] In step (3), the number of multiple selections is 2-3 times; the number of multiple scannings is 2-3 times.

[0020] The collector described in step (3) is a combination of one or more of butyl xanthate, ethyl xanthate, butyl ammonium black medicine, ethylthiocyanate or ethylthiocarbamate; the foaming agent is one of pine oil, kerosene or diesel.

[0021] In step (3), a collector and a foaming agent are added to the modified slurry for slurry adjustment, the collector is stirred for 2 to 4 minutes, and the foaming agent is stirred for 1 to 2 minutes.

[0022] In step (3), the flotation time of the roughing operation is 3 to 10 minutes, the flotation time of the primary cleaning operation is 1 to 5 minutes, and the flotation time of the primary scavenging operation is 1 to 6 minutes.

[0023] The present invention provides a low-temperature plasma modified and enhanced pyrite arsenic removal beneficiation method, which uses a high-voltage electrode to excite background gas to form plasma, and then blows the plasma into the water phase through a bubble generator. The active particles in the plasma diffuse in the water phase in the form of bubble nuclei. The rising and floating of the bubble nuclei drive the active particles to collide with suspended mineral particles, and transfer energy to O3, O, O * At the same time, the bubble nuclei carrying active particles continuously react with the water phase during the mass transfer process to generate secondary active groups such as OH free radicals and H2O2. These groups migrate or diffuse in the water phase, cooperate with the dissolved gas phase active particles, and jointly give the slurry a specific oxidizing atmosphere, thereby inducing selective modification of the mineral surface.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The low-temperature plasma modified and enhanced pyrite arsenic removal beneficiation method of the present invention adopts a microporous bubble generator to transfer plasma to the ore pulp in the form of bubble nuclei, promote the precipitation of active particles in the gas-liquid interface layer, and promote the active particles to fully react with the mineral particles suspended in the ore pulp under the action of mechanical stirring, and achieve selective modification of the mineral surface by controlling the modified voltage, current, gas flow, modification time and other parameters. Under the design concept of the present invention, the plasma modification gas and electricity parameters and modification time play a synergistic role, and finally achieve the selective modification of pyrite and arsenopyrite.

[0026] (2) The low-temperature plasma modified and enhanced arsenic removal method for pyrite described in the present invention adopts a detachable low-temperature plasma generator, and suspends the high-voltage electrode above the generator so that it is not in direct contact with the slurry, which greatly reduces the difficulty of subsequent maintenance and effectively solves the problems of surface oxidation, difficulty in replacement, and high maintenance cost of fixed electrodes after long-term use.

[0027] (3) The low-temperature plasma modified and enhanced arsenic removal method for pyrite described in the present invention adopts a multi-stage flotation operation. In the absence of arsenic inhibitors, only a collector and a frother are added to achieve selective recovery of pyrite, which effectively solves a series of problems such as large amount of arsenic inhibitors, difficult degradation, and poor selectivity, and greatly reduces the cost of mineral processing.

[0028] (4) The low-temperature plasma modified and enhanced arsenic removal beneficiation method of pyrite described in the present invention significantly reduces the slurry preparation time due to the absence of arsenic inhibitors, which is beneficial to the improvement of mine processing capacity; at the same time, only collectors and frothers are added in the flotation process, which effectively reduces the fluctuation of product indicators caused by unstable control of reagent dosage, and further reduces the maintenance cost of the beneficiation plant, so that pyrite concentrate products with arsenic content that meets the standards can be obtained at low cost and high efficiency.

[0029] (5) The low-temperature plasma modified and enhanced pyrite arsenic removal beneficiation method described in the present invention diffuses plasma to the mineral surface through bubbles, and has the advantages of high mass transfer efficiency, short modification time, more active species, less secondary pollution, etc. Relatively speaking, most of the active substances of the low-temperature plasma discharged on the water surface are lost in the gas phase through convection diffusion, resulting in a low mass transfer efficiency of active particles in the gas-liquid interface layer, and a longer processing time is required to achieve selective modification of the mineral surface. The modification method using bubble nuclei as the medium transfers plasma to the slurry through a microporous bubble generator, which greatly increases the contact area and probability between the plasma and the slurry, thereby greatly improving the modification rate of the mineral surface.

[0030] (6) The low-temperature plasma modified and enhanced pyrite arsenic removal beneficiation method described in the present invention has the advantages of high active particle mass transfer efficiency, fast modification rate, simple maintenance, strong selectivity, low production cost, and environmental friendliness. It is suitable for pyrite beneficiation and arsenic removal with a high arsenopyrite content. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a process flow chart of the low-temperature plasma modified enhanced pyrite arsenic removal beneficiation method. DETAILED DESCRIPTION

[0032] The present invention is further described below with reference to the embodiments.

