Organic silicon compound mixed defoaming agent for phosphorite flotation as well as preparation method and use method of organic silicon compound mixed defoaming agent

Abstract

The invention provides a phosphorite double-reverse flotation defoaming agent as well as a preparation method and an application method thereof. The defoaming agent is prepared from vinyl silicone oil, hydrogen-containing silicone oil, simethicone, polyether modified silicone oil, an emulsifier, white carbon black, MQ silicon resin, a dispersing agent, a catalyst, a thickening agent, water and the like, all the materials are uniformly mixed according to a certain proportion, and the mixture is prepared into a uniform emulsion by using high-speed dispersion equipment for use. The efficient defoaming agent is successfully synthesized by taking the silicone oil as a raw material, has good defoaming and foam inhibition performance, is fast in defoaming and lasting in foam inhibition, has excellent defoaming performance under a high-temperature condition, and has an important application value in phosphorite flotation production.

Description

Technical Field

[0001] This invention relates to the field of phosphate rock flotation, specifically to an organosilicon compound defoamer composition and its preparation method. Background Technology

[0002] Phosphate has a high content of aluminosilicate minerals. In the wet process of phosphoric acid production, the presence of magnesium oxide and aluminum oxide can cause phosphoric acid to form slag, which can also greatly affect the growth of calcium sulfate crystals, ultimately leading to P2O5 loss during concentration. The double reverse flotation method can effectively separate phosphate from gangue minerals such as dolomite and aluminosilicates. The process is simple and easy to operate.

[0003] When processing siliceous phosphate rock using the double-reverse flotation process, the cationic collector is sensitive to fine-grained minerals. The extensive use of cationic collectors and the recycling of return water easily lead to the formation of three-phase foam (solid, liquid, and gas). The small solid particles increase the mechanical strength of the bubble walls, making the foam more stable and hindering bubble coalescence and liquid film loss. This results in abundant and tough foam, making defoaming difficult, affecting flotation stability, and easily leading to overstable foam accumulation. Problems include viscous flotation foam with poor flowability, increased difficulty in conveying and dewatering the flotation concentrate pulp, reduced concentrate grade, increased impurity content in the concentrate, high suspended solids in the return water, and difficulty in reusing the return water.

[0004] Existing flotation processes are ill-suited to phosphate rock of varying quality and impurity content, failing to effectively remove impurities such as alumina, thus impacting flotation efficiency and prone to foam accumulation. To address these issues, researchers have explored emerging technologies such as gravity-flotation combined flotation, demonstrating promising prospects. This process, by optimizing collector selection and dosage and introducing defoamers, can effectively remove impurities such as alumina, improving phosphate concentrate quality. However, existing defoamer formulations are not yet fully optimized. When dealing with three-phase foam, the defoamer's own adsorption cannot fully spread on the liquid film, resulting in unsatisfactory defoaming effects that fail to meet practical application requirements. Furthermore, it is difficult for the defoamer to synergize effectively with flotation collectors, necessitating further improvements in defoaming performance and flotation indicators.

[0005] The problems of large volume, stickiness, and difficulty in dissipation of foam in the three-phase flotation of phosphate rock remain significant. To solve these problems, Wei Ming'an disclosed a defoaming method in patent CN103285625A. A spray pipe is suspended above the foam tank of the reverse flotation desilication of phosphate rock. The mechanical impact force and the rapid diffusion and penetration of the defoaming agent are used to destroy the foam film and achieve defoaming.

[0006] CN116492722A discloses a silicone defoamer composition for foam drainage gas extraction and its preparation method. This patent uses silicone paste, emulsifier, synergist, thickener, and deionized water to form the defoamer. The silicone paste prepared through a hydrosilylation reaction exhibits significant defoaming and foam-suppressing effects in gas extraction silicone defoamers. However, in practical applications, this patent still suffers from insufficient stability of the defoamer in acidic environments.

[0007] CN115283143A discloses a defoamer for amine flotation collectors, its preparation method, and its application method. This defoamer is a mixture of polyether-modified silicone oil and alkyl sulfonate, which can accelerate the foam dissipation process of amine flotation collectors, prevent cell run-off, and make the flotation process more stable. However, this patent still has the problem that the defoaming effect and flotation indicators of the defoamer need further optimization.

