A method for flotation of oxygen-enriched smelting furnace slag

Abstract

The present invention discloses a method for flotation of oxygen-enriched smelting slag, which relates to the technical field of slag recovery and includes: S1. The oxygen-enriched smelting slag is successively subjected to primary crushing and secondary crushing, and then the crushed slag is conveyed to a vibrating screen to screen out qualified granular materials; S2. The qualified granular materials and water are fed into a wet ball mill, and after wet ball milling, a pulp is formed. The pulp is classified to obtain qualified pulp; S3. Sodium sulfide, a mixture of modified chitosan starch, sodium lignosulfonate, xanthate, ethyl thionocarbamate, ethyl thionamide, butylamine black medicine and pine oil are added to the qualified pulp, and copper concentrate and tailings are obtained through flotation. The beneficial effects of the present invention are as follows: 1. The method of the present invention can recover the effective components in the oxygen-enriched smelting slag, and finally produce copper concentrate and cement additive products. The grade of copper in the copper concentrate is greater than 25%, and the copper recovery rate is greater than 80%.

Description

Technical Field

[0001] The present invention relates to the technical field of slag recovery, and particularly to a method for flotation of slag from an oxygen-enriched smelting furnace. Background Art

[0002] With the rapid development of industries such as the electroplating industry, the metal surface treatment industry, and the printed circuit board industry, a large amount of copper-containing wastewater has been generated. At present, factories usually adopt neutralization precipitation treatment for such wastewater, resulting in a large amount of copper-containing sludge. If such sludge is randomly stacked, copper ions in the sludge are very likely to dissolve and enter the water body or soil again, causing secondary pollution. In addition, copper is a non-renewable resource, and if it is discarded at will, it will inevitably cause a great waste of resources. Therefore, vigorously promoting the circular economy, turning copper-containing sludge into treasure, and at the same time reducing environmental pollution is the development trend in the field of environmental protection technology and even in the field of comprehensive resource utilization.

[0003] In order to recover copper from copper-containing sludge, the applicant melts the copper-containing sludge in an oxygen-enriched smelting furnace. Through smelting, the copper in the copper-containing sludge can be converted into black copper and matte. The obtained matte and black copper can be directly sold outside, or the black copper can be used as the raw material for an anode furnace, and anode copper can be obtained through further refining. Through the above method, the copper in the copper-containing sludge can be recovered and turned into treasure.

[0004] However, when copper-containing sludge is smelted in an oxygen-enriched smelting furnace, in addition to generating black copper and matte, a large amount of slag will also be produced, that is, slag from an oxygen-enriched smelting furnace. In addition to containing about 0.7-1.2% copper, the slag from an oxygen-enriched smelting furnace also contains components such as CaO, MgO, SiO 2 If these slags are directly discarded, not only does it pose a risk of polluting the environment, but also it causes a waste of resources. Therefore, how to recover the effective components in the slag from an oxygen-enriched smelting furnace is a technical problem that needs to be solved urgently. Summary of the Invention

[0005] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and provide a method for flotation of slag from an oxygen-enriched smelting furnace, that is, the slag generated by an oxygen-enriched smelting furnace is produced by a flotation production process, and through a crushing section, a ball milling section, a flotation section, a copper concentrate dehydration and tailing treatment section, finally copper concentrate and a cement additive are produced from the slag.

[0006] The technical solution of the present invention is as follows:

[0007] A method for flotation of slag from an oxygen-enriched smelting furnace includes the following steps:

[0008] S1. First, subject the oxygen-enriched smelting slag to primary crushing and then secondary crushing. Next, convey the crushed slag to a vibrating screen to screen out qualified granular materials. Among them, the particle size of the qualified granular materials is less than 12 mm, and the unqualified granular materials are returned to primary crushing;

[0009] S2. Feed the qualified granular materials and water from step S1 into a wet ball mill. After wet ball milling, form a pulp, and classify the pulp to obtain qualified pulp;

[0010] S3. Add sodium sulfide, a mixture of modified chitosan starch, sodium lignosulfonate, xanthate, ethyl thionocarbamate, ethyl thionamide, butylamine black medicine, and pine oil to the qualified pulp in step S2. After flotation, obtain copper concentrate and tailings.

[0011] In a preferred embodiment of the present invention, step S3 specifically includes the following steps:

[0012] Feed the qualified pulp in step S2 into roughing first. The overflow from roughing enters primary cleaning. Continuing, the overflow from primary cleaning enters secondary cleaning, then the overflow from secondary cleaning enters tertiary cleaning, and finally the overflow from tertiary cleaning enters a concentrate thickener to obtain copper concentrate;

[0013] The underflow from roughing enters primary scavenging. The underflow from primary scavenging continues to enter secondary scavenging. The underflow from secondary scavenging continues to enter tertiary scavenging. The underflow from tertiary scavenging continues to enter quaternary scavenging. The underflow from quaternary scavenging enters a tailings thickener to obtain the pulp as tailings.

[0014] In a preferred embodiment of the present invention, step S3 includes the following steps:

[0015] Return the underflow from primary cleaning to roughing, return the underflow from secondary cleaning to primary cleaning, and return the underflow from tertiary cleaning to secondary cleaning.

[0016] In a preferred embodiment of the present invention, the flotation in step S3 further includes the following steps:

[0017] Return the overflow from primary scavenging to roughing, return the overflow from secondary scavenging to primary scavenging, return the overflow from tertiary scavenging to secondary scavenging, and return the overflow from quaternary scavenging to tertiary scavenging.

[0018] In a preferred embodiment of the present invention, in step S3, based on the mass of the original ore, the dosages of each reagent are as follows:

[0019] During the rough selection process, the dosage of sodium sulfide is 200 - 400 g / t, the dosage of the modified chitosan starch mixture is 200 - 400 g / t, the dosage of sodium lignosulfonate is 100 - 200 g / t, the dosage of xanthate is 50 - 100 g / t, the dosage of ethyl thionocarbamate is 50 - 100 g / t, the dosage of ethyl thionazide is 50 - 100 g / t, the dosage of butylamine black medicine is 5 - 20 g / t, and the dosage of pine oil is 5 - 20 g / t;

[0020] During the first-stage cleaning process, the dosage of sodium sulfide is 100 - 200 g / t, the dosage of the modified chitosan starch mixture is 100 - 200 g / t, the dosage of sodium lignosulfonate is 50 - 100 g / t, the dosage of xanthate is 25 - 50 g / t, the dosage of ethyl thionocarbamate is 25 - 50 g / t, the dosage of ethyl thionazide is 25 - 50 g / t, the dosage of butylamine black medicine is 2.5 - 10 g / t, and the dosage of pine oil is 2.5 - 10 g / t;

[0021] During the second-stage cleaning process, the dosage of sodium sulfide is 50 - 100 g / t, the dosage of the modified chitosan starch mixture is 50 - 100 g / t, the dosage of sodium lignosulfonate is 25 - 50 g / t, the dosage of xanthate is 12 - 25 g / t, the dosage of ethyl thionocarbamate is 12 - 25 g / t, the dosage of ethyl thionazide is 12 - 25 g / t, the dosage of butylamine black medicine is 1.25 - 5 g / t, and the dosage of pine oil is 1.25 - 5 g / t;

