16results about "Fluosilicic acid" patented technology

The invention belongs to the field of inorganic chemical industry, and particularly relates to a method and a system for efficiently utilizing a phosphate fertilizer byproduct, the method comprises the following steps: carrying out acidolysis on fluosilicic acid with the concentration of more than or equal to 45% wt and concentrated sulfuric acid to generate a mixed solution of silicon tetrafluoride gas and fluorosulfonic acid; the mass ratio of the fluosilicic acid to the concentrated sulfuric acid is controlled to be 1: (4-15); pyrolyzing the obtained fluorosulfonic acid to generate dilute sulphuric acid, hydrogen fluoride and water vapor, forming 98% concentrated sulphuric acid from part of dilute sulphuric acid and fuming sulphuric acid, drying hydrogen fluoride to obtain crude hydrogen fluoride gas, and condensing and rectifying to obtain anhydrous hydrogen fluoride; the rest dilute sulphuric acid is partially compounded and then returned for acidolysis, and the rest dilute sulphuric acid is used for producing white carbon black and flows back to a wet-process phosphoric acid system; and circularly absorbing the obtained silicon tetrafluoride gas by using secondary concentrated fluosilicic acid to obtain fluosilicic acid with the mass concentration of more than or equal to 45%, recycling the fluosilicic acid for acidolysis reaction, and modifying the concentrated by-product silicon dioxide to obtain the high-activity white carbon black. The problems of energy consumption and cost are solved, and efficient circulation and poly-generation of fluorine and silicon resources are achieved in the whole process.

The invention belongs to the field of waste liquid recycling, and discloses a method for preparing potassium fluosilicate by using mixed waste acid, which comprises the following steps: S1, silica fume acidification pretreatment: soaking silica fume in an acid solution for acidification, carrying out precipitation separation on the silica fume, drying, and grinding to obtain acidified silica fume; s2, mixing the raw materials: uniformly mixing the acidified silica fume and the silicon dioxide powder; s3, preparation of fluosilicic acid: adding a mixture of acidified silica fume and silicon dioxide powder into the mixed waste acid, and uniformly stirring by a mechanical stirrer; and S4, preparation of potassium fluosilicate: adding a potassium chloride saturated solution into the fluosilicic acid solution to generate potassium fluosilicate precipitate. The method has the advantages and effects of being high in fluorine ion utilization efficiency, low in production cost and high in finished product purity.

This invention belongs to the field of fly ash treatment technology, specifically disclosing a method for separating potassium and sodium from fly ash, including the following steps: adjusting the acid concentration in the fly ash washing solution to 40-65% and the temperature to 40-65℃, adding a sodium precipitating agent and maintaining the reaction temperature, and filtering to obtain sodium salt and potassium-containing waste liquid. This invention utilizes precipitation to recover sodium ions from fly ash washing solution. After filtration, sodium salt precipitate and potassium-containing waste liquid are obtained. During this process, the reaction is controlled under acidic conditions to prevent potassium ion precipitation. At 40-60℃, the sodium precipitating agent reacts with sodium ions to obtain sodium salt precipitate with large crystals, which allows for more convenient and thorough filtration, resulting in better separation of potassium and sodium ions in the fly ash washing solution. The sodium salt precipitate is further washed with a displacement agent to replace the potassium ions attached to the surface of the sodium salt precipitate with sodium, improving the purity of the sodium salt product. Finally, multiple water washings are performed to reduce the acidity of the sodium salt precipitate, resulting in a sodium salt product with stable quality.

The invention discloses a method for synergistically preparing and purifying sodium fluosilicate by using fluorine-containing waste acid and fly ash. The method comprises the following steps: crushing household garbage incineration fly ash, pulping, pickling, and carrying out solid-liquid separation to obtain crude calcium water; sequentially carrying out heavy metal removal, denitrification, oxidation and neutralization treatment on the crude calcium water, and carrying out solid-liquid separation to obtain refined calcium water; carrying out primary calcium removal treatment on the obtained refined calcium water, and carrying out solid-liquid separation to obtain crude brine; carrying out deep calcium removal treatment on the crude brine to obtain refined brine mainly containing sodium chloride; pretreating the fluorine-containing waste acid to obtain a fluosilicic acid solution; mixing and reacting the fluosilicic acid solution with refined salt water, controlling the pH value of a reaction system to be less than 2, and performing solid-liquid separation to obtain crude sodium fluosilicate; and carrying out multistage countercurrent oxidation washing on the crude sodium fluosilicate, and drying to obtain a sodium fluosilicate product. And resource comprehensive utilization of the fluorine-containing waste acid and the fly ash is realized.