[0008] These methods have limited effectiveness in dealing with the three-phase foam accumulated during reverse flotation. There is a lack of a defoamer that can simultaneously take into account both strong hydrophobicity and semi-hydrophilicity. It is difficult to achieve good dispersibility and defoaming effect in phosphate rock with different qualities and impurity contents. There is an urgent need to develop a defoamer that can effectively solve the problem of a large amount of accumulated foam generated during the flotation of phosphate rock, so as to improve the stability and efficiency of flotation.

[0009] Developing a defoamer that is stable in acidic environments and provides rapid defoaming has become a key research focus. This defoamer would help improve flotation efficiency and enable the efficient utilization of low- to medium-grade siliceous calcium phosphate rock. Summary of the Invention

[0010] This application aims to provide a phosphate rock flotation defoamer product and its preparation and use method, particularly a phosphate rock flotation defoamer characterized by rapid defoaming, good dispersibility on the mineral surface, flexible pH adaptability and balanced foam suppression ability, and adaptability to different qualities and impurity contents.

[0011] To achieve the above objectives, the present invention is implemented through the following technical solution: The phosphate rock flotation defoamer product of this invention comprises the following raw materials by weight: 5-40 parts of strongly hydrophobic silicone paste, 5-40 parts of semi-hydrophilic silicone paste, 3-25 parts of polyether-modified silicone oil, 20-40 parts of emulsifier, 1-20 parts of dispersant, 0.1-10 parts of thickener, and 50-120 parts of deionized water; the average particle size of the strongly hydrophobic silicone paste, semi-hydrophilic silicone paste, and dispersant is 50-200 micrometers.

[0012] Preferably, the defoamer product comprises the following raw materials by weight: 10 parts of strongly hydrophobic silicone paste, 20 parts of semi-hydrophilic silicone paste, 6 parts of polyether-modified silicone oil, 25 parts of emulsifier, 6 parts of dispersant, 0.8 parts of thickener, and 72 parts of deionized water.

[0013] The strongly hydrophobic silicone paste comprises the following raw materials by weight: 60-100 parts of 20000cP vinyl silicone oil, 1-8 parts of hydrogen-containing silicone oil, 5-30 parts of hydrophobic silica, and 0.1-1 parts of catalyst.

[0014] Preferably, the strongly hydrophobic silicone paste comprises the following raw materials by weight: 83 parts of 20000cP vinyl silicone oil, 6 parts of hydrogen-containing silicone oil, 13 parts of hydrophobic silica, and 0.1 parts of catalyst.

[0015] The semi-hydrophilic silicone paste comprises the following raw materials by weight: 20-50 parts of 1000cP dimethyl silicone oil, 20-60 parts of 60000cP dimethyl silicone oil, 5-30 parts of precipitated silica, 5-30 parts of MQ silicone resin, 1-5 parts of silazane, and 0.1-1 parts of deionized water.

[0016] Preferably, the semi-hydrophilic silicone paste comprises the following raw materials by weight: 45 parts of 1000cP dimethyl silicone oil, 28 parts of 60000cP dimethyl silicone oil, 16 parts of fumed silica, 13 parts of MQ silicone resin, 3 parts of silazane, and 0.6 parts of deionized water.

[0017] The 20000cP vinyl silicone oil has a viscosity of 19500-20500cP at room temperature, a vinyl end content of 0.01-0.5%, a volatile content of <0.2%, a flash point of >200℃, and a refractive index of 1.400-1.410.

[0018] The hydrogen-containing silicone oil has a viscosity of 10-200 cP at room temperature, a volatile content of <1%, an active hydrogen content of 0.1-0.5%, a flash point of >100℃, and a refractive index of 1.390-1.410.

[0019] The hydrophobic silica is a white, fluffy powder, which is a hydrophobically modified fumed silica with a silica content ≥99% and a specific surface area of ​​200-300 m². 2 / g, volatile matter at 105℃ ≤2.5%.

[0020] The catalyst is selected from one or more composites of Castells platinum catalyst, Ashby platinum catalyst, platinum-vinylsiloxane complex catalyst, and platinum-olefin complex catalyst.

[0021] The 1000cP dimethyl silicone oil has a viscosity of 960-1040cP, volatile matter <0.2%, turbidity <3 NTU, and density of 0.965-0.98 g / cm³. 3 The refractive index is 1.40-1.405.

