46results about How to "Reduced silica content" patented technology

A method of cellulosic raw material desilication involves the steps of impregnating the cellulosic raw material with a solution containing sodium carbonate to form a silica-containing impregnation black liquor and an at least partially desilicated raw material, separating the silica-containing impregnation black liquor from the at least partially desilicated raw material, causticizing the separated silica-containing impregnation black liquor to precipitate silica-enriched calcium carbonate and separating the precipitated silica-enriched calcium carbonate from the causticized impregnation liquor. Up to 100% of the silica contained in the cellulosic raw material can be removed before the raw material is processed by any of conventional pumping methods.

Bayer process, comprising grinding (L, B) and then digestion (N2, A) of a bauxite by bringing it into contact with a sodium aluminate liquor (20b, 120b). Digestion consists of forming a slurry (3a, 103) that is then treated to separate insoluble residues (5a, 105a) from the sodium aluminate liquor. The liquor is then crystallized (D) and recycled back to green liquor (20, 120) after having been separated from the alumina trihydrate (11, 111) precipitated during crystallization. The process comprises a predesilication treatment (P) during which the ground bauxite is brought before digestion into contact with an aqueous sodic solution that has a content of carbonates, sulphates and possibly chlorides which, expressed as a percentage related to the caustic concentration, is less than half the corresponding impurities content of the spent liquor (8, 108). Preferably, the pure caustic soda used to compensate for caustic soda losses in the Bayer circuit that was previously injected just after evaporation is now added in the aqueous sodic solution for the predesilication treatment.

The invention provides a low-temperature co-fired ceramic material which is prepared by sintering the following raw materials: 23.5wt%-30.5wt% of silicic acid, 28.1wt%-34.4wt% of boric acid, 34.7wt%-42.2wt% of calcium hydroxide, 0.4wt%-1.5wt% of phosphoric acid and 2.8wt%-4.1wt% of zirconium nitrate. In the low-temperature co-fired ceramic material provided by the invention, the sintering temperature can be lowered by lowering the silicon dioxide content introduced by silicic acid and enhancing the boron trioxide introduced by boric acid; and meanwhile, the introduced zirconium and phosphorus elements can promote the formation of microcrystals in microcrystalline glass to lower the dielectric loss, and the formed microcrystal can enhance the heat conductivity and mechanical properties of the low-temperature co-fired ceramic material.

The invention discloses a comprehensive utilization method of a ferriferous fayalite material, relates to a processing method of the ferriferous fayalite material, and in particular relates to a method for separating and utilizing iron and silicon in fayalite. The method is characterized by comprising the following steps of: grinding the ferriferous fayalite material; mixing with alkaline liquor for leaching reaction; performing solid-liquid separation on obtained reaction slurry to obtain desilicated concentrate and silicon containing alkaline liquor; and oxidizing the desilicated concentrate in air to goethite. The method disclosed by the invention enriches, separates and extracts iron and silicon elements to form two products: goethite and silicon containing alkaline liquor through alkaline liquor leaching, wherein iron and silicon in ferriferous fayalite exist in solid and liquid states, so that the comprehensive utilization ratio of resources is high and the economic benefit is better.

The invention discloses a method of preparing a light thermal insulation material by employing bauxite tailings and relates to a comprehensive utilization method of bauxite tailings. The method is characterized by comprising the following steps of: adding the bauxite tailings into kaolin to calcined and reconstructed; and preparing the light thermal insulation material by taking the mixture as a raw material of the light thermal insulation material. The method disclosed by the invention makes full use of industrial solid wastes such as bauxite tailings, coal ash and flue gas desulfurization gypsum, and the material is low in cost, high in strength and good in thermal insulation property, and meanwhile, the requirement on SiO2 content is relatively low. The solid waste bauxite tailings can be scientifically utilized to realize reclamation of wastes, so that the method has far-reaching environmental-friendly meaning.