[0022] During the third-stage cleaning process, the dosage of sodium sulfide is 25 - 50 g / t, the dosage of the modified chitosan starch mixture is 25 - 50 g / t, the dosage of sodium lignosulfonate is 12.5 - 25 g / t, the dosage of xanthate is 6 - 12.5 g / t, the dosage of ethyl thionocarbamate is 6 - 12.5 g / t, the dosage of ethyl thionazide is 6 - 12.5 g / t, the dosage of butylamine black medicine is 0.6 - 2.5 g / t, and the dosage of pine oil is 0.6 - 2.5 g / t;

[0023] During the first-stage scavenging process, the dosage of sodium sulfide is 20 - 40 g / t, the dosage of the modified chitosan starch mixture is 20 - 40 g / t, the dosage of sodium lignosulfonate is 20 - 40 g / t, the dosage of xanthate is 6 - 10 g / t, the dosage of ethyl thionocarbamate is 6 - 10 g / t, the dosage of ethyl thionazide is 6 - 10 g / t, the dosage of butylamine black medicine is 2 - 5 g / t, and the dosage of pine oil is 2 - 5 g / t;

[0024] During the secondary scavenging process, the dosage of sodium sulfide is 10 - 20 g / t, the dosage of the modified chitosan starch mixture is 10 - 20 g / t, the dosage of sodium lignosulfonate is 10 - 20 g / t, the dosage of xanthate is 3 - 5 g / t, the dosage of ethyl thionocarbamate is 3 - 5 g / t, the dosage of ethyl thionamide is 3 - 5 g / t, the dosage of dibutyl dithiophosphate is 1 - 2.5 g / t, and the dosage of pine oil is 1 - 2.5 g / t;

[0025] During the tertiary scavenging process, the dosage of sodium sulfide is 5 - 10 g / t, the dosage of the modified chitosan starch mixture is 5 - 10 g / t, the dosage of sodium lignosulfonate is 5 - 10 g / t, the dosage of xanthate is 1.5 - 2.5 g / t, the dosage of ethyl thionocarbamate is 1.5 - 2.5 g / t, the dosage of ethyl thionamide is 1.5 - 2.5 g / t, the dosage of dibutyl dithiophosphate is 0.5 - 1.25 g / t, and the dosage of pine oil is 0.5 - 1.25 g / t;

[0026] During the quaternary scavenging process, the dosage of sodium sulfide is 2.5 - 5 g / t, the dosage of the modified chitosan starch mixture is 2.5 - 5 g / t, the dosage of sodium lignosulfonate is 2.5 - 5 g / t, the dosage of xanthate is 0.75 - 1.25 g / t, the dosage of ethyl thionocarbamate is 0.75 - 1.25 g / t, the dosage of ethyl thionamide is 0.75 - 1.25 g / t, the dosage of dibutyl dithiophosphate is 0.25 - 0.75 g / t, and the dosage of pine oil is 0.25 - 0.75 g / t.

[0027] A preferred embodiment of the present invention, the preparation method of the modified chitosan starch mixture includes:

[0028] Dissolve chitosan and modified starch in N,N - dimethylformamide, stir to obtain a dispersion phase, the concentration of the dispersion phase is 5 - 10%, then add sodium hydride to the dispersion phase, stir at 40 - 55 °C for 15 - 25 h to obtain an intermediate; add succinic anhydride to the intermediate, stir at 65 - 80 °C for 15 - 25 h, wash and dry the obtained product to prepare the modified chitosan starch mixture.

[0029] A preferred embodiment of the present invention, the preparation method of the modified starch includes: Add starch to water at a temperature of 50 - 60 °C, add a sodium hydroxide solution with a mass fraction of 1 - 2%, stir, and continue to add trimethyl ammonium chloride to react to obtain the modified starch.

[0030] A preferred embodiment of the present invention, in step S3, the qualified pulp in step S2, the raw material feeding and falling dust, the raw material crushing dust and the grinding dust are all passed through a stirring tank to adjust the pulp and mix evenly. After adjusting the pulp, first add a pH adjuster to 8 - 10, and then add the said medicament.

[0031] In a preferred embodiment of the present invention, the water content of the copper concentrate obtained in step S3 is ≤8%.

[0032] In a preferred embodiment of the present invention, the water content of the cement additive obtained in step S3 is ≤10%.

[0033] The present invention has at least one of the following beneficial effects:

[0034] 1. The method of flotation adopted in the present invention can recover the effective components in the oxygen-enriched smelting slag, and finally obtain the products of copper concentrate and cement additive. The grade of copper in the copper concentrate is greater than 25%, and the copper recovery rate is greater than 80%.

[0035] 2. The flotation section of the present invention adopts the operation of "one roughing, three cleaning, and four scavenging", which has a significant effect on recovering copper from copper smelting slag, can effectively improve the recovery rate of copper in the slag, and can control the copper content in the tailings to efficiently recover copper metal.

[0036] 3. In the flotation of the present invention, agents such as sodium sulfide, a mixture of modified chitosan starch, sodium lignosulfonate, xanthate, ethyl thionocarbamate, ethyl thionamide, butylamine black medicine, and pine oil are added. By adding the mixture of modified chitosan starch and sodium lignosulfonate, on the one hand, the dosage of sodium sulfide is reduced, thereby reducing the beneficiation cost of copper-molybdenum separation and reducing the environmental pollution caused by sodium sulfide. On the other hand, the stability and sulfidation efficiency of the sulfiding agent are improved, the surface of the copper oxide ore is modified, thereby improving the binding force between the copper ore and the collector and increasing the recovery rate of the copper concentrate; chitosan, starch, and sodium lignosulfonate, as natural modified polymers, are safe and environmentally friendly, can well improve the production environment, and eliminate the problems of harm to the human body and environmental damage caused by using a large amount of sodium sulfide or sodium cyanide as an inhibitor. And the present invention also modifies chitosan and starch, and chemically modifies and introduces characteristic functional groups into the molecular structures of starch and chitosan, which not only reduces the problem of poor selectivity of starch and chitosan, but also improves the inhibitory performance of the agent on iron minerals, reduces the loss of iron minerals, and thus increases the recovery rate of the copper concentrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is the process flow chart of the embodiment of the present invention;

[0038] Figure 2 is the process flow chart of the flotation section of the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0039] As Figure 1As shown in the figure, the present invention provides a method for flotation of oxygen-enriched smelting slag. The oxygen-enriched smelting slag, namely the slag generated during the smelting process of copper-containing sludge in an oxygen-enriched smelting furnace, adopts a flotation production process to produce copper concentrate and cement additives. Through the crushing section, ball milling section, flotation section, copper concentrate dewatering and tailings treatment section, copper concentrate and cement additive products are finally produced. The specific steps are as follows:

[0040] 1. Crushing section

[0041] The oxygen-enriched smelting slag raw materials produced by the applicant are directly transported to the flotation workshop of the expansion project by forklift nearby; after the purchased oxygen-enriched smelting slag raw materials enter the factory, they are stored in the raw material warehouse and transported to the flotation workshop of the expansion project by forklift.

