251 results about "Composite crystal" patented technology

Lithium dopant is introduced into lithium rich high capacity positive electrode active materials as a substitution for manganese within the complex metal oxides. In some embodiments, the lithium doped compositions can be written in a two component notation as x.Li2MnO3.(1−x)LiNiu+ΔMnu−Δ−dLidCowO2, where d ranges from about 0.004 to about 0.25 and 2u+w is approximately equal to 1. The materials are believed to form a layer-layer composite crystal structure that has very good cycling properties at high voltages, although the materials exhibit significant first cycle irreversible capacity loss.

The invention relates to a cyclic regeneration flue gas desulfurization method using magnesium compounds and ammonia. Firstly, the magnesium compounds and ammonia which is used as desulfurizer is made to be seriflux after mixed with water, and then is send to recycling tank and then to the thionizer using seriflux pump to absorb the sulfur dioxide therein via the contact with flue gas to get the purpose of desulfurization purification of the flue gas. Part of the desulfurization solution is drawn off and regenerated using ammonia or ammonium salt when the PH of the seriflux after absorbing the SO2 is low than 6.2. Regeneration uses the method of direct regeneration or oxydizing regeneration, and the precipitate such as magnesium sulphites, magnesium hydroxide or magnesium carbonate get after regeneration can be periodic duty. After concentrating crystallization, the ammiaonia sulfate of liquid phase can get the ammonium sulphate crystals, and is also made to be a composite Crystals of ammonium sulphate and magnesium sulfate. The invention reduces the desulfurization cost without secondary pollution at the precondition for ensuring the effect desulfurization of flue gas.

The invention discloses a nano toughening NdFeB magnetic material and a preparation method of the nano toughening NdFeB magnetic material. The main mechanism is that a nano composite crystal boundary phase is formed on an NdFeB main phase crystal boundary, an H-grade rare earth permanent magnetic material with high coercive force M is prepared without doping any heavy rare earth, and then, a SH-grade rare earth permanent magnetic material is prepared by adding a little heavy rare earth. The nano material is prepared by a plasma arc method, has a grain size of 5-80nm and mainly contains metallic elements, such as Al, Cu, Cr, Co, Fe, Zn and the like, and all kinds of rare earth elements. A NdFeB main phase having a rare earth content of Pr-Nd is prepared by a SC-HD process; after smelting and hydrogen breaking, the product grain size is milled to be about 3.5 microns by an air-current mill, and in the argon protection atmosphere, a nano additive is added in a manner of jetting composite, so the nano additive is uniformly attached to the NdFeB main phase. In the sintering process, the nano powder and the main phase form the crystal boundary, the coercive force of NdFeB is greatly increased, and since the product has uniform crystal components, the machining property is also elevated well, the NdFeB magnetic material can be applied to the wider field. At the same time, the technical process is simple, low-cost and suitable for the batch production.

A donor layer that is formed by performing a heat treatment for a crystal defect formed by proton radiation is provided in an n-type drift layer of an n− semiconductor substrate. The donor layer has an impurity concentration distribution including a portion with the maximum impurity concentration and a portion with a concentration gradient in which the impurity concentration is reduce to the same impurity concentration as that of the n-type drift layer in a direction from the portion with the maximum impurity concentration to both surfaces of the n-type drift layer. The crystal defect formed in the n-type drift layer is a composite crystal defect mainly caused by a vacancy, oxygen, and hydrogen.

The invention includes a composite material for use in a security device including a radiation diffracting component that exhibits a first optical effect and a photochromic component that exhibits a second optical effect. The composite material is particularly suited for use in authenticating articles, such as currency.

The invention relates to a production method of nano calcium carbonate special for organosilicon, comprising the following steps: generating Ca(OH)2 slurry by reacting lime CaO and a proper amount of water, producing the refined raw slurry by a hydraulic cyclone after screening the slurry through a screen cloth; adding a proper amount of crystal form control agent into the modulated raw slurry and placing the mixture into a carbonization tower after deposition and pumping kiln gas into the carbonization tower to perform carbonization reaction, and pumping the cold water into the carbonization tower from the bottom of carbonization tower after performing the carbonization reaction for a certain time; placing the boiler slurry into an activation drum and adding the dispersant into the drum and adding saponified surface treating agent into the activation drum after reacting for a certain time; filter pressing, dehydrating, drying and depolymerizing. The depolymerized material is sent to a mixer filled with N2 gas and subjected to secondary activating treatment using the coupling agent and crushed and packaged. The production method has features of low production device investment, nano calcium carbonate of composite crystal type, good affinity and harmony with the organosilicon, increased mechanical strength and durability of the downstream products of the organosilicon.

