Method for reducing fluorine content in sulfur concentrate by adopting magnetic separation-flotation combined process

Abstract

The invention relates to the technical field of mineral processing, in particular to a method for reducing fluorine content in sulfur concentrate by adopting a'magnetic separation-flotation 'combined process, which comprises the following steps: carrying out magnetic separation in advance under the condition that the magnetic field intensity of a magnetic roller is 900-1200Gs to obtain magnetic sulfur concentrate and magnetic sulfur tailings; performing one-time roughing and one-time concentration on the magnetic sulfur tailings to obtain fluorine-reduced sulfur concentrate; the method comprises the following steps: grinding the sulfur concentrate until-0.074 mm accounts for 82-85%, mechanically stirring for 15-18 minutes by adopting a high-efficiency stirring tank, and adding sodium hexametaphosphate, butyl xanthate and amyl xanthate at the same time to obtain the fluorine-reduced sulfur concentrate. Aiming at the problem that the fluorine content in the sulfur concentrate is high, the purpose of reducing the fluorine content index in the sulfur concentrate is achieved through re-grinding, mechanical stirring and reagent flotation.

Description

Technical Field

[0001] The invention relates to the technical field of mineral processing, in particular to a method for reducing the fluorine content in sulfur concentrate by adopting a "magnetic separation-flotation" combined process. Background Art

[0002] Fluoride ion is an extremely active ion that does not exist in a single state, but is produced by combining with other chemical components in the air. Under high-temperature combustion conditions, fluoride ions will be released in large quantities, causing harm to the environment and human body. Excessive fluorine content in sulfur concentrate will affect the value of the sulfur concentrate, seriously affecting the economic benefits of the enterprise. At the same time, fluorine is soluble in water and is easily discharged with mineral processing wastewater, causing great harm to drinking water and surrounding crops. During the roasting process, the high fluorine content in the sulfur concentrate will lead to low viscosity of the sintering liquid phase, and fluorine roasting will release toxic gases or produce corrosive substances, which poses a great safety hazard to the enterprise.

[0003] At present, the technology for reducing fluorine in sulfur concentrate is very lacking. Most mines use chemical precipitation and flotation defluorination methods to reduce the fluorine content in concentrate products. Among them, the chemical precipitation method is more common, that is, adding calcium ions to the product so that the fluorine ions in the product react with calcium ions to form calcium fluoride precipitates. However, calcium chloride will emulsify with the flotation minerals and flotation reagents, which will have an adverse effect on the mineral processing indicators. Flotation defluorination method is currently less studied. It has better separation effect than chemical precipitation method, and the reagents added to the slurry solution will not cause emulsification problems. Therefore, it is necessary to reduce the floatation of fluorine-containing minerals through reagents and strong external forces when flotating sulfur concentrate, thereby reducing the fluorine content in the sulfur concentrate. Summary of the invention

[0004] The object of the present invention is to provide a method for reducing the fluorine content in sulfur concentrate by adopting a combined process of "magnetic separation-flotation". The innovation lies in: (1) firstly recovering a part of the sulfur concentrate by magnetic separation to reduce the sulfur content entering flotation and reduce the sulfur selection cost; (2) after the sulfur concentrate is regrinded and the minerals are fully dispersed under strong stirring, a certain amount of dispersant is added to prevent fine particles from agglomerating together. Under the synergistic effect of mechanical strong stirring and dispersant, the mineral particles are dispersed to reduce their agglomeration, thereby reducing the entrainment of fluorine when the sulfur concentrate floats, thereby achieving the purpose of reducing the fluorine content in the sulfur concentrate.

[0005] To achieve the above purpose, the technical solution of the present invention is: a method for reducing the fluorine content in sulfur concentrate by using a "magnetic separation-flotation" combined process, the specific steps are as follows:

[0006] (1) pre-magnetically separating the magnetic sulfur concentrate at a magnetic field strength of 900-1200 Gs to obtain magnetic sulfur concentrate and magnetic sulfur tailings;

[0007] (2) The magnetic sulfur tailings are subjected to a roughing and a concentrating process to obtain a sulfur concentrate after defluorination.