[0042] After the oxygen-enriched smelting slag raw materials enter the flotation workshop, they first go through primary crushing (coarse crushing) and then are transported to secondary crushing (fine crushing) by a belt conveyor. The crushed raw materials are sent to a vibrating screen by a belt conveyor. The qualified granular materials (ore particle size less than 12 mm) under the screen enter the intermediate bin for coarse ore and serve as the raw materials for the next grinding section. The unqualified granular materials are returned to the coarse crushing for further crushing. Humid crushing is adopted during crushing, that is, water spraying is directly used while crushing, so as to reduce the generation of dust.

[0043] 2. Ball milling and classification section

[0044] This section adopts a closed-circuit wet grinding and classification form. The ore qualified after crushing in the raw material bin of the grinding bin is fed into a wet ball mill for grinding under the uniform swing of a feeder. Wet ball milling can directly add water for grinding in the ball mill. The mass ratio of the material to water is about 1:1, which can effectively avoid the generation and emission of dust. The ore constantly strikes and grinds with steel balls in the ball mill cylinder and then is discharged outside the ball mill to form pulp; after the ground raw materials are classified by a hydraulic single spiral heavy separator, the ore pulp with qualified grinding fineness enters the rough selection operation, and the underflow circulates back to the ball mill for re-grinding.

[0045] 3. Flotation section

[0046] The ground pulp and bag dust collection (including bag dust collection obtained by treating the dust from raw material feeding and discharging, raw material crushing dust and grinding dust, etc. by a bag dust collector) are uniformly stirred and adjusted in a stirring tank. After adjusting the pulp, a pH adjuster is first added to 8 - 10. The pH adjuster can be NaOH, Na 2 CO 3, such as KOH and ammonia water, and then add sodium sulfide, modified chitosan starch mixture, sodium lignosulfonate, xanthate, ethyl thionocarbamate - IPET - Z200, ethyl thionazide, butylamine black medicine and pine oil for flotation. The flotation process is to use the action of flotation agents on various mineral particles in the pulp, contact and collide with bubbles, adhere to the bubbles and carry them up to form a mineralized foam layer, separating copper ore from the pulp, and obtaining qualified copper concentrate slurry after flotation. The ratio of the material quantity to water in the flotation section is about 1:5, and the operation time is between 45 and 60 minutes.

[0047] Various agents are used during flotation to adjust the physical and chemical properties of the minerals to be selected and the flotation medium, thereby expanding the difference in the hydrophilic and hydrophobic properties of the ore, making it better sorted, and achieving the purpose of improving the metal recovery rate.

[0048] Inhibitor principle and function: When the concentration of HS - ions reaches a certain value, competitive adsorption occurs on the mineral surface, and HS - ions displace the xanthate anions that have been adsorbed on the mineral surface. The hydrophilic HS - ions themselves are adsorbed on the surface of sulfide minerals, increasing the hydrophilicity of the minerals, thus inhibiting the minerals. The solubility product of metal sulfides is smaller than that of metal xanthates. S 2- in the solution undergoes a displacement reaction with xanthate anions, displacing the xanthate, so it is inhibited. As natural modified polymers, the modified chitosan starch mixture and sodium lignosulfonate are safe and environmentally friendly. They can reduce the dosage of sodium sulfide, lower the beneficiation cost of copper - molybdenum separation, reduce the environmental pollution caused by sodium sulfide, and also improve the stability and sulfidation efficiency of sulfiding agents, thereby enhancing the binding force between copper ore and collectors and increasing the recovery rate of copper concentrate.

[0049] Collector principle and function: After collectors (xanthate, ethyl thionocarbamate - IPET - Z200 and ethyl thionazide) act on the mineral surface, because one end of the collector molecule reacts with the mineral, and the other end is hydrophobic and lipophilic, the flotation minerals. The polar collector consists of two parts: a polar group that can interact with the surface of mineral particles and a non - polar group that plays a hydrophobic role. When such a collector adsorbs on the surface of mineral particles, its molecules or ions are arranged in an orderly manner, with the polar group facing the surface of the mineral particles and the non - polar group facing outwards to form a hydrophobic film, thus making the raw material floatable.

[0050] Frother principle and function: Butylamine black medicine and pine oil are surface - active molecules with hydrophilic and hydrophobic groups. They are adsorbed directionally at the water - air interface, reducing the surface tension of the aqueous solution, making the air filled in the water easy to disperse into bubbles and stabilizing the bubbles. The frother and the collector are adsorbed together on the surface of mineral particles, causing the mineral particles to float.

[0051] Among them, the preparation method of the modified chitosan starch mixture includes:

[0052] Chitosan and modified starch are dissolved in N,N-dimethylformamide, and stirred to obtain a dispersion phase with a concentration of 5-10%. Then, sodium hydride is added to the dispersion phase, and stirred at 40-55°C for 15-25 h to obtain an intermediate. Succinic anhydride is added to the intermediate, and stirred at 65-80°C for 15-25 h. The obtained product is washed with acetone and dried to obtain a modified chitosan starch mixture.

[0053] The preparation method of the modified starch includes: adding starch into water at a temperature of 50-60°C, then adding polyethylene glycol, stirring for 1-2 h, filtering to obtain a precipitate, and drying; adding the precipitate into a sodium hydroxide solution with a mass fraction of 1-2%, stirring, and continuing to add trimethyl ammonium chloride to react to obtain the modified starch.

[0054] As Figure 2 shown, the flotation section adopts the operation of "one roughing, three cleaning and four scavenging", and the specific operation is as follows:

[0055] The standard fineness ore particles coming out of the hydraulic classifier enter the roughing. The overflow of the roughing enters the first cleaning, and the underflow enters the first scavenging; the overflow of the first scavenging and the underflow of the first cleaning are returned to the roughing together, and the underflow of the first scavenging flows to the second scavenging; the overflow of the second scavenging is returned to the first scavenging, and the underflow of the second scavenging flows to the third scavenging; the overflow of the third scavenging is returned to the second scavenging, and the underflow of the third scavenging flows to the fourth scavenging; the overflow of the fourth scavenging is returned to the third scavenging, and the underflow of the fourth scavenging enters the tailings thickener, and the discharged pulp is called tailings. The overflow of the second cleaning enters the third cleaning, and the overflow of the third cleaning enters the concentrate thickener to obtain crude copper ore, and the underflow of the third cleaning is returned to the second cleaning.

[0056] Specifically, the qualified pulp in step S2 first enters the roughing, enters the first cleaning through the overflow of the roughing, continues to enter the second cleaning through the overflow of the first cleaning, then enters the third cleaning through the overflow of the second cleaning, and finally enters the concentrate thickener through the overflow of the third cleaning to obtain copper concentrate; and the underflow of the first cleaning is returned to the roughing, the underflow of the second cleaning is returned to the first cleaning, and the underflow of the third cleaning is returned to the second cleaning;

[0057] The underflow of the roughing enters the first scavenging, the underflow of the first scavenging continues to enter the second scavenging, the underflow of the second scavenging continues to enter the third scavenging, the underflow of the third scavenging continues to enter the fourth scavenging, and the underflow of the fourth scavenging enters the tailings thickener to obtain the pulp as tailings; and the overflow of the first scavenging is returned to the roughing, the overflow of the second scavenging is returned to the first scavenging, the overflow of the third scavenging is returned to the second scavenging, and the overflow of the fourth scavenging is returned to the third scavenging.