The invention includes a composite material for use in a security device including a radiation diffracting component that exhibits a first optical effect and a photochromic component that exhibits a second optical effect. The composite material is particularly suited for use in authenticating articles, such as currency.

The invention discloses a composite crystal, a gamma ray detector and their preparation methods. The gamma ray detector comprises a composite crystal array and a photomultiplier. The composite crystal array is coupled with the photomultiplier by an optical coupling agent. The composite crystal array comprises the multiple composite crystal wires and light reflective layers having different lengths are filled between the multiple composite crystal wires. The multiple composite crystal wires are cut, grinded and polished to form the composite crystal. The composite crystal comprises scintillation crystals and a photoconductive material. The scintillation crystals and the photoconductive material are bonded by an adhesive and are aligned with each other without deviation, wherein the adhesive is optical cement. The gamma ray detector provided by the invention has a high space resolution ratio. The preparation method of the composite crystal has simple processes, can be realized easily, and adopts a high-stability and high-repeatability assembling technology.

The invention discloses a rodlike aragonite calcium carbonate preparation method. The method includes: crushing limestone, calcining, and digesting according to a lime-water mass ratio of 1:3-8 to obtain lime slurry; screening, filtering to remove residues, and adding water to adjust the solid content of the lime slurry to 7-20%, so that refined lime slurry is obtained; controlling the temperature of the refined lime slurry to 30-60 DEG C, adding a composite crystal form control agent being 0.5-2.0% of the mass of calcium hydroxide in the lime slurry, delivering to a carbonization tower, starting stirring, feeding kiln gas for carbonation, stopping gas feeding when pH reaches 8.0, and terminating carbonation to obtain precipitated calcium carbonate suspension; dewatering and drying according to a conventional method to obtain rodlike aragonite calcium carbonate. The calcium carbonate prepared according to the method is stable in crystal form, products are rodlike in appearance and large in specific surface area, and the aragonite phase content reaches 85% or above. In addition, the rodlike aragonite calcium carbonate preparation method has advantages of low energy consumption, high production efficiency, low cost, technical simplicity and the like and is easy for realization of industrial production.

The invention provides a preparation method of a carbon-doped titanium dioxide photocatalyst. The method comprises the steps of utilizing polyethylene glycol (PEG) as a dispersing agent for preparingmodified MOF-Al powder, i.e., a metal organic framework material of modified MOF-Al; utilizing the metal organic framework material of the modified MOF-Al as a template, and preparing to obtain a TiO2 / C nanometer composite crystal which is the carbon-doped titanium dioxide photocatalyst provided by the invention. The carbon-doped titanium dioxide photocatalyst is friendly to the environment, a photocatalyst preparation way is expanded, and meanwhile, the carbon-doped titanium dioxide photocatalyst not only has the characteristics of high specific surface area and high pore volume, is high in photocatalytic activity, and shows a better photocatalytic performance; in addition, the preparation method has the characteristic of simple preparation process.

The invention discloses an yttrium lithium fluoride composite crystal and a preparation method thereof, and belongs to the technical field of laser crystal preparation. According to the method, an yttrium lithium fluoride crystal on a c-axis crystal orientation is pre-boned at the end part of a doped yttrium lithium fluoride crystal on an a-axis crystal orientation with a direct bonding technology, and a first intermediate product is obtained; the intermediate product is subjected to pressure treatment in the direction perpendicular to the bonding surface of the first intermediate product, and a second intermediate product is obtained; and finally, under the vacuum condition, the second intermediate product is subjected to hot isostatic pressure treatment, and the yttrium lithium fluoride composite crystal is obtained. The prepared yttrium lithium fluoride composite crystal doesn't have the axial matching problem and has a low heat effect, thermally induced depolarization loss of the crystal is reduced, and the output power and the beam quality of a laser are improved.

