A process for reducing silicon content in feldspar based on lepidolite tailings

Abstract

This invention belongs to the field of lepidolite tailings technology, and particularly relates to a process for reducing the silicon content in feldspar based on lepidolite tailings. Specifically, it includes the following steps: pretreatment of lepidolite tailings; preparation of soluble starch cross-linked microspheres; preparation of quartz inhibitors; preparation of dicarboxylic acid anionic polyacrylamide; preparation of feldspar inhibitors; addition of quartz inhibitors under neutral conditions to float feldspar; and addition of feldspar inhibitors under alkaline conditions to float quartz. By adding quartz inhibitors to the slurry under neutral conditions, the soluble starch cross-linked microspheres can hinder the adsorption of anionic collectors on the quartz surface, thereby effectively inhibiting quartz and reducing the silicon content in the floated feldspar. By adding feldspar inhibitors to the slurry under alkaline conditions, pectin and dicarboxylic acid anionic polyacrylamide can hinder the effect of anionic collectors on feldspar, thereby effectively inhibiting feldspar and further reducing the silicon content in the feldspar.

Description

Technical Field

[0001] This invention belongs to the field of lepidolite tailings technology, and particularly relates to a process for reducing the silicon content in feldspar based on lepidolite tailings. Background Technology

[0002] Lepidolite is a mineral raw material for lithium extraction. During the lithium extraction process from lepidolite, a large amount of feldspar and other byproducts are generated. To reduce environmental pollution and resource waste, lepidolite tailings need to be treated. Flotation is the most feasible method for separating feldspar from quartz. However, the hydrofluoric acid method and the acid-free method are seriously polluting to the environment. Currently, the environmentally friendly acid-free method is more commonly used. Its mechanism is to add a combination of anionic and cationic collectors under neutral or alkaline conditions to separate feldspar from quartz, thereby improving the utilization value of lepidolite tailings.

[0003] Currently, when using the fluorine-free and acid-free method, anionic and cationic collectors are added under neutral conditions to float feldspar. Some anionic collectors adsorb onto the quartz surface, causing some quartz to be floated simultaneously. Then, under alkaline conditions, metal activators and anionic collectors are added to float quartz. However, some anionic collectors also adsorb onto the feldspar surface, causing some feldspar to be floated simultaneously. This results in the final feldspar containing a high amount of silicon. Therefore, it is necessary to develop a process based on lepidolite tailings to reduce the silicon content in feldspar, which can effectively separate quartz and feldspar to solve the above problems. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a process for reducing the silicon content in feldspar based on lepidolite tailings.

[0005] A process for reducing the silicon content in feldspar based on lepidolite tailings specifically includes the following steps:

[0006] S1: Pretreatment of lithium mica tailings

[0007] Lithium mica tailings are added to a grinding mill for grinding, and the slurry is added to an ultrasonic cleaner for ultrasonic treatment.

[0008] S2: Preparation of soluble starch cross-linked microspheres

[0009] Soluble starch was dissolved in water and heated to gelatinize until the solution became transparent, resulting in an aqueous phase. A second mixing container containing liquid paraffin was placed in a water bath, and an emulsifier was added to the second mixing container for water bath heating, resulting in an oil phase. The aqueous phase was slowly added to the oil phase using a dropper, and the mixture was stirred with a stirrer. Epichlorohydrin, a crosslinking agent, was added, and stirring was continued for water bath crosslinking. The crosslinked mixture was washed with water, extracted, filtered, and dried to obtain soluble starch crosslinked microspheres.

[0010] S3: Preparation of quartz inhibitors

[0011] Soluble starch cross-linked microspheres were added to deionized water and mixed evenly. 2-8g of soluble starch cross-linked microspheres were added per liter of deionized water to obtain a quartz inhibitor.

[0012] S4: Preparation of dicarboxylated anionic polyacrylamide

[0013] Acrylamide, anionic monomer and deionized water were added to the reaction vessel and stirred to dissolve. After adjusting the pH value, nitrogen gas was introduced into the reaction vessel. At the same time, oxidant, reducing agent and azo initiator dissolved in deionized water were added. The reaction yielded a gel-like product. The gel-like product was washed, pre-crushed, dried and pulverized to obtain dicarboxylic anionic polyacrylamide.

[0014] S5: Preparation of feldspar inhibitors

[0015] Pectin, dicarboxylated anionic polyacrylamide, and deionized water were mixed evenly. 0.1-0.3g of pectin and 0.2-1g of dicarboxylated anionic polyacrylamide were added per liter of deionized water to obtain feldspar inhibitors.

[0016] S6: Add quartz inhibitor under neutral conditions to float feldspar.

[0017] The slurry is added to the flotation machine, the pH of the slurry is adjusted to neutral, an anionic collector is added and stirred, then quartz inhibitor and sodium hexametaphosphate are added, followed by cationic collector dodecylamine hydrochloride, and sodium oleate is used as a feldspar activator to float the feldspar. The foam is collected, washed and dried to obtain feldspar after one flotation.

[0018] S7: Add feldspar inhibitor under alkaline conditions to float quartz.

[0019] Feldspar is mixed in deionized water and then added to a flotation machine. The pH of the pulp is adjusted to be alkaline, and a metal activator, an anion collector, and a feldspar inhibitor are added to activate it, so that quartz floats out of the pulp. The pulp is collected, washed, and dried to obtain feldspar with low silicon content after secondary flotation.

[0020] More preferably, step S1 involves pretreatment of the lepidolite tailings, specifically including the following steps:

[0021] S1.1: Lithium mica tailings and deionized water are added to the grinding mill for grinding. The grinding concentration is 60%-80%, the grinding media is ceramic balls, the grinding media filling rate is 35-45%, the grinding time is 5-10 min, and the mill speed is 500-600 r / min.

