Beneficiation method for improving flotation index of micro-fine particle gold ore

Abstract

The invention discloses a beneficiation method suitable for micro-fine particle gold ore, and belongs to the technical field of beneficiation. According to the method, lignosulfonate is added in the ore grinding process, on the basis of a grading separation technology, a conventional flotation process is adopted for the particle size of + 0.026 mm, a novel inhibitor sodium ethylenediamine tetra (methylene phosphonate) / pectin is matched, and relatively coarse gold ore is recycled; for the micro-fine particle gold ore with the size fraction of-0.026 mm, a similar mineral carrier is added to be combined with an artificially synthesized particle carrier for flotation, so that the beneficiation index of the micro-fine particle gold ore is improved. According to the method, efficient recovery of Au in the micro-fine particle gold ore (the Au grade of the micro-fine particle gold ore is 1.8 g / t-2. 5 g / t, the content of Al2O3 is 55%-65%, and the content of SiO2 is 10%-20%) is achieved, and the gold concentrate with the Au grade being 30.52 g / t and the Au recovery rate being 86.33% is obtained. The technical problem that the micro-fine particle gold ore is difficult to effectively recover is effectively solved, and the method has important significance on efficient utilization of the low-grade difficult-to-treat micro-fine particle gold ore.

Description

Technical Field

[0001] The invention relates to the technical field of gold ore dressing, and in particular to a ore dressing method for improving the flotation index of fine gold ore by combining a novel depressant with a carrier for flotation based on a graded separation process. Background Art

[0002] Gold (Ag) has long been used as currency and financial reserves due to its scarcity, chemical stability and high value, and is widely used in many fields such as jewelry, electronics, aerospace, and medical treatment. my country's gold resources are widely distributed but unevenly distributed, with various types of deposits, including quartz vein gold mines, altered rock gold mines, fine impregnation gold mines, and volcanic rock gold mines. Although there are many gold producing areas, there are relatively few large and super-large gold mines, and most of them are small and medium-sized deposits. In addition, the average grade of gold ore in my country is relatively low and its properties are complex, which increases the difficulty and cost of mining and beneficiation.

[0003] Fine-grained gold ore is an important component of gold resources. However, due to the extremely fine particle size of its gold-bearing minerals, which is usually less than 0.01mm, or even reaches the nanometer level, this leads to many challenges in the conventional flotation process, making it difficult for the flotation index to reach the ideal level. Specifically, the fine-grained gold ore has a small particle size, a sharp increase in specific surface area, and a corresponding increase in surface energy, which makes it easy to agglomerate and non-selective adsorption during the flotation process, affecting the selectivity and efficiency of flotation. In addition, its poor dispersibility in the slurry easily forms a local concentration gradient, and some fine-grained gold ores cannot fully contact the flotation reagents, missing the opportunity to be recovered by flotation. At the same time, the kinetic behavior of fine-grained gold ore in the flotation process is also different from that of larger-grained gold ore. Its momentum is small, and it is difficult to overcome the energy barrier between the ore particles and the bubbles and cannot adhere to the bubbles. In actual industrial production, in order to improve production efficiency, the flotation time is often limited, which further leads to the inability of fine-grained gold ore to be fully recovered. For example, the original gold ore of a certain gold mine in Qinghai contains about 37% mud minerals. During grinding, a large amount of secondary ore mud is easily produced, which affects the flotation recovery rate index.

[0004] Therefore, developing new flotation technology for fine-grained gold ores and realizing efficient recovery of fine-grained gold ores are of great significance for achieving efficient utilization of difficult-to-process low-grade fine-grained gold ores. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a mineral processing method for improving the flotation index of fine-grained gold ore.

[0006] The object of the present invention is to achieve the following technical solution: a beneficiation method for improving the flotation index of fine-grained gold ore, wherein the fine-grained gold ore has an Au grade of 1.8g / t-2.5g / t and an Al 2 O3 The content is 55%-65%, SiO 2 The content is 10%-20%, and more than 80% of the gold particles / gold-bearing minerals have a distribution particle size of less than 20 microns, including the following steps:

[0007] S1. Grinding: Grind the gold ore to -0.074mm, which accounts for 80% to 85% of the mass of the floating sample. Add lignin sulfonate during the grinding process;

[0008] S2, classification: the ore pulp obtained by the grinding is classified to obtain two parts of +0.026mm particle size and -0.026mm particle size into flotation slurry;

[0009] S3, coarse particle flotation: pH adjuster, inhibitor, collector and frother are added to the +0.026mm particle size flotation slurry in sequence to carry out coarse particle flotation operation;

[0010] S4, fine-grained flotation: add fine-grained gold ore flotation carrier, pH adjuster, inhibitor, collector, and frother into the -0.026mm particle size flotation slurry in sequence to carry out fine-grained flotation operation;

[0011] The lignin sulfonate is calcium lignin sulfonate or sodium lignin sulfonate; the fine-grained gold ore flotation carrier is composed of carrier 1 and carrier 2, carrier 1 is the tailings produced by the coarse-grained flotation, and carrier 2 is a ferroferric oxide-graphene oxide composite material or a polypropylene-ferroferric oxide nanocomposite material.