The invention relates to a method for preparing alpha-type high-strength gypsum from phosphogypsum, belonging to the technical field of building materials. The method for preparing alpha-type high-strength gypsum from phosphogypsum is characterized by employing a semi-liquid-phase process and comprising the following steps: 1) blending phosphogypsum with quicklime with an amount identical to the sum of P2O5 and F in the phosphogypsum so as to neutralize the phosphogypsum and then carrying out aging for 1 d ; 2) weighing, on the basis of the total mass of the phosphogypsum, 0.01-0.5% of ternary organic acid and 0.5-2% of hypervalent sulfate, mixing the ternary organic acid and the hypervalent sulfate, and dissolving the obtained mixture in water with a temperature of 80-90 DEG C so as to prepare a composite crystal-type control agent; 3) adding the composite crystal-type control agent and water in a solid-liquid ratio of 4: 1 to 2: 1 into the neutralized phosphogypsum so as to form thick slurry; and 4) spreading the prepared slurry in an autoclave in layers, each layer being 5-15 mm thick, carrying out constant-temperature treatment at 120-150 DEG C for 3-6h, and then carrying out drying and ball-milling so as to obtain alpha-type high-strength gypsum powder. With the method in the invention, the prepared alpha-type high-strength gypsum is in the form of a short-column-like crystal with stable quality, and has 2-hour flexural strength of 4.9 MPa and drying compressive strength of 32.3 MPa; and obvious social, environmental and economic benefits are obtained.

The invention discloses a multi-arm block copolymer and a preparation method as well as an application of the multi-arm block copolymer. Each arm of the multi-arm block copolymer is structured by a soft section and a hard section, wherein the soft section is poly-dl-lactide, or polycaprolactone or a copolymer of the poly-dl-lactide and the polycaprolactone; the hard section is poly-dextrolactic acid; a stereo composite crystal is formed through the poly-dextrolactic acid and the poly-dl-lactide of the multi-arm block copolymer and plays a role of a physical cross-link point; a multi-arm block copolymer system is fused and blended with the poly-dl-lactide, then a blend is formed by injection molding and a certain constant-temperature annealing treatment is carried out, so that the breaking elongation of the poly-dl-lactide can be obviously increased; and the multi-arm block copolymer can play a role of accelerating crystallization in the process of isothermal crystallization and still can retains good degradation and transparence properties, so that the important application prospects of the multi-arm block copolymer in modification of the mechanical property of the poly-L-lactic acid are shown.

The invention relates to a loaded titanium dioxide (TiO2) foam ceramic, and a preparation method and an application thereof. The preparation method includes the steps: (1) preparation of a nano TiO2 precursor; (2) pretreatment of polyurethane foams; (3) primary slurry coating; (4) secondary slurry coating; and (5) sintering. Through the two-time slurry coating method, nano TiO2 with an anatase form or an anatase and rutile composite crystal form is effectively firmly loaded on a foam ceramic core material, the preparation method is simple, no secondary sintering is required, the period is short, and the cost is low; a crystal form transformation control agent nano SiO2 is added in the nano TiO2 precursor, the problem of crystal form transformation of nano TiO2 at high temperature is solved, the crystal form is still the anatase form or the anatase and rutile composite crystal form after sintering at high temperature (800 DEG C to 1000 DEG C), and a relatively high photocatalytic performance is maintained; and aluminum dihydrogen phosphate is a binder, and the alumina photocatalytic foam ceramic core material is prepared at low temperature (800 DEG C to 1000 DEG C).

The invention discloses a completely-degradable polylactic acid composite material with high crystallinity. A poly-dextrolactic acid / poly-levolactic acid / polyethylene glycol composite material is prepared by the step of adding the polyethylene glycol poly-dextrolactic acid and the polyethylene glycol according to a certain ratio into the poly-levolactic acid in a solution blending way or a melt blending way. A stereo-structure composite crystal and a plasticizer polyethylene glycol which are generated in the blending process of the poly-dextrolactic acid and the poly-levolactic acid jointly accelerate the crystallization of the poly-levolactic acid, so that a polylactic acid sample with high crystallinity can be obtained in a fast cooling process; and all components added in the composite material are biodegradable, i.e., the composite material has high crystallinity and is also completely biodegradable. The preparation technology is simple, easy to operate and low in cost.