[0022] S1.2: Add the slurry to an ultrasonic cleaner for ultrasonic treatment. The ultrasonic power is 150-250W and the ultrasonic time is 1-2 minutes.

[0023] More preferably, step S2, which prepares soluble starch cross-linked microspheres, specifically includes the following steps:

[0024] S2.1: Add soluble starch to a mixing container containing water. The mass concentration of soluble starch is 35-45%. Adjust the pH value to 8-9 using a pH adjuster. Heat the mixing container using a water bath to dissolve the soluble starch and gelatinize it until the solution becomes transparent. Adjust the temperature of the water bath to 55-60℃ to cool the soluble starch solution and obtain the aqueous phase.

[0025] S2.2: Place the second mixing container containing liquid paraffin into a water bath at 55-60℃, then add the emulsifier to the second mixing container. Add 0.05-0.08g of emulsifier per milliliter of liquid paraffin. Heat the second mixing container in the water bath while stirring with a stirrer at a speed of 500-600r / min to completely dissolve the emulsifier and obtain the oil phase.

[0026] S2.3: Continue to bathe the mixing container containing the oil phase in a water bath device, adjust the water bath temperature to 45-50℃, slowly add the aqueous phase to the oil phase using a dropper, and stir with a stirrer at a speed of 400-500 r / min for 30-40 min to emulsify the system. Add the crosslinking agent epichlorohydrin and continue stirring for 3-4 h. The volume ratio of crosslinking agent, aqueous phase and oil phase is 1:(5-6):(40-50). Crosslink the mixture in a water bath at 45-50℃ for 4-5 h to obtain the crosslinked mixture.

[0027] S2.4: Wash the cross-linked mixture with water 3-4 times until it is clear and pH neutral, then add diethyl ether to extract the residual solvent, filter the extracted cross-linked mixture, and then dry it in a forced-air drying oven until the mass is constant at a drying temperature of 60-65℃ to obtain soluble starch cross-linked microspheres.

[0028] More preferably, step S4 involves preparing a dicarboxyl-type anionic polyacrylamide, specifically including the following steps:

[0029] S4.1: Add acrylamide, anionic monomer and deionized water to the reaction vessel. The mass ratio of acrylamide to anionic monomer is 1:(3-10). Stir to dissolve. Use a pH adjuster to adjust the pH of the solution in the reaction vessel to 4-5.

[0030] S4.2: Nitrogen gas is introduced into the reactor for 1-1.5 hours, and oxidant, reducing agent and azo initiator dissolved in deionized water are added at the same time. The concentration of oxidant is 0.02-0.05%, the mass ratio of oxidant to reducing agent is (1-3):1, and the mass fraction of azo initiator in anionic monomer is 0.05-0.2%. After reacting in the reactor for 4-6 hours, a gel-like product is obtained.

[0031] S4.3: Wash the gelatinous product with detergent until it turns white. After pre-crushing the gelatinous product with a crushing device, dry it in a drying oven, then crush it again with a crushing device, and store it in a storage container to obtain dicarboxylic anionic polyacrylamide.

[0032] More preferably, step S6 involves adding a quartz inhibitor under neutral conditions to float feldspar, specifically including the following steps:

[0033] S6.1: Add the slurry to the flotation machine. The temperature of the flotation slurry is 20-25℃. The pH value of the slurry is detected in real time by a pH meter and transmitted to the controller. The pH adjuster is loaded into the dropper. The controller controls the dropper to add the pH adjuster to the slurry, thereby adjusting the pH value of the slurry to 7-8.

[0034] S6.2: Add sodium dodecyl sulfate, an anionic collector, and stir for 1-2 minutes using a stirring device. Then add quartz inhibitor and sodium hexametaphosphate. The ratio of quartz inhibitor to slurry is 1:(90-100). Add 300-600g of sodium hexametaphosphate per liter of slurry. When the pH meter detects that the pH value of the slurry deviates from the range of 7-8, the controller automatically controls the dropper to continue adding pH adjuster to keep the pH value of the slurry within the range of 7-8.

[0035] S6.3: Add (0.15-0.2)×10 per liter of slurry -3 Add 0.05-0.08 mol of sodium oleate as a feldspar activator to the cationic collector dodecylamine hydrochloride, and stir with a stirring device for 1-2 minutes to allow feldspar to float out of the slurry. Then, perform flotation and skim-over for 3-5 minutes.

[0036] S6.4: Collect the foam, wash and dry the foam to obtain feldspar after one flotation.

[0037] More preferably, step S7 involves adding a feldspar inhibitor under alkaline conditions to float the quartz, specifically including the following steps:

[0038] S7.1: After the first flotation, the feldspar is added to the flotation machine and deionized water is added and stirred to adjust the slurry concentration to 60%-80%, the flotation slurry temperature is 20-25℃, and the pH value of the slurry is adjusted to 10-12 using a pH adjuster.

[0039] S7.2: Add a metal activator to the slurry, with a metal ion concentration of (1-1.2)×10⁻⁶ per liter of slurry. -3 mol, and add the anionic collector sodium dodecyl sulfonate and feldspar inhibitor, adding (1-1.2)×10 per liter of slurry. -3 The ratio of anionic collector to feldspar inhibitor to slurry is 1:(90-100), quartz is preferentially floated out of the slurry, and flotation is performed by skimming bubbles for 3-5 minutes.

[0040] S7.3: Collect the slurry, wash and dry it to obtain feldspar with low silicon content after secondary flotation.

[0041] More preferably, the ceramic ball ratio in step S1 is φ25mm:φ20mm:φ15mm = 1:(1-2):1.

[0042] More preferably, the emulsifier in step S2 is specifically span60.

