1169results about "Calcium/strontium/barium sulfates" patented technology

A process and system for purifying water is disclosed. For example, in one embodiment, the process may be used to remove a divalent salt, such as calcium sulfate, from a water source in order to prevent the divalent salt from precipitating during the process. The water source, for instance, may be fed to an ion separating device, such as an electrodialysis device. In the electrodialysis device, an ion exchange takes place between the divalent salt and another salt, such as a monovalent salt to produce two concentrated salt streams that contain salts having greater solubility in water than the divalent salt. In one embodiment, the two salt streams that are produced may then be combined to precipitate the divalent salt in a controlled manner. During the process, various other components contained within the water feed stream may also be removed from the stream and converted into useful products. In one particular embodiment, the process is configured to receive a byproduct stream from a reverse osmosis process.

The present invention relates to methods for the preparation of inorganic nanoparticles capable of fluorescence, wherein the nanoparticles consist of a host material that comprises at least one dopant. The synthesis of the invention in organic solvents allows to gain a considerably higher yield compared to the prior art synthesis in water. All kinds of objects can advantageously be marked and reliably authenticated by using an automated method on the basis of a characteristic emission. Further, the size distribution of the prepared nanoparticles is narrower which renders a subsequent size-selected separation process superfluous.

Processes for use of a controlled continuous high pressure multiple reactant streams flowing into a chemical mixer/reactor. Individual reactant streams are pressurized to about 8,000 to 50,000 psi and achieve velocities up to about 250 meters/second in the final stage of the chemical mixer/reactor.

Process for producing sodium bicarbonate for purifying flue gases, according to which an aqueous solution containing sodium sulfate is subjected to electrodialysis to produce a sodium hydroxide solution and a sodium bisulfate solution, the sodium hydroxide solution being carbonated in order to obtain sodium bicarbonate.

The invention discloses a method for preparing a modified calcium sulfate whisker by using desulfurization gypsum, comprising the following steps of sieving, pulping, performing hydro-thermal reaction and whisker surface modification, dewatering and drying, wherein the reaction temperature ranges from 107 DEG C to 180 DEG C, the concentration of desulfurization gypsum and water is 5-33wt% and the drying temperature ranges from 100 DEG C to 300 DEG C, and a modifier which is 0.05-5% of the weight of desulfurization gypsum in the calcium sulfate whisker suspension formed in hydro-thermal reaction. The invention solves the problem that CaSO4.0.5H2O whisker is easy to hydrate in the drying process tocause fracture of the whisker and enhances the compatibility of the calcium sulfate whisker and the high polymer materials. The prepared modified calcium sulfate whisker has a diameter of 0.5-6 micrometers, a length of 30-300 micrometers and a diameter ratio of 15-115 and the contact angle of water on the surface of the modified calcium sulfate whisker ranges from 12 to 140 degrees. The invention has the advantages of good modified effect, simple process, low production cost, the use of the non-toxic modifier and environmental-friendly preparation process.

The invention relates to a method for preparing calcium sulfate crystal whiskers (CaSO4) by using impurity-containing gypsum as a raw material. The method comprises the following steps of: removing main impurities in the raw material which is the low-priced impurity-containing gypsum resource in a mode of roasting, acid-complex leaching and alkaline leaching and simultaneously thinning crystal grains to obtain a superfine dihydrate calcium sulfate precursor which is high in purity and dispersibility; and preparing the anhydrous calcium sulfate crystal whiskers with a length of 20 to 2,000mu m, a diameter of 0.5 to 20 mu m, a length-diameter ratio of 40 to 1,000 and a weight percent content of over 95 percent in a mode of hydrothermal conversion-roasting of a fluxing agent. The method has the advantages of low-priced and easily bought raw materials, simple process, wide application range, and high added value. The calcium sulfate crystal whiskers prepared by the method have a big length-diameter ratio and regular shape, and can be used as reinforcing, heat insulating or flame retardant materials in industries of plastics, rubbers, coatings, papermaking, building materials and the like.