The invention discloses a frequency doubling self-regulating Q green laser inside a double-doped chrome yttrium aluminum garnet composite photassium titanyl phosphate cavity,and relates to a green laser. The self-regulating Q green laser is provided with a pumping source, a micro lens, a first column-shaped lens, a second column-shaped lens and a laser working medium Cr, Nd:YAG / KTP composite crystal. The pumping source, a micro lens, the first column-shaped lens, the second column-shaped lens and the laser working medium Cr, Nd:YAG / KTP composite crystal sequentially are arrayed on a same plain shaft from front to back. Anti-reflection film and a high-reflective film are plated on the rear surface of the laser working medium Cr, Nd:YAG / KTP composite crystal to serve as a back cavity lens of the laser cavity. High-reflective film and anti-reflection film are plated on the front surface of the laser working medium Cr, Nd:YAG / KTP composite crystal of the laser cavity. The number of optical elements used for the laser is small, the production cost is low, the structure is simple and compact, and the laser is convenient to produce and assemble and operate and use by a non-professional person.

The invention provides a preparation method of needle-like nano calcium carbonate. The method comprises the following steps: (1) adding a composite crystal form control agent in a calcium hydroxide suspension, wherein the composite crystal form control agent comprises an organic acid and water-soluble chloride or sulfate; (2) introducing a gas containing carbon dioxide in the suspension for carbonization reaction; (3) when the pH value of the suspension is reduced to 6.5-7.0, further introducing gas for 15-30 minutes, and then finishing the carbonization reaction. Compared with the existing technical scheme, the needle-like nano calcium carbonate product obtained by the preparation method has more appropriate average particle diameter, controllable particle diameter and good dispersibility; and the product dose not break under the ordinary grinding strength; and the production process is easy to regulate and control.

The invention provides a high energy ball milling process-containing preparation method for a nanometer multi-element composite crystal grain growth inhibitor. The chemical formula of the inhibitor is (V<x>,M1<1-x>)(C<y>,N<1-y>), wherein M1 is at least one selected from the group consisting of chromium, titanium, molybdenum, tantalum, niobium and zirconium, x is more than 0.5 and no more than 0.95, and y is no less than 0.1 and no more than 0.9; or the chemical formula of the inhibitor is (Cr<x>,M2<1-x>)2(C<y>,N<1-y>), wherein M2 is at least one selected from the group consisting of vanadium, titanium, molybdenum, tantalum, niobium and zirconium, x is more than 0.5 and no more than 0.95, and y is no less than 0.1 and no more than 0.9. The preparation method comprises the following steps: (1) batching; (2) high energy ball milling: a step of dry grinding raw materials batched in the step (1) with a high energy ball mill at a rotating speed of 350 to 700 rpm so as to obtain ball milling powder; and (3) sintering. The method provided by the invention can reduce sintering temperature, shorten a production period and lower down requirements on granularity of the raw materials.

The invention discloses an antibacterial agent for textiles. The antibacterial agent is characterized by comprising composite crystal of zinc phosphate and silver phosphate. A preparation method comprises the following steps of: adding soluble silver salt into macromolecular protective solution, and adjusting the pH value to be between 1 and 7; adding zinc phosphate powder; stirring in a water bath; and roasting the dried product at a high temperature to obtain the antibacterial agent for textiles. An application method comprises the following steps of: adding the antibacterial agent for textiles into water containing adhesive, stirring, and treating the solution through a Nanomizer high-pressure homogenizer to prepare finishing working solution; and selecting pure cotton or blended fabric, soaking the pure cotton or the blended fabric into the working solution, soaking and rolling with an open width padder, and conveying the pure cotton or the blended fabric to a drying oven for setting so as to obtain an antibacterial textile. The mixed crystal structure enables silver ions to be well protected in the crystal structure of the laminar zinc phosphate, so that the stability of the mixed crystal structure is greatly improved, and the antibacterial durability of the mixed crystal structure is greatly enhanced; the preparation method is simple, convenient and feasible, and is easy to reach the requirement of industrialized production; and the antibacterial agent is easily attached to the textiles, so the antibacterial agent achieves long-acting antibacterial property.