[0043] More preferably, the oxidant in step S4 is one of potassium persulfate, ammonium persulfate, and hydrogen peroxide; the reducing agent is one of sodium bisulfite, sodium sulfite, and ferrous sulfate; the azo initiator is one of azobisisobutyramidine hydrochloride and azobisisobutyramidine imidazoline hydrochloride; the detergent is one of acetone, anhydrous ethanol, diethyl ether, and a mixed solution of ethanol and acetone; and the anionic monomer has a structure containing a vinyl group and two carboxyl groups, specifically one of 2-acrylamidoglutaric acid and fumaric acid.

[0044] More preferably, the metal ion in step S7.2 is Ca. 2+ Mg 2+ And Al 3+ One of them.

[0045] The beneficial effects are: 1. By adding the prepared quartz inhibitor to the slurry under neutral conditions, sodium hexametaphosphate can remove the anionic collectors on the surface of quartz. Soluble starch cross-linked microspheres have a large number of hydroxyl groups, which can be adsorbed on the surface of quartz, thus hindering the adsorption of anionic collectors on the surface of quartz, thereby effectively inhibiting quartz and reducing the silicon content in the floating feldspar.

[0046] 2. This invention adds the prepared feldspar inhibitor to the slurry under alkaline conditions. Pectin and dicarboxylated anionic polyacrylamide can hinder the effect of anionic collectors on feldspar, while pectin and dicarboxylated anionic polyacrylamide do not affect the adsorption of anionic collectors on the quartz surface. This effectively inhibits feldspar, improves the floatability of quartz, and further reduces the silicon content in feldspar. Attached Figure Description

[0047] Figure 1 This is a flowchart of a process for reducing the silicon content in feldspar based on lepidolite tailings, used in an embodiment of the present invention. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] Example 1

[0050] A process for reducing silicon content in feldspar based on lepidolite tailings, referenced Figure 1 Specifically, it includes the following steps:

[0051] S1: Pretreatment of lithium mica tailings

[0052] Lithium mica tailings and deionized water were added to a grinding mill for grinding. The grinding concentration was 60%, the grinding media was ceramic balls, and the ceramic ball ratio was φ25mm:φ20mm:φ15mm = 1:1:1. The grinding media filling rate was 35%, the grinding time was 5 minutes, and the mill speed was 500 r / min.

[0053] The slurry was added to an ultrasonic cleaner for ultrasonic treatment with an ultrasonic power of 150W and an ultrasonic time of 1 minute to increase the difference in floatability between feldspar and quartz.

[0054] S2: Preparation of soluble starch cross-linked microspheres

[0055] Soluble starch is added to a mixing container containing water, with a mass concentration of 35%. The pH value is then adjusted to 8 using a pH adjuster. The mixing container is heated using a water bath to dissolve and gelatinize the soluble starch until the solution becomes transparent. The temperature of the water bath is adjusted to 55°C to cool the soluble starch solution, thus obtaining the aqueous phase.

[0056] The second mixing container containing liquid paraffin was placed in a water bath at 55°C. Then, an emulsifier, specifically Span 60, was added to the second mixing container at a rate of 0.05g per milliliter of liquid paraffin. The second mixing container was heated in a water bath while being stirred at a speed of 500r / min to completely dissolve the emulsifier and obtain the oil phase.

[0057] The mixing container containing the oil phase was continued to be bathed in a water bath device, and the water bath temperature was adjusted to 45°C. The aqueous phase was slowly added to the oil phase through a dropper, and the mixture was stirred with a stirrer at a speed of 400 r / min for 30 min to emulsify the system. The crosslinking agent epichlorohydrin was added and the mixture was stirred for another 3 h. The volume ratio of crosslinking agent, aqueous phase and oil phase was 1:5:40. The mixture was then crosslinked in a water bath at 45°C for 4 h to obtain the crosslinked mixture.

[0058] The cross-linked mixture was washed three times with water until it was clear and pH neutral. Then, diethyl ether was added to extract the residual solvent. The extracted cross-linked mixture was filtered and then dried in a forced-air drying oven until the mass was constant at a drying temperature of 60°C to obtain soluble starch cross-linked microspheres.

[0059] S3: Preparation of quartz inhibitors

[0060] Soluble starch cross-linked microspheres were added to deionized water and mixed evenly. 2g of soluble starch cross-linked microspheres were added per liter of deionized water to obtain a quartz inhibitor.

[0061] S4: Preparation of dicarboxylated anionic polyacrylamide

[0062] Acrylamide, anionic monomer, and deionized water were added to the reaction vessel. The mass ratio of acrylamide to anionic monomer was 1:3. The anionic monomer contained a vinyl group and two carboxyl groups, specifically one of 2-acrylamidoglutaric acid and fumaric acid. The mixture was stirred to dissolve the monomer, and the pH of the solution in the reaction vessel was adjusted to 4 using a pH adjuster.

[0063] Nitrogen gas was introduced into the reactor for 1 hour, and simultaneously an oxidant, a reducing agent, and an azo initiator dissolved in deionized water were added. The oxidant was one of potassium persulfate, ammonium persulfate, and hydrogen peroxide. The reducing agent was one of sodium bisulfite, sodium sulfite, and ferrous sulfate. The azo initiator was one of azobisisobutyramidine hydrochloride and azobisisobutyramidine imidazoline hydrochloride. The concentration of the oxidant was 0.02%, the mass ratio of oxidant to reducing agent was 1:1, and the mass fraction of the azo initiator to the anionic monomer was 0.05%. After reacting in the reactor for 4 hours, a gelatinous product was obtained.

