A beneficiation method for improving the flotation index of fine-grained gold ore

Abstract

The application discloses a beneficiation method suitable for micro-fine gold ore, and belongs to the technical field of mineral processing. The method adds lignosulfonate in the grinding process, takes the grading separation process as the basis, adopts the conventional flotation process for the +0.026mm size fraction, cooperates with the new type inhibitor agent sodium ethylenediaminetetramethylene phosphonate / pectin, and recovers relatively coarse gold ore; for the micro-fine gold ore of the -0.026mm size fraction, the combination flotation of the similar mineral carrier and the artificial synthetic particle carrier is added, so that the beneficiation indexes of the micro-fine gold ore are improved. The application realizes the efficient recovery of Au in the micro-fine gold ore (the micro-fine gold ore has the Au grade of 1.8g / t-2.5g / t, the Al2O3 content of 55%-65% and the SiO2 content of 10%-20%), and gold concentrate with the Au grade of 30.52g / t and the Au recovery rate of 86.33% is obtained. The application effectively solves the technical problem that the micro-fine gold ore is difficult to be effectively recovered, and has important significance for realizing the efficient utilization of low-grade and difficult-to-treat micro-fine gold ore.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gold ore dressing, and in particular to a dressing method for improving the flotation index of micro-fine gold ore by a new type of depressant combined carrier flotation based on a grading and separation process. BACKGROUND

[0002] Gold (Ag) has been used for currency and financial reserves for a long time due to its scarcity, chemical stability and high value, and is widely used in many fields such as jewelry, electronics industry, aerospace, medical treatment, etc. Gold ore resources in China are characterized by wide distribution but uneven distribution, and various types of ore deposits, including quartz vein type gold ore, altered rock type gold ore, micro-fine disseminated type gold ore, and volcanic rock type gold ore. Although there are many gold ore deposits, there are relatively few large and super large gold ore deposits, and most of them are medium and small sized ore deposits. Moreover, the average grade of gold ore in China is relatively low, and the ore properties are complex, which increases the difficulty and cost of mining and dressing.

[0003] Micro-fine gold ore is an important part of gold ore resources. However, due to the extremely fine particle size of the gold-bearing minerals, usually less than 0.01 mm, even reaching nanometer level, it brings many challenges in the conventional flotation process, making it difficult to achieve ideal flotation index. Specifically, the micro-fine gold ore has a small particle size, a sharply increased specific surface area, and a correspondingly increased surface energy, which leads to agglomeration and non-selective adsorption in the flotation process, affecting the selectivity and efficiency of flotation. In addition, the dispersion of micro-fine gold ore in the ore pulp is poor, and local concentration gradient is easily formed, so that part of the micro-fine gold ore cannot fully contact with the flotation reagents, missing the opportunity to be recovered by flotation. At the same time, the kinetic behavior of micro-fine gold ore in the flotation process is different from that of larger particles, and it is difficult for it to overcome the energy barrier between the ore particles and the bubbles and adhere to the bubbles. In actual industrial production, in order to improve production efficiency, the flotation time is often limited, further leading to insufficient recovery of micro-fine gold ore. For example, a gold ore in Qinghai contains about 37% argillaceous minerals, which easily produces a large amount of secondary slimes during grinding, affecting the flotation recovery rate.

[0004] Therefore, it is of great significance to develop new flotation technology for micro-fine gold ore and realize efficient recovery of micro-fine gold ore for efficient utilization of refractory low-grade micro-fine gold ore. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provide a dressing method for improving the flotation index of micro-fine gold ore.

[0006] The application aims to improve the flotation index of micro-fine gold ore, and the technical scheme is as follows:

[0007] S1, grinding: the gold ore is ground to-0.074mm content accounting for 80%-85% of the mass of the flotation sample, and lignosulfonate is added during the grinding process;

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

[0009] S3, coarse size flotation: pH adjuster, depressant, collector and frother are sequentially added into the +0.026mm size grade flotation slurry for coarse size flotation operation;

[0010] S4, fine size flotation: micro-fine gold ore flotation carrier, pH adjuster, depressant, collector and frother are sequentially added into the-0.026mm size grade flotation slurry for fine size flotation operation;

[0011] The lignosulfonate is calcium lignosulfonate or sodium lignosulfonate; the micro-fine gold ore flotation carrier is composed of carrier 1 and carrier 2, carrier 1 is the tailings produced by the coarse size flotation, and carrier 2 is four-iron oxide-graphene oxide composite material or polypropylene-four-iron oxide nanocomposite material.