[0022] The 60000cP dimethyl silicone oil has a viscosity of 59000-61000cP, volatile matter <0.5%, turbidity <5 NTU, and density of 0.970-0.985 g / cm³. 3 The refractive index is 1.4025-1.405.

[0023] The precipitated silica is a white powder with a silica content ≥99.8% and a specific surface area of ​​100-300 m². 2 / g, volatile matter at 105℃ ≤2%.

[0024] The MQ silicone resin is a white powder with a volatile content of <0.96%, a hydroxyl content of 4-6%, and a weight-average molecular weight of 6500-7000.

[0025] The silazane is a colorless and transparent liquid with a purity >99%, a density of 0.774–0.780 g / cm³, a flash point of 25–30℃, and a refractive index of 1.407–1.409.

[0026] The polyether-modified silicone oil is a double-terminated polyether-modified polysiloxane.

[0027] The emulsifier is any one or a combination of two or more of the following: fatty alcohol polyoxyethylene ether, isotridecyl alcohol polyoxyethylene ether, glyceryl stearate, polysorbate, and dehydrated sorbitan fatty acid ester.

[0028] The dispersant is selected from one or more of the following: alkylphenyl ether sulfate, block polyether polymer, alkylammonium salt polymer copolymer, imino anchoring group hyperbranched polyester compound, and fatty acid polyethylene glycol ester.

[0029] The thickener is any one or a combination of two or more of the following: hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, xanthan gum, and polyacrylate.

[0030] The preparation method described in this invention is as follows: (1) Add 20,000 cP of vinyl silicone oil to the reactor, and then slowly and in batches add hydrophobic silica while stirring to prevent dust from flying and clumping. Shear and stir for 1.5-3 hours to make the silica and vinyl silicone oil mix evenly. Under low speed stirring, slowly add the predetermined amount of catalyst. After mixing evenly, add hydrogen-containing silicone oil, heat to 50-80℃, and continue stirring and shearing for 2-4 hours. After cooling, obtain silicone paste.

[0031] (2) Preparation of semi-hydrophilic silicone paste: Add a certain amount of 1000 cP and 60000 cP dimethyl silicone oil to the reaction vessel, start low-speed stirring, add silazane and deionized water while stirring, stir for 0.5 h after the addition is complete, add precipitated silica in batches and stir while adding, and after stirring evenly, heat to 130-160℃, continue stirring and shearing for 3-4 h, turn on the vacuum pump to remove NH3, turn off the vacuum pump and heating device after 0.5 h, and obtain silicone paste after cooling.

[0032] (3) After mixing the thickener with deionized water, add it to the emulsification equipment and stir evenly. Then, add the dispersant, emulsifier, strong hydrophobic silicone paste, semi-hydrophilic silicone paste and polyether modified silicone oil in sequence. Stir evenly at low speed first, and then perform high-speed shear emulsification to control the particle size to 10-50 micrometers. Filter the material to obtain the phosphate rock double-reverse flotation defoamer.

[0033] The double reverse flotation process for phosphate rock in this embodiment of the invention is as follows: the raw phosphate rock is ground and the pulp concentration is adjusted to 20%~30%. The pulp with the adjusted concentration is fed into a spiral sluice for gravity separation to complete the desliming process before flotation. Anionic demagnesizing collector, dealuminizing collector and flotation defoamer are added to the concentrate pulp to conduct a double reverse flotation test. The mass of the concentrate and tailings from the flotation test is weighed and collected, and the recovery yield of the concentrate is calculated.

[0034] In this embodiment of the invention, when performing flotation of collophane, a marker is used to record the scale lines on the flotation cell and the scale is converted into volume. During the flotation process, the stirring frequency, aeration volume and scraper rotation frequency are fixed. The scale corresponding to the height of foam in the flotation cell before and after foam scraping is recorded. The foam scraping time is 5 minutes. After the process is completed, the total volume of foam generated is recorded.

[0035] In the embodiments of the present invention, the pH adjuster used is sodium hydroxide or phosphoric acid.

[0036] In this embodiment of the invention, the magnesium removal collector used is a fatty acid soap collector from Hubei Xingfa Chemical Co., Ltd., and the anionic magnesium removal collector is prepared into a solution with a concentration of 1.0-2.0% by adding water.

[0037] In the embodiments of the present invention, the magnesium removal collector used is an ether-amine mixture collector, and the cationic aluminum removal collector is prepared into a solution with a concentration of 1.0-2.0% by adding water.