[0064] The gelatinous product was washed with a detergent until it turned white. The detergent was one of acetone, anhydrous ethanol, diethyl ether, or a mixed solution of ethanol and acetone. The gelatinous product was pre-crushed by a crushing device, dried in a drying oven, and then crushed again. It was then stored in a storage container to obtain dicarboxylic anionic polyacrylamide.

[0065] S5: Preparation of feldspar inhibitors

[0066] Pectin, dicarboxylated anionic polyacrylamide, and deionized water were mixed evenly, and 0.1g of pectin and 0.2g of dicarboxylated anionic polyacrylamide were added per liter of deionized water to obtain feldspar inhibitor;

[0067] S6: Add quartz inhibitor under neutral conditions to float feldspar.

[0068] The slurry is added to the flotation machine at a temperature of 20°C. The pH value of the slurry is monitored in real time by a pH meter and transmitted to the controller. The pH adjuster is loaded into the dropper, and the controller controls the dropper to add the pH adjuster to the slurry, thereby adjusting the pH value of the slurry to 7.

[0069] Add sodium dodecyl sulfate, an anionic collector, and stir for 1 minute using a stirring device. The anionic collector will adsorb onto the surfaces of feldspar and quartz. Then, add quartz inhibitor and sodium hexametaphosphate. The ratio of quartz inhibitor to slurry is 1:90. Add 300g of sodium hexametaphosphate per liter of slurry. When the pH meter detects that the pH value of the slurry is not 7, the controller automatically controls the dropper to continue adding pH adjuster to keep the pH value of the slurry at 7. Sodium hexametaphosphate in the quartz inhibitor can remove the anionic collector from the surface of quartz. Soluble starch cross-linked microspheres have a large number of hydroxyl groups, which can be adsorbed onto the surface of quartz, hindering the adsorption of the collector on the surface of quartz, thereby effectively inhibiting quartz.

[0070] Add 0.15×10 to each liter of slurry -3 0.05 mol of sodium oleate as a feldspar activator was added to mol of cationic collector dodecylamine hydrochloride. The mixture was stirred for 1 min by a stirring device. The anions act as anionic active sites, and the cationic collector was adsorbed on the anionic active sites, thereby allowing the feldspar to float out of the slurry. The flotation was then skimmed for 3 min.

[0071] Collect the foam, wash and dry it to obtain feldspar after one flotation.

[0072] S7: Add feldspar inhibitor under alkaline conditions to float quartz.

[0073] After the first flotation, the feldspar was added to the flotation machine and deionized water was added and stirred to adjust the slurry concentration to 60%. The flotation slurry temperature was 20℃, and the pH value of the slurry was adjusted to 10 using a pH adjuster.

[0074] A metal activator is added to the slurry for activation; the metal ion is Ca. 2+ Mg 2+ And Al 3+ One of them has a metal ion concentration of 1×10⁻⁶ per liter of slurry. -3 mol, and add sodium dodecyl sulfonate anionic collector and feldspar inhibitor, 1×10 mol per liter of slurry. -3 The ratio of feldspar inhibitor to slurry is 1:90. Metal cations react with anionic collectors under alkaline conditions to form neutral complexes, which allows quartz to be preferentially floated out of the slurry. Pectin and dicarboxylated anionic polyacrylamide in the feldspar inhibitor can chemically adsorb on the feldspar surface, thus hindering the action of anionic collectors. However, pectin and dicarboxylated anionic polyacrylamide do not affect the adsorption of anionic collectors on the quartz surface, thereby inhibiting feldspar and improving the floatability of quartz. Floatation is carried out for 3 minutes.

[0075] The slurry is collected, washed, and dried to obtain feldspar with low silicon content after secondary flotation.

[0076] Example 2

[0077] A process for reducing silicon content in feldspar based on lepidolite tailings, referenced Figure 1 Specifically, it includes the following steps:

[0078] S1: Pretreatment of lithium mica tailings

[0079] Lithium mica tailings and deionized water were added to a grinding mill for grinding. The grinding concentration was 80%, the grinding media was ceramic balls, and the ratio of ceramic balls was φ25mm:φ20mm:φ15mm = 1:1:1. The grinding media filling rate was 35%, the grinding time was 5 minutes, and the mill speed was 500 r / min.

[0080] The slurry was added to an ultrasonic cleaner for ultrasonic treatment with an ultrasonic power of 150W and an ultrasonic time of 1 minute to increase the difference in floatability between feldspar and quartz.

[0081] S2: Preparation of soluble starch cross-linked microspheres

[0082] Soluble starch is added to a mixing container containing water, with a mass concentration of 45%. The pH value is then adjusted to 9 using a pH adjuster. The mixing container is heated using a water bath to dissolve and gelatinize the soluble starch until the solution becomes transparent. The temperature of the water bath is adjusted to 55°C to cool the soluble starch solution, thus obtaining the aqueous phase.

[0083] The second mixing container containing liquid paraffin was placed in a water bath at 55°C. Then, an emulsifier, specifically Span 60, was added to the second mixing container at a rate of 0.08g per milliliter of liquid paraffin. The second mixing container was heated in a water bath while being stirred at a speed of 500r / min to completely dissolve the emulsifier and obtain the oil phase.

[0084] The mixing container containing the oil phase was continued to be bathed in a water bath device, and the water bath temperature was adjusted to 45°C. The aqueous phase was slowly added to the oil phase through a dropper, and the mixture was stirred with a stirrer at a speed of 400 r / min for 30 min to emulsify the system. The crosslinking agent epichlorohydrin was added and the stirring was continued for 3 h. The volume ratio of crosslinking agent, aqueous phase and oil phase was 1:6:50. The mixture was crosslinked in a water bath at 45°C for 4 h to obtain a crosslinked mixture.