[0012] Further, in step S1, the lignosulfonate is used in an amount of 50-80g / t;

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

[0014] Further, the pH adjuster is sodium carbonate or sodium hydroxide; the depressant is sodium ethylenediaminetetramethylene phosphonate or pectin; the collector is composed of collector 1 and collector 2, collector 1 is ethyl xanthate, butyl xanthate or amyl xanthate; collector 2 is butylammonium black medicine or ethylthiuram disulfide; the frother is pine oil or methyl isobutyl carbinol.

[0015] Further, in step S2, the classification device is a hydrocyclone.

[0016] Further, in step S3, the coarse size flotation operation includes one roughing, three cleaning and two scavenging.

[0017] Further, in step S3, the coarse particle level flotation operation specifically includes:

[0018] 1) sequentially adding pH adjuster, depressant, collector, frother into the +0.026mm particle level flotation pulp, and roughing to obtain coarse particle level roughing concentrate and coarse particle level roughing tailings;

[0019] 2) the coarse particle level roughing concentrate is added with depressant and then subjected to three times of cleaning, and the final concentrate obtained by cleaning is concentrate one, and the middlings are sequentially returned to the previous operation, the depressant is added in the first cleaning, and the other cleanings are blank cleanings;

[0020] 3) the coarse particle level roughing tailings are added with collector and frother and subjected to two times of scavenging, the scavenging middlings are sequentially returned to the previous operation, and the scavenging tailings are tailings one;

[0021] Further, in step S3, the pH adjuster used in the roughing of the +0.026mm particle level flotation pulp is 1500-2500g / t of raw ore, the depressant is 200-400g / t of raw ore, the collector 1 and the collector 2 are 80-150g / t of raw ore and 40-80g / t of raw ore respectively, and the frother is 20-30g / t of raw ore;

[0022] The amount of the depressant used in the first cleaning is 40-80g / t of raw ore;

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

[0024] Further, in step S4, the fine particle level flotation operation includes one time of roughing, two times of cleaning and one time of scavenging.

[0025] Further, in step S4, the fine particle level flotation operation specifically includes:

[0026] (1) sequentially adding micro-fine particle gold ore flotation carrier, pH adjuster, gangue mineral depressant, gold ore collector and frother into the -0.026mm particle level flotation pulp, and roughing to obtain fine particle level roughing concentrate and fine particle level roughing tailings;

[0027] (2) the fine particle level roughing concentrate is subjected to two times of blank cleaning to obtain concentrate two, and the cleaning middlings are sequentially returned to the previous operation;

[0028] (3) the fine particle grade roughing tailings are added with a collector and a frother for once scavenging, the scavenging middlings are returned to the roughing operation, and after the artificial carrier is recovered through magnetic separation (magnetic field strength is 7800e, and the artificial carrier recovery rate is greater than 98%), the scavenging tailings are taken as tailings two.

[0029] Further, in the step S4, when the -0.026 mm particle size is floated, the pH regulator is used in an amount of 500-1000 g / t of raw ore, the depressant is used in an amount of 100-200 g / t of raw ore, the collector 1 and the collector 2 are used in amounts of 40-80 g / t of raw ore and 20-40 g / t of raw ore respectively, and the frother is used in an amount of 10-20 g / t of raw ore.

[0030] In the first scavenging, the collector 1 and the collector 2 are used in amounts of 20-40 g / t of raw ore and 10-20 g / t of raw ore respectively, and the frother is used in an amount of 0-5 g / t of raw ore.

[0031] It is worth noting that, in order to ensure the concentrate Au grade and recovery rate, based on the classification and separation process, under the action of the new depressant, the +0.026 mm particle size is subjected to conventional flotation, and the -0.026 mm particle size is subjected to combined carrier flotation.

[0032] (1) When grinding, lignosulfonate is added, which can be adsorbed on the surface of mineral particles, prevent particle agglomeration through electrostatic repulsion and steric hindrance effect, improve the grinding effect, and create good conditions for subsequent beneficiation operations such as flotation.

[0033] (2) When the +0.026 mm particle size is subjected to conventional flotation, a pH regulator is used to adjust the pulp potential; a new type of depressant, sodium ethylenediaminetetramethylene phosphonate (or pectin), is used to depress non-target minerals; and a gold-bearing mineral collector, ethyl xanthate (or butyl xanthate, pentyl xanthate), and ammonium black medicine (or ethyl thiuram sulfide), are added. Ethyl xanthate or butyl xanthate has good universal collecting ability for sulfide minerals, while ammonium black medicine (or ethyl thiuram sulfide) has good selective collecting ability for gold-bearing minerals. The combination of the two can strengthen the selective collecting ability of the gold-bearing minerals through synergistic effect, and better realize the efficient recovery of the gold-bearing minerals.