[0012] Further, in step S1, the amount of lignin sulfonate is 50-80 g / t;

[0013] In step S4, the total amount of the fine-grained gold ore flotation carrier is one tenth to one eighth of the -0.026 mm particle size ore amount, and the amount ratio of carrier 1 to carrier 2 is 20:1 to 10:1.

[0014] Furthermore, the pH adjuster is sodium carbonate or sodium hydroxide; the inhibitor is sodium ethylenediaminetetramethylenephosphonate or pectin; the collector is composed of collector 1 and collector 2, collector 1 is ethyl xanthate, butyl xanthate or amyl xanthate; the collector 2 is butyl ammonium black medicine or ethylthiocarbamate; the foaming agent is pine oil or methyl isobutyl carbinol.

[0015] Furthermore, in step S2, the equipment used for classification is a hydrocyclone.

[0016] Furthermore, in step S3, the coarse particle flotation operation includes a primary roughing process, a tertiary cleaning process and a secondary scavenging process.

[0017] Furthermore, in step S3, the coarse particle flotation operation is specifically as follows:

[0018] 1) pH adjuster, inhibitor, collector and frother are sequentially added to the +0.026 mm particle size flotation slurry to obtain coarse particle size roughing concentrate and coarse particle size roughing tailings;

[0019] 2) The coarse-grained rougher concentrate is subjected to three rounds of concentration after adding an inhibitor, and the concentrate finally obtained by the concentration is the first concentrate, and the middlings are sequentially returned to the previous level of operation, the inhibitor is added in the first concentration, and the other concentrations are blank concentrations;

[0020] 3) Adding a collector and a frother to the coarse-grained roughing tailings to carry out two scavenging operations, and returning the scavenged tailings to the previous operation in sequence, with the scavenged tailings being used as tailings 1;

[0021] Further, in step S3, when the +0.026 mm particle size is fed into the flotation slurry for roughing, the dosage of the pH adjuster is 1500-2500 g / t of ore, the dosage of the inhibitor is 200-400 g / t of ore, the dosage of the collector 1 and the collector 2 are 80-150 g / t of ore and 40-80 g / t of ore respectively, and the dosage of the foaming agent is 20-30 g / t of ore;

[0022] The dosage of the first concentration inhibitor is 40-80g / t of raw ore;

[0023] In the first scavenging, the dosage of collector 1 and collector 2 is 40-80g / t of raw ore and 20-40g / t of raw ore respectively, and the dosage of frother is 10-15g / t of raw ore; in the second scavenging, the dosage of collector 1 and collector 2 is 20-40g / t of raw ore and 10-20g / t of raw ore respectively, and the dosage of frother is 8-12g / t of raw ore.

[0024] Furthermore, in step S4, the fine particle flotation operation includes a roughing operation, a second cleaning operation and a scavenging operation.

[0025] Furthermore, in step S4, the fine particle flotation operation is specifically as follows:

[0026] (1) adding a fine gold ore flotation carrier, a pH adjuster, a gangue mineral inhibitor, a gold ore collector, and a frother to a -0.026 mm particle size flotation slurry in sequence, and performing rough separation to obtain a fine-grained roughing concentrate and a fine-grained roughing tailings;

[0027] (2) The fine-grained rougher concentrate is subjected to two blank concentrations to obtain concentrate 2, and the concentrated middlings are sequentially returned to the previous operation;

[0028] (3) The fine-grained roughing tailings are added with a collector and a frother for a scavenging operation, and the scavenged tailings are returned to the roughing operation. After the artificial carrier is recovered by magnetic separation (magnetic field strength is 780 Oe, and the artificial carrier recovery rate is greater than 98%), the scavenged tailings are used as tailings II.

[0029] Further, in step S4, when the -0.026 mm particle size is put into the flotation slurry for roughing, the dosage of pH adjuster is 500-1000 g / t of ore, the dosage of inhibitor is 100-200 g / t of ore, the dosage of collector 1 and collector 2 is 40-80 g / t of ore and 20-40 g / t of ore respectively, and the dosage of foaming agent is 10-20 g / t of ore;

[0030] The dosage of collector 1 and collector 2 in the first scavenging is 20-40g / t of raw ore and 10-20g / t of raw ore respectively, and the dosage of frother is 0-5g / t of raw ore.