[0085] The cross-linked mixture was washed three times with water until it was clear and pH neutral. Then, diethyl ether was added to extract the residual solvent. The extracted cross-linked mixture was filtered and then dried in a forced-air drying oven until the mass was constant at a drying temperature of 60°C to obtain soluble starch cross-linked microspheres.

[0086] S3: Preparation of quartz inhibitors

[0087] Soluble starch cross-linked microspheres were added to deionized water and mixed evenly. 8g of soluble starch cross-linked microspheres were added per liter of deionized water to obtain a quartz inhibitor.

[0088] S4: Preparation of dicarboxylated anionic polyacrylamide

[0089] Acrylamide, anionic monomer, and deionized water were added to the reaction vessel. The mass ratio of acrylamide to anionic monomer was 1:10. The anionic monomer contained a vinyl group and two carboxyl groups, specifically one of 2-acrylamidoglutaric acid and fumaric acid. The mixture was stirred to dissolve the monomer, and the pH of the solution in the reaction vessel was adjusted to 5 using a pH adjuster.

[0090] Nitrogen gas was introduced into the reactor for 1 hour, and simultaneously an oxidant, a reducing agent, and an azo initiator dissolved in deionized water were added. The oxidant was one of potassium persulfate, ammonium persulfate, and hydrogen peroxide. The reducing agent was one of sodium bisulfite, sodium sulfite, and ferrous sulfate. The azo initiator was one of azobisisobutyramidine hydrochloride and azobisisobutyramidine imidazoline hydrochloride. The concentration of the oxidant was 0.05%, the mass ratio of oxidant to reducing agent was 3:1, and the mass fraction of the azo initiator in the anionic monomer was 0.2%. After reacting in the reactor for 4 hours, a gelatinous product was obtained.

[0091] The gelatinous product was washed with a detergent until it turned white. The detergent was one of acetone, anhydrous ethanol, diethyl ether, or a mixed solution of ethanol and acetone. The gelatinous product was pre-crushed by a crushing device, dried in a drying oven, and then crushed again. It was then stored in a storage container to obtain dicarboxylic anionic polyacrylamide.

[0092] S5: Preparation of feldspar inhibitors

[0093] Pectin, dicarboxylated anionic polyacrylamide, and deionized water were mixed evenly. 0.3g of pectin and 1g of dicarboxylated anionic polyacrylamide were added per liter of deionized water to obtain feldspar inhibitor.

[0094] S6: Add quartz inhibitor under neutral conditions to float feldspar.

[0095] The slurry is added to the flotation machine at a temperature of 20°C. The pH value of the slurry is monitored in real time by a pH meter and transmitted to the controller. The pH adjuster is loaded into the dropper, and the controller controls the dropper to add the pH adjuster to the slurry, thereby adjusting the pH value of the slurry to 8.

[0096] Add sodium dodecyl sulfate, an anionic collector, and stir for 1 minute using a stirring device. The anionic collector will adsorb onto the surfaces of feldspar and quartz. Then, add quartz inhibitor and sodium hexametaphosphate. The ratio of quartz inhibitor to slurry is 1:100. Add 600g of sodium hexametaphosphate per liter of slurry. When the pH meter detects that the pH value of the slurry is not 8, the controller automatically controls the dropper to continue adding pH adjuster to keep the pH value of the slurry at 8. Sodium hexametaphosphate in the quartz inhibitor can remove the anionic collector from the surface of quartz. Soluble starch cross-linked microspheres have a large number of hydroxyl groups, which can be adsorbed onto the surface of quartz, hindering the adsorption of the collector on the surface of quartz, thereby effectively inhibiting quartz.

[0097] Add 0.2 × 10 to each liter of slurry -30.08 mol of sodium oleate as a feldspar activator was added to mol of cationic collector dodecylamine hydrochloride. The mixture was stirred for 1 min by a stirring device. The anions act as anionic active sites, and the cationic collector was adsorbed on the anionic active sites, thereby allowing the feldspar to float out of the slurry. The flotation was then skimmed for 3 min.

[0098] Collect the foam, wash and dry it to obtain feldspar after one flotation.

[0099] S7: Add feldspar inhibitor under alkaline conditions to float quartz.

[0100] After the first flotation, the feldspar was added to the flotation machine and deionized water was added and stirred to adjust the slurry concentration to 80%, the flotation slurry temperature was 20℃, and the pH value of the slurry was adjusted to 12 using a pH adjuster.

[0101] A metal activator is added to the slurry for activation; the metal ion is Ca. 2+ Mg 2+ And Al 3+ One of them has a metal ion concentration of 1.2 × 10⁻⁶ per liter of slurry. -3 mol, and add the anionic collector sodium dodecyl sulfonate and feldspar inhibitor, adding 1.2 × 10 mol / L of slurry. -3 The ratio of feldspar inhibitor to slurry is 1:100. Metal cations react with anionic collectors under alkaline conditions to form neutral complexes, which allows quartz to be preferentially floated out of the slurry. Pectin and dicarboxylated anionic polyacrylamide in the feldspar inhibitor can chemically adsorb on the feldspar surface, thus hindering the action of anionic collectors. However, pectin and dicarboxylated anionic polyacrylamide do not affect the adsorption of anionic collectors on the quartz surface, thereby inhibiting feldspar and improving the floatability of quartz. Floatation is carried out for 3 minutes.

[0102] The slurry is collected, washed, and dried to obtain feldspar with low silicon content after secondary flotation.

[0103] Example 3

[0104] A process for reducing silicon content in feldspar based on lepidolite tailings, referenced Figure 1 Specifically, it includes the following steps:

[0105] S1: Pretreatment of lithium mica tailings

[0106] Lithium mica tailings and deionized water were added to a grinding mill for grinding. The grinding concentration was 60%, the grinding media was ceramic balls, and the ceramic ball ratio was φ25mm:φ20mm:φ15mm = 1:2:1. The grinding media filling rate was 45%, the grinding time was 10 minutes, and the mill speed was 600 r / min.