The invention belongs to the technical field of aluminum fluoride production, and relates to a production technology of high-purity aluminum fluoride. The technology comprises the steps that: (1) hydrogen fluoride gas desiliconization is carried out, wherein fluorite and sulfuric acid are subjected to a reaction; produced hydrogen fluoride gas sequentially passes through a pre-purification tower and a purification tower, such that sulfuric acid washing and condensation are carried out; condensed acid overflows to a rectification tower through a crude acid tank, and is subjected to desiliconization; degassing is carried out in a degassing tower; and the obtained product overflows to a finished product tank through a rectified acid cooling device; (2) anhydrous hydrogen fluoride evaporation is carried out, wherein the finished product acid is pumped into a hydrogen fluoride distillation tower kettle by using a submerged pump; evaporation is carried out by using an evaporator in the tower kettle; hydrogen fluoride gas after evaporation is delivered through an integral superheater in the tower kettle, and directly flows into a fluidized bed; and (3) aluminum fluoride is produced, wherein the hydrogen fluoride gas enters the fluidized bed and is subjected to a reaction with aluminum hydroxide, such that aluminum fluoride is produced. According to the invention, because anhydrous hydrogen fluoride is adopted as a raw material, and the desiliconization treatment is carried out in the preparation process, the produced aluminum fluoride has the advantages of high purity, low silicon dioxide content, low discretionary reduction amount, and simple and feasible production process.

The invention provides a desulfurizing agent suitable for high-aluminum silicon steel and a preparation method thereof. The desulfurizing agent comprises the following components: 75-80 percent of calcium oxide (CaO), 10-15 percent of aluminum oxide (Al2O3), 3-6 percent of magnesium oxide (MgO), 3-6 percent of magnesium chloride (MgCl2), not greater than 1.5 percent of silicon dioxide (SiO2), not greater than 0.02 percent of all titanium (Ti) and not greater than 0.02 percent of all carbon (C). The preparation method comprises the following steps: (1) weighing the raw materials: 72-77 percent of CaO, 8-13 percent of Al2O3 and 10-20 percent of binder; (2) respectively crushing the CaO and the Al2O3 into particles of which the particle sizes are less than 0.1mm; (3) heating the CaO to 120-150 DEG C, and carrying out spray treatment on the CaO particles by using silicone oil so as to form a protective film; (4) mixing the CaO and the Al2O3 with the binder; and (5) pressing into balls by using a ball press, and drying and packaging. The desulfurizing agent provided by the invention is easy to store, has high desulfurizing rate and low environmental pollution and has low corrosion on the refractory of a vacuum slot body; in the desulfurizing process, the molten steel carburetion and titanizing can be controlled to be under 5ppm; and the desulfurizing rate can reach at least 50 percent on the premise of not increasing the refining time.

The invention discloses a fluorite beneficiation and separation method, and relates to the technical field of beneficiation process. The fluorite beneficiation and separation method includes the stepsof primary grinding, primary grading, primary roughing, senary refining and secondary scavenging, and specifically includes feeding flotation concentrates into a concentration tank, dehydrating the concentrated concentrates by a filter, drying the filtered concentrates by a roller dryer, putting the dried concentrates into jumbo bags to obtain finished products, feeding flotation tailings into atailings pond, recycling wastewater, collecting fluorite by oleic acid, taking water glass as a quartz inhibitor, and adjusting the pH of ore pulp to 8-9 by calcium carbonate. The fluorite beneficiation and separation method has the advantages of high flotation efficiency, simple process and low cost.

The invention relates to the technical field of sewage treatment, and particularly relates to a sewage purification method during sodium fluosilicate production. The method comprises the steps of adjusting the Na+ content in sewage and conducting flocculant precipitation, flyash mixing and membrane separation. According to the sewage purification method during the sodium fluosilicate production, silicon dioxide removal in the sewage during the sodium fluosilicate production is and a flocculant are researched, finally a composite flocculant is obtained through compounding on the condition of acheap carbon source and nitrogen source, silicon dioxide in the sewage can effectively precipitate, it is found through an experiment that the content of the silicon dioxide in the sewage can reach 4.77 mg/L to the lowest degree after treatment, the using amount of the flocculant is little and reduced, cyclic utilization of workshop production water is achieved, and the production cost is reduced.Besides, the flocculant researched in the method has the same good flocculation effect on sewage in other fields.

The invention provides a premelting type desulfurizing agent suitable for high-aluminum silicon steel and a preparation method thereof. The desulfurizing agent comprises the following components by weight percent: 80-85 percent of calcium oxide (CaO), 13-18 percent of aluminum oxide (Al2O3), not greater than 1.5 percent of magnesium oxide (MgO), not greater than 1.5 percent of silicon dioxide (SiO2), not greater than 0.02 percent of all titanium (Ti) and not greater than 0.02 percent of all carbon (C). The preparation method comprises the following steps: (1) weighing 87-90 percent of limestone of which the granularity is not greater than 10mm and 10-13 percent of Al2O3 of which the granularity is not greater than 10mm by weight percent; (2) putting the raw materials in a mixer and evenly mixing; (3) adding a mixture to a smelting furnace, then, blowing fuel oil for heating, and smelting; and (4) discharging, cooling and crushing for later use. The desulfurizing agent provided by the invention is easy to store, has high desulfurizing rate and has low erosion on the refractory of a vacuum slot body; and in the desulfurizing process, molten steel carburetion and titanizing can be controlled to be under 5 parts per million (ppm), and the desulfurizing rate can reach at least 60 percent on the premise of not increasing the refining time.

