A method for grading and quality-based treatment and resource utilization of asbestos tailings

Abstract

The present invention belongs to the technical field of solid waste treatment and resource utilization, and specifically relates to a method for asbestos tailings treatment and resource utilization. The present invention uses multi-stage crushing and screening sorting technology to treat asbestos tailings. On the basis of preparing stones of different particle sizes and machine-made sand, the tailings are ground and slurried for magnetic separation to recover iron concentrate; a collector, a foaming agent and a promoter are added to the magnetic separation tailings liquid, and flotation is performed after slurry adjustment to recover asbestos concentrate; the flotation tailings are further processed to obtain a cementitious material. The present invention uses a physical processing method to treat asbestos tailings, realizes the effective recovery and utilization of useful components in the asbestos tailings, and achieves low-carbon green treatment of asbestos tailings and resource utilization of all components.

Description

Technical Field

[0001] The invention belongs to the field of solid waste treatment and resource utilization, and specifically relates to a method for grading and quality-based treatment and resource utilization of asbestos tailings. Background Art

[0002] Asbestos, also known as asbestos fiber, has high tensile strength, high flexibility, resistance to chemical and thermal corrosion, good electrical insulation and spinnability. Therefore, it has been widely used in steel metallurgy, building materials industry, non-ferrous metals, chemical industry, environmental protection, military industry, aerospace and other fields.

[0003] Asbestos comes from the sorting and processing of asbestos mines. Common asbestos mines include serpentine asbestos mines, tremolite asbestos mines, amphibole asbestos mines, pyrophyllite asbestos mines and brucite asbestos mines. A large amount of asbestos tailings and other by-products will be produced during the mining and sorting process of asbestos mines. In addition to asbestos mines, asbestos tailings also contain serpentine, magnetite, quartz and other minerals. The chemical composition mainly includes SiO2 (35% to 45%), MgO (35% to 42%) and a small amount of Fe2O3, CaO, NiO, TiO2, etc. At present, asbestos tailings are mostly disposed of by stockpiling and simple treatment and backfilling. Since asbestos tailings contain fibers, they will cause certain harm to the ecological environment and health of residents in the mining area and surrounding areas. Therefore, it is very necessary to safely handle and recycle asbestos tailings.

[0004] To this end, researchers have conducted research on the resource utilization technology of asbestos tailings, attempting to drive the reduction and harmlessness of asbestos tailings through effective resource utilization. For example, Chinese patent CN113843257A discloses pre-treating asbestos tailings to obtain materials with a particle size of less than 150 mm, and then calcining them at a temperature of 650℃ to 1350℃ for 2min to 1.5h to obtain non-asbestos materials after phase inversion and detoxification, which can be used as building sand and gravel aggregates, fillers or fireproof materials. Chinese patent CN114057205A discloses that after crushing asbestos tailings to 300-400 mesh, the magnetic iron is separated with water, and then 1.2 times of concentrated sulfuric acid is added, stirred for 20 minutes and then leached with water. One ton of asbestos tailings can obtain about 100kg of Fe3O4 with a purity of 65%, about 800kg of sodium silicate with a purity of 30%-40%, 150-200kg of cement additives, and about 1000kg of magnesium sulfate with a purity of 90%. Chinese patent CN114524441A discloses a method of freezing and activating serpentine and asbestos tailings under negative pressure conditions, followed by alkaline leaching treatment and solid-liquid separation to obtain silicon leachate and magnesium oxide. It can be seen that the existing treatments often require calcination of asbestos tailings or leaching with acid-base solutions, which is prone to secondary pollution. Summary of the invention

[0005] In view of this, the present invention provides a method for grading and quality-based treatment and resource utilization of asbestos tailings. The present invention utilizes a physical processing method combining multi-stage crushing, screening and sorting, magnetic separation, and flotation to treat asbestos tailings, thereby achieving cascade recovery of asbestos tailings and clean resource utilization of all components.

