74 results about "Anhydrite" patented technology

The invention belongs to the field of phosphorus chemical industry, and particularly relates to a method for synchronously preparing type II anhydrite in a semi-hydrated-dihydrated wet-process phosphoric acid process and the type II anhydrite. The method comprises the following steps: carrying out slurry premixing, semi-hydrated crystallization, dihydrate conversion and dihydrate filtration to obtain dihydrate gypsum, after the semi-hydrated crystallization step, leading out a part of slurry, adding a lattice orientation agent and a crystal face selective adsorbent into an intermediate pretreatment tank for pretreatment, and adding concentrated sulfuric acid into an anhydrous crystallization reactor for anhydrous crystallization, and finally, carrying out solid-liquid separation, washing and drying to obtain the type II anhydrite. The method is simple in process, energy-saving and environment-friendly, co-production of the phosphoric acid product and the high-added-value II type anhydrous gypsum is realized, and the product yield is gt; therefore, the method has remarkable economic benefits and environmental benefits.

The invention relates to the technical field of concrete crack repairing, and particularly discloses a quick-hardening concrete crack repairing agent and a preparation method thereof. The invention relates to a quick-hardening concrete crack repairing agent, which is prepared from the following raw materials: 45 to 55 parts of sulphoaluminate cement; 10 to 15 parts of silica fume; 12 to 18 parts of metakaolin; 5-8 parts of a bimetallic composite seed crystal; 10 to 15 parts of double-layer shell nano anhydrite; 2-4 parts of magnesium oxide; 0.5 to 1 part of polypropylene fiber; 0.5 to 0.8 part of a water reducing agent; 15 to 20 parts of water; the bimetallic composite seed crystal is a zirconium and strontium element co-doped composite crystal nucleus; the double-shell nano anhydrite is composed of an inner core nano anhydrite, a middle aluminum sulfate early strength phase and an outer mesoporous SiO2 shell. The quick-hardening concrete crack repairing agent has the advantages of being short in setting time, high in early strength and excellent in interface bonding performance.

The invention provides a method and a device for determining spatio-temporal evolution of clastic rock diagenetic fluid in a fractured basin. The method for determining spatio-temporal evolution of clastic rock diagenetic fluid in the fractured basin comprises the following steps: acquiring authigenic minerals at different structural positions of the fractured basin; wherein the authigenic minerals comprise carbonate, quartz secondary enlargement and anhydrite; determining the paleofluid temperature of the authigenic mineral according to the uniform temperature of the saline inclusion of the authigenic mineral and the uniform temperature of the hydrocarbon inclusion; and determining the spatio-temporal evolution process of the clastic rock diagenetic fluid of the broken basin according to the paleo-fluid temperature, the predetermined burying history of the broken basin and the paleo-ground temperature gradient. According to the method, the activity time range of diagenesis fluid in clastic rock reservoirs at different structural positions is determined, so that fluid difference evolution modes of different structural positions of the broken lake basin are established, and technical support is finally provided for predicting causes of high-quality clastic rock reservoirs.

The invention discloses a calcining furnace for large-scale production of type II anhydrite from industrial byproduct gypsum, which is characterized in that a plurality of material inlets are formed in the calcining furnace and used for receiving materials from different sources, so that the fine powder circulation volume in a system is greatly reduced, and dust collection return materials directly enter the lower part of the calcining furnace, so that the productivity of the system is increased; the air inlet part of the calcining furnace adopts high-temperature flue gas, part of heat energy is recycled, and the use of air can be reduced, so that the oxygen content in the calcining furnace is always below the explosion limit, and the safety is improved; by means of temperature, pressure, oxygen content, air volume and other instruments, frequency conversion fan rotating speed, valve opening and the like, automatic control is adopted, and raw material amount, fuel consumption and mixed total air volume entering a calcining furnace are metered and controlled, so that the system has the advantages of reducing total air volume of the system, reducing total air displacement, reducing heat consumption, saving energy, improving heat exchange efficiency, improving effective utilization rate of energy, improving productivity and the like. And the product quality is improved.