[0033] Comparative Example 1

[0034] This comparative example 1 takes a high-arsenic pyrite from a certain place in Yunnan as the research object. The main mineral components of the ore are pyrite, arsenopyrite, quartz, dolomite, etc. The S grade is 31.47%, and the arsenic content is as high as 9.14%. The process steps are as shown in the attached figure. Figure 1 As shown, the specific steps include:

[0035] (1) Grinding: Grind high-arsenic pyrite to -0.074 mm, accounting for 52%;

[0036] (2) The slurry concentration of the slurry obtained in step (1) is controlled at 10%, and then transferred to the slurry reaction chamber, mechanical stirring is turned on, and a high-voltage electrode with a stainless steel spiral spring and a quartz plasma generator with a bubble generator (quartz sand) placed below is inserted into the slurry, and the lower end of the bubble generator is 0.5 cm away from the bottom of the slurry reaction chamber. Oxygen is introduced into the low-temperature plasma generator, and the oxygen flow rate is adjusted to 0.3L / min. The current and power of the plasma power supply are adjusted to 1A and 60W respectively, and oxygen is excited to generate plasma. The plasma is driven by the airflow through the bubble generator and blown into the slurry in the form of bubble nuclei. After reacting for 30 seconds, the modified slurry is obtained. The specific gas-electric parameters of the plasma generator and the modification parameters are shown in Table 1;

[0037] (3) Add the collector ethyl xanthate and the foaming agent pine oil to the modified slurry for slurry adjustment. After stirring for 2 minutes and 1 minute respectively, pyrite concentrate and tailings are obtained after one roughing, three concentrating and two scavenging respectively; the intermediate ore products of three concentrating and two scavenging are sequentially returned to the previous operation to form a flotation closed circuit. Among them, the flotation time of the roughing operation is 3 minutes, the flotation time of the concentrating I operation is 2 minutes, the flotation time of the concentrating II operation is 1.5 minutes, the flotation time of the concentrating III operation is 1 minute, the flotation time of the scavenging I operation is 2 minutes, and the flotation time of the scavenging II operation is 1 minute. The specific dosage of reagents for each operation is shown in Table 2, and the separation index is shown in Table 3.

[0038] The results show that when a shorter modification time (30s) is used, the pyrite concentrate contains 7.83% arsenic, and the arsenic minerals are hardly inhibited, indicating that a shorter modification time cannot achieve selective modification of plasma.

[0039] Comparative Example 2

[0040] This comparative example 2 takes high-arsenic pyrite from a certain place in Yunnan as the research object. The main mineral components of the ore are pyrite, arsenopyrite, quartz, dolomite, etc. The S grade is 31.47%, and the arsenic content is as high as 9.14%. The process steps are as shown in the attached figure. Figure 1 As shown, the specific steps include:

[0041] (1) Grinding: Grind high-arsenic pyrite to -0.074 mm, accounting for 52%;

[0042] (2) The slurry concentration of the slurry obtained in step (1) is controlled at 10%, and then transferred to the slurry reaction chamber, mechanical stirring is turned on, and a high-voltage electrode with a stainless steel spiral spring and a quartz plasma generator with a bubble generator (quartz sand) placed below is inserted into the slurry, and the lower end of the bubble generator is 0.5 cm away from the bottom of the slurry reaction chamber. Oxygen is introduced into the low-temperature plasma generator, and the oxygen flow rate is adjusted to 0.3L / min. The current and power of the plasma power supply are adjusted to 1A and 60W respectively, and oxygen is excited to generate plasma. The plasma is driven by the airflow through the bubble generator and blown into the slurry in the form of bubble nuclei. After reacting for 6 minutes, the modified slurry is obtained. The specific gas-electric parameters of the plasma generator and the modification parameters are shown in Table 1;

[0043] (3) Add the collector ethyl xanthate and the foaming agent pine oil to the modified slurry for slurry adjustment. After stirring for 2 minutes and 1 minute respectively, pyrite concentrate and tailings are obtained after one roughing, three concentrating and two scavenging respectively; the intermediate ore products of three concentrating and two scavenging are sequentially returned to the previous operation to form a flotation closed circuit. Among them, the flotation time of the roughing operation is 3 minutes, the flotation time of the concentrating I operation is 2 minutes, the flotation time of the concentrating II operation is 1.5 minutes, the flotation time of the concentrating III operation is 1 minute, the flotation time of the scavenging I operation is 2 minutes, and the flotation time of the scavenging II operation is 1 minute. The specific dosage of reagents for each operation is shown in Table 2, and the separation index is shown in Table 3.