[0006] In order to solve the above technical problems, the present invention provides a method for grading and quality-based treatment and resource utilization of asbestos tailings, comprising the following steps:

[0007] The asbestos tailings are crushed in the first stage, and the first screening is performed using a double-layer screen with mesh sizes of 50 mm and 0.5 mm to obtain materials with a particle size of 0.5 to 50 mm and a first tailing ore with a particle size of less than 0.5 mm;

[0008] The material with a particle size of 0.5 to 50 mm is crushed in the second stage, and a double-layer sieve with sieve holes of 31.5 mm and 0.5 mm is used for the second screening to obtain a material with a particle size of 0.5 to 31.5 mm and a second tailing ore with a particle size of less than 0.5 mm;

[0009] The material with a particle size of 0.5 to 31.5 mm is crushed at level III, and a multi-layer screen with mesh sizes of 0.5 mm, 4.76 mm, 10 mm and 15 mm is used for the third screening to obtain 1-3 stones, 1-2 stones, 5-1 stones, machine-made sand and a third tailing ore with a particle size of less than 0.5 mm; the particle size of the machine-made sand is 0.5 to 4.76 mm;

[0010] The first tail ore, the second tail ore and the third tail ore are mixed and ground to obtain tail ore powder, wherein the particle size of the tail ore powder is -74 μm;

[0011] The tailings powder is pulped and then subjected to magnetic separation to obtain iron concentrate and magnetic separation tailings liquid respectively;

[0012] Adding a flotation agent to the magnetic separation tailings liquid, mixing thoroughly, and then slurrying for flotation to obtain asbestos concentrate and flotation tailings liquid respectively;

[0013] The flotation tailings liquid is post-processed to obtain a gelled material.

[0014] Preferably, the pulping comprises the following steps:

[0015] The tail ore powder and water are mixed to obtain slurry; the mixing method includes mechanical stirring or ultrasonic oscillation.

[0016] Preferably, the speed of the mechanical stirring is 200 to 3000 r / min; the time of the mechanical stirring is 5 to 20 min;

[0017] The frequency of the ultrasonic oscillation is ≥20kHz, and the power density of the ultrasonic oscillation is ≥0.35W / cm 2 ; The ultrasonic oscillation time is 8 to 25 minutes.

[0018] Preferably, the magnetic separation is wet magnetic separation, and the magnetic field strength used in the magnetic separation is ≤1.0T; the time of the magnetic separation is 1 to 10 minutes.

[0019] Preferably, the flotation reagent includes a collector, a frother and a promoter.

[0020] Preferably, the collector comprises dodecylamine and / or octadecylamine and etheramine;

[0021] The foaming agent is an oleic acid foaming agent;

[0022] The accelerator includes one or more of sodium hexametaphosphate, water glass, lignin sulfonate and naphthalene sulfonate;

[0023] The amount of the collector is (1-10) / 1000 of the mass of the magnetic separation tailings liquid;

[0024] The dosage of the foaming agent is (0.1-2) / 1000 of the mass of the magnetic separation tailings liquid;

[0025] The dosage of the promoter is (0.05-1) / 1000 of the mass of the magnetic separation tailings liquid.

[0026] Preferably, the mixing of adding the flotation agent into the magnetic separation tailings liquid comprises mechanical stirring and ultrasonic dispersion performed sequentially.

[0027] Preferably, the stirring speed is 200 to 3000 r / min, and the stirring time is 3 to 15 min;

[0028] The ultrasonic power density of the ultrasonic dispersion is ≥0.35W / cm 2 The ultrasonic dispersion time is 8 to 25 minutes.

[0029] Preferably, the flotation is microbubble flotation;

[0030] The flotation time is 2 to 15 minutes.

[0031] Preferably, the post-processing includes:

[0032] The flotation tailings liquid is subjected to solid-liquid separation to obtain a solid;

[0033] The solid is dried to obtain a gelled material.

[0034] The invention provides a method for grading and quality-based treatment and resource utilization of asbestos tailings, comprising the following steps: performing I-level crushing on the asbestos tailings, performing a first screening using a double-layer screen with sieve holes of 50 mm and 0.5 mm, and obtaining materials with a particle size of 0.5 to 50 mm and a first tailing ore with a particle size of less than 0.5 mm; performing II-level crushing on the materials with a particle size of 0.5 to 50 mm, and performing a second screening using a double-layer screen with sieve holes of 31.5 mm and 0.5 mm, and obtaining materials with a particle size of 0.5 to 31.5 mm and a second tailing ore with a particle size of less than 0.5 mm; .5~31.5mm materials are crushed at level III, and a multi-layer screen with mesh sizes of 0.5mm, 4.76mm, 10mm and 15mm is used for the third screening to obtain 1-3 stones, 1-2 stones, 5-1 stones, machine-made sand and a third tailing ore with a particle size of less than 0.5mm; the particle size of the machine-made sand is 0.5~4.76mm; the first tailing ore, the second tailing ore and the third tailing ore are mixed and ground to obtain tailing ore powder, and the particle size of the tailing ore powder is -74μm; the tailing ore powder is pulped and magnetically separated to obtain iron concentrate and magnetic tailings liquid respectively. The flotation agent is added to the magnetic tailings liquid, mixed and slurried for flotation to obtain asbestos concentrate and flotation tailings liquid respectively. The flotation tailings liquid is post-treated to obtain a cementitious material. The present invention uses multi-stage crushing and screening and sorting technology to process asbestos tailings, and prepares stones and machine-made sand of different particle sizes; then grinds the tailings and makes pulp for magnetic separation to recover iron concentrate; flotation is performed on the magnetic separation tailings liquid after magnetic separation to recover asbestos concentrate; and the flotation tailings liquid is post-processed to obtain a cementitious material. The present invention uses a physical processing method to process asbestos tailings, recovers useful components in the asbestos tailings and utilizes all components, thereby realizing low-carbon, clean resource utilization of asbestos tailings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a process flow chart for the classification and quality-based treatment and resource utilization of asbestos tailings. DETAILED DESCRIPTION