The invention belongs to the field of building materials, and particularly relates to an anhydrous gypsum-based terrazzo floor material and a preparation method thereof. The anhydrite-based terrazzo floor material is prepared from the following raw materials: anhydrite, quenched stone, building gypsum, ash calcium, potassium sulfate, calcium formate, a water reducing agent, a defoaming agent, rubber powder and hydroxypropyl methyl cellulose. The invention relates to a building material, which is prepared from the following raw materials in parts by weight: 525 to 550 parts of anhydrite, 350 to 450 parts of quenched stone, 30 to 40 parts of building gypsum, 15 to 20 parts of ash calcium, 4 to 7 parts of potassium sulfate, 0.5 to 0.8 part of potassium acid calcium, 1.5 to 2.0 parts of water reducing agent, 0.4 to 0.6 part of defoaming agent, 0.10 to 0.15 part of hydroxypropyl methyl cellulose and 6 to 8 parts of rubber powder. The anhydrous gypsum-based terrazzo floor material is high in early strength and low in cost compared with a cement-based inorganic terrazzo in a construction period. The development of companies is facilitated, and the product is more competitive in the market.

The application provides a method for testing gypsum moisture content based on nuclear magnetic resonance, comprising the following steps: performing nuclear magnetic resonance test on a gypsum sample to be tested to obtain a nuclear magnetic resonance signal amplitude; the magnetic field strength of the nuclear magnetic resonance test is less than or equal to 1T; obtaining the mass of water in the gypsum sample according to a predetermined standard curve and the signal amplitude; obtaining the gypsum moisture content according to the mass of water in the gypsum sample and the mass of the gypsum sample to be tested; and the predetermined standard curve is a linear relationship curve of the mass of water in the gypsum and the signal amplitude. The application adopts a low-field nuclear magnetic resonance method (magnetic field strength less than or equal to 1T) to non-destructively determine the water content in the gypsum, thereby determining the type of the gypsum (anhydrite, hemihydrate gypsum and dihydrate gypsum). The method provided by the application does not need to dry the gypsum sample to be tested, has the advantages of rapidness and non-destructiveness, and has a wide application prospect in the determination of water content in the gypsum field and the determination of different types of gypsum.

The invention provides a method for preparing anhydrous gypsum through phosphogypsum crystal transformation and purification, and relates to the technical field of industrial solid waste recycling. The method comprises the following steps: uniformly mixing the phosphogypsum, the acidic mixed solution and the crystal modifier, reacting under specific conditions, and filtering while hot after the reaction is finished, thereby obtaining the anhydrous gypsum. According to the technical scheme, the growth process of the anhydrous gypsum is regulated and controlled by introducing the specific crystal modifier, so that the anhydrous gypsum with high purity and high compressive strength is obtained. The method is suitable for preparing the anhydrite by taking the industrial byproduct phosphogypsum with high phosphorus impurity content as the raw material, the produced anhydrite is good in crystallization conversion, excellent in product quality, simple in process, high in efficiency and low in energy consumption, the water demand is lower than that of a traditional method, the phosphogypsum waste can be utilized, and resource circulation is realized.

The invention discloses a nano C-A-S-H seed crystal and a nano C-A-S-H enhanced low-content high-belite cement-slag cementing material, and belongs to the technical field of building materials. The raw materials of the nano C-A-S-H seed crystal comprise a silicon source, a calcium source, an aluminum source, polycarboxylic acid and alkali and are synthesized by adopting a chemical precipitation method, the Al / Si ratio is 0.5, the Ca / Si ratio is 1.2-2.0, and the water-solid ratio is (8-12): 1. The nano C-A-S-H enhanced low-doping-amount high-belite cement-slag cementing material disclosed by the invention comprises nano C-A-S-H seed crystals and a cementing material, wherein the doping amount of the nano C-A-S-H seed crystals is 1-3wt%; the cementing material comprises granulated blast furnace slag, high belite cement clinker and anhydrite. The nano C-A-S-H seed crystal is creatively doped into the low-doping-amount high-belite cement-slag cementing material, so that the early strength and construction efficiency of the material are remarkably improved, continuous increase of the later strength is guaranteed, meanwhile, efficient utilization of the low-doping-amount high-belite cement and the slag is realized, and the low-doping-amount high-belite cement-slag cementing material has excellent performance and environmental protection value.