[0038] In this embodiment of the invention, the phosphate rock is a concentrate after gravity separation, with a P2O5 content of 24%-28%, an MgO content of 4%-6%, and an Al2O3 content of 3%-5%.

[0039] Beneficial effects of this invention: 1. This invention, through optimized formulation and component design, develops a compound defoamer product with strong hydrophobicity and semi-hydrophilicity. It can defoam quickly without prolonged foam suppression, achieving a balance between defoaming and foam suppression. Moreover, it can maintain a stable structure in acidic environments and is not easily deactivated, significantly improving the applicability and practicality of the defoamer. It is stable under pH conditions of 2.0-6.0, with an initial defoaming time of less than 2 minutes.

[0040] 2. The defoamer product of this invention has good dispersibility, which can significantly improve the dispersion performance of phosphate rock with different qualities and impurity contents. It can effectively solve the problem of a large amount of three-phase foam generated during the flotation of phosphate rock, effectively prevent foam accumulation, and significantly improve the stability and efficiency of flotation.

[0041] 3. The defoamer product of the present invention can effectively reduce the surface tension of the solution system through the synergistic effect of multiple functional components, improve the collection efficiency of the collector on hydrophobic mineral particles, and promote the collection of gangue minerals such as calcite and dolomite by the collector; thus effectively improving the quality and recovery rate of phosphate concentrate.

[0042] When the defoamer of this invention is used in flotation tests, the volume of foam formed after flotation is reduced by 1 / 2 to 2 / 3 compared to when no defoamer is added. The defoamer of this invention uses safe and non-toxic raw materials, has a simple preparation method, stable chemical composition and properties, and requires a small dosage. It can effectively reduce the foam generated during flotation, making the flotation process more stable. It can be used in the flotation process of phosphate rock of various qualities and impurity contents, and is especially suitable for the gravity-flotation combined process of medium and low grade siliceous calcium phosphate rock, which can effectively improve flotation efficiency and phosphate concentrate quality. Detailed Implementation

[0043] The present invention will be further described below with reference to the embodiments. However, these embodiments should not be construed as limiting the scope of protection of the present invention. Experimental methods in the following embodiments, unless otherwise specified, were performed according to conventional methods or product instructions. In the embodiments of the present invention, 1 part is 1 kg.

[0044] Example 1 Raw material ratio: 10 parts of strong hydrophobic silicone paste, 20 parts of semi-hydrophilic silicone paste, 6 parts of polyether modified silicone oil, 25 parts of emulsifier, 3 parts of dispersant, 0.8 parts of thickener, and 72 parts of deionized water.

[0045] The raw material ratio of the highly hydrophobic silicone paste is as follows: 83 parts of 20000cP vinyl silicone oil, 6 parts of hydrogen-containing silicone oil, 13 parts of hydrophobic silica, and 0.1 parts of catalyst.

[0046] The raw material ratio of semi-hydrophilic silicone paste is as follows: 45 parts of 1000cP dimethyl silicone oil, 28 parts of 60000cP dimethyl silicone oil, 16 parts of fumed silica, 13 parts of MQ silicone resin, 3 parts of silazane, and 0.6 parts of deionized water.

[0047] Polyether-modified silicone oil: Double-terminated polyether-modified polysiloxane Emulsifier: A 1:1 composite of fatty alcohol polyoxyethylene ether and isomeric tridecyl alcohol polyoxyethylene ether Dispersant: Block polyether polymer Thickener: Hydroxyethyl cellulose Weigh the raw materials of the above components and add them to the emulsification equipment. After stirring evenly, turn on the shearing device in the emulsification tank to shear the particle size of the emulsion defoamer to 10-30 micrometers. Filter and discharge to obtain phosphate rock double reverse flotation defoamer. Then seal and package it to prepare defoamer 1. Store it in a dry and cool environment and add it directly to the flotation cell when using.

[0048] Example 2 The composition of each raw material is the same as in Example 1, except that the proportions are as follows: 5 parts of strong hydrophobic silicone paste, 20 parts of semi-hydrophilic silicone paste, 6 parts of polyether modified silicone oil, 25 parts of emulsifier, 3 parts of dispersant, 0.8 parts of thickener, and 78 parts of deionized water.