[0036] The present invention provides a method for grading and quality-based treatment and resource utilization of asbestos tailings, comprising the following steps:

[0037] The asbestos tailings are crushed in the first stage, and the first screening is performed using a double-layer screen with mesh sizes of 50 mm and 0.5 mm to obtain materials with a particle size of 0.5 to 50 mm and a first tailing ore with a particle size of less than 0.5 mm;

[0038] The material with a particle size of 0.5 to 50 mm is crushed in the second stage, and a double-layer sieve with sieve holes of 31.5 mm and 0.5 mm is used for the second screening to obtain a material with a particle size of 0.5 to 31.5 mm and a second tailing ore with a particle size less than 0.5 mm;

[0039] The material with a particle size of 0.5 to 31.5 mm is crushed in step III, and a multi-layer screen with mesh sizes of 0.5 mm, 4.76 mm, 10 mm and 15 mm is used for the third screening to obtain 1-3 stones, 1-2 stones, 5-1 stones, machine-made sand and a third tailing ore with a particle size of less than 0.5 mm; the particle size of the machine-made sand is 0.5 to 4.76 mm;

[0040] The first tail ore, the second tail ore and the third tail ore are mixed and ground to obtain tail ore powder, wherein the particle size of the tail ore powder is -74 μm;

[0041] The tailings powder is pulped and then subjected to magnetic separation to obtain iron ore concentrate and magnetic separation tailings liquid respectively;

[0042] Adding a flotation agent to the magnetic separation tailings liquid, mixing, slurrying and flotation to obtain asbestos concentrate and flotation tailings liquid respectively;

[0043] The flotation tailings liquid is post-processed to obtain a gelled material.

[0044] The present invention performs I crushing on the asbestos tailings, and performs the first screening using a double-layer screen with mesh sizes of 50 mm and 0.5 mm to obtain materials with a particle size of 0.5 to 50 mm and a first tailings with a particle size of less than 0.5 mm. In the present invention, the asbestos tailings preferably include serpentine asbestos tailings, tremolite asbestos tailings, amphibole asbestos tailings and other asbestos tailings.

[0045] The present invention has no special limitation on the method of the first-stage crushing, as long as it can crush and reach the desired particle size. In the present invention, when a material with a particle size greater than 50 mm is obtained after the first screening, it is preferred to repeat the first-stage crushing and the first screening for the material with a particle size greater than 50 mm. The present invention has no special requirements on the number of repetitions, as long as the particle size of all materials can be less than or equal to 50 mm.

[0046] The present invention performs II-stage crushing on the material with a particle size of 0.5 to 50 mm, and performs a second screening using a double-layer screen with sieve holes of 31.5 mm and 0.5 mm to obtain a material with a particle size of 0.5 to 31.5 mm and a second tail ore with a particle size of less than 0.5 mm. The present invention has no special limitation on the method of II-stage crushing, as long as it can effectively crush and reach the required particle size. In the present invention, when the material with a particle size greater than 31.5 mm is obtained after the second screening, it is preferred to repeat the II-stage crushing and the second screening on the material with a particle size greater than 31.5 mm. The present invention has no special requirements on the number of repetitions, as long as the particle size of all materials can be less than or equal to 31.5 mm.