A ternary hydraulic binder composition including the mineralogical compound C4A3$ (ye'elimite) and a member selected from the group consisting of gypsum, calcium sulfate hemihydrate, anhydrite and mixtures thereof (collectively named C$Hx with x being a rational number from 0 to 2), and optionally C2S (belite), including an added content of the mineralogical compound C12A7 (dodecacalcium heptaaluminate). Moreover, it suggests a process for the manufacture thereof, a process for the manufacture of a construction chemical composition including water, and the use of the ternary composition in construction chemical compositions including knifing fillers, screeds, and repair mortars, tile adhesives, tiling grouts, plasters, base coats and sealings.

The application discloses anhydrite calcining system and relates to the technical field of gypsum processing. The anhydrite calcining system comprises a calcining assembly and a crushing assembly. A discharging port is arranged on the calcining assembly. A crushing inlet is arranged on the crushing assembly. A ring-shaped support frame is rotatably arranged on the discharging port. A sealing base plate is installed on the ring-shaped support frame through a sealing connecting assembly. Soft pipes are connected to the ring-shaped support frame through a pipeline connecting assembly. The other ends of the soft pipes are connected to the crushing inlet. The crushing assembly and the calcining assembly are connected through the soft pipes. When the calcining is finished and the discharging is performed, the gypsum product obtained from the calcining assembly is guided from the discharging port to the crushing inlet position. The dust in the product is also limited between the soft pipes. In this process, the dust can be prevented from being raised into the air.

The application belongs to the technical field of comprehensive utilization of solid waste and building materials, and particularly relates to a method for preparing and activating type II anhydrite, and specific steps are as follows: after the gypsum and a compound conversion agent are measured according to a mass ratio and uniformly mixed, type II anhydrite is obtained by dehydration conversion at 120-200 DEG C for 30-60 min, the type II anhydrite is ground to a specific surface area of 400+ / -20 m 2 / kg, calcium active material and an activator are added and uniformly mixed to obtain type II anhydrite products. The water requirement of the type II anhydrite according to the application at a standard consistency is 40-45% of the mass of the mixture, the initial setting time is 30-60 min, the final setting time is 120-180 min, the 28-day flexural strength is greater than 6 MPa, the compressive strength is greater than 25 MPa, and the softening coefficient is greater than 0.8. Compared with the existing calcination method, the dehydration temperature of the application is low and more energy-saving, and compared with the liquid phase method, the application has a simple process, large capacity, does not need drying, and does not have the problem of water balance in the production process. The application provides a new technology for preparing water-resistant and high-strength gypsum products from gypsum, especially chemical gypsum such as phosphogypsum, and has great significance for promoting the resource utilization of phosphogypsum.

The invention discloses low-carbon environment-friendly self-leveling mortar and a preparation method thereof, and belongs to the technical field of mortar. Comprising the following steps: mixing P.O42.5 cement, 42.5 sulphoaluminate cement, building desulfurization gypsum, S95-grade granulated blast furnace slag powder, a gelling reinforcing filler, silica fume, grading machine-made sand, grading tailing sand and heavy calcium powder, and stirring in a stirrer for 30-50 seconds to obtain a mixed dry material; and adding mixing water, cellulose ether and an auxiliary agent into the mixed dry material, and stirring to obtain the low-carbon environment-friendly self-leveling mortar. The low-carbon environment-friendly self-leveling mortar with good product performance is obtained by optimizing formula composition, selecting granulated blast furnace slag powder, silica fume and fly ash to replace P.O 42.5 cement, selecting grading machine-made sand and tailing sand to replace grading dried river sand, and selecting building desulfurization gypsum to replace natural anhydrous gypsum.