[0044] The results show that when a longer modification time (6 min) is used, the pyrite concentrate contains 0.25% arsenic and the arsenic minerals are significantly inhibited. However, the yield of pyrite concentrate is only 18.74% and the recovery rate of S is only 30.26%, indicating that a longer modification time will inhibit both minerals at the same time, resulting in a decrease in the recovery rate of valuable components.

[0045] Example 1

[0046] In this Example 1, a high-arsenic pyrite in Yunnan was used as the research object. The main mineral components of the ore were pyrite, arsenopyrite, quartz, dolomite, etc. The S grade was 31.47%, and the arsenic content was as high as 9.14%. The process steps are shown in the attached figure. Figure 1 As shown, the specific steps include:

[0047] (1) Grinding: Grind high-arsenic pyrite to -0.074 mm, accounting for 52%;

[0048] (2) The slurry concentration of the slurry obtained in step (1) is controlled at 10%, and then transferred to the slurry reaction chamber, mechanical stirring is turned on, and then a high-voltage electrode with a stainless steel spiral spring and a quartz plasma generator with a bubble generator (quartz sand) placed below is inserted into the slurry, and the lower end of the bubble generator is 0.5 cm away from the bottom of the slurry reaction chamber. Oxygen is introduced into the low-temperature plasma generator, and the oxygen flow rate is adjusted to 0.3L / min. The current and power of the plasma power supply are adjusted to 1A and 60W respectively, and oxygen is excited to generate plasma. The plasma is driven by the airflow through the bubble generator and blown into the slurry in the form of bubble nuclei. After reacting for 1 minute, the modified slurry is obtained. The specific gas-electric parameters of the plasma generator and the modification parameters are shown in Table 1;

[0049] (3) Adding the collector ethyl xanthate and the frother pine oil to the modified pulp for slurry adjustment, stirring for 2 minutes and 1 minute respectively, and obtaining pyrite concentrate and tailings after one roughing, three cleanings and two scavengings; that is, after adding the collector and the frother, a roughing operation is carried out, and a rough concentrate and a rough tailing are obtained after the roughing operation; then the rough concentrate is subjected to three cleanings, and the rough tailings are subjected to two scavengings, wherein the tailings of the first cleaning and the concentrate of the first scavenging are combined into a middling ore and returned to the roughing operation; the middling ore of the second cleaning is returned to the first cleaning operation, and the middling ore of the third cleaning is returned to the second cleaning operation; the middling ore of the second scavenging is returned to the first scavenging operation; that is, the middling ore products of the three cleanings and the two scavengings are sequentially returned to the previous operation to form a flotation closed circuit.

[0050] Among them, the flotation time of the roughing operation is 3 minutes, the flotation time of the concentrating I operation is 2 minutes, the flotation time of the concentrating II operation is 1.5 minutes, the flotation time of the concentrating III operation is 1 minute, the flotation time of the scavenging I operation is 2 minutes, and the flotation time of the scavenging II operation is 1 minute. The specific dosage of reagents for each operation is shown in Table 2, and the separation indicators are shown in Table 3.

[0051] Example 2

[0052] In Example 2, high-arsenic pyrite from a certain place in Inner Mongolia was used as the research object. The main mineral components of the ore were pyrite, arsenopyrite, quartz, feldspar, mica, etc. The S grade was 34.12%, and the arsenic content was as high as 7.45%. The process steps are as shown in the attached figure. Figure 1 As shown, the specific steps include:

[0053] (1) Grinding: Grind high-arsenic pyrite to -0.074 mm, accounting for 68%;

[0054] (2) The slurry concentration of the slurry obtained in step (1) is controlled at 15%, and then transferred to the slurry reaction chamber, mechanical stirring is turned on, and then a quartz plasma generator with a stainless steel rod-shaped high-voltage electrode and a bubble generator (porous ceramic ball) is inserted into the slurry, and the lower end of the bubble generator is 0.7 cm away from the bottom of the slurry reaction chamber. Oxygen is introduced into the low-temperature plasma generator, and the oxygen flow rate is adjusted to 1L / min. The current and power of the plasma power supply are adjusted to 1.5A and 40W respectively, and oxygen is excited to generate plasma. The plasma is driven by the airflow through the bubble generator and blown into the slurry in the form of bubble nuclei. After reacting for 40 seconds, the modified slurry is obtained. The specific gas-electric parameters of the plasma generator and the modification parameters are shown in Table 1;