The invention aims at providing a bowl-shaped flexible three-dimensional array ultrasonic probe. The bowl-shaped flexible three-dimensional array ultrasonic probe has the advantages of locating accuracy, simple device and the like. The bowl-shaped flexible three-dimensional array ultrasonic probe comprises a bowl-shaped flexible shell, a composite piezoelectric crystal plate, a coupling agent injecting device, connecting lines and the like, wherein the bowl-shaped structure can well attach to the detected surface of a flexible body, an ultrasonic transducer adopts the multi-array-element array composite crystal plate structure, the plurality of array elements are distributed according to the Fibonacci helical line, 2n array elements compose the ultrasonic array transducer, according to the delaying sequence, each array element emits ultrasonic waves once, the other array elements including the emitting array element receive signals, and a storage records and stores the 2n signals. In combination with the phased array technology principle, the aperture synthesis technology is adopted for carrying out data after-treatment on the extracted 2n signals, and then the image reflecting the information including the position, degree and the like of the lesion tissue is obtained.

A modularized composite crystal preparation system comprises a furnace frame, a furnace chamber, a crystal growth temperature field module, a rotary lifting and weighing unit and a lifting mechanism.The furnace chamber is arranged on the furnace frame, the front side of the furnace chamber is provided with a front door, the lateral side of the furnace chamber is provided with a light-permeable window, the crystal growth temperature field module is arranged in the furnace chamber, the rotary lifting and weighing unit is arranged on the upper portion of the furnace chamber, the lower portion ofthe rotary lifting and weighing unit is connected with a lifting rod, and the crystal growth temperature field module is one of a micro-pulling-down module, a lifting module and a laser base heatingmodule. The system is a multi-purpose system, a body portion is universal to different crystal growth methods, convenience in replacement of the crystal growth temperature field module is achieved, crystal growth in different methods is realized, different types of functional crystals can be prepared, exploratory development of universities and scientific research institutions on multiple varieties of crystals can be met, and growth demands of small-batch crystals in industrial production can be met.

The invention belongs to thermoelectric material manufacturing technology field. The current micron crystal grain CoSb3 material thermal conductivity is high. Although nanometer is low, its electric conductivity is greatly reduced to make ZT maximum only be 0.057 in 300-800K temperature range. The features of a nanometer / micron compound grain structure CoSb3 thermoelectric material manufacturing are using 80-100nm metallic cobalt and 20-40um antimony simple substance elemental powder as raw material; weighting and mixing by CoSb3 compound chemical formula under the protection of argon gas; grinding powder; doing SPS reaction in situ synthesis; and the pressure is 30-50MPa; heating rate is 120-150 centigrade degree per minute; temperature is 450-550 centigrade degree; holding time is 3-5min; atmosphere is vacuum. The thermoelectric material has nanometer / micron compound grain structure. The ZT value is 0.34 at 700K.

The invention relates to the field of the high polymer material blending alloy, and specifically relates to a high-tenacity polylactic acid PLA / PBAT blending alloy and a preparation method thereof. The PLA, the PBAT, the PDLA-PBAT-PLDA triblock copolymer are used as the raw material, and a banburying machine is used for preparing the PLA / / PBAT / PDLA-PBAT-PDLA blending alloy, the content of the PDLA-PBAT-PLDA triblock copolymer in a blending system is 1%-10%. The PLA / PBAT blending alloy prepared by the invention takes the PDLA-PBAT-PDLA triblock copolymer as the compatilizer, the PDLA chain segment can form the steric composite crystal (SC) in-situ with the PLA when performing the melt blending, the PLA and PBAT two-phase interfacial force is improved, and the mechanical performance of the alloy is obviously improved. The blending alloy disclosed by the invention is simple in process, normal in equipment and easy to realize industrial production.

The invention relates to room temperature phosphorescent material based on phenyl-2-naphthylamine or phenyl-2-naphthylamine and 4,4-dibromodiphenyl composite crystal, preparation method of the material, and application of the material in the organic white light material field, safety anti-counterfeiting identification field and other fields, and belongs to the technical field of organic room temperature phosphorescent materials. 2-Naphthylamine is connected with benzene rings or naphthalene rings having different substitutions, this type of molecules is as good as naphthylamine in emitting deep blue light and can also efficiently emit yellow-green phosphorescent light at low temperature. 4,4-Dibromodiphenyl provides, on one hand, heavy atoms for a body so that interstitial crossing rate of objective molecules from single linear state to triple linear state is increased, and avoids, on the other hand, the quenching of the objective molecules due to accumulation, thereby ensuring efficient luminescent efficiency. A white light luminescent material can be prepared by using fluorescent-phosphorescent double emission of the system, and long-life phosphorescent emission is potentially significant to bio-labeling and anti-counterfeiting identification fields.