[0034] (3) When the -0.026 mm size fraction is floated, two types of carriers (coarse tailings and artificial carriers) are added. The fine-grained minerals are difficult to collide and adhere to the bubbles due to their small size and light weight, resulting in low flotation recovery. The coarse tailings can provide a surface for the fine-grained minerals to adhere to, increasing the contact opportunity between the fine-grained minerals and the bubbles, thereby improving the flotation recovery. The ferroferric oxide-graphene oxide composite has a synergistic effect with the flotation reagents. During the flotation process, the flotation reagents can interact with the functional groups on the surface of the ferroferric oxide-graphene oxide composite, enhancing the hydrophilicity or hydrophobicity of the ferroferric oxide-graphene oxide, thereby improving its selective adsorption capacity for gold particles. The polypropylene-ferroferric oxide carrier can have a high selective adsorption capacity for fine-grained gold by adjusting its surface properties and composition, and has less adsorption for other impurity minerals. In the flotation process, the flotation reagents and the carrier cooperate with each other to further improve the selectivity of flotation; the polypropylene-ferroferric oxide carrier can adsorb the flotation reagents and deliver them to the fine-grained gold, enhancing the hydrophobicity of the gold particle surface, thereby making it easier to combine with the flotation bubbles.

[0035] (4) After the carrier flotation is completed, the fine tailings (tailings two), and the ferroferric oxide has magnetic properties, which can be used to separate and recover the ferroferric oxide-graphene oxide and polypropylene-ferroferric oxide carriers using a magnetic field. The tailings two and the tailings one are combined as the total tailings.

[0036] The principle of the present application is:

[0037] During grinding, the addition of lignosulfonate can act as a grinding aid and inhibit some gangue minerals. Based on the classification and separation process, during conventional flotation of the +0.026 mm coarse size fraction, the pulp potential is adjusted by adjusting agents, and the new inhibitor sodium ethylenediaminetetramethylene phosphonate or pectin selectively disperses and inhibits non-target minerals, and the combined collector synergistically enhances the recovery of target minerals, thereby recovering the relatively coarse and easy-to-float gold minerals in the gold ore. For the flotation of the -0.026 mm size fraction of the gold ore, the coarse tailings of the +0.026 mm size fraction 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 two types of carriers are combined and added to have a synergistic effect, which enhances the hydrophobicity of the gold particle surface, thereby making it easier to combine with the flotation bubbles, and improving the flotation index of the fine-grained gold ore.

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

[0039] (1) Improving resource recovery rate

[0040] 1) The classification and separation process ensures the targeted treatment of different particle sizes of gold ore

[0041] For +0.026mm conventional flotation, by adjusting the reagent to adjust the pulp potential and the synergistic effect of new inhibitors and combined collectors, the relatively coarse embedded gold minerals in gold ore can be effectively recovered. For the flotation of-0.026mm size fraction of gold ore, coarse tailings and magnetic artificial composite materials are introduced as carriers, which synergistically enhance the binding ability of micro-fine gold ore to flotation bubbles, significantly improving the recovery rate of micro-fine gold ore.

[0042] 2) Carrier combination to expand the recovery range

[0043] Coarse tailings as the main flotation carrier provide the basis for the attachment of micro-fine gold ore, increasing its contact opportunities with the flotation system, while magnetic artificial composite materials, ferroferric oxide-graphene oxide (or polypropylene-ferroferric oxide), as the second carrier, further enhance the hydrophobicity of gold particles and their binding ability to bubbles. The use of two carrier combinations covers a wider size range, ensuring that gold minerals of different sizes are effectively recovered, thereby improving the overall recovery rate of gold resources.

[0044] (2) Improve product quality

[0045] In +0.026mm conventional flotation, new inhibitors such as ethylenediamine tetramethylene phosphonic acid sodium or pectin can selectively disperse and inhibit non-target minerals, effectively reducing the mixing of impurity minerals during flotation and improving the grade of 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 magnetic artificial composite materials on micro-fine gold ore can reduce the attachment of other impurity particles, further improving the purity of the concentrate.