The invention provides a method for producing dehydrated calcium sulfate whisker, comprising: using copper, lead, zinc, aluminium, nickel, cobalt, stannum, non-ferrous metal secondary resource cycle utilizing, calcium nitrate solution produced in treating process of electroplating waste, calcium chloride solution, or mixed water solution of calcium nitrate and calcium chloride as raw material, using sulfuric acid as calcium ion precipitant, adding whisker shape regulating agent, controlling reaction condition, regenerating aqua fortis or hydrochloric acid lixiviant, and simultaneously producing ultralong and big length to diameter ratio calcium sulphate dihydrate whisker. After calcium sulphate dihydrate whisker is deposited from calcium nitrate solution, calcium chloride solution or the mixed solution of calcium nitrate and calcium chloride are deposited, the water solution is translated to be nitric acid solution, hydrochloric acid solution or a mixed solution of nitric acid and hydrochloric acid, returning back to leaching out or treating process for processing non-ferrous metal mineral substance, non-ferrous metal secondary resource or electroplating remove. The calcium sulphate dihydrate whisker is treated by microwave heating, forming calcium sulfate hemihydrate or anhydrous sulphate of calcium after dehydration.

The invention discloses a method for the production of phosphoric acid and the combined production of a-hemihydrate gypsum through a dehydrate-hemihydrate wet phosphoric acid technology. A dehydrate part production technology is characterized in that the reaction tank temperature is 70-80DEG C, the retention time is 1.5-3h, the free sulfate radical concentration is 1-2%, and the produced wet phosphoric acid concentration omega(P2O5) is 35-39%. A hemihydrate part production technology is characterized in that the reaction tank temperature is 86-94DEG C, the retention time is 1-2h, and the mass concentration of free sulfate radicals is 6-8%. Phosphoric acid produced through the hemihydrate technology has a concentration omega(P2O5) of 10-15% and is used as a recycle acid of the dehydrate part, the crystal water content of the combined-production hemihydrate gypsum is 5-7%, the mass percentage of free P2O5 in gypsum is less than 0.4%, and the crystal form of the produced hemihydrate gypsum is a-hemihydrate gypsum. Compared with the dehydrate technology, the method disclosed in the invention improves the phosphoric acid concentration and improves the phosphorus recovery rate to above 98%, and the combined-production a-hemihydrate gypsum can be directly used as a building gypsum product, so energy consumption saving is realized.

Methods and apparatus for the production of low sodium lithium carbonate and lithium chloride from a brine concentrated to about 6.0 wt % lithium are disclosed. Methods and apparatus for direct recovery of technical grade lithium chloride from the concentrated brine are also disclosed.

A process is disclosed for making a blend of alpha- and beta-stucco including a slurry calcination step to produce alpha calcium sulfate hemihydrate followed by a fluidized bed calcination step to produce beta calcium sulfate hemihydrate. The process starts with 50-75% gypsum-containing solids slurry, and then steam calcines the slurry in a first reactor to form partially calcined gypsum slurry which contains calcium sulfate dihydrate and alpha calcium sulfate hemihydrate. The partially calcined slurry is then dewatered. Then the filter cake is fed into a kettle to complete the calcination process by converting the calcium sulfate dihydrate of the filter cake material into beta calcium sulfate hemihydrate.

The invention relates to potassium feldspar decomposition and comprehensive utilization technology and in particular relates to a process for decomposing potassium feldspar by adopting a low-temperature semidry method for comprehensive utilization. The process comprises the steps of fully mixing potassium feldspar, fluorite and sulfuric acid, then adding the mixture to a converter reactor to react at 180-250 DEG C, separating SiF4 and HF generated through a reaction from a system under the condition of negative pressure, carrying out absorption with ethanol and water solution to prepare white carbon black, recovering fluorine resources in the process from the solution in the forms of ammonium fluoride and other aids by adopting the method of adding ammonia water and applying the recovered fluorine sources to decomposition of potassium feldspar and carrying out a series of processes such as extraction on the solids after a reaction to obtain calcium sulfate whisker, potassium fluosilicate, aluminium hydroxide and ferric sulfate products. Compared with the method for decomposing potassium feldspar by a high temperature method, the process has the advantages that the reaction conditions are mild and the requirements for equipment are lower; the white carbon black is directly prepared through gas hydrolysis, thus avoiding the tedious course from solid phase separation; and the fluorine resources introduced to the decomposition course are recycled by adopting the mode of ammonium fluoride, thus avoiding waste of the fluorine resources.