[0047] The present invention performs III-level crushing on the material with a particle size of 0.5 to 31.5 mm, and performs the third screening using a multi-layer screen with sieve holes of 0.5 mm, 4.76 mm, 10 mm and 15 mm to obtain 1-3 stones, 1-2 stones, 5-1 stones, machine-made sand and a third tailing ore with a particle size less than 0.5 mm; the particle size of the machine-made sand is 0.5 to 4.76 mm. The present invention has no special restrictions on the method of III-level crushing, and it is sufficient to effectively crush and reach the required particle size. In the present invention, the 1-3 stones refer to crushed stones with a particle size of 15 to 31.5 mm; the 1-2 stones refer to crushed stones with a particle size of 10 to 15 mm; and the 5-1 stones refer to crushed stones with a particle size of 4.76 to 10 mm. In the present invention, the 1-3 stones, 1-2 stones, 5-1 stones and machine-made sand can be used as building materials.

[0048] After obtaining the first tailings, the second tailings and the third tailings, the present invention mixes the first tailings, the second tailings and the third tailings and grinds them to obtain tailings powder, wherein the particle size of the tailings powder is -74 μm. The present invention has no special requirements for the mixing, as long as the mixing can be uniform. The present invention has no special requirements for the grinding, as long as the grinding can be effective and the required particle size can be achieved.

[0049] After obtaining the tail ore powder, the present invention pulps the tail ore powder and then performs magnetic separation to obtain iron concentrate and magnetic separation tailings liquid, respectively. In the present invention, the pulping preferably includes the following steps: mixing the tail ore powder with water to obtain a slurry. In the present invention, the mass ratio of the tail ore powder to water is preferably 1000:50-250, and more preferably 1000:60-250. In the present invention, the mixing method preferably includes mechanical stirring or ultrasonic oscillation, and more preferably mechanical stirring. In the present invention, the rotation speed of the mechanical stirring is preferably 200-3000r / min, and more preferably 250-3000r / min; the time of the mechanical stirring is preferably 5-20min, and more preferably 5-15min. In the present invention, the frequency of the ultrasonic oscillation is preferably ≥20kHz, and more preferably 25-50kHz; the power density of the ultrasonic oscillation is preferably ≥0.35W / cm 2 , more preferably 0.5 to 1.5 W / cm 2 , and more preferably 1 to 1.45 W / cm 2 ; The ultrasonic oscillation time is preferably 8 to 25 minutes, more preferably 8 to 20 minutes.

[0050] In the present invention, the magnetic separation is preferably wet magnetic separation, and the magnetic field strength used in the magnetic separation is preferably ≤1.0T, more preferably 0.4-0.85T; the time of the magnetic separation is preferably 1-10min, more preferably 2-8min.

[0051] The present invention recovers the iron concentrate in the tail ore powder through magnetic separation, and the recovery rate of the iron concentrate can preferably reach more than 80%, more preferably 80.69-86.66%. In the present invention, the total iron content (TFe) in the iron concentrate is preferably more than 55%, more preferably more than 60.19%.

[0052] After magnetic separation, the present invention adds a flotation agent to the magnetic separation tailings liquid, fully mixes, and then adjusts the slurry for flotation to obtain asbestos concentrate and flotation tailings liquid, respectively. In the present invention, the flotation agent preferably includes a collector, a foaming agent and a promoter. In the present invention, the collector preferably includes dodecylamine and / or octadecylamine and etheramine, and more preferably includes dodecylamine or octadecylamine and etheramine. In the present invention, when the collector is dodecylamine and octadecylamine and etheramine, the present invention has no special requirements for the ratio of dodecylamine and octadecylamine to etheramine, and an appropriate ratio can be used. In the present invention, the foaming agent is preferably an oleic acid foaming agent; the oleic acid foaming agent is preferably oleic acid or sodium oleate solution, and more preferably sodium oleate solution. In the present invention, the promoter preferably includes one or more of sodium hexametaphosphate, water glass, lignin sulfonate and naphthalene sulfonate, and more preferably lignin sulfonate and naphthalene sulfonate or a mixture of the two. In the present invention, when the promoter includes two or more of the above-mentioned agents, the present invention has no special limitation on the ratio of the specific agents, and an equal proportion ratio can be adopted. In an embodiment of the present invention, the promoter is sodium hexametaphosphate and naphthalene sulfonate in a mass ratio of 1:1 or water glass and lignin sulfonate in a mass ratio of 60:40. In the present invention, the promoter mainly plays the role of enhancing wetting and dispersion, and promotes the asbestos particles to be fully dispersed in the slurry and effectively wetted.