[0055] (3) Add butyl xanthate as a collector and kerosene as a foaming agent to the modified slurry for slurry preparation. After stirring for 3 minutes and 2 minutes respectively, pyrite concentrate and tailings are obtained after one roughing, two concentrating and two scavenging respectively; the intermediate products of two concentrating and two scavenging are sequentially returned to the previous operation to form a flotation closed circuit. Among them, the flotation time of the roughing operation is 5 minutes, the flotation time of the concentrating I operation is 3 minutes, the flotation time of the concentrating II operation is 2 minutes, the flotation time of the scavenging I operation is 3 minutes, and the flotation time of the scavenging II operation is 3 minutes. The specific dosage of reagents for each operation is shown in Table 2, and the separation index is shown in Table 3.

[0056] Example 3

[0057] In Example 3, high-arsenic pyrite from a certain place in Guizhou was used as the research object. The main mineral components of the ore were pyrite, arsenopyrite, quartz, mica, etc. The S grade was 27.18%, the Au grade was 2.43 g / t, and the arsenic content was as high as 2.14%. The process steps are as shown in the attached figure. Figure 1 As shown, the specific steps include:

[0058] (1) Grinding: Grind the high-arsenic pyrite concentrate to -0.074 mm, accounting for 76%;

[0059] (2) The slurry concentration of the slurry obtained in step (1) is controlled at 20%, and then transferred to the slurry reaction chamber, mechanical stirring is turned on, and then a glass plasma generator with a built-in tungsten carbon steel multi-needle rod-shaped high-voltage electrode and a bubble generator (gas disk stone) is inserted into the slurry, and the lower end of the bubble generator is 1 cm away from the bottom of the slurry reaction chamber. Air is introduced into the low-temperature plasma generator, and the air flow rate is adjusted to 7L / min. The current and power of the plasma power supply are adjusted to 1.2A and 30W respectively, and the air is excited to generate plasma. The plasma is driven by the airflow through the bubble generator and blown into the slurry in the form of bubble nuclei. After reacting for 5 minutes, the modified slurry is obtained. The specific gas-electric parameters of the plasma generator and the modification parameters are shown in Table 1;

[0060] (3) Add collectors ethylthiocyanate and butyl ammonium black powder and foaming agent diesel to the modified slurry for slurry adjustment. After stirring for 4 minutes and 2 minutes respectively, gold-bearing pyrite concentrate and tailings are obtained after one roughing, two concentrating and three scavenging respectively; the intermediate products of two concentrating and three scavenging are sequentially returned to the previous operation to form a flotation closed circuit. Among them, the flotation time of the roughing operation is 8 minutes, the flotation time of the concentrating I operation is 4 minutes, the flotation time of the concentrating II operation is 3 minutes, the flotation time of the scavenging I operation is 5 minutes, the flotation time of the scavenging II operation is 3 minutes, and the flotation time of the scavenging III operation is 2 minutes. The specific dosage of reagents for each operation is shown in Table 2, and the separation index is shown in Table 3.

[0061] Example 4

[0062] In this Example 4, arsenic-containing pyrite from a certain place in Guangxi was used as the research object. The main mineral components of the ore were pyrite, arsenopyrite, quartz, feldspar, etc. The S grade was 37.12% and the arsenic content was 0.50%. The process steps are as shown in the attached figure. Figure 1 As shown, the specific steps include:

[0063] (1) Grinding: Grind the arsenic pyrite to -0.074 mm, accounting for 95%;

[0064] (2) The slurry concentration of the slurry obtained in step (1) is controlled at 30%, and then transferred to the slurry reaction chamber, mechanical stirring is turned on, and then a glass plasma generator with a built-in tungsten carbon steel spiral spring high-voltage electrode and a bubble generator (gas disk stone) is inserted into the slurry, and the lower end of the bubble generator is 0.5 cm away from the bottom of the slurry reaction chamber. Air is introduced into the low-temperature plasma generator, and the air flow rate is adjusted to 10L / min. The current and power of the plasma power supply are adjusted to 1.0A and 50W respectively, and the air is excited to generate plasma. The plasma is driven by the airflow through the bubble generator and blown into the slurry in the form of bubble nuclei. After reacting for 3 minutes, the modified slurry is obtained. The specific gas-electric parameters of the plasma generator and the modification parameters are shown in Table 1;