The invention relates to a method for extracting aluminum oxide, monox and ferric oxide from gangue combustion ashes. Coal blending is carried out according to heating value conditions after the gangue is pretreated, gangue activation is achieved while calcination generation is carried out, and the produced electricity and steam are supplied for a system to use; the aluminum oxide is extracted from the ashes by an acid method, the monox is extracted by an alkaline method, and the ferric oxide is extracted by comprehensive utilization of by-products; and acid, alkaline, lime, an extractant andCO2 which are required by each craft link are recycled inside the system. The invention has the beneficial effects that gangue reclamation is implemented by using the method; the energy and the chemical components in the gangue are fully utilized; the discharge amounts of greenhouse gases and waste ashes are greatly reduced, and the economic benefit of the system is improved; and the method is a novel technology of gangue greening and high added-value utilization, and has obvious competitive advantage.

The present invention includes pure single-crystalline metal oxide and metal fluoride nanostructures, and methods of making same. These nanostructures include nanorods and nanoarrays.

The present invention belongs to the field of chemical technology and is especially a complexing process of preparing nanometer BaSO4. The process includes two main steps of complexing reaction and deposition reaction. Specifically. Ba2+ ion solution and EDTA complexing agent solution produce complexing reaction in a reactor to produce complex solution with certain stability and ammonia water being used for regulating system pH value. The complex solution is made to react with sulfate radical solution while stirring to prepare nanometer level BaSO4 particles as precipitate. The nanometer level BaSO4 product is hexagonal crystal and blue in color, and has grain size of 20-40 nm and average grain size of 25 nm. The process is stable in operation, and the product has high quality and dispersivity.

Production of non-metallic calcium sulfate whiskers is carried out by taking converter slag as raw materials, grinding, leaching out sulfuric acid, filtering to obtain calcium sulfate suspended solution, synthesizing by high-temperature crystallizing method, separating and drying to obtain the final product. The purity is above 98%. It's cheap, has better quality and short process flow path. It can be used as filler, friction material, building material or thermal-insulating material and used to substitute glass fiber.

The invention provides a preparation method of nano barium sulfate with the controllable particle size distribution. The preparation method takes BaCl2 and Na2SO4 as raw materials, respectively prepares two types of solution and then simultaneously adds the two types of solution into a rotary liquid membrane reactor with the high-speed rotation at the same flow rate for carrying out nucleation reaction, and centrifugal washing and drying are carried out to the obtained slurry to obtain the nano BaSO4 with the particle size of 30-120nm and the narrower particle size distribution. The purpose of precisely controlling the particle size of the product can be achieved by regulating and controlling the rotational speed, the gap and other operation parameters of the reactor, thereby being capable of preparing the BaSO4 with the particle size of 30-40nm. The method combines the advantages of a micro-reactor and a high gravity reactor and simultaneously avoids the shortcomings of the micro-emulsion method, the complex method and the like, thereby having small reaction space and high preparation speed and being capable of meeting the requirements on the industrial preparation of the nano BaSO4.

The invention provides a method for recycling impurity salts generated in industrial wastewater treatment. The method comprises the following steps: (1) calcining impurity salts generated in an industrial wastewater treatment process, cooling, dissolving in pure water, and obtaining a high-concentration sodium chloride solution; (2) performing solid-liquid separation, and removing residual organisms in the solution; (3) successively removing sulfate radicals and calcium ions, adjusting the pH of the solution to neutral, and obtaining a high-purity sodium chloride solution; and (4) crystallizing the high-purity sodium chloride solution obtained in step (3), obtaining a sodium chloride crystal product, and washing to obtain the high-purity sodium chloride crystal product. By adopting the method, the effective treatment and recycling of impurity salts generated in the industrial wastewater zero emission process of electric power, petroleum chemistry, coal chemistry and the like; moreover, the method is simple in treatment process and moderate in operation conditions, and is a high-efficiency and stable impurity salt recycling method; and a final product sodium chloride is high in recycling rate and purity.