[0046] (3) Reduce production costs

[0047] 1) Tailings and artificial composite materials as flotation carriers

[0048] The introduction of +0.026mm coarse tailings as a flotation carrier realizes the recycling of waste. This not only reduces the discharge and processing cost of tailings, but also reduces the demand for new carrier materials, saving resources and procurement costs.

[0049] Although magnetic artificial composite materials, ferroferric oxide-graphene oxide (or polypropylene-ferroferric oxide), may require some cost investment in the preparation process, their efficient performance and recyclability enable them to reduce production costs in the long term. These composite materials can be easily recovered and reused through magnetic separation and other methods, reducing material consumption and waste.

[0050] 2) Reduce reagent dosage

[0051] Lignosulfonate as grinding aid and partial gangue mineral depressant in the grinding process can reduce energy consumption and the need for other depressants in the grinding process. At the same time, in the flotation process, by optimizing the combination of regulators, depressants 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 improves the flotation effect while reducing the discharge of harmful chemicals to the environment. Some traditional inhibitors and collectors may contain heavy metals or toxic substances, while the reagents in the present invention are more environmentally friendly.

[0055] 2) Use of recyclable materials

[0056] The recyclability of magnetic artificial composites reduces material waste and environmental pollution. These materials can be recycled and reused after flotation through magnetic separation and other methods, reducing the demand for new resources and reducing waste. At the same time, the use of recyclable materials also conforms to the concept of circular economy, helping to promote the sustainable development of the mining industry. BRIEF DESCRIPTION OF DRAWINGS

[0057] Figure 1 is a schematic flowchart of the present invention;

[0058] Figure 2 is a schematic flowchart of Comparative Examples 1 and 2. DETAILED DESCRIPTION

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

[0060] Example 1

[0061] 1. Ore characteristics:

[0062] The gold ore in a certain area in the west of China is of arsenopyrite type, and has the following unfavorable characteristics: complex mineral composition, fine dissemination size of gold particles / carrying minerals (more than 80% of the gold particles / carrying minerals have a dissemination size less than 20 microns), and high content of clay minerals. The grade of the raw ore is 2.20 g / t, which is not high, but meets the requirements for the exploitation of rock gold under the current economic and technical conditions. The content of SiO2 in the ore is 60.28%, and the content of Al2O3 is 14.57%, indicating that the content of quartz and silicate and aluminosilicate minerals in the ore is high. The content of As in the ore is 0.31%, and the content of C is 1.10%, which can easily affect the quality of the flotation concentrate. Therefore, the gold element is the main recovery element in the raw ore. The grinding and classification process and the reagent system in the concentrator are not suitable, and the grade and recovery rate of the gold concentrate are low.

[0063] 2. Mineral processing technology:

[0064] (1) Lignin sulfonate calcium 50 g / t is added for grinding, and the ore is ground to a content of 82% of -0.074 mm. The ore slurry is classified to obtain two particle sizes of +0.026 mm and -0.026 mm.

[0065] (2) Sodium carbonate 2000 g / t of raw ore, ethylenediamine tetramethylene phosphonic acid sodium 320 g / t of raw ore, collector 1 butyl xanthate 100 g / t of raw ore, collector 2 butyl ammonium black 50 g / t of raw ore, frother methyl isobutyl carbinol 24 g / t of raw ore are added to the +0.026 mm particle size, and after mixing, rough flotation is carried out to obtain rough concentrate and rough tailings. Ethylenediamine tetramethylene phosphonic acid sodium is added to the rough concentrate for three times of cleaning to obtain concentrate one, the dosage of the depressant in the first cleaning is 40 g / t of raw ore, and the last two cleanings are blank cleanings, and the middlings in the cleanings are returned in sequence. Collector 1 butyl xanthate 50 g / t of raw ore, collector 2 butyl ammonium xanthate 30 g / t of raw ore, and frother methyl isobutyl carbinol 12 g / t of raw ore are added to the rough tailings for the first time of scavenging, collector 1 butyl xanthate 30 g / t of raw ore, collector 2 butyl ammonium xanthate 15 g / t of raw ore, and frother methyl isobutyl carbinol 10 g / t of raw ore are added to the tailings of the first time of scavenging for the second time of scavenging, and the tailings of the scavenging are tailings one.