[0053] In the present invention, the added amount of the collector is preferably (1 to 10) / 1000 of the mass of the magnetic separation tailings liquid, and more preferably (1 to 9) / 1000; the added amount of the foaming agent is preferably (0.1 to 2) / 1000 of the mass of the magnetic separation tailings liquid, and more preferably (0.1 to 1.5) / 1000; the added amount of the promoter is preferably (0.05 to 1) / 1000 of the mass of the magnetic separation tailings liquid, and more preferably (0.05 to 0.85) / 1000.

[0054] In the present invention, the mixing preferably includes mechanical stirring and ultrasonic dispersion performed in sequence. In the present invention, the rotation speed of the mechanical stirring is preferably 200 to 3000 r / min, more preferably 200 to 2500 r / min; the time of the mechanical stirring is preferably 3 to 15 min, more preferably 3 to 12 min. In the present invention, the ultrasonic power density of the ultrasonic dispersion is preferably ≥ 0.35 W / cm 2 , more preferably 0.5 to 1.5 W / cm 2 The ultrasonic dispersion time is preferably 5 to 25 min, more preferably 5 to 20 min.

[0055] In the present invention, the flotation is preferably microbubble flotation; and before the microbubble flotation, the mixed dispersion is preferably passed through a bubble generator to form micro-nano bubbles. In the present invention, the flotation time is preferably 2 to 15 minutes, more preferably 2 to 13 minutes.

[0056] The present invention recovers asbestos concentrate in the tail ore powder through flotation, and the recovery rate of the asbestos concentrate is preferably above 65%, more preferably 67.86-85.76%. In the present invention, the MgO / SiO2 ratio in the asbestos concentrate is preferably 0.90-1.20, more preferably 0.95-1.20.

[0057] After flotation, the present invention performs post-treatment on the flotation tailings liquid to obtain a gelled material. In the present invention, the post-treatment preferably includes:

[0058] The flotation tailings liquid is subjected to solid-liquid separation to obtain a solid;

[0059] The solid is dried to obtain a gelled material.

[0060] In the present invention, the solid-liquid separation is preferably filter press. The present invention has no special requirements for the filter press, and the conventional method in the art can be adopted. The present invention has no special requirements for the drying method, and the conventional drying method in the art can be adopted. In the present invention, the moisture content of the dried product is preferably ≤10%, more preferably ≤8.5%.

[0061] In the present invention, the cementitious material can partially replace the raw materials of cement or refractory materials.

[0062] In the present invention, the process flow chart of the method for grading and quality-based treatment and resource utilization of asbestos tailings is as follows: Figure 1 As shown. The present invention performs I-level crushing and screening of asbestos tailings to obtain the first tailings, performs II-level crushing and screening of materials with a particle size of 0.5 to 50 mm to obtain the second tailings, and performs III-level crushing and screening of materials with a particle size of 0.5 to 31.5 mm to obtain crushed stone, machine-made sand and the third tailings of different particle sizes; the first tailings, the second tailings and the third tailings are mixed and then ground and slurried, and the obtained slurry is subjected to magnetic separation to recover the iron concentrate; the magnetically separated tailings liquid is subjected to flotation to recover the asbestos concentrate, and the flotation tailings liquid is post-processed to obtain a cementitious material. The present invention performs graded and quality-based treatment and resource utilization of asbestos tailings through multi-stage crushing and precise classification, as well as a physical processing method combining magnetic separation and flotation, so as to realize the low-carbon green full-component resource utilization of asbestos tailings.

[0063] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0064] Example 1

[0065] Two kinds of asbestos tailings in Sichuan Province and two kinds of asbestos tailings in Qinghai Province were used as raw materials, wherein the two kinds of asbestos tailings samples in Sichuan Province were recorded as 1# sample and 2# sample, and the two kinds of asbestos tailings samples in Qinghai Province were recorded as 3# sample and 4# sample, and the components of each sample are shown in Table 1;

[0066] The asbestos tailings are crushed in the first stage, and the first screening is performed using a double-layer screen with mesh sizes of 50 mm and 0.5 mm to obtain materials with a particle size of 0.5 to 50 mm and a first tailing ore with a particle size of less than 0.5 mm; when the material with a particle size greater than 50 mm is obtained after the first screening, the material with a particle size greater than 50 mm is repeatedly crushed in the first stage and screened in the first stage until the particle size of the material is less than 50 mm;