[0049] Weigh the raw materials of the above components and add them to the emulsification equipment. After stirring evenly, turn on the shearing device in the emulsification tank to shear the particle size of the emulsion defoamer to 10-50 micrometers. Filter and discharge to obtain phosphate rock double reverse flotation defoamer. Then seal and package it to prepare defoamer 2. Store it in a dry and cool environment and add it directly to the flotation cell when using.

[0050] Example 3 The composition of each raw material is the same as in Example 1, except that the proportions are as follows: 20 parts of strong hydrophobic silicone paste, 20 parts of semi-hydrophilic silicone paste, 6 parts of polyether modified silicone oil, 25 parts of emulsifier, 3 parts of dispersant, 0.8 parts of thickener, and 62 parts of deionized water.

[0051] Weigh the raw materials of the above components and add them to the emulsification equipment. After stirring evenly, turn on the shearing device in the emulsification tank to shear the particle size of the emulsion defoamer to 10-30 micrometers. Filter and discharge to obtain phosphate rock double reverse flotation defoamer. Then seal and package it to prepare defoamer 3. Store it in a dry and cool environment and add it directly to the flotation cell when using.

[0052] Example 4 The composition of each raw material is the same as in Example 1, except that the proportions are as follows: 10 parts of strong hydrophobic silicone paste, 5 parts of semi-hydrophilic silicone paste, 6 parts of polyether modified silicone oil, 25 parts of emulsifier, 3 parts of dispersant, 0.8 parts of thickener, and 87 parts of deionized water.

[0053] Weigh the raw materials of the above components and add them to the emulsification equipment. After stirring evenly, turn on the shearing device in the emulsification tank to shear the particle size of the emulsion defoamer to 10-30 micrometers. Filter and discharge to obtain phosphate rock double reverse flotation defoamer. Then seal and package it to prepare defoamer 4. Store it in a dry and cool environment and add it directly to the flotation cell when using.

[0054] Example 5 The composition of each raw material is the same as in Example 1, except that the proportions are as follows: 10 parts of strong hydrophobic silicone paste, 30 parts of semi-hydrophilic silicone paste, 6 parts of polyether modified silicone oil, 25 parts of emulsifier, 3 parts of dispersant, 0.8 parts of thickener, and 62 parts of deionized water.

[0055] Weigh the raw materials of the above components and add them to the emulsification equipment. After stirring evenly, turn on the shearing device in the emulsification tank to shear the particle size of the emulsion defoamer to 10-50 micrometers. Filter and discharge to obtain phosphate rock double reverse flotation defoamer. Then seal and package it to prepare defoamer 5. Store it in a dry and cool environment and add it directly to the flotation cell when using.

[0056] Example 6 The composition of each raw material is the same as in Example 1, except that the proportions are as follows: 10 parts of strong hydrophobic silicone paste, 20 parts of semi-hydrophilic silicone paste, 20 parts of polyether modified silicone oil, 25 parts of emulsifier, 3 parts of dispersant, 0.8 parts of thickener, and 58 parts of deionized water.

[0057] Weigh the raw materials of the above components and add them to the emulsification equipment. After stirring evenly, turn on the shearing device in the emulsification tank to shear the particle size of the emulsion defoamer to 10-50 micrometers. Filter and discharge to obtain phosphate rock double reverse flotation defoamer. Then seal and package it to prepare defoamer 6. Store it in a dry and cool environment and add it directly to the flotation cell when using.

[0058] Example 7 The composition of each raw material is the same as in Example 1, except that the proportions are as follows: 10 parts of strong hydrophobic silicone paste, 20 parts of semi-hydrophilic silicone paste, 6 parts of polyether modified silicone oil, 35 parts of emulsifier, 3 parts of dispersant, 0.8 parts of thickener, and 62 parts of deionized water.

[0059] Weigh the raw materials of the above components and add them to the emulsification equipment. After stirring evenly, turn on the shearing device in the emulsification tank to shear the particle size of the emulsion defoamer to 10-50 micrometers. Filter and discharge to obtain phosphate rock double reverse flotation defoamer. Then seal and package it to prepare defoamer 6. Store it in a dry and cool environment and add it directly to the flotation cell when using.

[0060] To further verify the feasibility and effectiveness of the present invention and to select the optimal solution, the inventors conducted a series of experiments, as follows: 1. Experiment 1 1.1 Raw material selection experiment: Five formulations were set up, and the specific schemes are as follows: Formula 1 – “Two types of composite silicone paste are used in the raw materials” Raw material ratio: 10 parts of strong hydrophobic silicone paste, 20 parts of semi-hydrophilic silicone paste, 6 parts of polyether modified silicone oil, 25 parts of emulsifier, 3 parts of dispersant, 0.8 parts of thickener, and 72 parts of deionized water.