[0066] (3) -0.026 mm fraction is added with a flotation carrier, the total dosage of the carrier is one-tenth of the -0.026 mm fraction of the ore, the dosage ratio of carrier 1 (part of the tailings one) to carrier 2 ferroferric oxide-graphene oxide is 20:1; the dosage of pH regulator sodium carbonate is 500 g / t of raw ore, the dosage of inhibitor sodium ethylenediaminetetramethylene phosphonate is 100 g / t of raw ore, the dosages of collector 1 butyl xanthate and collector 2 butyl ammonium black drug are 40 g / t of raw ore and 20 g / t of raw ore respectively, and the dosage of frother is 10 g / t of raw ore; coarse concentration of the -0.026 mm fraction is completed to obtain coarse concentrate and coarse tailings. The coarse concentrate is subjected to two times of blank concentration to obtain concentrate two; the coarse tailings are subjected to scavenging to obtain tailings two, the dosages of collector 1 butyl xanthate and collector 2 butyl ammonium black drug are 20 g / t of raw ore and 10 g / t of raw ore respectively, and the dosage of frother methyl isobutyl carbinol is 5 g / t of raw ore.

[0067] (4) The artificial carrier ferroferric oxide-graphene oxide is recovered (the magnetic field strength of the magnetic separation equipment is 780 Oe, and the recovery rate of the artificial carrier is 98.5%), and the concentrate one and the concentrate two are combined to obtain the final concentrate, and the tailings one and the tailings two are combined to obtain the final tailings.

[0068] 3. Mineral processing test index:

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

[0070] Table 1

[0071] Product name Yield (%) Au grade (g / t) Au recovery (%) Concentrate 6.21 30.52 86.33 Tails 93.79 0.32 13.67 Run-of-mine 100.00 2.20 100.00

[0072] As shown by the results in Table 1, the Au grade of the concentrate is 30.52 g / t, which is 13.90 times of the raw ore, and the recovery rate is as high as 86.33%.

[0073] Example 2

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

[0075] (1) Lignin sulfonate sodium 60 g / t is added for grinding, and the ore is ground to -0.074 mm content of 80%. The ore slurry is classified to obtain +0.026 mm and -0.026 mm fractions.

[0076] (2) +0.026 mm fraction adding pH regulator sodium hydroxide 1500 g / t of raw ore, depressant pectin 300 g / t of raw ore, collector 1 ethyl xanthate 120 g / t of raw ore, collector 2 ethyl thiocarbamate 60 g / t of raw ore, frother pine oil 20 g / t of raw ore, after conditioning, roughing flotation is carried out, and rough concentrate and rough tailings are obtained. The rough concentrate is added with depressant pectin for three times of cleaning, and concentrate one is obtained, the dosage of depressant pectin in cleaning 1 is 60 g / t of raw ore, the last two cleanings are blank cleanings, and the middlings in cleaning are returned in sequence. To the rough tailings, collector 1 ethyl xanthate 60 g / t of raw ore, collector 2 ethyl thiocarbamate 30 g / t of raw ore, and frother pine oil 12 g / t of raw ore are added, and first scavenging is carried out; to the tailings of the first scavenging, collector 1 ethyl xanthate 30 g / t of raw ore, collector 2 ethyl thiocarbamate 15 g / t of raw ore, and frother pine oil 10 g / t of raw ore are added, and second scavenging is carried out, and the tailings of the scavenging are taken as tailings one.

[0077] (3) -0.026 mm fraction adding flotation carrier, the total dosage of the carrier is one eighth of the amount of -0.026 mm fraction, the dosage ratio of carrier 1 (part of tailings one) to carrier 2 polypropylene-ferroferric oxide is 15:1; the dosage of pH regulator sodium hydroxide is 600 g / t of raw ore, the dosage of depressant pectin is 120 g / t of raw ore, the dosages of collector 1 ethyl xanthate and collector 2 ethyl thiocarbamate are 40 g / t of raw ore and 20 g / t of raw ore respectively, and the dosage of frother pine oil is 10 g / t of raw ore; -0.026 mm fraction roughing is completed, and rough concentrate and rough tailings are obtained. The rough concentrate is subjected to two times of blank cleaning, and concentrate two is obtained; the rough tailings are subjected to scavenging, and tailings two is obtained, the dosages of scavenging collector 1 and collector 2 are 20 g / t of raw ore and 10 g / t of raw ore respectively, and the dosage of frother pine oil is 2.5 g / t of raw ore.

[0078] (4) recovering artificial carrier polypropylene-ferroferric oxide (the magnetic field strength of the magnetic separation equipment is 7800e, and the recovery rate of the artificial carrier is 98.4%), and concentrate one and concentrate two are combined as final concentrate, and tailings one and tailings two are combined as final tailings.

[0079] 3, beneficiation test index:

[0080] On the basis of detailed conditional tests, good technical indexes are obtained in the closed-circuit flotation test, and the results are shown in Table 2.