[0067] The material with a particle size of 0.5-50mm is crushed in the second stage, and a double-layer screen with mesh sizes of 31.5mm and 0.5mm is used for the second screening to obtain a material with a particle size of 0.5-31.5mm and a second tail ore with a particle size of less than 0.5mm; when the material with a particle size greater than 31.5mm is obtained after the second screening, the material with a particle size greater than 31.5mm is repeatedly crushed in the second stage and the second screening is performed until the particle size of all materials is less than 31.5mm; the material with a particle size of 0.5-31.5mm is crushed in the third stage, and a double-layer screen with mesh sizes of 0.5mm, 4.76mm, 10mm and 15mm is used for the second screening. The third screening is carried out with a multi-layer sieve of m to obtain 1-3 gravel, 1-2 gravel, 5-1 gravel, machine-made sand and a third tailings ore with a particle size of less than 0.5 mm; the particle size of the machine-made sand is 0.5-4.76 mm, and the yields of the obtained crushed stone and machine-made sand are listed in Table 2-1; the crushing index of the machine-made sand is tested in accordance with GB / T14684-2022 "Sand for Construction", and the results are shown in Table 2-2; it can be seen from Table 2-2 that the asbestos tailings are graded and treated according to their quality, and the machine-made sand obtained can meet the compression index requirements of the first-level sand in "Sand for Construction", indicating that the machine-made sand and gravel can be used as construction sand and aggregate for road traffic.

[0068] The first tailings ore, the second tailings ore and the third tailings ore are mixed and ground to obtain tailings ore powder with a particle size of -74 μm;

[0069] The tailings powder and water were mixed in a mass ratio of 1000:70, stirred at a speed of 1250r / min for 12 minutes to form a slurry, and the slurry was magnetically separated for 6.5 minutes under a magnetic field intensity of 0.5T to obtain iron concentrate and magnetic tailings liquid respectively; the recovery rate data of iron concentrate and total iron are shown in Table 3.

[0070] Table 1 Chemical composition of asbestos tailings

[0071] Element 1# Sample Sample 2# Sample #3 Sample 4# <![CDATA[SiO2]]> 46.126 46.679 45.551 47.908 MgO 40.007 38.395 43.043 41.475 <![CDATA[Fe2O3]]> 7.058 7.184 8.65 6.354 <![CDATA[Al2O3]]> 3.548 4.118 1.377 1.03 <![CDATA[K2O]]> 1.052 0.766 0.028 0.012 <![CDATA[Na2O]]> 0.712 0.611 - 0.087 CaO 0.688 1.299 0.352 0.287 <![CDATA[Cr2O3]]> 0.272 0.27 0.365 0.327 <![CDATA[SO3]]> 0.074 0.068 0.115 0.089 <![CDATA[P2O5]]> 0.011 0.033 0.008 0.012 Cl 0.019 0.036 0.011 0.009 <![CDATA[TiO2]]> 0.046 0.093 0.052 0.016 MnO 0.089 0.113 0.1 0.095 NiO 0.24 0.278 0.303 0.259 <![CDATA[Co3O4]]> 0.027 0.028 0.028 0.029 ZnO 0.004 0.007 0.005 0.005 <![CDATA[Rb2O]]> 0.004 0.004 - - SrO 0.005 0.005 - - <![CDATA[Y2O3]]> 0.002 0.001 - - <![CDATA[ZrO2]]> 0.003 0.006 - - PbO 0.011 0.004 - -

[0072] Table 2-1 The yield of crushed stone obtained after graded crushing and screening

[0073]

[0074]

[0075] Table 2-2 Crushing index of machine-made sand made from asbestos tailings

[0076]

[0077] Table 3 Recovery rate of iron ore concentrate products recovered

[0078] sample 1# 2# 3# 4# Iron concentrate recovery rate / % 81.63 86.05 80.69 85.37 Total iron content / % 67.24 65.99 65.32 63.49

[0079] It can be seen from Table 3 that the recovery rate of iron concentrate from asbestos tailings can reach more than 80%, and the grade of the iron concentrate generally exceeds 63.49%.

[0080] A mixture of sodium hexametaphosphate and naphthalenesulfonate in a mass ratio of 1:1 was used as an accelerator, a mixture of octadecylamine and etheramine in a mass ratio of 1:1 was used as a collector, and a sodium oleate solution with a mass concentration of 20% was used as a frother. The magnetic separation tailings liquid, accelerator, collector and frother were mechanically stirred at a speed of 800 r / min for 5 minutes and a power density of 1.35 W / cm 2 Under the conditions of , ultrasonic dispersion was carried out for 10 minutes, and after forming micro-nano bubbles through a bubble generator, microbubble flotation was performed for 5 minutes to obtain asbestos concentrate and flotation tailings liquid respectively; during the flotation process, the mass ratio of magnetic separation tailings liquid, promoter, collector and frother was 1000:0.15:5:1.2; the recovery rate of asbestos concentrate and MgO content are listed in Table 4; the flotation tailings were hydraulically filtered and dried to obtain a gelled material with a moisture content of 3.8%.