[0058] Reagents are added during the process of "one roughing, three cleaning and four scavenging". Calculated by the mass of the raw ore, the dosages of each reagent are as follows:

[0059] During the rough selection process, the dosage of sodium sulfide is 200 - 400 g / t, the dosage of the modified chitosan starch mixture is 200 - 400 g / t, the dosage of sodium lignosulfonate is 100 - 200 g / t, the dosage of xanthate is 50 - 100 g / t, the dosage of ethyl thionocarbamate is 50 - 100 g / t, the dosage of ethyl thionazide is 50 - 100 g / t, the dosage of butylamine black medicine is 5 - 20 g / t, and the dosage of pine oil is 5 - 20 g / t;

[0060] During the first-stage fine selection process, the dosage of sodium sulfide is 100 - 200 g / t, the dosage of the modified chitosan starch mixture is 100 - 200 g / t, the dosage of sodium lignosulfonate is 50 - 100 g / t, the dosage of xanthate is 25 - 50 g / t, the dosage of ethyl thionocarbamate is 25 - 50 g / t, the dosage of ethyl thionazide is 25 - 50 g / t, the dosage of butylamine black medicine is 2.5 - 10 g / t, and the dosage of pine oil is 2.5 - 10 g / t;

[0061] During the second-stage fine selection process, the dosage of sodium sulfide is 50 - 100 g / t, the dosage of the modified chitosan starch mixture is 50 - 100 g / t, the dosage of sodium lignosulfonate is 25 - 50 g / t, the dosage of xanthate is 12 - 25 g / t, the dosage of ethyl thionocarbamate is 12 - 25 g / t, the dosage of ethyl thionazide is 12 - 25 g / t, the dosage of butylamine black medicine is 1.25 - 5 g / t, and the dosage of pine oil is 1.25 - 5 g / t;

[0062] During the third-stage fine selection process, the dosage of sodium sulfide is 25 - 50 g / t, the dosage of the modified chitosan starch mixture is 25 - 50 g / t, the dosage of sodium lignosulfonate is 12.5 - 25 g / t, the dosage of xanthate is 6 - 12.5 g / t, the dosage of ethyl thionocarbamate is 6 - 12.5 g / t, the dosage of ethyl thionazide is 6 - 12.5 g / t, the dosage of butylamine black medicine is 0.6 - 2.5 g / t, and the dosage of pine oil is 0.6 - 2.5 g / t;

[0063] During the first-stage scavenging process, the dosage of sodium sulfide is 20 - 40 g / t, the dosage of the modified chitosan starch mixture is 20 - 40 g / t, the dosage of sodium lignosulfonate is 20 - 40 g / t, the dosage of xanthate is 6 - 10 g / t, the dosage of ethyl thionocarbamate is 6 - 10 g / t, the dosage of ethyl thionazide is 6 - 10 g / t, the dosage of butylamine black medicine is 2 - 5 g / t, and the dosage of pine oil is 2 - 5 g / t;

[0064] During the secondary scavenging process, the dosage of sodium sulfide is 10 - 20 g / t, the dosage of the modified chitosan starch mixture is 10 - 20 g / t, the dosage of sodium lignosulfonate is 10 - 20 g / t, the dosage of xanthate is 3 - 5 g / t, the dosage of ethyl thionocarbamate is 3 - 5 g / t, the dosage of ethyl thionazide is 3 - 5 g / t, the dosage of butylamine black drug is 1 - 2.5 g / t, and the dosage of pine oil is 1 - 2.5 g / t;

[0065] During the tertiary scavenging process, the dosage of sodium sulfide is 5 - 10 g / t, the dosage of the modified chitosan starch mixture is 5 - 10 g / t, the dosage of sodium lignosulfonate is 5 - 10 g / t, the dosage of xanthate is 1.5 - 2.5 g / t, the dosage of ethyl thionocarbamate is 1.5 - 2.5 g / t, the dosage of ethyl thionazide is 1.5 - 2.5 g / t, the dosage of butylamine black drug is 0.5 - 1.25 g / t, and the dosage of pine oil is 0.5 - 1.25 g / t;

[0066] During the quaternary scavenging process, the dosage of sodium sulfide is 2.5 - 5 g / t, the dosage of the modified chitosan starch mixture is 2.5 - 5 g / t, the dosage of sodium lignosulfonate is 2.5 - 5 g / t, the dosage of xanthate is 0.75 - 1.25 g / t, the dosage of ethyl thionocarbamate is 0.75 - 1.25 g / t, the dosage of ethyl thionazide is 0.75 - 1.25 g / t, the dosage of butylamine black drug is 0.25 - 0.75 g / t, and the dosage of pine oil is 0.25 - 0.75 g / t.

[0067] 4. Copper concentrate concentration and filtration

[0068] The copper concentrate selected in the cleaning process of the flotation section is discharged into the thickener through a pipeline for sedimentation and concentration, and then a ceramic filter press is used for dehydration. The copper concentrate obtained after dehydration is transported to the copper concentrate product warehouse and awaits external sales. The wastewater discharged from the thickener and the dehydrator is discharged into the recycled water tank.

[0069] During the production process, to ensure that the produced copper concentrate meets the requirement of moisture content ≤ 8%, the construction unit takes regular sampling to detect the moisture content of the copper concentrate; when it is found that the moisture content of the copper concentrate is greater than 8%, it is returned to the concentration and filtration for further pressure filtration treatment until it meets the product requirements before being warehoused for sale.

[0070] 5. Tailings disposal

[0071] After the crude copper concentrate is selected in the cleaning process of the flotation section, the pulp discharged from its scavenging process is called tailings. The tailings are discharged into the thickener through a pipeline for sedimentation and concentration treatment, and then a ceramic filter press is used for dehydration. The tailings after dehydration (with moisture content ≤ 10%, by-product "cement additive") are transported to the cement additive warehouse and await external sales. The water discharged from the thickener and the dehydrator is discharged into the recycled water tank.

[0072] The tailings discharged from the final process of "one roughing, three fines and four sweeping" are treated by the process of "thickener sedimentation and concentration treatment + ceramic filter dehydration". The working principle and treatment efficiency of the thickener and ceramic filter are as follows:

[0073] Thickener: It is a solid-liquid separation equipment based on gravity sedimentation, suitable for dewatering of concentrates and tailings in ore dressing plants. Its working principle is to discharge the thickened underflow pulp from the underflow port at the bottom of the thickener with the help of a slow-running rake (1 / 3-1 / 5r / min) installed in the thickener, and produce a relatively clean clarified liquid (overflow) at the top of the thickener, which is discharged from the annular chute at the top. Its dehydration efficiency is about 40%-50%.