The invention provides an anhydrous ardealite-based foaming door core board and a preparation method thereof.The anhydrous ardealite-based foaming door core board is prepared from anhydrous ardealite, cement, fly ash, water, a foaming agent, short fibers and a modifier.The preparation method includes the steps that the water is added into a stirrer, the short fibers and the modifier are added, then the stirrer is started, dry powder is added, the foaming agent is added after the dry powder is evenly stirred, and the foaming agent is added; adjusting the foaming amount; pouring the slurry into a mold, curing for 2 hours, and demolding; after demolding, the foaming agent is arranged at intervals in a side-standing mode, heat and moisture are dissipated, the foaming agent leaves a factory after being naturally cured for 3-5 days or is dried after being naturally cured for 1 day so as to shorten the factory time, and the modifier promotes the foaming agent to form hundreds of millions of closed thick-wall small round hole structures in the slurry to strongly support the strength of door core plates. Meanwhile, erosion of water and carbon dioxide in air is isolated, excellent durability is kept, and the excellent performance of the gypsum-based fireproof door core plate can be guaranteed; the production process is simple, raw material cost is low, and comprehensive production cost is reduced.

The invention discloses a plugging composition for plugging an oil field water flow dominant channel. The plugging composition contains ultrafine powder, a thickening regulator and a filtration regulator, wherein the ultrafine powder is prepared from 40.5 to 69.2 parts of hexagonal calcium silicate, 11.5 to 28.6 parts of calcite, 5.8 to 14.7 parts of clay mineral, 5.2 to 14.6 parts of quartz, 0 to 0.9 part of potassium feldspar, 0 to 2.6 parts of plagioclase, 0 to 0.6 part of dolomite, 0 to 2.1 parts of hornblende, 0 to 0.4 part of gypsum and 0 to 3.8 parts of anhydrite; the thickening regulator is sodium lignin sulfonate, hydroxymethyl cellulose and / or boric acid; the filtration property regulator is a terpolymer of 2-acrylamido-2-methylpropanesulfonic acid / acrylamide / hydroxy carboxylic acid, barium sulfate and / or 1788 type polyvinyl alcohol; the mass ratio of the thickening regulator to the ultrafine powder is (0.05-4): 100; the mass ratio of the filtration modifier to the ultrafine powder is (0.5-5): 100. The invention also discloses a preparation method and application thereof. The plugging composition provided by the invention can be matched with water flow dominant channels of reservoirs with different permeability.

The invention concerns an ettringitic and stratlingitic binder composition comprising:A) Crystaline calcium aluminate Cement (CAC),B) Ground Granulated Blast Furnace Slag (GGBS), andC) Sulfate source selected from the group consisting of Anhydrite calcium sulfate (AC$) and / or alkali sulfate (A$).

The invention relates to the technical field of firework cylinders, in particular to a firework mold pressing cylinder based on cassava flour pregelatinization and a preparation method thereof, and the mold pressing cylinder is prepared from the following raw materials in parts by weight: a framework material compounded by crystal transformation method II type anhydrous gypsum and calcium carbonate stone powder, pregelatinized cassava flour, wood fibers, stearic acid and a proper amount of water. The tapioca flour is pre-gelatinized by warm water at 40-60 DEG C, and the pre-gelatinization degree is greater than or equal to 80 The crystal transformation method II type anhydrous gypsum is prepared from ardealite through a low-temperature crystal transformation method. The preparation method comprises the following steps: pre-gelatinizing the tapioca flour, pulping, mixing with other dry blends and hot water, and finally carrying out high-temperature compression molding. Through the synergistic effect of the pre-gelatinized tapioca flour and the crystal transformation method gypsum, the dry basis dosage of the tapioca flour is remarkably reduced, meanwhile, the compressive strength and the falling resistance of the mold pressing barrel are greatly improved, the multiple purposes of reducing the cost, improving the performance and absorbing industrial solid waste phosphogypsum are achieved, the product quality is stable, and the mold pressing barrel is suitable for industrial production.