[0107] The slurry was added to an ultrasonic cleaner for ultrasonic treatment with an ultrasonic power of 250W and an ultrasonic time of 2 minutes to increase the difference in floatability between feldspar and quartz.

[0108] S2: Preparation of soluble starch cross-linked microspheres

[0109] Soluble starch is added to a mixing container containing water, with a mass concentration of 35%. The pH value is then adjusted to 8 using a pH adjuster. The mixing container is heated using a water bath to dissolve and gelatinize the soluble starch until the solution becomes transparent. The temperature of the water bath is adjusted to 60°C to cool the soluble starch solution, thus obtaining the aqueous phase.

[0110] The second mixing container containing liquid paraffin was placed in a 60°C water bath. Then, an emulsifier, specifically Span 60, was added to the second mixing container at a rate of 0.05g per milliliter of liquid paraffin. The second mixing container was heated in the water bath while being stirred at a speed of 600r / min to completely dissolve the emulsifier and obtain the oil phase.

[0111] The mixing container containing the oil phase was continued to be bathed in a water bath device, and the water bath temperature was adjusted to 50°C. The aqueous phase was slowly added to the oil phase through a dropper, and the mixture was stirred with a stirrer at a speed of 500 r / min for 40 min to emulsify the system. The crosslinking agent epichlorohydrin was added and the mixture was stirred for another 4 h. The volume ratio of crosslinking agent, aqueous phase and oil phase was 1:5:40. The mixture was then crosslinked in a water bath at 50°C for 5 h to obtain a crosslinked mixture.

[0112] The cross-linked mixture was washed four times with water until it was clear and pH neutral. Then, diethyl ether was added to extract the residual solvent. The extracted cross-linked mixture was filtered and then dried in a forced-air drying oven until the mass was constant at a drying temperature of 65°C to obtain soluble starch cross-linked microspheres.

[0113] S3: Preparation of quartz inhibitors

[0114] Soluble starch cross-linked microspheres were added to deionized water and mixed evenly. 2g of soluble starch cross-linked microspheres were added per liter of deionized water to obtain a quartz inhibitor.

[0115] S4: Preparation of dicarboxylated anionic polyacrylamide

[0116] Acrylamide, anionic monomer, and deionized water were added to the reaction vessel. The mass ratio of acrylamide to anionic monomer was 1:3. The anionic monomer contained a vinyl group and two carboxyl groups, specifically one of 2-acrylamidoglutaric acid and fumaric acid. The mixture was stirred to dissolve the monomer, and the pH of the solution in the reaction vessel was adjusted to 4 using a pH adjuster.

[0117] Nitrogen gas was introduced into the reactor for 1.5 hours, and simultaneously an oxidant, a reducing agent, and an azo initiator dissolved in deionized water were added. The oxidant was one of potassium persulfate, ammonium persulfate, and hydrogen peroxide. The reducing agent was one of sodium bisulfite, sodium sulfite, and ferrous sulfate. The azo initiator was one of azobisisobutyramidine hydrochloride and azobisisobutyramidine imidazoline hydrochloride. The concentration of the oxidant was 0.02%, the mass ratio of oxidant to reducing agent was 1:1, and the mass fraction of the azo initiator in the anionic monomer was 0.05%. After reacting in the reactor for 6 hours, a gel-like product was obtained.

[0118] The gelatinous product was washed with a detergent until it turned white. The detergent was one of acetone, anhydrous ethanol, diethyl ether, or a mixed solution of ethanol and acetone. The gelatinous product was pre-crushed by a crushing device, dried in a drying oven, and then crushed again. It was then stored in a storage container to obtain dicarboxylic anionic polyacrylamide.

[0119] S5: Preparation of feldspar inhibitors

[0120] Pectin, dicarboxylated anionic polyacrylamide, and deionized water were mixed evenly, and 0.1g of pectin and 0.2g of dicarboxylated anionic polyacrylamide were added per liter of deionized water to obtain feldspar inhibitor;

[0121] S6: Add quartz inhibitor under neutral conditions to float feldspar.

[0122] The slurry is added to the flotation machine at a temperature of 25°C. The pH value of the slurry is monitored in real time by a pH meter and transmitted to the controller. The pH adjuster is loaded into the dropper, and the controller controls the dropper to add the pH adjuster to the slurry, thereby adjusting the pH value of the slurry to 7.

[0123] Add sodium dodecyl sulfate, an anionic collector, and stir for 2 minutes using a stirring device. The anionic collector will be adsorbed onto the surface of feldspar and quartz. Then add quartz inhibitor and sodium hexametaphosphate. The ratio of quartz inhibitor to slurry is 1:90. Add 300g of sodium hexametaphosphate per liter of slurry. When the pH meter detects that the pH value of the slurry is not 7, the controller automatically controls the dropper to continue adding pH adjuster to keep the pH value of the slurry at 7. Sodium hexametaphosphate in the quartz inhibitor can remove the anionic collector from the surface of quartz. Soluble starch cross-linked microspheres have a large number of hydroxyl groups, which can be adsorbed onto the surface of quartz, hindering the adsorption of the collector on the surface of quartz, thereby effectively inhibiting quartz.

[0124] Add 0.15×10 to each liter of slurry -30.05 mol of sodium oleate as a feldspar activator was added to mol of cationic collector dodecylamine hydrochloride. The mixture was stirred for 2 min by a stirring device. The anions act as anionic active sites, and the cationic collector was adsorbed on the anionic active sites, thereby allowing the feldspar to float out of the slurry. The flotation was then skimmed for 5 min.