[0061] Formula 2 – “No strongly hydrophobic, fast-setting silicone paste was used in the raw materials” Raw material ratio: 20 parts semi-hydrophilic silicone paste, 6 parts polyether modified silicone oil, 25 parts emulsifier, 3 parts dispersant, 0.8 parts thickener, and 82 parts deionized water.

[0062] Formula 3 – “No semi-hydrophilic silicone paste was used in the raw materials” Raw material ratio: 10 parts of strong hydrophobic silicone paste, 6 parts of polyether modified silicone oil, 25 parts of emulsifier, 3 parts of dispersant, 0.8 parts of thickener, and 92 parts of deionized water.

[0063] Formula 4 – “No polyether-modified silicone oil was used in the raw materials” Raw material ratio: 10 parts strong hydrophobic silicone paste, 20 parts semi-hydrophilic silicone paste, 25 parts emulsifier, 3 parts dispersant, 0.8 parts thickener, and 78 parts deionized water.

[0064] Formula 5 – “No emulsifiers were used in the raw materials” Raw material ratio: 10 parts of strong hydrophobic silicone paste, 20 parts of semi-hydrophilic silicone paste, 6 parts of polyether modified silicone oil, 3 parts of dispersant, 0.8 parts of thickener, and 97 parts of deionized water.

[0065] 1.2 Preparation method: Weigh the raw materials of the above components and add them to the emulsification equipment. After stirring evenly, turn on the shearing device in the emulsification tank to shear the particle size of the emulsion defoamer to 10-50 micrometers. Filter and discharge to obtain the phosphate rock double reverse flotation defoamer. Then seal and package it and store it in a dry and cool environment. When using, add it directly to the flotation cell.

[0066] 1.3 Performance Test Data and Results: When performing flotation of collophane ore, the gravity-separated concentrate pulp is added to the flotation machine, along with an appropriate amount of return water from the flotation workshop, adjusting the pulp concentration to 20-30%. The stirring speed is set to 1800-2200 rpm, and stirring is performed for 2-3 minutes. Air is then introduced, with the air flow rate controlled at 0.3-0.5 m³ / min. 3 / h.

[0067] In this embodiment of the invention, during the demagnesification and dealuminization dual reverse flotation, a pH adjuster and a demagnesification collector XF-01 are added to the flotation machine. After stirring evenly, the flotation defoamer prepared according to formulas 1-5 is added, with a dosage of 200-400 g / t phosphate rock. A demagnesification reverse flotation test is conducted, controlling the flotation time to 3-5 min, and the concentrate pulp at the bottom of the flotation cell is collected. Return water is added to adjust the pulp concentration, and then the dealuminization collector XF-02 is added. After stirring evenly, the flotation defoamer prepared according to formulas 1-5 is added to the flotation machine, with a dosage of 200-400 g / t phosphate rock. A dealuminization reverse flotation test is conducted, controlling the flotation time to 3-5 min, and the concentrate and tailings from the flotation test are collected separately.

[0068] Record the scale corresponding to the foam height in the flotation cell before and after foam removal, and record the total volume of foam generated after the process is completed. After flotation, shake the tailings slurry foam with a small intensity to observe the defoaming effect and record the time required for 80% defoaming. The test data such as the grade of flotation concentrate and foam condition obtained by the double reverse flotation process are shown in Table 1.

[0069] Table 1 Performance Test Data

[0070] As shown in Table 1: The defoamer obtained by Formula 1 has the following performance: concentrate recovery rate of 71.62%, concentrate P2O5 grade of 33.06%, concentrate impurity MgO content of 0.85%, concentrate impurity Al2O3 content of 1.52%, foam volume of 220mL, and 80% of foam is eliminated in only 10s. Its comprehensive indicators are excellent.

[0071] Compared to formula 1, the defoamers obtained from formulas 2-4 have lower concentrate recovery and P2O5 grade, higher MgO and Al2O3 content in the concentrate, incomplete impurity removal, larger foam volume, and slower defoaming. Formula 5 defoamer has almost no defoaming effect; its flotation concentrate indicators are close to those of the formula without defoamer.