[0031] It is worth noting that in order to ensure the Au grade and recovery rate of the concentrate, the present invention adopts conventional flotation for the +0.026 mm particle size and combined carrier flotation for the -0.026 mm particle size based on the classification and sorting process under the action of a new type of inhibitor:

[0032] (1) When grinding, adding lignin sulfonate can be adsorbed on the surface of mineral particles, preventing particle agglomeration through electrostatic repulsion and steric hindrance effect, improving the grinding effect, and creating good conditions for subsequent flotation and other mineral processing operations. In addition, lignin sulfonate can selectively adsorb on the surface of gangue minerals, playing a certain inhibitory role.

[0033] (2) During conventional flotation of the +0.026 mm particle size, a pH adjuster is used to adjust the pulp potential; a new inhibitor, sodium ethylenediaminetetramethylenephosphonate (or pectin), is used to inhibit non-target minerals; and gold-bearing mineral collectors, ethyl xanthate (or butyl xanthate, amyl xanthate) and butyl ammonium black medicine (or ethylthiocarbamate) are added. Ethyl xanthate or butyl xanthate has a good general capture ability for sulfide minerals, while butyl ammonium black medicine (or ethylthiocarbamate) has a good selective capture ability for gold-bearing minerals. The combination of the two can enhance the selective capture ability for gold-bearing minerals through synergistic effect, thereby better realizing the efficient recovery of gold-bearing minerals.

[0034] (3) - When flotation is performed at a particle size of 0.026 mm, two types of carriers (coarse tailings and artificial carriers) are added. Due to their small particle size and light weight, fine-grained minerals are difficult to effectively collide and adhere to bubbles during flotation, resulting in a low flotation recovery rate. Coarse-grained tailings, as carriers, can provide a surface for fine-grained minerals to adhere to, increasing the contact opportunities between fine-grained minerals and bubbles, thereby improving the flotation recovery rate. There is a synergistic effect between the ferroferric oxide-graphene oxide composite material and the flotation agent. During the flotation process, the flotation agent can interact with the functional groups on the surface of the ferroferric oxide-graphene oxide composite material, enhancing the hydrophilicity or hydrophobicity of the ferroferric oxide-graphene oxide, thereby improving its selective adsorption capacity for gold ore particles. The polypropylene-ferroferric oxide carrier can adjust its surface properties and composition to have a higher selective adsorption capacity for fine-grained gold ore, while having less adsorption for other impurity minerals. During the flotation process, the flotation agent and the carrier cooperate with each other to further improve the flotation selectivity; the polypropylene-ferroferric oxide carrier can adsorb the flotation agent and transfer it to the fine-grained gold ore, thereby enhancing the hydrophobicity of the gold ore particle surface, making it easier to combine with the flotation bubbles.

[0035] (4) After the carrier flotation is completed, the fine tailings (tailings 2) are magnetic. The ferroferric oxide is magnetic, and the ferroferric oxide-graphene oxide and polypropylene-ferroferric oxide carriers can be separated and recovered by using the magnetic field. Tailings 2 and tailings 1 are combined as the total tailings.

[0036] The principle of the present invention is:

[0037] During grinding, the addition of lignin sulfonate can act as a grinding aid and inhibit some gangue minerals. Based on the grading and sorting process, during the conventional flotation of +0.026mm coarse particles, the slurry potential is adjusted by the adjusting agent, the new inhibitor sodium ethylenediaminetetramethylenephosphonate or pectin selectively disperses and inhibits non-target minerals, and the combined collector synergistically strengthens the recovery of the target minerals, thereby recovering the relatively coarse and easy-to-float gold minerals embedded in the gold mine; for the flotation of -0.026mm gold ore, +0.026mm coarse tailings are introduced as the main flotation carrier, and the magnetic artificial composite material ferroferric oxide-graphene oxide (or polypropylene-ferroferric oxide) is used as the second carrier. The combination of the two carriers plays a synergistic role, enhancing the hydrophobicity of the gold ore particle surface, making it easier to combine with the flotation bubbles, and playing a role in improving the flotation index of fine gold ore.

[0038] The beneficial effects of the present invention are:

[0039] (1) Improve resource recovery rate

[0040] 1) Grading and sorting technology ensures targeted treatment of gold ores of different particle sizes

[0041] For +0.026mm conventional flotation, the slurry potential is adjusted by the adjusting agent, and the synergistic effect of the new inhibitor and the combined collector can effectively recover the relatively coarse and easily floatable gold minerals embedded in the gold ore. For the flotation of -0.026mm gold ore, coarse tailings and magnetic artificial composite materials are introduced as carriers, and the synergistic effect enhances the binding ability of fine gold ore and flotation bubbles, significantly improving the recovery rate of fine gold minerals.

[0042] 2) Adding carrier combinations to expand the recovery range

[0043] As the main flotation carrier, coarse tailings provide a base for the fine gold ore to attach, increasing its contact with the flotation system, while the magnetic artificial composite material ferroferric oxide-graphene oxide (or polypropylene-ferroferric oxide) as the second carrier further enhances the hydrophobicity of gold ore particles and their ability to bind to bubbles. The combination of the two carriers covers a wider range of particle sizes, ensuring that gold minerals of different particle sizes can be effectively recovered, thereby improving the overall recovery rate of gold resources.