The invention belongs to the technical field of concrete materials, and particularly relates to a method for preparing a millstone from a type II anhydrous gypsum base. The II-type anhydrous gypsum-based inorganic millstone concrete is prepared from the following raw materials: II-type anhydrous gypsum, building gypsum, yellow phosphorus slag, ash calcium, an additive, gravel, sand and water. The concrete raw materials comprise, by weight, 34 to 38 parts of II-type anhydrous gypsum, 1 to 3 parts of building gypsum, 1 to 3 parts of yellow phosphorus slag, 1 to 2 parts of ash calcium, 0.4 to 0.6 part of an additive, 25 to 30 parts of rubble with a particle size of 2 to 10 mm, 12 to 17 parts of rubble with a particle size of 10 to 16.5 mm, 12 to 13 parts of sand with a particle size of 20 to 50 meshes, 5 to 6 parts of quartz sand with a particle size of 60 to 90 meshes, and 12 to 13 parts of water. Through scientific and reasonable raw material ratio and rigorous and meticulous preparation process, many problems existing in preparation of the inorganic millstone from the II-type anhydrous gypsum in the prior art are successfully solved.

The application provides a preparation method of anhydrite light self-leveling mortar. The anhydrite self-leveling mortar is prepared by mixing and stirring desulfurization gypsum, lime cement, self-made light gypsum sand, type II anhydrite and an additive in a specific ratio, and the volume density of the anhydrite self-leveling mortar is between 800 Kg / m 3 1000 Kg / m 3 , the 28d absolute dry compressive strength is 31MPa-40MPa, which is far greater than the 28d absolute dry compressive strength (20MPa) of the existing self-leveling mortar, wherein the light gypsum sand with high strength, water resistance, environmental protection and low cost is used in the formula, and the cost of the self-leveling mortar is greatly reduced.

The embodiment of the invention discloses a method and device for calculating the mineral content of a complex lithologic stratum containing anhydrite, and the method comprises the steps: calculating the shale content through a shale content empirical formula method by using a logging curve corresponding to logging information; performing argillaceous correction on the neutron density logging information according to the pure rock volume physical model to obtain corrected neutron density logging information; calculating the initial calculation content and porosity of the anhydrite mineral by using the corrected neutron density logging information, and obtaining the iterative calculation content of the anhydrite mineral and the iterative calculation content of other minerals through iterative calculation until a preset porosity condition is met; according to the shale content, the iterative calculation content of the anhydrite minerals and other minerals is correspondingly converted into the mineral component content under the lithologic condition of the shale minerals, and the mineral component content serves as the content of each mineral component of the complex lithologic stratum. According to the scheme, reasonable stratum mineral content information can be obtained, and a good actual production application effect is achieved.

A process for recycling plaster waste from the general public, the process comprises a step (S1) for sorting the solid waste in order to obtain a portion (A) known as gypsum, and a portion (B) known as reject; a step (S2) of generating fuel from at least part of the portion (B) of rejects by an exothermic process; a step (S3) for generating anhydrite from at least part of the gypsum portion (A); the process further comprising the recovery of at least part of the heat (C) generated by the exothermic process, in that the step (S3) of generating anhydrite comprises the heating of the at least part of the portion (A) of gypsum produced from the at least part of the heat (C).

The present application relates to the technical field of inorganic non-metallic materials, and particularly relates to a gypsum-based cementing material and a preparation method thereof, the gypsum-based cementing material comprising the following components in percentage by mass: 25-50% of type 2 anhydrite powder, 10-30% of hemihydrate gypsum powder, 10-20% of cement clinker powder, 20-25% of active micro powder, 3-5% of quicklime, and 1-5% of an activator. The gypsum-based cementing material of the present application is based on type 2 anhydrite and hemihydrate gypsum, and cement clinker powder is added thereto, so that the hydration performance of the cementing material can be significantly improved; the active micro powder and quicklime powder are further added, so that the cementing structure of the cementing material can be improved, a multi-element cementing system is formed, and the stability and durability of the cementing system are significantly improved; and the activator is further added, so that a calcium aluminate cementing body can be quickly formed during the hydration of the cementing material, the hydration conditions are further optimized, and the gypsum-based cementing material is more suitable for construction.