[0072] In conclusion, Formula 1 is the preferred formula.

[0073] 2. Experiment Two 2.1 Preparation method: The optimal formulation 1 obtained from the investigation under "1. Experiment 1" was used for the screening test of the best ratio, specifically the 7 formulations such as Examples 1-7.

[0074] Weigh the raw materials of the above components and add them to the emulsification equipment. After stirring evenly, turn on the shearing device in the emulsification tank to shear the particle size of the emulsion defoamer to 10-50 micrometers. Filter and discharge to obtain the phosphate rock double reverse flotation defoamer. Then seal and package it and store it in a dry and cool environment. When using, add it directly to the flotation cell.

[0075] 2.2 Performance test data and results: When performing flotation of collophane ore, the gravity-separated concentrate pulp is added to the flotation machine, along with an appropriate amount of return water from the flotation workshop, adjusting the pulp concentration to 20-30%. The stirring speed is set to 1800-2200 rpm, and stirring is performed for 2-3 minutes. Air is then introduced, with the air flow rate controlled at 0.3-0.5 m³ / min. 3 / h.

[0076] In this embodiment of the invention, during the demagnesification and dealuminization dual reverse flotation, a pH adjuster and a demagnesification collector XF-01 are added to the flotation machine. After stirring evenly, the flotation defoamer prepared according to formulas 1-5 is added, with a dosage of 200-400 g / t phosphate rock. A demagnesification reverse flotation test is conducted, controlling the flotation time to 3-5 min, and the concentrate pulp at the bottom of the flotation cell is collected. Return water is added to adjust the pulp concentration, and then the dealuminization collector XF-02 is added. After stirring evenly, the flotation defoamer prepared according to formula AG is added to the flotation machine, with a dosage of 200-400 g / t phosphate rock. A dealuminization reverse flotation test is conducted, controlling the flotation time to 3-5 min, and the concentrate and tailings from the flotation test are collected separately. Record the scale corresponding to the foam height in the flotation cell before and after foam removal, and record the total volume of foam generated after the process. After flotation, shake the tailings slurry with a small intensity to observe the defoaming effect and record the time required for 80% defoaming. The test data obtained by the double reverse flotation process, such as the grade of flotation concentrate and foam condition, are shown in Table 2.

[0077] Table 2 Performance Test Data

[0078] As can be seen from the results in Table 2, the flotation defoamers prepared in Examples 1-7 resulted in a concentrate recovery rate of over 69.65% after double reverse flotation, which was significantly higher than that without the defoamer, effectively improving the quality and recovery rate of the phosphate concentrate. The MgO content of the obtained concentrate was less than 0.91%, and the Al2O3 content was less than 1.71%. The auxiliary collector effectively removed the impurities, and the foam volume was reduced by more than half compared to that without the defoamer. After flotation, the tailings slurry foam was shaken at a low intensity, and the remaining foam was found to be quickly eliminated.

[0079] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A defoaming agent for double-reverse flotation of phosphate rock, characterized in that, The ingredients, by weight, include: 5-40 parts of strongly hydrophobic silicone paste; 5-40 parts of semi-hydrophilic silicone paste; 3-25 parts of polyether-modified silicone oil; 20-40 parts of emulsifier; 1-20 parts of dispersant; 0.1-10 parts of thickener; and 50-120 parts of deionized water.

2. The defoamer for phosphate rock double-reverse flotation according to claim 1, characterized in that, The strongly hydrophobic silicone paste is composed of the following components: 60-100 parts of 20000cP vinyl silicone oil, 1-8 parts of hydrogen-containing silicone oil, 5-30 parts of hydrophobic silica, and 0.1-1 parts of catalyst.

3. The defoamer for phosphate rock double-reverse flotation according to claim 1, characterized in that, The semi-hydrophilic silicone paste is composed of the following components: 20-50 parts of 1000cP dimethyl silicone oil, 20-60 parts of 60000cP dimethyl silicone oil, 5-30 parts of precipitated silica, 5-30 parts of MQ silicone resin, 1-5 parts of silazane, and 0.1-1 parts of deionized water.