[0044] (2) Improve product quality

[0045] In +0.026mm conventional flotation, the new inhibitor sodium ethylenediaminetetramethylenephosphonate or pectin can selectively disperse and inhibit non-target minerals, which effectively reduces the mixing of impurity minerals during the flotation process and improves the grade of the concentrate. By precisely controlling the pulp potential and the effect of the inhibitor, efficient inhibition of non-target minerals can be achieved, thereby improving the quality of the final product. The use of carriers also helps to improve the selectivity of flotation. The selective adsorption of fine gold ores by magnetic artificial composite materials can reduce the adhesion of other impurity particles and further improve the purity of the concentrate.

[0046] (3) Reduce production costs

[0047] 1) Tailings and man-made composite materials as flotation carriers

[0048] The introduction of coarse tailings with a particle size of +0.026 mm as flotation carriers has achieved the reuse of waste. This not only reduces the discharge and treatment costs of tailings, but also reduces the demand for new carrier materials, saving resources and procurement costs.

[0049] Although the magnetic artificial composite material ferroferric oxide-graphene oxide (or polypropylene-ferroferric oxide) may require a certain amount of cost investment during the preparation process, its high performance and recyclability can reduce production costs in long-term use. These composite materials can be easily recycled and reused through methods such as magnetic separation, reducing material consumption and waste.

[0050] 2) Reduce the dosage of medicine

[0051] Lignin sulfonate acts as a grinding aid and a partial inhibitor of gangue minerals in the grinding process, which can reduce the energy consumption and demand for other inhibitors in the grinding process. At the same time, in the flotation process, by optimizing the combination of regulators, inhibitors and collectors, the total dosage of reagents can be reduced, thereby reducing costs.

[0052] (4) Environmentally friendly

[0053] 1) Reduce waste emissions

[0054] The use of coarse tailings as carriers reduces the discharge of tailings and the pressure on the environment. The use of new inhibitors and combined collectors not only improves the flotation effect, but also reduces the discharge of environmentally harmful chemicals. Some traditional inhibitors and collectors may contain heavy metals or toxic substances, while the selection of agents in the present invention pays more attention to environmental friendliness.

[0055] 2) Use of recyclable materials

[0056] The recyclability of magnetic man-made composite materials reduces material waste and environmental pollution. These materials can be recovered and reused through methods such as magnetic separation after flotation, reducing the demand for new resources and reducing the generation of waste. At the same time, the use of recyclable materials is also in line with the concept of circular economy and helps promote the sustainable development of the mining industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a flow chart of the principle of the present invention;

[0058] Figure 2 It is the principle flow chart of comparative examples 1 and 2. DETAILED DESCRIPTION

[0059] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0060] Example 1

[0061] 1. Ore characteristics:

[0062] The arsenopyrite gold mine in a certain place in western my country has unfavorable characteristics such as complex mineral composition, fine distribution of gold particles / gold-bearing minerals (more than 80% of the gold particles / gold-bearing minerals have a distribution size of less than 20 microns), and high content of clay minerals. The grade of the original ore gold is 2.20g / t. Although the grade is not high, it meets the requirements for rock gold mining under current economic and technical conditions; SiO in the ore 2 The content is 60.28%, Al 2 O 3The content is 14.57%, indicating that the ore contains high content of quartz, silicate and aluminosilicate minerals. The As content in the ore is 0.31% and the C content is 1.10%, which easily affects the quality of flotation concentrate. Therefore, gold is the most important element to be recovered in the original ore. At present, the grinding and grading process and reagent system of the ore dressing plant are not suitable, and the grade and recovery rate of gold concentrate are low.

[0063] 2. Ore dressing process:

[0064] (1) Grinding: Add 50 g / t of calcium lignin sulfonate and grind the ore to -0.074 mm with a content of 82%. The slurry is graded to obtain two particle sizes of +0.026 mm and -0.026 mm.

[0065] (2) Add 2000g / t sodium carbonate as an adjusting agent, 320g / t sodium ethylenediaminetetramethylenephosphonate as an inhibitor, 100g / t sodium butyl xanthate as a collector, 50g / t sodium butyl ammonium black powder as a collector, and 24g / t sodium methyl isobutyl carbinol as a foaming agent to the 0.026mm particle size, and perform flotation roughing after slurry adjustment to obtain roughing concentrate and roughing tailings. Add sodium ethylenediaminetetramethylenephosphonate as an inhibitor to the roughing concentrate for three times of concentrating to obtain concentrate 1, and the dosage of concentrating 1 inhibitor is 40g / t of the ore. The last two times of concentrating are blank concentrating, and the concentrating middlings are returned in order. Collector 1 butyl xanthate 50g / t original ore, collector 2 butylammonium xanthate 30g / t original ore, and foaming agent methyl isobutyl carbinol 12g / t original ore were added to the roughing tailings for the first scavenging. Collector 1 butyl xanthate 30g / t original ore, collector 2 butylammonium xanthate 15g / t original ore, and foaming agent methyl isobutyl carbinol 10g / t original ore were added to the tailings for the first scavenging, and the second scavenging was carried out. The scavenged tailings were used as tailings one.