[0074] Ceramic filter: Ceramic filter is a new, efficient and energy-saving solid-liquid separation equipment, suitable for dehydration in mineral processing plants. The working principle of ceramic filter is based on the principle of capillary pores. It uses microporous ceramics as the filter medium. It is a solid-liquid separation equipment designed with a large number of microporous ceramics with capillary action principles. The disc filter under negative pressure working state uses the unique water-permeable and air-impermeable characteristics of the microporous ceramic filter plate to extract the vacuum in the inner cavity of the ceramic filter plate to generate a pressure difference with the outside, so that the suspended materials in the material tank are adsorbed on the ceramic filter plate under the action of negative pressure. The solid materials cannot pass through the microporous ceramic filter plate and are retained on the surface of the ceramic plate. The liquid passes smoothly into the gas-liquid distribution device (vacuum barrel) due to the vacuum pressure difference and the hydrophilicity of the ceramic filter plate, and is discharged or recycled to achieve the purpose of solid-liquid separation. Its dehydration efficiency for copper concentrate and copper tailings can reach 85% to 90%.

[0075] The present invention is further described in detail below with specific examples, but the present invention is not limited to the following specific examples.

[0076] The following examples use oxygen-enriched smelting slag produced by smelting in an oxygen-enriched smelting furnace of a certain factory as raw material. The copper grade in the oxygen-enriched smelting slag is about 1.05%.

[0077] Example 1

[0078] A flotation method for oxygen-enriched smelting slag comprises the following steps:

[0079] (1) Crushing: The oxygen-enriched smelting slag is crushed in primary and secondary crushing, and then the crushed raw materials are conveyed to the vibrating screen to screen out qualified particles, where the ore particle size of the qualified particles is less than 12 mm, and the unqualified particles are returned to the primary crushing;

[0080] (2) Ball milling: Qualified pellets and water are fed into a wet ball mill to form a slurry, which is then graded;

[0081] (3) Flotation: The process of "one roughing, three cleaning and four scavenging" is adopted. Reagents are added during the process of "one roughing, three cleaning and four scavenging". Based on the mass of the original ore, the dosages of each reagent are as follows:

[0082] During the roughing process, the dosage of sodium sulfide is 200 g / t, the dosage of the modified chitosan starch mixture is 200 g / t, the dosage of sodium lignosulfonate is 100 g / t, the dosage of xanthate is 50 g / t, the dosage of ethyl thionocarbamate is 50 g / t, the dosage of ethyl thionamide is 50 g / t, the dosage of butylamine black medicine is 5 g / t, and the dosage of pine oil is 5 g / t;

[0083] During the first-stage cleaning process, the dosage of sodium sulfide is 100 g / t, the dosage of the modified chitosan starch mixture is 100 g / t, the dosage of sodium lignosulfonate is 50 g / t, the dosage of xanthate is 25 g / t, the dosage of ethyl thionocarbamate is 25 g / t, the dosage of ethyl thionamide is 25 g / t, the dosage of butylamine black medicine is 2.5 g / t, and the dosage of pine oil is 2.5 g / t;

[0084] During the second-stage cleaning process, the dosage of sodium sulfide is 50 g / t, the dosage of the modified chitosan starch mixture is 50 g / t, the dosage of sodium lignosulfonate is 25 g / t, the dosage of xanthate is 12 g / t, the dosage of ethyl thionocarbamate is 12 g / t, the dosage of ethyl thionamide is 12 g / t, the dosage of butylamine black medicine is 1.25 g / t, and the dosage of pine oil is 1.25 g / t;

[0085] During the third-stage cleaning process, the dosage of sodium sulfide is 25 g / t, the dosage of the modified chitosan starch mixture is 25 g / t, the dosage of sodium lignosulfonate is 12.5 g / t, the dosage of xanthate is 6 g / t, the dosage of ethyl thionocarbamate is 6 g / t, the dosage of ethyl thionamide is 6 g / t, the dosage of butylamine black medicine is 0.6 g / t, and the dosage of pine oil is 0.6 g / t;

[0086] During the first-stage scavenging process, the dosage of sodium sulfide is 20 g / t, the dosage of the modified chitosan starch mixture is 20 g / t, the dosage of sodium lignosulfonate is 20 g / t, the dosage of xanthate is 6 g / t, the dosage of ethyl thionocarbamate is 6 g / t, the dosage of ethyl thionamide is 6 g / t, the dosage of butylamine black medicine is 2 g / t, and the dosage of pine oil is 2 g / t;

[0087] During the second-stage scavenging process, the dosage of sodium sulfide is 10 g / t, the dosage of the modified chitosan starch mixture is 10 g / t, the dosage of sodium lignosulfonate is 10 g / t, the dosage of xanthate is 3 g / t, the dosage of ethyl thionocarbamate is 3 g / t, the dosage of ethyl thionamide is 3 g / t, the dosage of butylamine black medicine is 1 g / t, and the dosage of pine oil is 1 g / t;

[0088] During the three-stage scavenging process, the dosage of sodium sulfide is 5 g / t, the dosage of the modified chitosan starch mixture is 5 g / t, the dosage of sodium lignosulfonate is 5 g / t, the dosage of xanthate is 1.5 g / t, the dosage of ethyl thionocarbamate is 1.5 g / t, the dosage of ethyl thionazide is 1.5 g / t, the dosage of butylamine black medicine is 0.5 g / t, and the dosage of pine oil is 0.5 g / t;

[0089] During the four-stage scavenging process, the dosage of sodium sulfide is 2.5 g / t, the dosage of the modified chitosan starch mixture is 2.5 g / t, the dosage of sodium lignosulfonate is 2.5 g / t, the dosage of xanthate is 0.75 g / t, the dosage of ethyl thionocarbamate is 0.75 g / t, the dosage of ethyl thionazide is 0.75 g / t, the dosage of butylamine black medicine is 0.25 g / t, and the dosage of pine oil is 0.25 g / t.

[0090] Among them, the preparation method of the modified chitosan starch mixture includes:

[0091] Dissolve 2 g of chitosan and 1 g of modified starch in N,N-dimethylformamide, stir to obtain a dispersion phase, the concentration of the dispersion phase is 5%, then add 10 g of sodium hydride to the dispersion phase, stir at 45 °C for 20 h to obtain an intermediate; add 12 g of succinic anhydride to the intermediate, stir at 70 °C for 20 h, and wash the obtained product with acetone and then dry it to obtain the modified chitosan starch mixture.

[0092] The preparation method of the modified starch includes: Add 50 g of starch to 50 mL of water at 50 °C, add it to 4 g of a sodium hydroxide solution with a mass fraction of 1%, stir, and continue to add 5 g of trimethylammonium chloride, and react at a temperature of 50 °C to obtain the modified starch.

[0093] (4) Copper concentrate concentration and filtration: The copper concentrate slurry is concentrated and dehydrated to obtain copper concentrate;

[0094] (5) Tailings disposal: The tailings slurry is concentrated and dehydrated to obtain a cement additive.