The application discloses a production process of a building hard gypsum binder, and belongs to the technical field of binder production, and comprises the following steps: step S1, hard gypsum raw ore is crushed in a jaw crusher, then is coarsely ground in a ball mill to obtain hard gypsum coarse powder, then the hard gypsum coarse powder and monocyanoamine are added into deionized water to be stirred and mixed to obtain a slurry, the slurry is added into a wet grinding machine to be finely ground, and after drying and scattering, hard gypsum fine powder is obtained; step S2, the hard gypsum fine powder is transferred into a rotary kiln to be calcined, is scattered after being cooled to room temperature, and calcined modified hard gypsum is obtained, a composite activator, slag and Portland cement clinker are added into the calcined modified hard gypsum to be uniformly mixed, and a building hard gypsum binder is obtained; through fine grinding and calcination treatment, the hydration activity of the hard gypsum in the binder is improved, the prepared hard gypsum binder has the advantages of fast hydration speed, uniform hydration degree, high strength after hydration and hardening, and good volume stability.

The application provides a high-coating lightweight plastering gypsum and a preparation method thereof. The mechanical strength of the lightweight plastering gypsum prepared by mixing and stirring building gypsum, II anhydrous hard gypsum, self-prepared lightweight gypsum sand, vitrified microbeads and additives in a specific ratio can reach excellent performance such as a tensile bonding strength of 0.6-0.8 MPa under standard conditions and a tensile bonding strength of 0.28-0.4 MPa under humid conditions, which is greatly improved compared with the existing lightweight plastering gypsum with a tensile bonding strength of greater than or equal to 0.3 MPa.

The invention relates to a method for purifying calcium sulfate, in particular for reducing radioactive components, phosphorus-containing or fluorine-containing impurities and heavy metals originating from what is known as phosphogypsum resulting from phosphoric acid production, based on recrystallization of the anhydrite form into the dihydrate form in a sulfuric acid solution and separation into a coarse fraction and a fine fraction, wherein the fine fraction contains the undesired impurities, in particular the radioactive component. The invention also relates to a system for carrying out such a method.

The application provides a preparation method of a soft rock standard cylinder sample, which adopts fast hard gypsum to wrap a soft rock sample, and the gypsum provides a holding force for the soft rock sample after solidification, enhances the overall stability of the soft rock sample, and thus ensures that the soft rock sample can bear the impact force of direct lathe turning processing. Then, the soft rock sample wrapped by the gypsum is subjected to lathe turning processing by using a lathe, and a standard cylinder sample is formed in one step. The diameter tolerance of the standard cylinder sample obtained by one rough turning processing is less than 0.05 mm, and there is no need to polish again. Meanwhile, one end surface of the standard cylinder sample is directly flattened by using lathe turning processing, and the flatness is high. The other end surface is cut by using wire cutting, and the non-parallelism of the two end surfaces is less than 0.05 mm. The application can efficiently and stably prepare a standard sample meeting the national standard, and the preparation success rate can reach more than 90%, and thus the problems of low preparation efficiency and low preparation success rate of the soft rock sample are solved.

The invention provides an efficient curing agent preparation device based on anhydrite and a preparation method of the efficient curing agent preparation device and belongs to the technical field of soft soil curing agent preparation. A feeding pipeline is installed on the side portion of a pretreatment module, and a dry-mixing crushing module used for first-time mixing operation is installed on the side portion of the feeding pipeline; the bottom of the dry-mixing crushing module is connected with a wet-mixing dispersing module for secondary mixing operation, and a standard box body is placed at the bottom of the wet-mixing dispersing module. Raw materials are fully dried through a temperature control rod, the quality of the raw materials is accurately controlled through a sensor, the proportion of a curing agent is optimized, a double-box mixing structure (upper box crushing and lower cavity wet mixing) is combined, the raw materials are fully scattered and efficiently mixed, the quality of the curing agent is improved, meanwhile, powder and slurry in the raw materials are cleaned through a dry mixing / wet mixing cleaning box, and the curing agent quality is improved. Meanwhile, the self-cleaning structure does not need to stop the device for cleaning, so that high efficiency, energy conservation and cost reduction are achieved, the device does not need to be opened for cleaning, and dust is prevented from flying out to pollute the environment.