[0066] (3) Add flotation carriers at -0.026 mm particle size, the total amount of carriers used is one tenth of the amount of -0.026 mm particle size ore, the amount ratio of carrier 1 (part of tailings 1) to carrier 2 ferroferric oxide-graphene oxide is 20:1; add pH adjuster sodium carbonate at an amount of 500 g / t of raw ore, inhibitor sodium ethylenediaminetetramethylenephosphonate at an amount of 100 g / t of raw ore, collector 1 butyl xanthate and collector 2 butylammonium black medicine at an amount of 40 g / t of raw ore and 20 g / t of raw ore respectively, and frother at an amount of 10 g / t of raw ore; complete the roughing of -0.026 mm particle size to obtain rough concentrate and roughing tailings. The rough concentrate was blank-selected twice to obtain concentrate 2; the rough tailings were scavenged to obtain tailings 2, and the dosage of scavenging collector 1 butyl xanthate and collector 2 butyl ammonium black medicine was 20g / t of original ore and 10g / t of original ore respectively, and the dosage of foaming agent methyl isobutyl carbinol was 5g / t of original ore.

[0067] (4) Recovering the artificial carrier ferroferric oxide-graphene oxide (the magnetic separation equipment is a magnetic drum, the magnetic field strength is 780 Oe, and the recovery rate of the artificial carrier is 98.5%), the concentrate 1 and the concentrate 2 are combined into the final concentrate, and the tailings 1 and the tailings 2 are combined into the final tailings.

[0068] 3. Ore dressing test indicators:

[0069] Based on detailed conditional tests, the flotation closed-circuit test obtained good technical indicators, and the results are shown in Table 1.

[0070] Table 1

[0071] Product Name Yield (%) Au grade (g / t) Au recovery rate (%) Concentrate 6.21 30.52 86.33 Tailings 93.79 0.32 13.67 Ore 100.00 2.20 100.00

[0072] From the results in Table 1, it can be seen that the Au grade of the concentrate is 30.52 g / t, which is 13.90 times richer than that of the original ore, and the recovery rate is as high as 86.33%.

[0073] Example 2

[0074] 1. The ore characteristics are the same as those in Example 1, and the ore dressing process is as follows:

[0075] (1) Grinding: Add 60 g / t of sodium lignin sulfonate and grind the ore to -0.074 mm with a content of 80%. The slurry is graded to obtain two particle sizes of +0.026 mm and -0.026 mm.

[0076] (2) Add 1500g / t sodium hydroxide as the adjusting agent, 300g / t pectin as the inhibitor, 120g / t ethyl xanthate as the collector, 60g / t ethylthiocarbamate as the collector, and 20g / t pine oil as the foaming agent to the 0.026mm particle size, and then perform flotation roughing to obtain roughing concentrate and roughing tailings. Add pectin as the inhibitor to the roughing concentrate and perform three rounds of selection to obtain concentrate 1, and select 1 inhibitor pectin at a dosage of 60g / t ore. The last two rounds of selection are blank selections, and the selected middlings are returned in order. Collector 1 ethyl xanthate 60g / t original ore, collector 2 ethylthiocarbamate 30g / t original ore, and foaming agent pine oil 12g / t original ore were added to the roughing tailings for the first scavenging; collector 1 ethyl xanthate 30g / t original ore, collector 2 ethylthiocarbamate 15g / t original ore, and foaming agent pine oil 10g / t original ore were added to the tailings for the first scavenging, and the second scavenging was carried out, and the scavenged tailings were used as tailings one.

[0077] (3) Add flotation carriers at -0.026 mm particle size, the total amount of carriers used is one eighth of the amount of -0.026 mm particle size ore, the amount ratio of carrier 1 (part of tailings 1) to carrier 2 polypropylene-ferric oxide is 15:1; add pH adjuster sodium hydroxide at an amount of 600 g / t of raw ore, inhibitor pectin at an amount of 120 g / t of raw ore, collector 1 ethyl xanthate and collector 2 ethylthiocarbamate at an amount of 40 g / t of raw ore and 20 g / t of raw ore respectively, and frother pine oil at an amount of 10 g / t of raw ore; complete the -0.026 mm particle size roughing to obtain a rough concentrate and roughing tailings. The rougher concentrate was blank-selected twice to obtain concentrate 2; the rougher tailings were scavenged to obtain tailings 2, and the dosages of scavenging collector 1 and collector 2 were 20g / t of original ore and 10g / t of original ore respectively, and the dosage of foaming agent pine oil was 2.5g / t of original ore.