[0008] Sulfuric acid is used for activation, and a combined collector of butyl xanthate 340-380 g / t + amyl xanthate 50-80 g / t is added to perform sulfur roughing, and the reaction time is at least 3 minutes to obtain a sulfur roughing concentrate product and a sulfur roughing tailing. The sulfur roughing concentrate product is then further added with a combined collector of butyl xanthate 170-190 g / t + amyl xanthate 20-40 g / t to perform a primary concentration to obtain a sulfur concentrate product, and the reaction time is at least 3 minutes. The sulfur roughing tailings are further subjected to a primary scavenging to recover selectable sulfur minerals;

[0009] (3) Sulfur concentrate "regrinding + mechanical stirring + dispersant" defluorination flotation: The sulfur concentrate is ground to -0.074mm, accounting for 82-85%. After mechanical stirring in a high-efficiency stirring tank for a certain period of time, dispersant sodium hexametaphosphate 280-320g / t and butyl xanthate 350-380g / t + amyl xanthate 50-80g / t combined collectors are added for concentration. The reaction time is at least 3 minutes to obtain defluorinated sulfur concentrate products and sulfur concentrate 1 products.

[0010] In step (2), the amount of sulfuric acid used is 8-12 kg / t, and the reaction time is at least 3 min.

[0011] In step (2), the sulfur roughing tailings are subjected to at least one blank sweep.

[0012] In step (3), a high-efficiency stirring tank is used for mechanical stirring for 15-18 minutes.

[0013] The outstanding advantages of the present invention are:

[0014] In the above scheme, a part of the sulfur concentrate is firstly recovered by the magnetic separation method, which not only reduces the sulfur content entering the flotation, but also reduces the sulfur selection cost; in addition, the mineral dispersion degree is enhanced by mechanical stirring, the agglomeration of fluorine is reduced, and the entrainment of fluorine when the sulfur concentrate floats up is reduced, and mechanical stirring is more environmentally friendly. The present invention uses the "magnetic separation-flotation" combined process to reduce the fluorine content in the sulfur concentrate, which is green, environmentally friendly, and low-cost, and has important industrial application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a flow chart of the method for reducing the fluorine content in sulfur concentrate by adopting the combined process of "magnetic separation-flotation" described in the present invention. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments.

[0017] Example 1

[0018] This embodiment is an example of the method of reducing the fluorine content in sulfur concentrate by using the combined process of "magnetic separation-flotation" described in the present invention.

[0019] Mineral Raw Materials

[0020] The sulfur concentrate of a mine in Guangdong has a fluorine content of 0.080-0.090%, which is relatively high. The sulfur concentrate is mainly pyrite, followed by pyrrhotite and a small amount of chalcopyrite; the sample contains a small amount of tungsten minerals, mainly scheelite, and a very small amount of wolframite; there are many types of gangue minerals in the sample, among which quartz, diopside, garnet, and tremolite are the main ones, followed by epidote, muscovite, biotite, phlogopite, chlorite, actinolite, plagioclase, and a small amount of calcite, limonite, zeolite, talc, etc. The sample also contains a certain amount of sulfate that is slightly soluble in water, mainly gypsum. Fluorine-containing minerals are mainly fluorite and cryolite.

[0021] The specific steps are as follows:

[0022] (1) The sulfur crude concentrate is fully stirred and evenly separated by a magnetic drum at a magnetic field strength of 1000 Gs to obtain magnetic sulfur concentrate and magnetic sulfur tailings, wherein the grade and recovery rate of fluorine in the magnetic sulfur concentrate are 0.069% and 2.89%, respectively; the grade and recovery rate of fluorine in the magnetic sulfur tailings are 0.087% and 97.11%, respectively.

[0023] (2) 10 kg / t of sulfuric acid was added to the magnetic sulfur tailings as an activating agent*, and "360 g / t of butyl xanthate + 60 g / t of amyl xanthate" was added as a combined collector to carry out a sulfur roughing test; the obtained concentrate product was then added with "180 g / t of butyl xanthate + 30 g / t of amyl xanthate" as a combined collector for another concentration to obtain a sulfur concentrate, and the obtained tailings product was scavenged, wherein the grade and recovery rate of fluorine in the sulfur concentrate were 0.051% and 15.63%, respectively, and the grade and recovery rate of fluorine in the obtained tailings were 0.10% and 81.48%, respectively.

[0024] (3) The sulfur concentrate was re-grinded to control the grinding fineness to -0.074 mm, accounting for 82%. The ground product was mechanically stirred for 15 minutes, and 300 g / t of sodium hexametaphosphate as a dispersant and "360 g / t of butyl xanthate + 60 g / t of amyl xanthate" as a combined collector were added for selection to obtain defluorinated sulfur concentrate and sulfur concentrate 1.

[0025] (4) Conduct a closed-circuit experiment on the entire process, experimental flow chart Figure 1The test results are shown in Table 1. As shown in Table 1, through the combination of sulfur concentrate magnetic levitation, sulfur concentrate regrinding-mechanical stirring and chemical agent coordinated dispersion and fluorine reduction closed-circuit test, a fluorine-reduced sulfur concentrate product with a sulfur grade of 47.69% and a fluorine grade of 0.038% and a sulfur concentrate 1 product with a sulfur grade of 47.07% and a fluorine grade of 0.53% can be obtained.