The invention provides a method for extracting tungsten from scheelite and producing high-quality calcined gypsum, comprising the following steps: adding a mixed acid of phosphoric acid and sulphuric acid to decompose scheelite; and after decomposition, adding hydrated gypsum seed crystals to finish the dewatering conversion process of dihydrate gypsum to obtain hydrated gypsum with good properties. The invention has the following advantages: the efficient atmospheric pressure leaching of scheelite is realized, the resource and energy consumption is saved, and the decomposition rate of scheelite can reach over 98%; the serious problems of Cl<-> corrosion and HCl volatilization in the traditional acid decomposition process can be overcome; the recycling of phosphoric acid is basically realized, and the leaching cost and the wastewater discharge are greatly reduced; the leaching device is simple, the operation is convenient and industrialization is easy to realize; the obtained byproduct gypsum has pure quality and can be used to produce gypsum boards, and can be used in retarder, plaster and the like produced by using cement; and due to the recrystallization process, the P2O5 content in gypsum is further reduced to below 0.5%.

The invention discloses a preparation method of modified nano barium sulfate powder which is easy to disperse and good in heat resistance and an application of modified nano barium sulfate, and meanwhile provides a toughened and enhanced masterbatch prepared by taking the modified nano barium sulfate powder as a main body and a preparation method of the masterbatch. The invention has the beneficial effects that the prepared modified nano barium sulfate powder has the advantages of easy dispersion, excellent heat resistance, high whiteness, low water content and the like, and can be applied to preparing the toughened and enhanced masterbatch in the fields of tubular products, sheets, thin films, non-woven fabrics, fibers, injection molding plastic products and the like; the prepared masterbatch remarkably improves the mechanical properties such as tear strength and impact strength of the products such as thin films.

The invention belongs to the technical field of a limestone/gypsum wet flue gas desulfurization technology, and particularly relates to an additive for strengthening a wet flue gas desulfurization technology, which comprises the following components in percentage by mass: 35-45% of mixed organic acid, 5-10% of organic acid salt, 6-9% of surfactant, 1-6% of heavy metal salt and 35-45% of dirt dispersion agent; and the mixed organic acid comprises adipic acid, wherein the percentage of mass of the adipic acid in the mixed organic acid is not less than 50%. The additive can be added and used for strengthening the wet flue gas desulfurization technology, improve the desulfurization efficiency of a system, reduce the energy consumption, strengthen oxidization, improve the limestone quality and restrain system scaling, and accordingly, the purposes of energy conservation, consumption reduction and waste recycling are realized.

The invention relates to the technical field of processes for treating acidic arsenic-contained wastewater discharged by non-ferrous smelting and sulfuric acid industries and particularly discloses a process for treating high-arsenic and high cadmium waste acid by using a three-stage lime-ferric salt method. The process comprises the following three stages: firstly, gypsum manufacture: adding lime to adjust the pH value to 2, and carrying out solid-liquid separation to obtain gypsum slag, wherein the gypsum slag can be used for manufacturing cement; secondly, neutralization, oxidation and arsenic sedimentation: adding lime into a supernatant liquid, adjusting the pH value to 5-6, adding ferrous sulfate according to the ferrum-to-arsenic ratio of 4:1, continuously aerating, adding anionic polyacrylamide for coagulation, and removing most of arsenic; and thirdly, neutralization and coagulation: adding lime to adjust the pH value to 9, adding ferrous sulfate according to the ferrum-to-arsenic ratio of 4:1, continuously aerating, adding anionic polyacrylamide for coagulation, and removing residual arsenic and heavy metal ions. After wastewater with the highest arsenic concentration of 14740mg/L and the highest cadmium concentration of 130mg/L is treated by using the process, the concentration of arsenic in the wastewater is reduced to 0.25g/L, no cadmium is found, and therefore, the wastewater achieves the national discharge standard.

The invention provides a process for comprehensively utilizing desalinated seawater after desalination, including the following steps: the desalinated seawater is collected and potassium is extracted; magnesium is extracted; evaporation concentration is carried out and bromine is extracted; marine gypsum is extracted; salt is made with the desalinated seawater; the desalinated seawater is refined to produce liquid salt. The steps for extracting the potassium, magnesium and bromine of the invention can be inter-modulated. The process has the advantages that: Ca<2+> in saturated brine treated by the process is reduced by 85.21-94.29 percent, Mg<+2> is reduced by 51.22-63.98 percent, SO4<2-> is reduced by 85.57-93.82 percent, Br<-> is reduced by 75 percent, k<+> is reduced by 70 percent, Na<+> is increased by 3.06-5.86 percent and Cl<-> is increased by 7.96-9.38 percent. As ingredient of the brine changes, impendence of the brine evaporation is reduced; yield and quality of the sea salt are improved. The process for producing solar salt can not only effectively utilize chemical resource in the desalinated seawater but also greatly improve the yield and quality of the sea salt product. Bittern quantity of the brine is greatly reduced; if the produced saturated brine is refined, the liquid salt can be produced to directly supply an alkali plant for sintering the alkali.