[0081] Table 4 Recovery rate of asbestos concentrate recovered

[0082] sample 1# 2# 3# 4# Asbestos concentrate recovery rate / % 67.86 85.78 78.19 70.89 <![CDATA[MgO / SiO2 ratio]]> 1.03 0.98 1.05 1.00

[0083] It can be seen from Table 4 that the recovery rate of asbestos concentrate can reach more than 67.86%, and the MgO content and MgO / SiO2 ratio in the asbestos concentrate can reach the MgO content and MgO / SiO2 ratio of the ideal asbestos mine.

[0084] Example 2

[0085] Two kinds of asbestos tailings from Sichuan Province and two kinds of asbestos tailings from Qinghai Province were treated according to the method of Example 1, except that the mechanical stirring mixing method was changed to ultrasonic oscillation during slurrying, and the frequency of ultrasonic oscillation was 25 kHz and the power density was 1.45 W / cm 2, the time of ultrasonic oscillation is 15 minutes; during the flotation process, the mechanical stirring and mixing time of the magnetic tailings liquid and the flotation agent is 6 minutes, the time of ultrasonic dispersion is 9 minutes, and the time of microbubble flotation is 8 minutes.

[0086] The recovery rate of the iron concentrate recovered in Example 2 is shown in Table 5, and the yield and MgO content of the asbestos concentrate recovered are shown in Table 6.

[0087] Table 5 Recovery rate of iron concentrate from magnetic separation of tailings

[0088] sample 1# 2# 3# 4# Iron concentrate recovery rate / % 84.39 86.66 83.97 86.44 Total iron content / % 65.56 66.12 65.55 67.23

[0089] It can be seen from Table 5 that the recovery rate of iron concentrate recovered from asbestos tailings by magnetic separation can reach more than 80%, and the grade of iron concentrate can reach more than 65.55%.

[0090] Table 6 Recovery rate of asbestos concentrate recovered by flotation

[0091] sample 1# 2# 3# 4# Asbestos concentrate recovery rate / % 72.33 81.87 80.99 81.35 <![CDATA[MgO / SiO2 ratio]]> 1.05 0.99 1.03 1.02

[0092] It can be seen from Table 6 that the recovery rate of asbestos concentrate can reach more than 72.33%, and the MgO content and MgO / SiO2 ratio in the asbestos concentrate can basically reach the MgO content and MgO / SiO2 ratio of the ideal asbestos ore.

[0093] Example 3

[0094] Two asbestos tailings from Sichuan Province and two asbestos tailings from Qinghai Province were treated according to the method of Example 2, except that water glass and lignin sulfonate with a mass ratio of 60:40 were used as promoters during the flotation process. The yield and MgO content of the asbestos concentrate are shown in Table 7.

[0095] Table 7 Recovery rate of asbestos concentrate recovered by flotation

[0096] sample 1# 2# 3# 4# Asbestos concentrate recovery rate / % 76.44 85.23 81.66 85.67 <![CDATA[MgO / SiO2 ratio]]> 1.01 0.99 1.02 1.05

[0097] It can be seen from Table 7 that the recovery rate of asbestos concentrate can reach more than 76.44%, and the MgO content and MgO / SiO2 ratio in the asbestos concentrate can basically reach the MgO content and MgO / SiO2 ratio of the ideal asbestos ore.

[0098] Example 4

[0099] Two kinds of asbestos tailings from Sichuan Province and two kinds of asbestos tailings from Qinghai Province were treated according to the method of Example 3, except that: during the flotation process, the time for mechanical stirring and mixing of the magnetic tailings liquid and the flotation reagent was 7.5 minutes, the time for ultrasonic dispersion was 10 minutes, and the time for microbubble flotation was 11 minutes. The yield of the obtained asbestos concentrate and the MgO content of the product are listed in Table 8.