[0081] Table 2

[0082] Product name Yield (%) Au grade (g / t) Au recovery (%) Concentrate 6.44 29.67 86.82 Tails 93.56 0.31 13.18 Run-of-mine 100.00 2.20 100.00

[0083] From the results of Table 2, the concentrate Au grade is 29.67 g / t, which is 13.48 times enrichment compared with the run-of-mine, and the recovery rate is as high as 86.82%. By changing the type and dosage of the flotation reagent, the Au in the ore is also well recovered by the beneficiation method.

[0084] Example 3

[0085] 1. The ore properties are the same as in Example 1, and the beneficiation process is as follows:

[0086] (1) Add 70 g / t of calcium lignosulfonate to the grinding process to grind the ore to a fineness of 85% passing 0.074 mm. Grade the slurry to obtain two size fractions, +0.026 mm and -0.026 mm.

[0087] (2) Add 1800 g / t of sodium hydroxide as a conditioning agent, 200 g / t of sodium ethylenediaminetetramethylene phosphonate as a depressant, 80 g / t of 1-amyloxycellulose as a collector 1, 40 g / t of ethylthiuram disulfide as a collector 2, and 30 g / t of methyl isobutyl carbinol as a frother to the +0.026 mm fraction, and then perform roughing flotation after conditioning. The roughing concentrate is subjected to three cleaning stages with 40 g / t of sodium ethylenediaminetetramethylene phosphonate as a depressant to obtain a concentrate 1. The two subsequent cleaning stages are blank cleaning, and the middlings are returned in sequence. Add 40 g / t of 1-amyloxycellulose as a collector 1, 20 g / t of ethylthiuram disulfide as a collector 2, and 15 g / t of methyl isobutyl carbinol as a frother to the roughing tailings, and perform a first scavenging stage. Add 20 g / t of 1-amyloxycellulose as a collector 1, 10 g / t of ethylthiuram disulfide as a collector 2, and 12 g / t of methyl isobutyl carbinol as a frother to the first scavenging tailings, and perform a second scavenging stage. The scavenging tailings are tailings 1.

[0088] (3) Add a flotation carrier to the -0.026 mm fraction, with a total carrier dosage of 10% of the -0.026 mm fraction. The dosage ratio of carrier 1 (part of tailings 1) to carrier 2 (ferroferric oxide-graphene oxide) is 8:1. Add 600 g / t of sodium hydroxide as a pH conditioner, 100 g / t of sodium ethylenediaminetetramethylene phosphonate as a depressant, 40 g / t of 1-amyloxycellulose as a collector 1, 20 g / t of ethylthiuram disulfide as a collector 2, and 20 g / t of methyl isobutyl carbinol as a frother. Complete roughing flotation of the -0.026 mm fraction to obtain a rough concentrate and a roughing tailings. The rough concentrate is subjected to two blank cleaning stages to obtain a concentrate 2. The roughing tailings are subjected to scavenging to obtain tailings 2. The scavenging dosage of 1-amyloxycellulose as a collector 1, ethylthiuram disulfide as a collector 2, and methyl isobutyl carbinol as a frother is 20 g / t, 10 g / t, and 5 g / t, respectively.

[0089] (4) Recovery of artificial carrier ferroferric oxide-graphene oxide (magnetic separation equipment is a magnetic roller, the magnetic field strength is 780 Oe, the artificial carrier recovery rate is 98.7%), concentrate one and concentrate two are combined as the final concentrate, tailings one and tailings two are combined as the final tailings.

[0090] 3. Beneficiation test index:

[0091] On the basis of detailed conditional tests, a good technical index was obtained in the closed-circuit flotation test, and the results are shown in Table 3.

[0092] Table 3

[0093]

[0094] As can be seen from the results in Table 3, the concentrate Au grade is 29.80 g / t, which is 13.54 times that of the raw ore, and the recovery rate is as high as 85.96%. By changing the type and dosage of the flotation reagent, the Au in the ore is also well recovered by the beneficiation method.

[0095] Comparative Example 1

[0096] Comparative Example 1 uses the same raw ore as Example 1, adopts a conventional grinding-flotation process, i.e., without carrying out classification separation, and the lignosulfonate is not added to the mill but is added to the flotation process, and the types of reagents for the rest of the flotation operations are the same as those in Example 1, and the dosage of each reagent is the sum of the dosages corresponding to the operations of the two particle sizes +0.026 mm and -0.026 mm in Example 1, and the flow sheet is shown in FIG. 2. Figure 2 .