[0078] (4) Recovering the artificial carrier polypropylene-ferroferric oxide (the magnetic separation equipment is a magnetic drum, the magnetic field strength is 780 Oe, and the artificial carrier recovery rate is 98.4%), the concentrate 1 and the concentrate 2 are combined into the final concentrate, and the tailings 1 and the tailings 2 are combined into the final tailings.

[0079] 3. Ore dressing test indicators:

[0080] Based on detailed conditional tests, the flotation closed-circuit test obtained good technical indicators, and the results are shown in Table 2.

[0081] Table 2

[0082] Product Name Yield (%) Au grade (g / t) Au recovery rate (%) Concentrate 6.44 29.67 86.82 Tailings 93.56 0.31 13.18 Ore 100.00 2.20 100.00

[0083] From the results in Table 2, we can see that the Au grade of the concentrate is 29.67 g / t, which is 13.48 times higher than that of the original ore, and the recovery rate is as high as 86.82%. By changing the type and dosage of flotation reagents, this beneficiation method can also recover Au in the ore well.

[0084] Example 3

[0085] 1. The ore characteristics are the same as those in Example 1, and the ore dressing process is as follows:

[0086] (1) Grinding: Add 70 g / t of calcium lignin sulfonate and grind the ore to -0.074 mm with a content of 85%. The slurry is graded to obtain two particle sizes of +0.026 mm and -0.026 mm.

[0087] (2) Add 1800g / t sodium hydroxide as the adjusting agent, 200g / t sodium ethylenediaminetetramethylenephosphonate as the inhibitor, 80g / t amyl xanthate as the collector 1, 40g / t ethathione as the collector 2, and 30g / t methyl isobutyl carbinol as the frother at the particle size of +0.026mm, and perform flotation roughing after slurry adjustment to obtain roughing concentrate and roughing tailings. Add sodium ethylenediaminetetramethylenephosphonate as the inhibitor to the roughing concentrate for three times of concentration to obtain concentrate 1, and the dosage of inhibitor 1 is 40g / t of the raw ore. The last two concentrations are blank concentrations, and the selected middlings are returned in order. Collector 1 amyl xanthate 40g / t original ore, collector 2 ethylthiocarbamate 20g / t original ore, and foaming agent methyl isobutyl carbinol 15g / t original ore were added to the roughing tailings for the first scavenging. Collector 1 amyl xanthate 20g / t original ore, collector 2 ethylthiocarbamate 10g / t original ore, and foaming agent methyl isobutyl carbinol 12g / t original ore were added to the tailings for the first scavenging, and the second scavenging was carried out. The scavenged tailings were used as tailings one.

[0088] (3) Add flotation carriers at -0.026 mm particle size, the total amount of carriers used is one tenth of the amount of -0.026 mm particle size ore, the amount ratio of carrier 1 (part of tailings 1) to carrier 2 ferroferric oxide-graphene oxide is 8:1; add pH adjuster sodium hydroxide at an amount of 600 g / t of raw ore, inhibitor sodium ethylenediaminetetramethylenephosphonate at an amount of 100 g / t of raw ore, collector 1 amyl xanthate and collector 2 ethiocarbamate at an amount of 40 g / t of raw ore and 20 g / t of raw ore respectively, and frother methyl isobutyl carbinol at an amount of 20 g / t of raw ore; complete the roughing of -0.026 mm particle size to obtain a rough concentrate and roughing tailings. The rougher concentrate was blank-selected twice to obtain concentrate 2; the rougher tailings were scavenged to obtain tailings 2, and the dosages of scavenging collector 1 amyl xanthate and collector 2 ethylthiocarbamate were 20g / t of original ore and 10g / t of original ore respectively, and the dosage of foaming agent methyl isobutyl carbinol was 5g / t of original ore.

[0089] (4) Recovering the artificial carrier ferroferric oxide-graphene oxide (the magnetic separation equipment is a magnetic drum, the magnetic field strength is 780 Oe, and the recovery rate of the artificial carrier is 98.7%), the concentrate 1 and the concentrate 2 are combined into the final concentrate, and the tailings 1 and the tailings 2 are combined into the final tailings.

[0090] 3. Ore dressing test indicators:

[0091] Based on detailed conditional tests, the flotation closed-circuit test obtained good technical indicators, and the results are shown in Table 3.

[0092] Table 3

[0093]

[0094] From the results in Table 3, we can see that the Au grade of the concentrate is 29.80 g / t, which is 13.54 times higher than that of the original ore, and the recovery rate is as high as 85.96%. By changing the type and dosage of flotation reagents, this beneficiation method can also recover Au in the ore well.