[0026] Table 1 Results of sulfur concentrate regrinding-mechanical stirring-chemical agent synergistic dispersion and defluorination test / %

[0027]

[0028] From the test results in Table 1, it can be seen that: first, a magnetic sulfur concentrate with a grade of 27.27% was obtained by magnetic separation; through mechanical stirring + dispersant, the fluorine grade in the obtained fluorine-reduced sulfur concentrate was reduced from 0.086% of the original ore to 0.038%, and the sulfur grade was as high as 47.69%, with a recovery rate of 77.00%, and a fluorine-reduced sulfur concentrate with a low fluorine content was successfully obtained.

[0029] Example 2

[0030] This embodiment is another example of the method for reducing the fluorine content in sulfur concentrate by using the combined process of "magnetic separation-flotation" described in the present invention. The mineral raw materials are the same as those in the embodiment, and the steps are as follows:

[0031] 1) The sulfur crude concentrate is fully stirred and evenly separated by a magnetic drum at a magnetic field strength of 900 Gs to obtain magnetic sulfur concentrate and magnetic sulfur tailings, wherein the grade and recovery rate of fluorine in the magnetic sulfur concentrate are 0.066% and 2.77%, respectively, and the grade and recovery rate of fluorine in the magnetic sulfur tailings are 0.083% and 96.23%, respectively.

[0032] (2) 9.0 kg / t of sulfuric acid was added to the magnetic sulfur tailings as an activator, and "340 g / t of butyl xanthate + 50 g / t of amyl xanthate" was added as a combined collector to carry out a sulfur roughing test; the obtained concentrate product was then added with "170 g / t of butyl xanthate + 20 g / t of amyl xanthate" as a combined collector for another concentration to obtain a sulfur concentrate, and the obtained tailings product was scavenged, wherein the grade and recovery rate of fluorine in the sulfur concentrate were 0.066% and 20.20%, respectively, and the grade and recovery rate of fluorine in the obtained tailings were 0.089% and 77.03%, respectively.

[0033] (3) The sulfur concentrate was re-grinded to control the grinding fineness to -0.074 mm, accounting for 82%. The ground product was mechanically stirred for 15 minutes, and a dispersant of sodium hexametaphosphate (280 g / t) and a combined collector of "butyl xanthate (350 g / t) + amyl xanthate (50 g / t)" were added to obtain defluorinated sulfur concentrate and sulfur concentrate 1.

[0034] (4) Conduct a closed-circuit experiment on the entire process, experimental flow chart Figure 1 The test results are shown in Table 1. As shown in Table 1, through the combination of sulfur concentrate magnetic levitation, sulfur concentrate regrinding-mechanical stirring and chemical agent coordinated dispersion and fluorine reduction closed-circuit test, a fluorine-reduced sulfur concentrate product with a sulfur grade of 47.73% and a fluorine grade of 0.041% and a sulfur concentrate 1 product with a sulfur grade of 47.29% and a fluorine grade of 0.55% can be obtained.

[0035] Table 2 Sulfur concentrate regrinding-mechanical stirring-chemical agent synergistic dispersion defluorination test results / %

[0036]

[0037] From the test results in Table 2, it can be seen that: first, a magnetic sulfur concentrate with a grade of 27.53% was obtained by magnetic separation; through mechanical stirring + dispersant, the fluorine grade in the obtained fluorine-reduced sulfur concentrate was reduced from 0.082% of the original ore to 0.041%, and the sulfur grade was as high as 47.73%, with a recovery rate of 73.52%, and a fluorine-reduced sulfur concentrate with a low fluorine content was successfully obtained.

[0038] Example 3

[0039] This embodiment is another example of the method for reducing the fluorine content in sulfur concentrate by using the combined process of "magnetic separation-flotation" described in the present invention. The mineral raw materials are the same as those in the embodiment, and the steps are as follows:

[0040] 1) The sulfur crude concentrate is fully stirred and evenly separated by a magnetic drum at a magnetic field strength of 1200 Gs to obtain magnetic sulfur concentrate and magnetic sulfur tailings, wherein the grade and recovery rate of fluorine in the magnetic sulfur concentrate are 0.068% and 3.02% respectively; the grade and recovery rate of fluorine in the magnetic sulfur tailings are 0.089% and 96.98% respectively.