[0125] Collect the foam, wash and dry it to obtain feldspar after one flotation.

[0126] S7: Add feldspar inhibitor under alkaline conditions to float quartz.

[0127] After the first flotation, the feldspar was added to the flotation machine and deionized water was added and stirred to adjust the slurry concentration to 60%. The flotation slurry temperature was 25℃, and the pH value of the slurry was adjusted to 10 using a pH adjuster.

[0128] A metal activator is added to the slurry for activation; the metal ion is Ca. 2+ Mg 2+ And Al 3+ One of them has a metal ion concentration of 1×10⁻⁶ per liter of slurry. -3 mol, and add sodium dodecyl sulfonate anionic collector and feldspar inhibitor, 1×10 mol per liter of slurry. -3 The ratio of feldspar inhibitor to slurry is 1:90. Metal cations react with anionic collectors under alkaline conditions to form neutral complexes, which allows quartz to be preferentially floated out of the slurry. Pectin and dicarboxylated anionic polyacrylamide in the feldspar inhibitor can chemically adsorb on the feldspar surface, thus hindering the action of anionic collectors. However, pectin and dicarboxylated anionic polyacrylamide do not affect the adsorption of anionic collectors on the quartz surface, thereby inhibiting feldspar and improving the floatability of quartz. Floatation and skimming are performed for 3-5 minutes.

[0129] The slurry is collected, washed, and dried to obtain feldspar with low silicon content after secondary flotation.

[0130] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A process for reducing the silicon content in feldspar based on lepidolite tailings, characterized in that, Specifically, the following steps are included: S1: Pretreatment of lithium mica tailings Lithium mica tailings are added to a grinding mill for grinding, and the slurry is added to an ultrasonic cleaner for ultrasonic treatment. S2: Preparation of soluble starch cross-linked microspheres Soluble starch was dissolved in water and heated to gelatinize until the solution became transparent, resulting in an aqueous phase. A second mixing container containing liquid paraffin was placed in a water bath, and an emulsifier was added to the second mixing container for water bath heating, resulting in an oil phase. The aqueous phase was slowly added to the oil phase using a dropper, and the mixture was stirred with a stirrer. Epichlorohydrin, a crosslinking agent, was added, and stirring was continued for water bath crosslinking. The crosslinked mixture was washed with water, extracted, filtered, and dried to obtain soluble starch crosslinked microspheres. S3: Preparation of quartz inhibitors Soluble starch cross-linked microspheres were added to deionized water and mixed evenly. 2-8g of soluble starch cross-linked microspheres were added per liter of deionized water to obtain a quartz inhibitor. S4: Preparation of dicarboxylated anionic polyacrylamide Acrylamide, anionic monomer, and deionized water are added to a reaction vessel, stirred and dissolved, and after adjusting the pH value, nitrogen gas is introduced into the reaction vessel. Simultaneously, an oxidant, a reducing agent, and an azo initiator dissolved in deionized water are added. The reaction yields a gelatinous product. The gelatinous product is washed, pre-crushed, dried, and pulverized using a detergent to obtain dicarboxyl-type anionic polyacrylamide. Specifically, the oxidant is one of potassium persulfate, ammonium persulfate, and hydrogen peroxide; the reducing agent is one of sodium bisulfite, sodium sulfite, and ferrous sulfate; the azo initiator is one of azobisisobutyramidine hydrochloride and azobisisobutyramidine imidazoline hydrochloride; and the detergent is one of acetone, anhydrous ethanol, diethyl ether, and a mixed solution of ethanol and acetone. The anionic monomer contains a vinyl group and two carboxyl groups, specifically one of 2-acrylamidoglutaric acid and fumaric acid. S5: Preparation of feldspar inhibitors Pectin, dicarboxylated anionic polyacrylamide, and deionized water were mixed evenly. 0.1-0.3g of pectin and 0.2-1g of dicarboxylated anionic polyacrylamide were added per liter of deionized water to obtain feldspar inhibitors. S6: Add quartz inhibitor under neutral conditions to float feldspar. The ultrasonically treated slurry is added to the flotation machine, the pH of the slurry is adjusted to neutral, an anionic collector is added and stirred, then quartz inhibitor and sodium hexametaphosphate are added, followed by cationic collector dodecylamine hydrochloride, and sodium oleate is used as a feldspar activator to float the feldspar. The foam is collected, washed and dried to obtain feldspar after one flotation. S7: Add feldspar inhibitor under alkaline conditions to float quartz. Feldspar after the first flotation is mixed with deionized water and then added to the flotation machine. The pH of the pulp is adjusted to be alkaline, and a metal activator, anion collector, and feldspar inhibitor are added to activate it, so that quartz floats out of the pulp. The pulp is collected, washed, and dried to obtain feldspar with low silicon content after the second flotation.

2. The process for reducing silicon content in feldspar based on lepidolite tailings according to claim 1, characterized in that, Step S1 involves preprocessing the lithium mica tailings, specifically including the following steps: S1.1: Add lithium mica tailings and deionized water into the grinding mill for grinding. The grinding concentration is 60%-80%, the grinding media is ceramic balls, the grinding media filling rate is 35-45%, the grinding time is 5-10 min, and the mill speed is 500-600 r / min. S1.2: Add the slurry to an ultrasonic cleaner for ultrasonic treatment. The ultrasonic power is 150-250W and the ultrasonic time is 1-2 minutes.