A process for preparing the desulfurized alpha-semi-hydrated gypsum by ordinary-pressure salt solution method includes oxidizing the deposited calcium sulfite slurry generated by desulfurizing fume, thickening, adding salt solution, mixing, crystallizing, centrifugal solid-liquid separation washing and drying. The washing water is evaporated to obtain concentrated salt solution for reuse.

The invention discloses an acidolysis method of magnesium-containing phosphate rock. The method provided by the invention is characterized by comprising the following steps of: carrying out acidolysis on the magnesium-containing phosphate rock to obtain a water-soluble calcium, magnesium and phosphoric acid containing acidolysis solution, carrying out acidolysis on the phosphate rock by using the generated phosphoric acid to generate Ca(H2PO4)2.H2O solid, performing a reaction between H2SO4 and water-soluble calcium to generate high-pureness calcium sulfate whisker, and performing a reaction between water-soluble magnesium and phosphor in the acidolysis solution and NH3 to generate character separation magnesium ions of a MgNH4PO4 solid so as to realize complete high-efficiency comprehensive utilization of the acidolyzed magnesium-containing phosphate rock. The focus of the invention is to change magnesium ions into controllable parameters which are beneficial to circulation of the acidolysis solution. The magnesium-containing phosphate rock can be efficiently utilized, and also the compound magnesium ammonium phosphate can be used to realize the separation of phosphor magnesium from a circulation medium HCl or HNO3 or CaCL, Ca(NO3)2, thus realizing the combination and combined production with a present ammonium phosphate and phosphor product processing technology. The method provided by the invention has advantages of concise technology, less investment, low energy consumption, low cost, high benefit and no discharge of ''three wastes (waste gas, wastewater and industrial residue)'', and fully presents great business value and great resource value of the high magnesium-containing phosphate rock.

The invention provides a method for recrystallizing and purifying desulphurized gypsum, which mainly comprises the four steps of acid-washing, dissolution, crystallization and washing, and specifically comprises the following steps of: removing impurities, reacted with acids, in the desulphurized gypsum by the aid-washing, dissolving calcium sulphate in the desulphurized gypsum into the acid solution at a relatively higher temperature by utilizing the characteristic that the solubility of the calcium sulphate in the specific acid solution is remarkably changed with the temperature, performing solid-liquid separation to remove undissolved solid-phase impurities at the high temperature, performing cooling recrystallization and the solid-liquid separation on a liquid phase at a relatively lower temperature, and washing and drying a filter cake to obtain high-purity gypsum, wherein the liquid phase in the dissolution and recrystallization processes can be reused. Through the method provided by the invention, the gypsum with relatively higher purity and whiteness can be prepared by selecting a proper solid-to-liquid ratio, proper temperatures and proper acid concentration and performing dissolution and crystallization for a certain time, and the performance of the desulphurized gypsum is remarkably improved.

The invention discloses a method for wet production of phosphoric acid and a byproduct, namely white gypsum, relating to the technical field of phosphorus chemical industry. The method is mainly used for solving the problems in the traditional wet production of phosphoric acid that the byproduct, namely phosphogypsum is high in impurity content, poor in quality and yellow grey, dark grey and black in appearance, can be stacked only as waste and pollutes the environment. The method comprises the steps of firstly, reacting phosphorite powder (slurry) (the content of phosphorus pentoxide in phosphorite is 18-35%) and phosphoric acid of a volume, which is 16-32w% of the weight of phosphorus pentoxide, for 15-60 minutes at the temperature of 45-70 DEG C while stirring, so as to produce mixed slurry containing phosphoric acid, a calcium phosphate solution, phosphorite carrying acid insoluble matters and a small amount of produced calcium fluoride, ferric phosphate and aluminum phosphate solid impurities; continuously or intermittently precipitating the mixed slurry for 1.0-3.5 hours, and carrying out layered separation, so as to obtain a phosphoric acid and calcium phosphate mixed solution and thick slurry containing solid impurities; adding 40-98w% sulfuric acid while stirring, reacting sulfuric acid and the phosphoric acid and calcium phosphate mixed solution for 10-40 minutes, precipitating for layering, and separating, thereby obtaining phosphoric acid and white gypsum. The method has the advantage that the pollution to atmosphere, soil and groundwater due to phosphogypsum stacking is reduced.