[0095] Example 2

[0096] A method for flotation of oxygen-enriched smelting furnace slag, comprising the following steps:

[0097] (1) Crushing: The oxygen-enriched smelting furnace slag is successively subjected to primary crushing and secondary crushing, and then the crushed raw material is conveyed to a vibrating screen to screen out qualified granular materials. Among them, the particle size of the qualified granular materials is less than 12 mm, and the unqualified granular materials are returned to primary crushing;

[0098] (2) Ball milling: Feed the qualified granular materials and water into a wet ball mill, form a slurry through wet ball milling, and classify the slurry;

[0099] (3) Flotation: The process of "one roughing, three cleanings, and four scavengings" is adopted. Reagents are added during the "one roughing, three cleanings, and four scavengings" process. Based on the mass of the original ore, the dosages of each reagent are as follows:

[0100] During the roughing process, the dosage of sodium sulfide is 300 g / t, the dosage of the modified chitosan starch mixture is 300 g / t, the dosage of sodium lignosulfonate is 150 g / t, the dosage of xanthate is 75 g / t, the dosage of ethyl thionocarbamate is 75 g / t, the dosage of ethyl thionamide is 75 g / t, the dosage of butylamine black medicine is 12.5 g / t, and the dosage of pine oil is 12.5 g / t;

[0101] During the first-stage cleaning process, the dosage of sodium sulfide is 150 g / t, the dosage of the modified chitosan starch mixture is 150 g / t, the dosage of sodium lignosulfonate is 75 g / t, the dosage of xanthate is 37.5 g / t, the dosage of ethyl thionocarbamate is 37.5 g / t, the dosage of ethyl thionamide is 37.5 g / t, the dosage of butylamine black medicine is 6 g / t, and the dosage of pine oil is 6.5 g / t;

[0102] During the second-stage cleaning process, the dosage of sodium sulfide is 75 g / t, the dosage of the modified chitosan starch mixture is 75 g / t, the dosage of sodium lignosulfonate is 37.5 g / t, the dosage of xanthate is 18.5 g / t, the dosage of ethyl thionocarbamate is 18.5 g / t, the dosage of ethyl thionamide is 18.55 g / t, the dosage of butylamine black medicine is 3 g / t, and the dosage of pine oil is 3.5 g / t;

[0103] During the third-stage cleaning process, the dosage of sodium sulfide is 37.5 g / t, the dosage of the modified chitosan starch mixture is 37.5 g / t, the dosage of sodium lignosulfonate is 9.25 g / t, the dosage of xanthate is 9.25 g / t, the dosage of ethyl thionocarbamate is 9.25 g / t, the dosage of ethyl thionamide is 9.25 g / t, the dosage of butylamine black medicine is 1.5 g / t, and the dosage of pine oil is 1.5 g / t;

[0104] During the first-stage scavenging process, the dosage of sodium sulfide is 30 g / t, the dosage of the modified chitosan starch mixture is 30 g / t, the dosage of sodium lignosulfonate is 30 g / t, the dosage of xanthate is 8 g / t, the dosage of ethyl thionocarbamate is 8 g / t, the dosage of ethyl thionamide is 8 g / t, the dosage of butylamine black medicine is 3.5 g / t, and the dosage of pine oil is 3.5 g / t;

[0105] During the second-stage scavenging process, the dosage of sodium sulfide is 15 g / t, the dosage of the modified chitosan starch mixture is 15 g / t, the dosage of sodium lignosulfonate is 15 g / t, the dosage of xanthate is 4 g / t, the dosage of ethyl thionocarbamate is 4 g / t, the dosage of ethyl thionamide is 4 g / t, the dosage of butylamine black medicine is 1.75 g / t, and the dosage of pine oil is 1.75 g / t;

[0106] During the third-stage scavenging process, the dosage of sodium sulfide is 7.5 g / t, the dosage of the modified chitosan starch mixture is 7.5 g / t, the dosage of sodium lignosulfonate is 7.50 g / t, the dosage of xanthate is 2 g / t, the dosage of ethyl thionocarbamate is 2 g / t, the dosage of ethyl thionamide is 2 g / t, the dosage of dibutyl dithiophosphate is 0.8 g / t, and the dosage of pine oil is 0.8 g / t;

[0107] During the fourth-stage scavenging process, the dosage of sodium sulfide is 3.75 g / t, the dosage of the modified chitosan starch mixture is 3.75 g / t, the dosage of sodium lignosulfonate is 3.75 g / t, the dosage of xanthate is 1 g / t, the dosage of ethyl thionocarbamate is 1 g / t, the dosage of ethyl thionamide is 1 g / t, the dosage of dibutyl dithiophosphate is 0.5 g / t, and the dosage of pine oil is 0.5 g / t.

[0108] Among them, the preparation method of the modified chitosan starch mixture includes:

[0109] Dissolve 2 g of chitosan and 1 g of modified starch in N,N-dimethylformamide, stir to obtain a dispersion phase, the concentration of the dispersion phase is 5%, then add 10 g of sodium hydride to the dispersion phase, stir at 45 °C for 20 h to obtain an intermediate; add 12 g of succinic anhydride to the intermediate, stir at 70 °C for 20 h, and wash the obtained product with acetone and then dry it to obtain the modified chitosan starch mixture.

[0110] The preparation method of the modified starch includes: Add 50 g of starch to 50 mL of water at 50 °C, add it to 4 g of a 1% sodium hydroxide solution, stir, and continue to add 5 g of trimethylammonium chloride, with a reaction temperature of 50 °C to obtain the modified starch.

[0111] (4) Copper concentrate concentration and filtration: The copper concentrate slurry is concentrated and dehydrated to obtain copper concentrate;

[0112] (5) Tailings disposal: The tailings slurry is concentrated and dehydrated to obtain a cement additive.

[0113] Example 3

[0114] A method for flotation of oxygen-enriched smelting furnace slag, comprising the following steps:

[0115] (1) Crushing: The oxygen-enriched smelting furnace slag is successively subjected to primary crushing and secondary crushing, and then the crushed raw material is transported to a vibrating screen to screen out qualified granular materials. Among them, the particle size of the qualified granular materials is less than 12 mm, and the unqualified granular materials are returned to primary crushing;

[0116] (2) Ball milling: Feed the qualified granular materials and water into a wet ball mill, form a slurry through wet ball milling, and classify the slurry;

[0117] (3) Flotation: The process of "one roughing, three cleanings, and four scavengings" is adopted. Reagents are added during the process of "one roughing, three cleanings, and four scavengings". Based on the mass of the original ore, the dosages of each reagent are as follows:

[0118] During the roughing process, the dosage of sodium sulfide is 400 g / t, the dosage of the modified chitosan starch mixture is 400 g / t, the dosage of sodium lignosulfonate is 200 g / t, the dosage of xanthate is 100 g / t, the dosage of ethyl thionocarbamate is 100 g / t, the dosage of ethyl thionamide is 100 g / t, the dosage of dibutyl dithiophosphate is 20 g / t, and the dosage of pine oil is 20 g / t;

[0119] During the first-stage cleaning process, the dosage of sodium sulfide is 200 g / t, the dosage of the modified chitosan starch mixture is 200 g / t, the dosage of sodium lignosulfonate is 100 g / t, the dosage of xanthate is 50 g / t, the dosage of ethyl thionocarbamate is 50 g / t, the dosage of ethyl thionamide is 50 g / t, the dosage of dibutyl dithiophosphate is 10 g / t, and the dosage of pine oil is 10 g / t;

[0120] During the second-stage cleaning process, the dosage of sodium sulfide is 100 g / t, the dosage of the modified chitosan starch mixture is 100 g / t, the dosage of sodium lignosulfonate is 50 g / t, the dosage of xanthate is 25 g / t, the dosage of ethyl thionocarbamate is 25 g / t, the dosage of ethyl thionamide is 25 g / t, the dosage of dibutyl dithiophosphate is 5 g / t, and the dosage of pine oil is 5 g / t;