[0097] Beneficiation test index:

[0098] Table 4

[0099]

[0100] As can be seen by comparing the results in Table 1 and Table 4, the Au recovery rate index of Comparative Example 1 is not as good as that of Example 1, which is 6.11 percentage points lower than that of Example 1, fully highlighting the significant effect of adding lignosulfonate to the grinding process in advance and classification separation (conventional flotation of coarse particles-carrier flotation of fine particles).

[0101] Comparative Example 2

[0102] Comparative Example 2 uses the same raw ore as Example 1 and the same grinding-flotation process, but does not add lignosulfonate, and the types of reagents for the rest of the flotation operations are the same as those in Example 1.

[0103] Beneficiation test index:

[0104] Table 5

[0105]

[0106] Comparative Example 2 has lower Au grade and Au recovery than Example 1, with Au grade being 0.98 g / t lower and Au recovery being 3.02 percentage points lower. It can be seen that the lignosulfonate can effectively improve the grinding effect and inhibit part of the gangue minerals, thus creating good conditions for flotation and other beneficiation operations.

[0107] Comparative Example 3

[0108] Comparative Example 3 uses the same raw ore as Example 1 and uses the same beneficiation process, only changing the type of depressant to carboxymethyl cellulose (CMC) with the same dosage as sodium ethylenediaminetetramethylene phosphonate in Example 1, and the rest of the flotation operation is consistent with Example 1.

[0109] Beneficiation test index:

[0110] Table 6

[0111] Product name Yield (%) Au grade (g / t) Au recovery (%) Concentrate 5.40 32.34 79.71 Tails 94.60 0.47 20.29 Run-of-mine 100.00 2.19 100.00

[0112] Comparing the results of Table 1, Table 2 and Table 6, it can be seen that the Au recovery of Comparative Example 3 is lower than that of Example 1 and Example 2, with Au recovery being 6.62 percentage points and 7.11 percentage points lower, respectively, further highlighting the significant effect of sodium ethylenediaminetetramethylene phosphonate and pectin as gangue depressants.

[0113] Comparative Example 4

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

[0115] Beneficiation test index:

[0116] Table 7

[0117] Product name Yield (%) Au grade (g / t) Au recovery (%) Concentrate 5.38 32.54 79.74 Tails 94.62 0.47 20.26 Run-of-mine 100.00 2.20 100.00

[0118] Comparing the results of Table 1 and Table 7, it can be seen that the Au recovery of Comparative Example 4 is lower than that of Example 1, with Au recovery being 6.59 percentage points lower, again highlighting the significant effect of the combination of similar mineral carriers (+0.026 mm flotation tailings 1) and synthetic carriers for flotation.

[0119] The foregoing is considered as illustrative only of the principles of the application. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the application to the exact construction and operation described. Accordingly, all such variations are intended to be included within the scope of the present application as defined in the claims below and their equivalents.

Claims

1. A beneficiation method for improving the flotation index of fine-grained gold ore, the fine-grained gold ore having a gold grade of 1.8 g / t to 2.5 g / t, an Al2O3 content of 55% to 65%, a SiO2 content of 10% to 20%, and more than 80% of gold particles / carrying gold minerals having an embedded particle size of less than 20 microns, characterized in that, The method comprises the following steps: S1, grinding: grinding the gold ore to a content of -0.074 mm of 80-85% of the mass of the flotation sample, and adding lignosulfonate in the grinding process; S2, classification: classifying the obtained ore slurry to obtain +0.026 mm and -0.026 mm two parts of the flotation slurry; S3, coarse particle flotation: sequentially adding a pH regulator, an inhibitor, a collector and a foaming agent into the +0.026 mm particle flotation slurry for coarse particle flotation operation; S4, fine particle flotation: sequentially adding a micro-fine particle gold ore flotation carrier, a pH regulator, an inhibitor, a collector and a foaming agent into the -0.026 mm particle flotation slurry for fine particle flotation operation; The lignosulfonate is calcium lignosulfonate or sodium lignosulfonate; the micro-fine particle gold ore flotation carrier is composed of carrier 1 and carrier 2, carrier 1 is the tailings produced in the coarse particle flotation, and carrier 2 is a four-iron oxide-graphene oxide composite material or a polypropylene-four-iron oxide nano composite material.