[0095] Comparative Example 1

[0096] Comparative Example 1 uses the same raw ore as Example 1, and adopts a conventional grinding-flotation process, that is, no classification and sorting is carried out, and lignin sulfonate is not added to the mill, but to the flotation process. The types of other flotation reagents are consistent with those in Example 1, and the amounts of various reagents are the sum of the amounts corresponding to the two particle sizes of +0.026 mm and -0.026 mm in Example 1. The process is as shown in the attached figure. Figure 2 .

[0097] Ore dressing test indicators:

[0098] Table 4

[0099]

[0100] By comparing the results in Table 1 and Table 4, it can be seen that the Au recovery rate index of Comparative Example 1 is not as good as that of Example 1, and the Au recovery rate is 6.11 percentage points lower, which fully highlights the significant effects of adding lignin sulfonate to the grinding process in advance and the classification and sorting (coarse particle conventional flotation-fine particle carrier flotation).

[0101] Comparative Example 2

[0102] Comparative Example 2 uses the same raw ore and the same grinding-flotation process as Example 1, but no lignin sulfonate is added, and the other types of flotation reagents are consistent with those in Example 1.

[0103] Ore dressing test indicators:

[0104] Table 5

[0105]

[0106] Comparing the results in Table 5 and Table 1, it can be seen that the Au grade and recovery rate of Comparative Example 2 are not as good as those of Example 1, with the Au grade being 0.98 g / t lower and the Au recovery being 3.02 percentage points lower. It can be seen that lignin sulfonate can effectively improve the grinding effect, inhibit some gangue minerals, and create good conditions for flotation and other mineral processing operations.

[0107] Comparative Example 3

[0108] Comparative Example 3 uses the same raw ore and the same beneficiation process as Example 1, only the type of inhibitor is changed to carboxymethyl cellulose (CMC), the dosage is consistent with that of sodium ethylenediaminetetramethylenephosphonate in Example 1, and the rest of the flotation operation dosing system is consistent with that of Example 1.

[0109] Ore dressing test indicators:

[0110] Table 6

[0111] Product Name Yield (%) Au grade (g / t) Au recovery rate (%) Concentrate 5.40 32.34 79.71 Tailings 94.60 0.47 20.29 Ore 100.00 2.19 100.00

[0112] By comparing the results in Table 1, Table 2 and Table 6, it can be seen that the Au recovery rate index of Comparative Example 3 is not as good as that of Example 1 and Example 2, and the Au recovery rates are 6.62 percentage points and 7.11 percentage points lower, respectively, further highlighting the significant effects of sodium ethylenediaminetetramethylenephosphonate and pectin as gangue inhibitors.

[0113] Comparative Example 4

[0114] Comparative Example 4 uses the same raw ore as Example 1, and -0.026 mm flotation uses only tailings 1 as the flotation carrier, the amount used is consistent with the amount of tailings 1 used in Example 1, and the rest of the flotation operation dosing system is consistent with Example 1.

[0115] Ore dressing test indicators:

[0116] Table 7

[0117] Product Name Yield (%) Au grade (g / t) Au recovery rate (%) Concentrate 5.38 32.54 79.74 Tailings 94.62 0.47 20.26 Ore 100.00 2.20 100.00

[0118] By comparing the results in Table 1 and Table 7, it can be seen that the Au recovery rate index of Comparative Example 4 is not as good as that of Example 1, and the Au recovery rate is 6.59 percentage points lower, which once again highlights the significant effect of the flotation of the same mineral carrier (+0.026mm flotation tailings -) combined with the artificial synthetic carrier.

[0119] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for improving the flotation index of fine gold ore, wherein the fine gold ore has an Au grade of 1.8g / t-2.5g / t, an Al2O3 content of 55%-65%, a SiO2 content of 10%-20%, and more than 80% of the gold particles / gold-bearing minerals have a particle size of less than 20 microns, characterized in that: The following steps are involved: S1. Grinding: Grind the gold ore to -0.074mm, which accounts for 80% to 85% of the mass of the floating sample. Add lignin sulfonate during the grinding process; S2, classification: the ore pulp obtained by the grinding is classified to obtain two parts of +0.026mm particle size and -0.026mm particle size into flotation slurry; S3, coarse particle flotation: pH adjuster, inhibitor, collector and frother are added to the +0.026mm particle size flotation slurry in sequence to carry out coarse particle flotation operation; S4, fine-grained flotation: add fine-grained gold ore flotation carrier, pH adjuster, inhibitor, collector, and frother into the -0.026mm particle size flotation slurry in sequence to carry out fine-grained flotation operation; The lignin sulfonate is calcium lignin sulfonate or sodium lignin sulfonate; the fine-grained gold ore flotation carrier is composed of carrier 1 and carrier 2, carrier 1 is the tailings produced by the coarse-grained flotation, and carrier 2 is a ferroferric oxide-graphene oxide composite material or a polypropylene-ferroferric oxide nanocomposite material.