This invention discloses a method for separating fluorosilicic acid and hydrofluoric acid using an anion exchange membrane, comprising the following steps: adding a flocculant to a fluorosilicic acid-hydrofluoric acid mixture, aging it, then adding a desulfurizing agent to carry out a desulfurization reaction to obtain a mixed solution, adding the mixed solution to the feed side of an anion exchange membrane for membrane separation, and obtaining a hydrofluoric acid solution with a mass concentration of 2-30% on the clear water side after separation. This invention uses a flocculant to rapidly settle solids such as sodium fluorosilicate and potassium fluorosilicate in the fluorosilicic acid-hydrofluoric acid mixture, uses a desulfurizing agent to remove sulfuric acid, and then uses an anion exchange membrane to effectively separate fluorosilicic acid and hydrofluoric acid in the fluorosilicic acid-hydrofluoric acid mixed solution. The hydrofluoric acid separated by membrane separation has high purity and high output value, increases the utilization rate of by-product hydrofluoric acid, and reduces costs.

The present application belongs to the technical field of waste liquid treatment, and particularly relates to a graphite purification waste liquid treatment method and a treatment system. The present application introduces a pre-acid pickling system to utilize waste acid twice, reduces the amount of acid used in the acid pickling process of graphite purification, improves the use efficiency of acid liquid, thereby reducing the cost of the graphite purification process and significantly enhancing the overall economy. The present application also introduces a sodium fluorosilicate production line, effectively realizing the resource utilization of residual fluorosilicic acid and fluorosilicate in waste water. Not only can the operation cost of reagents in the subsequent water treatment process be effectively reduced, but also the produced sodium fluorosilicate can be sold to improve economic benefits. An evaporation crystallization system is used to crystallize and recover valuable salts in waste water. The obtained crystalline salt can be further used as a raw material for other products. The treatment system provided by the present application can realize the resource utilization and recycling of waste acid and waste water, and achieve zero emission.

The invention discloses a preparation method of phosphorus ore defluorination and low-power-consumption yellow phosphorus. The preparation method comprises the steps of first-stage reaction, batching and balling, second-stage reaction, tail gas purification and electric furnace reduction. The method comprises the following steps: by taking medium-low-grade complex collophanite, phosphoric acid, low-silicon high-calcium phosphorite and calcium carbonate or calcium oxide as raw materials, carrying out a first-stage reaction by regulating the ratio of CaO to P2O5 in a mixture for one time; regulating and controlling the ratio of CaO / P2O5 to SiO2 / CaO for the second time, pelletizing, and calcining to carry out a second-stage reaction. The reaction gas is silicon tetrafluoride, and is used for preparing anhydrous hydrogen fluoride and other fluorine-containing products after being purified; the reaction solid phase is low-fluorine high-grade phosphorite, when the phosphorite is used for preparing yellow phosphorus, the fluorine overflow rate and the dust rate are greatly reduced, the phosphorus reduction rate is obviously improved, and the power consumption of the yellow phosphorus is obviously reduced. The technology is a preferred route for energy conservation and consumption reduction of yellow phosphorus and efficient recovery of fluorine resources; meanwhile, phosphorus, fluorine and silicon elements in the middle-low-grade complex collophanite can be directly utilized in a high-valued mode, and a new route is opened up for efficient utilization of a large amount of low-grade complex collophanite in China.

Described herein is a method for chemically breaking down per- and polyfluoroalkyl substances (PFAs), whereby to convert the PFAs to products that are more friendly to the environment than are per- and polyfluoroalkyl substances. Also described are compositions containing PFAs and components that under the conditions described herein effect such breakdown, as well as an apparatus that can be used to effect the chemical transformation.

The invention relates to the technical field of phosphorus chemical industry and three-waste resourceful treatment, and discloses a silicon dioxide-assisted phosphoric acid concentration fluorine recovery process, which comprises the following steps: mixing anhydrous hydrogen fluoride byproduct silicon slag with dilute phosphoric acid to prepare slurry with the solid content of 9.0-9.5%; after being homogenized by a buffer tank, the slurry is premixed and diluted on line through a dilute phosphoric acid branch, and is injected into a concentration system; in the concentration process, silicon dioxide is used for promoting hydrogen fluoride to be converted into volatile silicon tetrafluoride to escape and be recycled. In order to solve the scaling problem in the conveying process, a double-pipeline switching mechanism is established, and 3%-5% dilute sulphuric acid is used for conducting periodic acid pickling maintenance on a shutdown pipeline. Through dynamic flow control, the fluorine recovery rate is greatly improved while the solid content of the concentrated phosphoric acid product is ensured to be qualified, the problems that pipelines are easy to block and fluorine resources are wasted in the traditional process are solved, and efficient resource utilization of the silicon slag is realized.

The invention discloses a method for recovering and preparing potassium fluosilicate from fluorine-potassium-containing silicon dioxide solid by-products, and belongs to the technical field of inorganic fluoride salt, the fluorine-potassium-containing silicon dioxide solid by-products are mixed with sulfuric acid or hydrochloric acid for acid immersion cleaning, then primary solid-liquid separation is carried out, and filter residues rich in silicon dioxide and first filtrate are obtained; carrying out secondary temperature-controlled washing and secondary solid-liquid separation on the filter residue to obtain a purified silicon dioxide product and a second filtrate; and combining the first filtrate and the second filtrate, adding fluosilicic acid into the combined filtrate according to a chemical reaction stoichiometric ratio, reacting at the temperature not lower than 50 DEG C to generate potassium fluosilicate crystals, and finally performing solid-liquid separation, washing and drying to obtain a potassium fluosilicate product. According to the method, potassium recycling is achieved, waste acid liquid after reaction is returned to the immersion cleaning process for recycling, zero emission of acid is achieved, meanwhile, the purity of the by-product silicon dioxide is improved to 85% or above through the simple acid immersion cleaning process, the purity of the silicon dioxide can be improved to 90% or above through secondary washing, and the method is suitable for industrial production. And the total yield of potassium fluosilicate is remarkably improved, the product recovery rate reaches 95% or above, and good economic benefits and social benefits are achieved.