3. The process for reducing silicon content in feldspar based on lepidolite tailings according to claim 2, characterized in that, Step S2 involves preparing soluble starch cross-linked microspheres, specifically including the following steps: S2.1: Add soluble starch to a mixing container containing water. The mass concentration of soluble starch is 35-45%. Adjust the pH value to 8-9 using a pH adjuster. Heat the mixing container using a water bath to dissolve the soluble starch and gelatinize it until the solution becomes transparent. Adjust the temperature of the water bath to 55-60℃ to cool the soluble starch solution and obtain the aqueous phase. S2.2: Place the second mixing container containing liquid paraffin into a water bath at 55-60℃, then add the emulsifier to the second mixing container. Add 0.05-0.08g of emulsifier per milliliter of liquid paraffin. Heat the second mixing container in the water bath while stirring with a stirrer at a speed of 500-600r / min to completely dissolve the emulsifier and obtain the oil phase. S2.3: Continue to bathe the mixing container containing the oil phase in a water bath device, adjust the water bath temperature to 45-50℃, slowly add the aqueous phase to the oil phase using a dropper, and stir with a stirrer at a speed of 400-500 r / min for 30-40 min to emulsify the system. Add the crosslinking agent epichlorohydrin and continue stirring for 3-4 h. The volume ratio of crosslinking agent, aqueous phase and oil phase is 1:(5-6):(40-50). Crosslink the mixture in a water bath at 45-50℃ for 4-5 h to obtain the crosslinked mixture. S2.4: Wash the cross-linked mixture with water 3-4 times until it is clear and pH neutral, then add diethyl ether to extract the residual solvent, filter the extracted cross-linked mixture, and then dry it in a forced-air drying oven until the mass is constant at a drying temperature of 60-65℃ to obtain soluble starch cross-linked microspheres.

4. The process for reducing silicon content in feldspar based on lepidolite tailings according to claim 3, characterized in that, Step S4 involves the preparation of dicarboxylated anionic polyacrylamide, specifically including the following steps: S4.1: Add acrylamide, anionic monomer and deionized water to the reaction vessel. The mass ratio of acrylamide to anionic monomer is 1:(3-10). Stir to dissolve. Use a pH adjuster to adjust the pH of the solution in the reaction vessel to 4-5. S4.2: Nitrogen gas is introduced into the reactor for 1-1.5 hours, and oxidant, reducing agent and azo initiator dissolved in deionized water are added at the same time. The concentration of oxidant is 0.02-0.05%, the mass ratio of oxidant to reducing agent is (1-3):1, and the mass fraction of azo initiator in anionic monomer is 0.05-0.2%. After reacting in the reactor for 4-6 hours, a gel-like product is obtained. S4.3: Wash the gelatinous product with detergent until it turns white. After pre-crushing the gelatinous product with a crushing device, dry it in a drying oven, then crush it again with a crushing device, and store it in a storage container to obtain dicarboxylic anionic polyacrylamide.

5. The process for reducing silicon content in feldspar based on lepidolite tailings according to claim 4, characterized in that, Step S6 involves adding a quartz inhibitor under neutral conditions to float feldspar, specifically including the following steps: S6.1: Add the slurry to the flotation machine. The temperature of the flotation slurry is 20-25℃. The pH value of the slurry is detected in real time by a pH meter and transmitted to the controller. The pH adjuster is loaded into the dropper. The controller controls the dropper to add the pH adjuster to the slurry, thereby adjusting the pH value of the slurry to 7-8. S6.2: Add sodium dodecyl sulfate, an anionic collector, and stir for 1-2 minutes using a stirring device. Then add quartz inhibitor and sodium hexametaphosphate. The ratio of quartz inhibitor to slurry is 1:(90-100). Add 300-600g of sodium hexametaphosphate per liter of slurry. When the pH meter detects that the pH value of the slurry deviates from the range of 7-8, the controller automatically controls the dropper to continue adding pH adjuster to keep the pH value of the slurry within the range of 7-8. S6.3: Add (0.15-0.2) × 10 per liter of slurry -3 Add 0.05-0.08 mol of sodium oleate as a feldspar activator to the cationic collector dodecylamine hydrochloride, and stir with a stirring device for 1-2 minutes to allow feldspar to float out of the slurry. Then, perform flotation and skim-over for 3-5 minutes. S6.4: Collect the foam, wash and dry the foam to obtain feldspar after one flotation.

6. The process for reducing silicon content in feldspar based on lepidolite tailings according to claim 5, characterized in that, Step S7 involves adding a feldspar inhibitor under alkaline conditions to float the quartz, specifically including the following steps: S7.1: After the first flotation, the feldspar is added to the flotation machine and deionized water is added and stirred to adjust the slurry concentration to 60%-80%, the flotation slurry temperature is 20-25℃, and the pH value of the slurry is adjusted to 10-12 using a pH adjuster. S7.2: Add a metal activator to the slurry, with a metal ion concentration of (1-1.2)×10⁻⁶ per liter of slurry. -3 mol, and add the anionic collector sodium dodecyl sulfonate and feldspar inhibitor, adding (1-1.2)×10 per liter of slurry. -3 The ratio of anionic collector to feldspar inhibitor to pulp is 1:(90-100), quartz is preferentially floated out of the pulp, and flotation is skimmed for 3-5 minutes. S7.3: Collect the slurry, wash and dry it to obtain feldspar with low silicon content after secondary flotation.

7. The process for reducing silicon content in feldspar based on lepidolite tailings according to claim 2, characterized in that, The ceramic ball ratio in step S1 is φ25mm:φ20mm:φ15mm = 1:(1-2):

1.

8. The process for reducing silicon content in feldspar based on lepidolite tailings according to claim 3, characterized in that, The emulsifier in step S2 is specifically Span60.

9. The process for reducing silicon content in feldspar based on lepidolite tailings according to claim 6, characterized in that, The metal ion in step S7.2 is one of Ca2+, Mg2+ and Al3+.

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