The invention relates to a multi-layer composite structure ceramic brake pad material and a manufacturing method of the multi-layer composite structure ceramic brake pad material. Ceramic brake pad material powder, reinforced performance material graphene and multi-component composite crystals serve as raw materials, and calculation and preparation of material powder of various layers, vibration of mixed materials of various layers, multi-layer structure preforming, the hot-press curing technology, the heat treatment technology and the follow-up machining working procedure are conducted in sequence, so that the multi-layer composite structure ceramic brake pad material is manufactured. The high utilization ratio of the brake pad layer thickness is achieved through ceramic multi-layer gradient distribution, and compared with a uniformly-distributed brake pad, a multi-layer composite structure ceramic brake pad has the advantages that the relative consumption of the reinforced performance material can be reduced, and the friction performance can be guaranteed. Meanwhile, a large number of heavy metal raw materials are not used, and the multi-layer composite structure ceramic brake pad material has the advantages of being green and environmentally friendly, stable in friction performance at the high temperature, long in service life and the like.

The invention discloses a method for synthesizing a NaA type molecular sieve membrane on the surface of an organic hollow fiber. The method comprises the following steps: synthesizing 800nm NaA type molecular sieve crystal seeds through adopting a hydrothermal synthesis technology, blending and dissolving the crystal seeds and an organic matter in an organic solvent according to a certain ratio to prepare a coating solution, carrying out a dip coating technology to obtain an organic hollow fiber carrier with a composite crystal seed layer, and synthesizing the NaA type molecular sieve membrane on the surface of the composite carrier by adopting the hydrothermal synthesis technology. The molecular sieve membrane has the excellent ethanol / water separation performance of an inorganic membrane, and also has the characteristics of large specific surface area, large filling density and low cost of an organic hollow fiber membrane. The crystal seed layer made in the invention is uniformly distributed, and the molecular sieve membrane obtained in the invention has the advantages of continuous and compact surface, high selectivity and flux, low price, and suitableness for large scale production.

The invention relates to a garnet composite crystal with a multi-segment doping concentration gradient and a growing method thereof. The garnet composite crystal has the following structural general formula: (Lnx1Re1-x1) 3B2C3O12 / (Lnx2Re1-x2) 3B2C3O12 / (Lnx3Re1-x3) 3B2C3O12 / ... / (LnxnRe1-xn) 3B2C3O12, wherein Ln is equal to Nd or Yb or Tm or Ho, x1 is more than 0 and less than 1, x2 is more than 0 and less than 1, x3 is more than 0 and less than 1, xn is more than 0 and less than 1, and n is more than 3; Re is equal to Lu, Y or Gd; B is equal to Sc, Al or Ga; and C is equal to Al or Ga; and the garnet composite crystal has a garnet structure. The growing method comprises the following steps of: making the composite crystal grow by an optical float-zone method; proportioning the raw materials according to chemometry in the general formula; preparing polycrystal charge bars according to the predesigned segments and length; and loading the polycrystal charge bars into an optical float-zone furnace for growing. The method has the advantages of high speed, short cycle, no crucible in the process crystal growth, less pollution on crystals, obvious gradient concentration segments and relatively simple process. The growing crystals have high transparency and few cracks and are suitable for growing of the garnet composite crystals with the concentration gradients.

The invention relates to a composite crystal modifier for preparing alpha-type high-strength gypsum, which belongs to the technical field of gypsum additives and gypsum deep processing. The crystal modifier is formed by compounding inorganic fluoride salt accounting for 0.02 to 6 percent of the mass of a dihydrate gypsum dry base, and multi-element organic acid or organic acid salt accounting for0.02 to 1 percent of the mass of the dihydrate gypsum dry base. By utilizing the composite crystal modifier disclosed by the invention, when the alpha-type high-strength gypsum is prepared from dihydrate gypsum under a hydrothermal condition, a crystal habit of the alpha-type semi-hydrate gypsum can be effectively regulated and controlled, the alpha-type semi-hydrate gypsum can form short cylindrical alpha-type semi-hydrate gypsum crystals, so that the high-strength gypsum with the pressure resisting strength greater than 25MPa and a product thereof can be prepared. The composite crystal modifier is particularly suitable for preparing the alpha-type high-strength gypsum by adopting phosphorus gypsum with high fluorine impurity content as a raw material.