[0065] (3) Add the collector ethionamide and the foaming agent pine oil to the modified slurry for slurry adjustment. After stirring for 4 minutes and 2 minutes respectively, pyrite concentrate and tailings are obtained after one roughing, two concentrating and two scavenging respectively; the intermediate ore products of two concentrating and two scavenging are sequentially returned to the previous operation to form a flotation closed circuit. Among them, the flotation time of the roughing operation is 10 minutes, the flotation time of the concentrating I operation is 5 minutes, the flotation time of the concentrating II operation is 3 minutes, the flotation time of the scavenging I operation is 6 minutes, and the flotation time of the scavenging II operation is 4 minutes. The specific dosage of reagents for each operation is shown in Table 2, and the separation indicators are shown in Table 3.

[0066] Table 1 Important gas-electric parameters of plasma modification of Comparative Examples 1-2 and Examples 1-4

[0067]

[0068] Table 2 Flotation reagent dosage of Comparative Examples 1-2 and Examples 1-4 (g / ton·feed)

[0069]

[0070]

[0071] Table 3 Comparative Examples 1-2 and Examples 1-4 Selection Index

[0072]

Claims

1. A method for beneficiating pyrite by low-temperature plasma modification and strengthening arsenic removal, characterized in that: It consists of the following steps: (1) Grinding: Grind the arsenic-containing pyrite to -0.074 mm, accounting for 50% to 95%; (2) the slurry obtained in step (1) is controlled at a concentration of 10-30%, and then transferred to a slurry reaction chamber, and mechanical stirring is started; a low-temperature plasma generator with a built-in high-voltage electrode and a bubble generator at the bottom is inserted into the slurry, gas is introduced into the low-temperature plasma generator, the current and voltage of the low-temperature plasma power supply are adjusted, the gas is excited to generate plasma, and the plasma is driven by the airflow through the bubble generator and blown into the slurry in the form of bubble nuclei, and after the reaction is complete, a modified slurry is obtained; (3) adding a collector and a frother to the modified slurry for slurry adjustment, and obtaining pyrite concentrate and high-arsenic tailings products after one roughing, multiple cleaning and multiple scavenging respectively; in: In step (2), the distance between the bottom end of the bubble generator and the bottom of the slurry reaction chamber is 0.5-1 cm; In step (2), the discharge gas is one of air or oxygen, with a flow rate of 0.3-10 L / min; the discharge current is 1-1.5 A, the discharge power is 30-60 W, and the plasma modification time is 40 s-5 min; In step (3), the amount of collector used in the roughing operation is 50-200 g / t, and the amount of frother used is 20-60 g / t; no collector and frother are added in the concentrating operation; the amount of collector and frother used in the scavenging operation is 1 / 4-1 / 2 of that in the previous operation; the intermediate ore products of the concentrating and scavenging in step (3) are sequentially returned to the previous operation to form a flotation closed circuit; The collector described in step (3) is a combination of one or more of butyl xanthate, ethyl xanthate, butyl ammonium black medicine, ethylthiocyanate or ethylthiocarbamate; the foaming agent is one of pine oil, kerosene or diesel.

2. The method for arsenic removal from pyrite by low-temperature plasma modification according to claim 1, characterized in that: The mass content of arsenic in the arsenopyrite in step (1) is ≥ 0.5%.

3. The method for arsenic removal from pyrite by low-temperature plasma modification according to claim 2, characterized in that: The mass content of arsenic in the arsenic-containing pyrite in step (1) is 0.5-10%.

4. The method for arsenic removal from pyrite by low-temperature plasma modification according to claim 1, characterized in that: The low-temperature plasma generator described in step (2) is made of quartz or glass; the high-voltage electrode is in the shape of a spiral spring, a rod or a multi-needle rod, and the high-voltage electrode material is stainless steel or tungsten carbon steel; the bubble generator is made of quartz sand, porous ceramic balls or gas disk stone porous media.

5. The method for arsenic removal from pyrite by low-temperature plasma modification according to claim 1, characterized in that: In step (3), a collector and a frother are added to the modified slurry for slurry adjustment. The stirring time of the collector is 2 to 4 minutes, and the stirring time of the frother is 1 to 2 minutes.

6. The method for arsenic removal from pyrite by low-temperature plasma modification according to claim 1, characterized in that: In step (3), the flotation time of the roughing operation is 3-10 minutes, the flotation time of the primary cleaning operation is 1-5 minutes, and the flotation time of the primary scavenging operation is 1-6 minutes; the number of multiple cleaning operations in step (3) is 2-3 times; the number of multiple scavenging operations is 2-3 times.

Images