[0041] (2) 12 kg / t of sulfuric acid was added to the magnetic sulfur tailings as an activator, and "380 g / t of butyl xanthate + 80 g / t of amyl xanthate" was added as a combined collector to carry out a sulfur roughing test; the obtained concentrate product was then added with "190 g / t of butyl xanthate + 40 g / t of amyl xanthate" as a combined collector for another concentration to obtain a sulfur concentrate, and the obtained tailings product was scavenged, wherein the grade and recovery rate of fluorine in the sulfur concentrate were 0.049% and 14.69%, respectively, and the grade and recovery rate of fluorine in the obtained tailings were 0.104% and 82.29%, respectively.

[0042] (3) The sulfur concentrate was re-grinded to control the grinding fineness to -0.074 mm, accounting for 85%. The ground product was mechanically stirred for 17 minutes. At the same time, 320 g / t of sodium hexametaphosphate as a dispersant and 370 g / t of butyl xanthate + 60 g / t of amyl xanthate as a combined collector were added to obtain defluorinated sulfur concentrate and sulfur concentrate 1.

[0043] (4) Conduct a closed-circuit experiment on the entire process, experimental flow chart Figure 1 The test results are shown in Table 1. As shown in Table 1, through the combination of sulfur concentrate magnetic levitation, sulfur concentrate regrinding-mechanical stirring and chemical agent coordinated dispersion and fluorine reduction closed-circuit test, a fluorine-reduced sulfur concentrate product with a sulfur grade of 47.59% and a fluorine grade of 0.035% and a sulfur concentrate 1 product with a sulfur grade of 47.23% and a fluorine grade of 0.58% can be obtained.

[0044] Table 3 Sulfur concentrate regrinding-mechanical stirring-chemical agent synergistic dispersion defluorination test results / %

[0045]

[0046] From the test results in Table 3, it can be seen that: first, a magnetic sulfur concentrate with a grade of 26.98% was obtained by magnetic separation; through mechanical stirring + dispersant, the fluorine grade in the obtained fluorine-reduced sulfur concentrate was reduced from 0.088% of the original ore to 0.035%, and the sulfur grade was as high as 47.59%, with a recovery rate of 77.12%, and a fluorine-reduced sulfur concentrate with a low fluorine content was successfully obtained.

Claims

1. A method for reducing the fluorine content in sulfur concentrate by using a combined process of "magnetic separation-flotation", characterized in that: The specific steps are as follows: (1) pre-magnetically separating the magnetic sulfur concentrate at a magnetic field strength of 900-1200 Gs to obtain magnetic sulfur concentrate and magnetic sulfur tailings; (2) The magnetic sulfur tailings are subjected to a roughing and a concentrating process to obtain a sulfur concentrate after defluorination. Sulfuric acid is used for activation, and a combined collector of butyl xanthate 340-380 g / t + amyl xanthate 50-80 g / t is added to perform sulfur roughing, and the reaction time is at least 3 minutes to obtain a sulfur roughing concentrate product and a sulfur roughing tailing. The sulfur roughing concentrate product is then further added with a combined collector of butyl xanthate 170-190 g / t + amyl xanthate 20-40 g / t to perform a primary concentration to obtain a sulfur concentrate product, and the reaction time is at least 3 minutes. The sulfur roughing tailings are further subjected to a primary scavenging to recover selectable sulfur minerals; (3) Sulfur concentrate "regrinding + mechanical stirring + dispersant" fluorine reduction flotation: The sulfur concentrate is ground to -0.074mm, accounting for 82-85%. After mechanical stirring in a high-efficiency stirring tank for a certain period of time, a dispersant sodium hexametaphosphate 280-320g / t and a combined collector of butyl xanthate 350-380g / t + amyl xanthate 50-80g / t are added for concentration. The reaction time is at least 3 minutes to obtain a fluorine-reduced sulfur concentrate product and a sulfur concentrate 1 product; The fluorine grade in the obtained fluorine-reduced sulfur concentrate is reduced from 0.082% to 0.088% of the original ore to 0.035% to 0.041%, and the sulfur grade is as high as 47.59% to 47.73%, with a recovery rate of 73.52% to 77.12%, thereby obtaining a fluorine-reduced sulfur concentrate with a lower fluorine content.

2. The method for reducing the fluorine content in sulfur concentrate by using the combined process of "magnetic separation-flotation" according to claim 1, characterized in that: In step (2), the amount of sulfuric acid used is 8-12 kg / t, and the reaction time is at least 3 min.

3. The method for reducing the fluorine content in sulfur concentrate by using the combined process of "magnetic separation-flotation" according to claim 1, characterized in that: In step (2), the sulfur roughing tailings are subjected to at least one blank sweep.

4. The method for reducing the fluorine content in sulfur concentrate by using the combined process of "magnetic separation-flotation" according to claim 1 is characterized in that: In step (3), a high-efficiency stirring tank is used for mechanical stirring for 15-18 minutes.

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