2. A method for improving the flotation index of fine gold ore according to claim 1, characterized in that: In step S1, the amount of lignin sulfonate is 50-80 g / t; In step S4, the total amount of the fine-grained gold ore flotation carrier is one tenth to one eighth of the -0.026 mm particle size ore amount, and the amount ratio of carrier 1 to carrier 2 is 20:1 to 10:

1.

3. A method for improving the flotation index of fine gold ore according to claim 2, characterized in that: The pH adjuster is sodium carbonate or sodium hydroxide; the inhibitor is sodium ethylenediaminetetramethylenephosphonate or pectin; the collector is composed of collector 1 and collector 2, collector 1 is ethyl xanthate, butyl xanthate or amyl xanthate; the collector 2 is butyl ammonium black medicine or ethylthiocarbamate; the foaming agent is pine oil or methyl isobutyl carbinol.

4. A method for improving the flotation index of fine gold ore according to claim 2, characterized in that: In step S2, the equipment used for classification is a hydrocyclone.

5. A method for improving the flotation index of fine gold ore according to claim 3, characterized in that: In step S3, the coarse particle flotation operation includes a primary roughing separation, a tertiary cleaning separation and a secondary scavenging separation.

6. A method for improving the flotation index of fine gold ore according to claim 5, characterized in that: In step S3, the coarse particle flotation operation is specifically as follows: 1) pH adjuster, inhibitor, collector and frother are sequentially added to the +0.026 mm particle size flotation slurry to obtain coarse particle size roughing concentrate and coarse particle size roughing tailings; 2) The coarse-grained rougher concentrate is subjected to three rounds of concentration after adding an inhibitor, and the concentrate finally obtained by the concentration is the first concentrate, and the middlings are sequentially returned to the previous level of operation, the inhibitor is added in the first concentration, and the other concentrations are blank concentrations; 3) Collecting agent and frother are added to the coarse-grained roughing tailings to carry out two scavenging operations, and the scavenging tailings are returned to the previous operation in sequence, and the scavenging tailings are used as tailings 1.

7. A method for improving the flotation index of fine gold ore according to claim 6, characterized in that: In step S3, when the +0.026 mm particle size is fed into the flotation slurry for roughing, the dosage of the pH adjuster is 1500-2500 g / t of the ore, the dosage of the inhibitor is 200-400 g / t of the ore, the dosage of the collector 1 and the collector 2 are 80-150 g / t of the ore and 40-80 g / t of the ore, respectively, and the dosage of the foaming agent is 20-30 g / t of the ore; The dosage of the first concentration inhibitor is 40-80g / t of raw ore; In the first scavenging, the dosage of collector 1 and collector 2 is 40-80g / t of raw ore and 20-40g / t of raw ore respectively, and the dosage of frother is 10-15g / t of raw ore; in the second scavenging, the dosage of collector 1 and collector 2 is 20-40g / t of raw ore and 10-20g / t of raw ore respectively, and the dosage of frother is 8-12g / t of raw ore.

8. A method for improving the flotation index of fine gold ore according to claim 3, characterized in that: In step S4, the fine particle flotation operation includes a roughing operation, a second cleaning operation and a scavenging operation.

9. A method for improving the flotation index of fine gold ore according to claim 8, characterized in that: In step S4, the fine particle flotation operation is specifically as follows: (1) adding a fine gold ore flotation carrier, a pH adjuster, a gangue mineral inhibitor, a gold ore collector, and a frother to a -0.026 mm particle size flotation slurry in sequence, and performing rough separation to obtain a fine-grained roughing concentrate and a fine-grained roughing tailings; (2) The fine-grained rougher concentrate is subjected to two blank concentrations to obtain concentrate 2, and the concentrated middlings are sequentially returned to the previous operation; (3) The fine-grained roughing tailings are added with a collector and a frother for a scavenging operation, and the scavenged tailings are returned to the roughing operation. After the artificial carrier is recovered by magnetic separation, the scavenged tailings are used as the second tailings.

10. A method for improving the flotation index of fine gold ore according to claim 9, characterized in that: In step S4, when the -0.026 mm particle size is put into the flotation slurry for roughing, the dosage of pH adjuster is 500-1000 g / t of raw ore, the dosage of inhibitor is 100-200 g / t of raw ore, the dosage of collector 1 and collector 2 is 40-80 g / t of raw ore and 20-40 g / t of raw ore respectively, and the dosage of foaming agent is 10-20 g / t of raw ore; The dosage of collector 1 and collector 2 in the first scavenging is 20-40g / t of raw ore and 10-20g / t of raw ore respectively, and the dosage of frother is 0-5g / t of raw ore.

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