[0100] Table 8 Recovery rate of asbestos concentrate recovered by flotation

[0101]

[0102]

[0103] It can be seen from Table 8 that the recovery rate of asbestos concentrate can reach more than 81.10%, and the MgO content and MgO / SiO2 ratio in the asbestos concentrate can basically reach the MgO content and MgO / SiO2 ratio of the ideal asbestos ore.

[0104] By utilizing the treatment method provided by the present invention, asbestos tailings treatment and effective resource utilization can be achieved.

[0105] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for grading and quality-based treatment and resource utilization of asbestos tailings, comprising the following steps: The asbestos tailings are crushed in the first stage, and the first screening is performed using a double-layer screen with mesh sizes of 50 mm and 0.5 mm to obtain materials with a particle size of 0.5 to 50 mm and a first tailing ore with a particle size of less than 0.5 mm; The material with a particle size of 0.5-50 mm is crushed in the second stage, and a double-layer sieve with sieve holes of 31.5 mm and 0.5 mm is used for the second screening to obtain a material with a particle size of 0.5-31.5 mm and a second tail ore with a particle size less than 0.5 mm; The material with a particle size of 0.5-31.5 mm is crushed at level III, and a multi-layer screen with mesh sizes of 0.5 mm, 4.76 mm, 10 mm and 15 mm is used for the third screening to obtain 1-3 stones, 1-2 stones, 5-1 stones, machine-made sand and a third tailing ore with a particle size of less than 0.5 mm; the particle size of the machine-made sand is 0.5-4.76 mm; The first tail ore, the second tail ore and the third tail ore are mixed and ground to obtain tail ore powder, wherein the particle size of the tail ore powder is -74 μm; The tailings powder is pulped and then subjected to magnetic separation to obtain iron concentrate and magnetic separation tailings liquid respectively; Adding a flotation agent to the magnetic tailings liquid, mixing them thoroughly, and then slurrying and flotation to obtain asbestos concentrate and flotation tailings liquid respectively; the flotation agent comprises a collector, a frother and a promoter; the frother is an oleic acid frother; the collector comprises dodecylamine and / or octadecylamine and etheramine; the promoter comprises one or more of sodium hexametaphosphate, water glass, lignin sulfonate and naphthalene sulfonate; the amount of the collector is (1-10) / 1000 of the mass of the magnetic tailings liquid; the amount of the frother is (0.1-2) / 1000 of the mass of the magnetic tailings liquid; the amount of the promoter is (0.05-1) / 1000 of the mass of the magnetic tailings liquid; The flotation tailings liquid is post-processed to obtain a gelled material.

2. The method for grading and quality-based treatment and resource utilization of asbestos tailings according to claim 1, characterized in that: The pulping comprises the following steps: The tail ore powder and water are mixed to obtain slurry; the mixing method includes mechanical stirring or ultrasonic oscillation.

3. The method for grading and quality-based treatment and resource utilization of asbestos tailings according to claim 2, characterized in that: The speed of the mechanical stirring is 200-3000 r / min; the time of the mechanical stirring is 5-20 min; The frequency of the ultrasonic oscillation is ≥20kHz, and the power density of the ultrasonic oscillation is ≥0.35W / cm 2 ; The ultrasonic oscillation time is 8~25min.

4. The method for grading and quality-based treatment and resource utilization of asbestos tailings according to claim 1, characterized in that: The magnetic separation is wet magnetic separation, and the magnetic field strength used in the magnetic separation is ≤1.0T; the time of the magnetic separation is 1 to 10 minutes.

5. The method for grading and quality-based treatment and resource utilization of asbestos tailings according to claim 1, characterized in that: The mixing of adding the flotation reagent into the magnetic separation tailings liquid includes mechanical stirring and ultrasonic dispersion performed in sequence.

6. The method for grading and quality-based treatment and resource utilization of asbestos tailings according to claim 5, characterized in that: The stirring speed is 200-3000 r / min, and the stirring time is 3-15 min.

7. The method for grading and quality-based treatment and resource utilization of asbestos tailings according to claim 5, characterized in that: The ultrasonic power density of the ultrasonic dispersion is ≥0.35W / cm 2 The ultrasonic dispersion time is 8 to 25 minutes.

8. The method for grading and quality-based treatment and resource utilization of asbestos tailings according to claim 1, characterized in that: The flotation is microbubble flotation; The flotation time is 2 to 15 minutes.

9. The method for grading and quality-based treatment and resource utilization of asbestos tailings according to claim 1, characterized in that: The post-processing includes: The flotation tailings liquid is subjected to solid-liquid separation to obtain a solid; The solid is dried to obtain a gelled material.

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