In one aspect, a process for preparing a Mn4+ doped phosphor of Formula I is provided Ax[MFy]:Mn4+ (I). The process includes combining a first aqueous solution including a source of Mn with a second solution including H2MF6 to form a third solution, and combining the third solution with a fourth solution including a source of A to form the Mn4+ doped phosphor, where A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; x is the absolute value of the charge of the [MFy] ion; and y is 5, 6 or 7. Methods, phosphors and devices are also provided.

A phosphor composition includes a red phosphor material having a red decay rate and a green phosphor material having a green decay rate. The red phosphor material includes a Mn4+ doped phosphor of Formula I and a Eu3+ doped uranium phosphor,and a difference between the red decay rate and the green decay rate is no more than 7 ms, AxMFy:Mn4+ (I), wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Hf, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; x is an absolute value of a charge of the MFy ion; and y is 5, 6 or 7. A device is also provided.

The invention discloses a closed-cycle double-tower gas stripping phosphoric acid concentration and defluorination integrated system and method. The two towers are combined in series, and phosphoric acid with the P2O5 concentration of 28-42%, especially wet-process fluorine-containing crude phosphoric acid, is refined into phosphoric acid with the P2O5 concentration gt through a carrier gas closed circulation turbulent ball packed tower; the mass concentration of F is 1t; 0.1% of high-quality strong phosphoric acid and by-product fluosilicic acid with H2SiF6 concentration of not less than 18% are obtained. A heat source and a cold source of the system are circularly provided by a heat pump working medium, a refrigerant is connected in series with a heat absorption temperature area at 30-40 DEG C, and a heating medium is connected in series with a heat release temperature area at 150-80 DEG C. According to the method disclosed by the invention, the total energy consumption for processing one ton of P2O5 product by taking the semi-hydrated wet-process phosphoric acid with the P2O5 concentration of 40% as the raw material is 400kW.h, the total energy consumption for processing one ton of P2O5 product by taking the dihydrated wet-process phosphoric acid with the P2O5 concentration of 28% as the raw material is 950kW.h, and the benefits of energy conservation, water conservation, emission reduction and income increase are remarkable.

The application discloses a method for reducing the content of fluosilicic acid in magnesium fluosilicate product, comprising the following steps: 1) analyzing and detecting the content of fluosilicic acid in magnesium fluosilicate crystals; 2) dissolving the magnesium fluosilicate crystals in a saturated magnesium fluosilicate solution to prepare a magnesium fluosilicate solution; and 3) adding a magnesium hydroxide solution into the magnesium fluosilicate solution in a magnesium fluosilicate cooling crystallization tank, and after sufficient reaction, the magnesium fluosilicate is obtained through cooling crystallization, centrifugal separation and drying; the method can reduce the content of fluosilicic acid in the finished product magnesium fluosilicate, and meanwhile, no new impurities are introduced.

The present application belongs to the technical field of wet-process phosphoric acid production, and particularly relates to a method for cleaning an extraction fluorine absorption device. In the method, acid circulating water, which is by-produced in the production of 58% concentrated phosphoric acid by a phosphoric acid concentration device and contains hydrogen fluoride, is used as make-up water for an extraction fluorine absorption system. The hydrogen fluoride reacts with silicon dioxide to generate fluorosilicic acid, which is used as a raw material for anhydrous hydrogen fluoride. In the production process, the deposition of silica gel is reduced, the fouling of the wall and pipeline of a fluorine absorption tower is avoided, the cleaning amount and shutdown frequency are reduced, and the cleaning frequency and the life safety of cleaning personnel are reduced.

This invention relates to a method for synthesizing high-viscosity magnesium silicate and its derivatives using complexation and dispersion effects. The method includes the following steps: mixing a magnesium-containing compound, a silicon-containing compound, a modified compound, and an additive, wherein the additive is one or more of a complexing agent, a dispersant, and a steric hindrance agent. After meeting the reaction conditions, the mixture is transferred to a pressure vessel. After the reaction is complete, the mixture is removed, cooled, and dried to obtain the high-viscosity magnesium silicate and its derivatives. The beneficial effects are: This invention utilizes the complexing agent and the barrier effect of the dispersant to intensify the hydration reaction during grinding, avoiding particle aggregation and condensation. This ensures thorough mixing of magnesium, silicon, and other reactants, meeting the chemical reaction conditions. It can replace bentonite to achieve a higher thickening effect, and the product can be made into a colorless and transparent thickening solution. Specifically, a 2 t% aqueous solution can form a gel-like jelly with complete swelling, resulting in a wider range of applications and a better market prospect.