[0121] During the third-stage cleaning process, the dosage of sodium sulfide is 50 g / t, the dosage of the modified chitosan starch mixture is 50 g / t, the dosage of sodium lignosulfonate is 25 g / t, the dosage of xanthate is 12.5 g / t, the dosage of ethyl thionocarbamate is 12.5 g / t, the dosage of ethyl thionamide is 12.5 g / t, the dosage of dibutyl dithiophosphate is 2.5 g / t, and the dosage of pine oil is 2.5 g / t;

[0122] During the first-stage scavenging process, the dosage of sodium sulfide is 40 g / t, the dosage of the modified chitosan starch mixture is 40 g / t, the dosage of sodium lignosulfonate is 40 g / t, the dosage of xanthate is 10 g / t, the dosage of ethyl thionocarbamate is 10 g / t, the dosage of ethyl thionamide is 10 g / t, the dosage of dibutyl dithiophosphate is 5 g / t, and the dosage of pine oil is 5 g / t;

[0123] During the second-stage scavenging process, the dosage of sodium sulfide is 20 g / t, the dosage of the modified chitosan starch mixture is 20 g / t, the dosage of sodium lignosulfonate is 20 g / t, the dosage of xanthate is 5 g / t, the dosage of ethyl thionocarbamate is 5 g / t, the dosage of ethyl thionamide is 5 g / t, the dosage of dibutyl dithiophosphate is 2.5 g / t, and the dosage of pine oil is 2.5 g / t;

[0124] During the three-stage scavenging process, the dosage of sodium sulfide is 10 g / t, the dosage of the modified chitosan starch mixture is 10 g / t, the dosage of sodium lignosulfonate is 10 g / t, the dosage of xanthate is 2.5 g / t, the dosage of ethyl thionocarbamate is 2.5 g / t, the dosage of ethyl thionazide is 2.5 g / t, the dosage of dibutyl dithiophosphate is 1.25 g / t, and the dosage of pine oil is 1.25 g / t;

[0125] During the four-stage scavenging process, the dosage of sodium sulfide is 5 g / t, the dosage of the modified chitosan starch mixture is 5 g / t, the dosage of sodium lignosulfonate is 5 g / t, the dosage of xanthate is 1.25 g / t, the dosage of ethyl thionocarbamate is 1.25 g / t, the dosage of ethyl thionazide is 1.25 g / t, the dosage of dibutyl dithiophosphate is 0.75 g / t, and the dosage of pine oil is 0.75 g / t.

[0126] Among them, the preparation method of the modified chitosan starch mixture includes:

[0127] Dissolve 2 g of chitosan and 1 g of modified starch in N,N-dimethylformamide, stir to obtain a dispersion phase, the concentration of the dispersion phase is 5%, then add 10 g of sodium hydride to the dispersion phase, stir at 45 °C for 20 h to obtain an intermediate; add 12 g of succinic anhydride to the intermediate, stir at 70 °C for 20 h, and wash the obtained product with acetone and then dry it to obtain the modified chitosan starch mixture.

[0128] The preparation method of the modified starch includes: add 50 g of starch to 50 mL of water at 50 °C, add it to 4 g of a sodium hydroxide solution with a mass fraction of 1%, stir, and continue to add 5 g of trimethyl ammonium chloride, and react at a temperature of 50 °C to obtain the modified starch.

[0129] (4) Copper concentrate concentration and filtration: The copper concentrate slurry is concentrated and dehydrated to obtain copper concentrate;

[0130] (5) Tailings disposal: The tailings slurry is concentrated and dehydrated to obtain a cement additive.

[0131] Comparative Example 1

[0132] The difference from Example 1 is that: in the flotation section ("one roughing, three cleaning, and four scavenging"), neither the modified chitosan starch mixture nor the sodium lignosulfonate reagent is added, and the others are the same as in Example 1.

[0133] Comparative Example 2

[0134] The difference from Example 1 is that: the flotation section only performs "one roughing, one cleaning, and one scavenging", and the others are the same as in Example 1.

[0135] Comparative Example 3

[0136] The difference from Example 1 is that in the flotation section, only "one roughing, two cleaning, and two scavenging" are carried out, and the rest is the same as in Example 1.

[0137] Test:

[0138] The copper grade and recovery rate in the copper concentrates obtained from Examples 1 to 3 and Comparative Examples 1 to 3 were detected, and the results are shown in Table 1.

[0139] Table 1

[0140] Grade of copper in copper concentrate Copper recovery rate Example 1 Approximately equal to 25.5% Approximately equal to 81% Example 2 Approximately equal to 28.7% Approximately equal to 85% Example 3 Approximately equal to 32.2% Approximately equal to 88% Comparative Example 1 Approximately equal to 8.5% Approximately equal to 62% Comparative Example 2 Approximately equal to 19.4% Approximately equal to 71% Comparative Example 3 Approximately equal to 21.8% Approximately equal to 75%

[0141] As can be seen from Table 1, the copper grade in the copper concentrates of Examples 1 to 3 is about 25 - 32%, and the copper recovery rate is about 81 - 88%. Therefore, the copper recovery effect of the present invention is remarkable, and it can efficiently recover copper metal in the slag, increasing economic benefits for the enterprise. Comparing Examples 1 to 3 with Comparative Examples 1 to 3, the copper grade and copper recovery rate in the copper concentrates of Examples 1 to 3 are both greater than those of Comparative Examples 1 to 3. This shows that whether to add the medicament-modified chitosan starch mixture and sodium lignosulfonate and the flotation method will affect the grade and recovery rate of copper concentrates. The present invention can effectively recover copper in the slag by using the medicament-modified chitosan starch mixture and sodium lignosulfonate together with sodium sulfide, xanthate, ethyl thionocarbamate, ethyl thionamide, butylamine black medicine, and pine oil, and adopting the flotation method of "one roughing, three cleaning, and four scavenging".

[0142] As mentioned above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A method for flotation of oxygen-enriched smelting furnace slag, characterized in that, it comprises the following steps: S1. The oxygen-enriched smelting furnace slag is successively subjected to primary crushing and secondary crushing, and then the crushed furnace slag is conveyed to a vibrating screen, and qualified granular materials are screened out. Among them, the particle size of the qualified granular materials is less than 12 mm, and the unqualified granular materials are returned to primary crushing; S2. The qualified granular materials and water in step S1 are fed into a wet ball mill, and after wet ball milling, a pulp is formed. The pulp is classified to obtain qualified pulp; S3. Sodium sulfide, a mixture of modified chitosan starch, sodium lignosulfonate, xanthate, ethyl thionocarbamate, ethyl thionamide, butylamine black medicine and pine oil are added to the qualified pulp in step S2, and copper concentrate and tailings are obtained through flotation; Among them, the preparation method of the modified chitosan starch mixture includes: Dissolve chitosan and modified starch in N,N-dimethylformamide, stir to obtain a dispersion phase, and the concentration of the dispersion phase is 5-10%. Then add sodium hydride to the dispersion phase and stir at 40-55 °C for 15-25 h to obtain an intermediate; add succinic anhydride to the intermediate and stir at 65-80 °C for 15-25 h, and wash and dry the obtained product to prepare the modified chitosan starch mixture; The preparation method of the modified starch includes: adding starch to water at a temperature of 50-60 °C, adding a sodium hydroxide solution with a mass fraction of 1-2%, stirring, and continuing to add trimethylammonium chloride to react to obtain modified starch.