2. The mineral processing method of claim 1, wherein, In step S1, the amount of lignosulfonate is 50-80 g / t; In step S4, the total amount of the micro-fine particle gold ore flotation carrier is one-tenth to one-eighth of the amount of -0.026 mm particle ore, and the amount ratio of carrier 1 to carrier 2 is 20:1 to 10:

1.

3. The mineral processing method of claim 2, wherein the method is characterized by, The pH regulator is sodium carbonate or sodium hydroxide; the inhibitor is sodium ethylenediamine tetramethylene phosphonate or pectin; the collector is composed of collector 1 and collector 2, collector 1 is ethyl xanthate, butyl xanthate or amyl xanthate; collector 2 is butyl ammonium black medicine or ethyl thiuram disulfide; and the foaming agent is pine oil or methyl isobutyl carbinol.

4. The mineral processing method of claim 2, wherein the mineral processing method is characterized by, In step S2, the classification device is a hydrocyclone.

5. The mineral processing method of claim 3, wherein the mineral processing method is characterized by, In step S3, the coarse particle flotation operation includes one roughing, three cleaning and two scavenging.

6. The mineral processing method of improving the flotation index of fine gold particles according to claim 5, characterized in that, In step S3, the coarse particle flotation operation specifically comprises: 1) sequentially adding a pH regulator, an inhibitor, a collector and a foaming agent into the +0.026 mm particle flotation slurry to obtain coarse particle roughing concentrate and coarse particle roughing tailings; 2) the coarse particle roughing concentrate is added with an inhibitor for three cleaning, and the final concentrate obtained by cleaning is concentrate one, and the middlings are sequentially returned to the previous operation, the inhibitor is added in the first cleaning, and the other cleanings are blank cleanings; 3) the coarse particle roughing tailings are added with a collector and a foaming agent for two scavengings, and the middlings of the scavengings are sequentially returned to the previous operation, and the tailings of the scavengings are tailings one.

7. The mineral processing method of improving the flotation index of fine gold particles according to claim 6, characterized in that, In step S3, the amount of the pH regulator is 1500-2500 g / t of the raw ore, the amount of the inhibitor is 200-400 g / t of the raw ore, the amounts of collector 1 and collector 2 are 80-150 g / t of the raw ore and 40-80 g / t of the raw ore, respectively, and the amount of the foaming agent is 20-30 g / t of the raw ore when the +0.026 mm particle flotation slurry is roughed; The amount of the inhibitor in the first cleaning is 40-80 g / t of the raw ore. The first cleaning collector 1 and collector 2 are respectively used in an amount of 40-80 g / t of raw ore and 20-40 g / t of raw ore, and the foaming agent is used in an amount of 10-15 g / t of raw ore; the second cleaning collector 1 and collector 2 are respectively used in an amount of 20-40 g / t of raw ore and 10-20 g / t of raw ore, and the foaming agent is used in an amount of 8-12 g / t of raw ore.

8. The mineral processing method of improving the flotation index of fine gold particles according to claim 3, characterized in that, In step S4, the fine particle level flotation operation includes once roughing, twice cleaning and once cleaning.

9. The mineral processing method of claim 8, wherein the mineral processing method is characterized by, In step S4, the fine particle level flotation operation is specifically: (1) adding the micro-fine particle gold ore flotation carrier, the pH adjusting agent, the gangue mineral inhibitor, the gold ore collector and the foaming agent into the-0.026 mm particle level flotation ore pulp in sequence to obtain the fine particle level roughing concentrate and the fine particle level roughing tailings through roughing; (2) the fine particle level roughing concentrate is subjected to twice blank cleaning to obtain the concentrate II, and the middlings of the cleaning are sequentially returned to the previous operation; (3) the fine particle level roughing tailings are added with the collector and the foaming agent to perform once cleaning, the cleaning middlings are returned to the roughing operation, and after the artificial carrier is recovered through magnetic separation, the cleaning tailings are used as the tailings II.

10. The mineral processing method of improving the flotation index of fine gold particles according to claim 9, characterized in that, In step S4, when the-0.026 mm particle level flotation ore pulp is roughed, the pH adjusting agent is used in an amount of 500-1000 g / t of raw ore, the inhibitor is used in an amount of 100-200 g / t of raw ore, the collector 1 and the collector 2 are respectively used in an amount of 40-80 g / t of raw ore and 20-40 g / t of raw ore, and the foaming agent is used in an amount of 10-20 g / t of raw ore. The first cleaning collector 1 and collector 2 are respectively used in an amount of 20-40 g / t of raw ore and 10-20 g / t of raw ore, and the foaming agent is used in an amount of 0-5 g / t of raw ore.

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