4. The defoamer for phosphate rock double-reverse flotation according to claim 1, characterized in that, The polyether-modified silicone oil is a double-terminated polyether-modified polysiloxane, and the emulsifier is selected from one or more of the following: fatty alcohol polyoxyethylene ether, isotridecyl alcohol polyoxyethylene ether, glyceryl stearate, polysorbate, and dehydrated sorbitan fatty acid ester. The dispersant is selected from one or more of the following: alkyl phenyl ether sulfate, block polyether polymer, alkyl ammonium salt polymer, imino anchoring group hyperbranched polyester compound, and fatty acid polyethylene glycol ester. The thickener is selected from one or more of the following: hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, xanthan gum, and polyacrylate.

5. The defoaming agent for phosphate rock double-reverse flotation according to claim 2, characterized in that, The 20000cP vinyl silicone oil has a viscosity of 19500-20500cP at room temperature, a vinyl end content of 0.01-0.5%, a volatile content of <0.2%, a flash point of >200℃, and a refractive index of 1.400-1.

410. The hydrogen-containing silicone oil has a viscosity of 10-200 cP at room temperature, a volatile content of <1%, an active hydrogen content of 0.1-0.5%, a flash point of >100℃, and a refractive index of 1.390-1.

410. The hydrophobic silica contains ≥99% silica and has a specific surface area of ​​200~300 m². 2 / g, volatile matter at 105℃ ≤2.5%; The catalyst is selected from one or more composites of Castells platinum catalyst, Ashby platinum catalyst, platinum-vinylsiloxane complex catalyst, and platinum-olefin complex catalyst.

6. The defoamer for phosphate rock double-reverse flotation according to claim 3, characterized in that, The 1000cP dimethyl silicone oil has a viscosity of 960-1040cP at room temperature, volatile matter <0.2%, turbidity <3 NTU, and density of 0.965~0.98 g / cm³. 3 The refractive index is 1.40~1.405; The 60000cP dimethyl silicone oil has a viscosity of 59000-61000cP at room temperature, volatile matter <0.5%, turbidity <5 NTU, and density of 0.970~0.985 g / cm³. 3 The refractive index is 1.4025~1.

405. The precipitated silica is a white powder with a silica content ≥99.8% and a specific surface area of ​​100-300 m². 2 / g, volatile matter at 105℃ ≤2%, the MQ silicone resin is a white powder with volatile matter <0.96, hydroxyl content 4~6%, weight average molecular weight 6500~7000, and the silazane is a colorless transparent liquid with purity >99%, density 0.774~0.780g / cm³, flash point 25~30℃, and refractive index 1.407~1.

409.

7. The defoaming agent for phosphate rock double-reverse flotation according to any one of claims 1-6, characterized in that, The average particle size of the defoamer is 10-50 micrometers.

8. A method for preparing a strongly hydrophobic silicone paste according to any one of claims 1-7, characterized in that, Includes the following steps: (1) Preparation of strong hydrophobic silicone paste: Add 20,000 cP of vinyl silicone oil to the reaction vessel, and then slowly and in batches add hydrophobic silica while stirring to prevent dust from flying and clumping. Shear and stir to make the silica and vinyl silicone oil mix evenly. Under low speed stirring, slowly add a predetermined amount of catalyst. After mixing evenly, add hydrogen-containing silicone oil, heat to 50-80℃, continue stirring and shearing, and cool to obtain strong hydrophobic silicone paste. (2) Preparation of semi-hydrophilic silicone paste: Add a certain amount of 1000 cP dimethyl silicone oil and 60000 cP dimethyl silicone oil to the reaction vessel, turn on low speed stirring, add silazane and deionized water while stirring, stir after adding, add precipitated silica in batches and stir while adding, and after stirring evenly, raise the temperature to 130-160℃, continue stirring and shearing, turn on the vacuum pump to remove NH3, then turn off the vacuum pump and heating device, and obtain semi-hydrophilic silicone paste after cooling; (3) After mixing the thickener with deionized water, add it to the emulsification equipment, and then add the dispersant, emulsifier, strong hydrophobic silicone paste, semi-hydrophilic silicone paste and polyether modified silicone oil in sequence. After stirring evenly, shear emulsify and control the particle size to 10-50 micrometers, and then filter out the material.

9. The application of the phosphate rock double-reverse flotation defoamer as described in any one of claims 1-7 in the phosphate rock double-reverse flotation process.

10. The application according to claim 9, characterized in that, The defoamer is added during the magnesium removal and / or aluminum removal flotation stage, at a dosage of 200-400 g / t phosphate rock, with a flotation pH of 2.0-6.0.

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