2. A method for flotation of oxygen-enriched smelting furnace slag according to claim 1, characterized in that, step S3 specifically includes the following steps: The qualified pulp in step S2 first enters rough selection, and the overflow from rough selection enters first-stage cleaning. Continuing, the overflow from the first-stage cleaning enters second-stage cleaning, and then the overflow from the second-stage cleaning enters third-stage cleaning. Finally, the overflow from the third-stage cleaning enters a concentrate thickener to obtain copper concentrate; The underflow from rough selection enters first-stage scavenging, the underflow from the first-stage scavenging continues to enter second-stage scavenging, the underflow from the second-stage scavenging continues to enter third-stage scavenging, the underflow from the third-stage scavenging continues to enter fourth-stage scavenging, and the underflow from the fourth-stage scavenging enters a tailings thickener to obtain the pulp as tailings.

3. A method for flotation of oxygen-enriched smelting furnace slag according to claim 2, characterized in that, the flotation in step S3 further includes the following steps: Return the underflow from the first-stage cleaning to rough selection, return the underflow from the second-stage cleaning to the first-stage cleaning, and return the underflow from the third-stage cleaning to the second-stage cleaning.

4. A method for flotation of oxygen-enriched smelting furnace slag according to claim 2, characterized in that, step S3 further includes the following steps: Return the overflow from the first-stage scavenging to rough selection, return the overflow from the second-stage scavenging to the first-stage scavenging, return the overflow from the third-stage scavenging to the second-stage scavenging, and return the overflow from the fourth-stage scavenging to the third-stage scavenging.

5. A method for flotation of oxygen-enriched smelting furnace slag according to claim 2, characterized in that, in step S3, based on the mass of the original ore, the dosages of each reagent are respectively: During the rough selection process, the dosage of sodium sulfide is 200 - 400 g / t, the dosage of the modified chitosan starch mixture is 200 - 400 g / t, the dosage of sodium lignosulfonate is 100 - 200 g / t, the dosage of xanthate is 50 - 100 g / t, the dosage of ethyl thionocarbamate is 50 - 100 g / t, the dosage of ethyl thionazide is 50 - 100 g / t, the dosage of butylamine black drug is 5 - 20 g / t, and the dosage of pine oil is 5 - 20 g / t; During the first-stage cleaning process, the dosage of sodium sulfide is 100 - 200 g / t, the dosage of the modified chitosan starch mixture is 100 - 200 g / t, the dosage of sodium lignosulfonate is 50 - 100 g / t, the dosage of xanthate is 25 - 50 g / t, the dosage of ethyl thionocarbamate is 25 - 50 g / t, the dosage of ethyl thionazide is 25 - 50 g / t, the dosage of butylamine black drug is 2.5 - 10 g / t, and the dosage of pine oil is 2.5 - 10 g / t; During the second-stage cleaning process, the dosage of sodium sulfide is 50 - 100 g / t, the dosage of the modified chitosan starch mixture is 50 - 100 g / t, the dosage of sodium lignosulfonate is 25 - 50 g / t, the dosage of xanthate is 12 - 25 g / t, the dosage of ethyl thionocarbamate is 12 - 25 g / t, the dosage of ethyl thionazide is 12 - 25 g / t, the dosage of butylamine black drug is 1.25 - 5 g / t, and the dosage of pine oil is 1.25 - 5 g / t; During the third-stage cleaning process, the dosage of sodium sulfide is 25 - 50 g / t, the dosage of the modified chitosan starch mixture is 25 - 50 g / t, the dosage of sodium lignosulfonate is 12.5 - 25 g / t, the dosage of xanthate is 6 - 12.5 g / t, the dosage of ethyl thionocarbamate is 6 - 12.5 g / t, the dosage of ethyl thionazide is 6 - 12.5 g / t, the dosage of butylamine black drug is 0.6 - 2.5 g / t, and the dosage of pine oil is 0.6 - 2.5 g / t; During the first-stage scavenging process, the dosage of sodium sulfide is 20 - 40 g / t, the dosage of the modified chitosan starch mixture is 20 - 40 g / t, the dosage of sodium lignosulfonate is 20 - 40 g / t, the dosage of xanthate is 6 - 10 g / t, the dosage of ethyl thionocarbamate is 6 - 10 g / t, the dosage of ethyl thionazide is 6 - 10 g / t, the dosage of butylamine black drug is 2 - 5 g / t, and the dosage of pine oil is 2 - 5 g / t; During the second-stage scavenging process, the dosage of sodium sulfide is 10 - 20 g / t, the dosage of the modified chitosan starch mixture is 10 - 20 g / t, the dosage of sodium lignosulfonate is 10 - 20 g / t, the dosage of xanthate is 3 - 5 g / t, the dosage of ethyl thionocarbamate is 3 - 5 g / t, the dosage of ethyl thionazide is 3 - 5 g / t, the dosage of butylamine black drug is 1 - 2.5 g / t, and the dosage of pine oil is 1 - 2.5 g / t; During the three-stage scavenging process, the dosage of sodium sulfide is 5 - 10 g / t, the dosage of the modified chitosan starch mixture is 5 - 10 g / t, the dosage of sodium lignosulfonate is 5 - 10 g / t, the dosage of xanthate is 1.5 - 2.5 g / t, the dosage of ethyl thionocarbamate is 1.5 - 2.5 g / t, the dosage of ethyl thionamide is 1.5 - 2.5 g / t, the dosage of butylamine black drug is 0.5 - 1.25 g / t, and the dosage of pine oil is 0.5 - 1.25 g / t; During the four-stage scavenging process, the dosage of sodium sulfide is 2.5 - 5 g / t, the dosage of the modified chitosan starch mixture is 2.5 - 5 g / t, the dosage of sodium lignosulfonate is 2.5 - 5 g / t, the dosage of xanthate is 0.75 - 1.25 g / t, the dosage of ethyl thionocarbamate is 0.75 - 1.25 g / t, the dosage of ethyl thionamide is 0.75 - 1.25 g / t, the dosage of butylamine black drug is 0.25 - 0.75 g / t, and the dosage of pine oil is 0.25 - 0.75 g / t.

6. A method for flotation of oxygen-enriched smelting furnace slag according to claim 1, characterized in that, In step S3, the qualified pulp in step S2, together with the raw material feeding and dropping dust, raw material crushing dust and grinding dust, is uniformly mixed through a stirring tank. After pulp mixing, first add a pH adjuster to 8 - 10, and then add the corresponding flotation reagents.

7. A method for flotation of oxygen-enriched smelting furnace slag according to claim 1, characterized in that, The moisture content of the copper concentrate obtained in step S3 is ≤8%.

8. A method for flotation of oxygen-enriched smelting furnace slag according to claim 1, characterized in that, The moisture content of the cement additive obtained in step S3 is ≤10%.

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