The invention relates to calcium aluminate for desulfurization of ultralow titanium and carbon steel and a preparation method thereof. The calcium aluminate comprises more than or equal to 94% of Ca12Al14O33, less than or equal to 2% of Ca3Al2O6, less than or equal to 2% of Ca2SiO4, less than or equal to 1.5% of MgO, less than or equal to 0.01% of pure Ti and less than or equal to 0.02% of pure carbon. The preparation method comprises the following steps of: (1) preparing materials according to the following proportions: 60-65% of CaO and 35-40% of Al; (2) mixing the proportioned raw material particles in a material mixer; (3) adding the mixed materials into a smelting furnace, and blowing fuel to heat the furnace to make furnace temperature achieve 950-1050 DEG C; (4) blowing oxygen into the furnace, heating the furnace body to 1450-1500 DEG C; and (5) cooling and crushing premelted slag into 5-30 mm blocks. The desulfurizing agent provided by the invention has the advantages of low production cost, easy for storage, low melting point, high slag melting speed, high desulfurization effect and small corrosion to refractory materials, and the carbon increase amount and the titanium increase amount of liquid steel can be effectively controlled.

The invention discloses a high-power half-medium-low-grade silicon-calcium phosphorite combined separation process, and belongs to the field of phosphorite separation. The process specifically comprises the following steps that a high-power half-medium-low-grade silicon-calcium phosphorite is subjected to wet grinding and then reverse flotation is carried out to obtain flotation concentrate and tailings, the flotation concentrate is subjected to graded desliming, low-magnesium and low-half graded coarse-grained materials are final concentrate, and fine-grained materials are taken as middlings;and the concentrate product is allowed to be subjected to downstream wet-process phosphoric acid, middling smelting yellow phosphorus and tailing cemented filling treatment. According to the process,the content of concentrate metal ion oxide and silicon dioxide is reduced through reverse flotation and grading desliming combined separation. The middlings with certain phosphorus content and high silicon content are used for smelting yellow phosphorus, and the comprehensive utilization rate of phosphorus resources is high; the tailings cemented filling treatment is carried out, and no three wastes are discharged by a system.

A powdered composite filtration medium includes composite particles that include at least one diatomite particle and at least one expanded perlite particle sintered together. The composite powdered filtration medium may include from about 7 wt % to about 90 wt % diatomite, from about 93 wt % to about 10 wt % expanded perlite. Less than about 1% total crystalline silica may be present in the medium. The medium may have a permeability of at least 0.25 darcy. The diatomite and expanded perlite may be sintered or calcined with or without a fluxing agent.

The invention relates to a method for preparing cryolite. The method comprises the steps that 1) wastewater containing silicon and fluorine is mixed with ammonium hydroxide, and a chemical desiliconization reaction is carried out; 2) liquid-solid separation is carried out to obtain white carbon black and an ammonium fluoride desiliconized liquid; 3) the ammonium fluoride desiliconized liquid is mixed with a sodium aluminate solution, and a synthesis reaction is carried out; 4) liquid-solid separation is carried out to obtain the cryolite. The method for preparing the cryolite has the advantages that a high-quality cryolite product is obtained by recycling from the wastewater containing the silicon and fluorine and a white carbon black byproduct is also obtained; the recovery rate of fluorine resources in the wastewater is 90% or above, the obtained cryolite has high purity and good fluidity, and the mass fraction of SiO2 is less than 0.1%; the raw material can be acidic fluorine-containing wastewater discharged from the aluminum fluoride industry, fluorosilicic acid discharged from the phosphate fertilizer industry or ammonium fluoride alkaline wastewater discharged from the niobium and tantalum industry, and the resource recovery rates of fluorine and silicon are not affected; the process conditions are mild, high-efficiency circulation of the medium is easily achieved, the industrial operability is strong, and the economic benefits are outstanding.