The invention belongs to the technical field of recycling of electrolytic aluminum industrial wastes and specifically discloses a processing method for an aluminum electrolysis waste cathode carbon block. The processing method comprises the following steps: breaking the waste cathode carbon block and then adding water for ball-milling, performing decyanation treatment, leaching with hot water, leaching with concentrated sulfuric acid, washing and performing flotation, thereby acquiring a first-level carbon powder product and a second-level carbon powder product; reacting a primary acid leaching solution with a sodium hydroxide solution and filtering, thereby acquiring solid aluminum hydroxide; mixing the reaction filtrate with lime and filtering, thereby acquiring calcium sulfate; using water for absorbing the mixed gas formed by the primary washing gas and the acid leaching gas, thereby acquiring a hydrofluoric acid solution; mixing the prepared hydrofluoric acid solution with a ball-milling separating liquor and a hot water leaching separating liquor; adding aluminum hydroxide into the mixed liquor; filtering and separating the reactants; filtering, thereby acquiring the liquid phase of reusable water and the solid phase of fluorine-containing aluminum hydroxide; and roasting, thereby acquiring a fluorine-containing aluminum hydroxide product. According to the method providedby the invention, the harmless comprehensive recycling of the aluminum electrolysis waste cathode carbon block is realized.

Systems are disclosed for making and using micro-porous particulates at least partially composed of metal sulfides, particularly alkaline earth metal and transition metal sulfides, as sorbents for removal of mercury from flue gas. Calcium sulfide micro-porous powders derived from the high temperature reduction of calcium sulfate and calcium sulfite are disclosed to be reactive substrates for a group of sorbents for adsorption of mercury from coal combustion flue gases produced by the utilities industry, as well as from natural gas and gaseous and liquid hydrocarbons. The sorbents are useful for cost-effectively adsorbing elemental mercury and oxidized mercury species such as mercuric chloride from flue gases, including those containing acid gases (e.g., SO.sub.2, NO and NO.sub.2, and HCl), over a wide range of temperatures.

A technology for producing sodium bicarbonate from mirabilite comprises steps as follows: mirabilite and distillation waste liquor mixed liquor is used as a raw material, sodium carbonate is added to the solution after absorption of ammonia, magnesium, iron and calcium ions in the solution are removed after the solution is subjected to a precipitation reaction at 15-50 DEG C, and a refined solution is obtained; carbon dioxide is added to the refined solution for carbonatation, and sodium bicarbonate solids and heavy alkali mother liquor are obtained through separation after the refined solution is subjected to a replacement reaction at 15-50 DEG C; lime is added to the heavy alkali mother liquor, and ammonia gas, carbon dioxide, calcium sulfate and distillation waste liquor are obtained after distillation reaction at 15-120 DEG C; ammonia gas and carbon dioxide are recovered to ammonia absorption and carbonatation procedures respectively; the distillation waste liquor and mirabilite in Step A are mixed to be recycled. The technology has the characteristics that mirabilite is directly utilized, ammonia is recycled, the comprehensive utilization rate of distillation waste liquor waste is high, the production cost is low, the waste residue discharge is low, the technology is environment-friendly, and the like.

A method and apparatus for providing an evenly mixed additive enhanced gypsum slurry to a web. Calcined gypsum and water are inserted into a mixer through at least one inlet of the mixer. The contents are agitated to form a slurry. The slurry is passed from an outlet of the mixer into a conduit. An additive is introduced into the slurry along a length of the conduit to achieve a flow stream of a slurry/additive mixture. A cross section of the flow stream is expanded in the conduit while not changing direction of the flow stream and a direction of the flow stream is changed while not expanding the cross section of the flow stream and conduit, all prior to the flow steam exiting from an outlet of the conduit.