The invention relates to a premixed binder for mortar comprising, relative to the total weight of the premixed binder: - from 10 wt.-% to less than 95 wt.-% of a cement C comprising Portland clinker and optionally mineral components, the cement C preferably comprising Portland clinker in an amount of at least 20% by weight, relative to the total weight of the cement C, - from 0.25 to 7.5 wt.-% of amorphous calcium aluminate cement, CAC, relative to the total weight of the premixed binder, the amorphous CAC having an amorphous phase content of at least 50% by weight relative to the total weight of CAC, - from 0.25 to 7.5 wt.-% of anhydrite, - from 0.25 to 7.5 wt.-% calcium sulfoaluminate cement, CSA, the premixed binder being essentially free of lithium salts. The invention further relates to the use of the premixed binder to prepare a mortar, to the corresponding mortar (essentially free of lithium salts) and use thereof as repair mortar or as adhesive between construction building blocks.

The invention discloses a low-carbon early-strength phosphorus type II anhydrous gypsum epoxy resin-based self-leveling mortar material, which is prepared from the following raw materials: phosphorus type II anhydrous gypsum, epoxy resin, a curing agent, a silane coupling agent, building gypsum, silica fume, fly ash, ground steel slag, carbide slag, calcined sulfate, slag, cement, sand, a plasticizer, a water reducing agent, a retarder, a defoaming agent and water. According to the invention, industrial solid wastes such as anhydrite, fly ash and carbide slag are taken as raw materials, a combined double-excitation system based on calcined sulfate and carbide slag is adopted, and an organic-inorganic composite technology is combined, so that the problems that the existing self-leveling mortar is difficult to consider early strength and slurry viscosity, and the early strength and the slurry viscosity are poor due to contradiction between an exciting agent and a water reducing agent can be effectively solved. On the basis of ensuring the working performance of the slurry, the early-stage, middle-stage and later-stage mechanical strength and waterproof performance are effectively considered; and high value-added resource utilization of various industrial solid wastes can be realized, and the method has remarkable economic and environmental benefits.

This invention provides anhydrous gypsum-polypropylene composite hollow board and its preparation method. The anhydrous gypsum-polypropylene composite hollow board comprises the following components by weight percentage: 30%-65% modified anhydrous gypsum powder, 30%-65% polypropylene resin, 1%-3% compatibilizer, 1%-3% lubricant, and 0.1%-0.3% antioxidant. The modified anhydrous gypsum powder is prepared by modifying hydroxylated anhydrous gypsum powder with a composite surface modifier formed by compounding long-chain fatty acids or their derivatives with a coupling agent. The anhydrous gypsum-polypropylene composite hollow board is prepared by a two-step method: first, a high-filler functional masterbatch is prepared, and then the hollow board is extruded. By modifying the anhydrous gypsum powder and combining it with the two-step preparation method, the problems of weak interfacial bonding between anhydrous gypsum and the polypropylene matrix and poor dispersibility with high filler content are solved, thus systematically improving the mechanical properties and processing performance of the composite hollow board.

This invention relates to the field of high-efficiency expansive agent technology, and in particular to a slow-release high-efficiency expansive agent for concrete, its preparation method, and its application. The method includes the following steps: crushing limestone, bauxite, hematite, gypsum dihydrate, magnesite, and silica, then ball-milling and sieving to obtain a mixed raw material powder; heating to 650-850℃ and holding for 20-40 minutes, then raising the temperature to 950-1200℃ and holding for 30-60 minutes, continuing to raise the temperature to 1250-1300℃ and holding for 40-70 minutes, and finally cooling to 150-200℃ to obtain clinker; mixing the clinker powder with anhydrite until uniform, adding admixtures and a hydration regulator / activator, and grinding; adding a slow-release coating agent via high-pressure atomization spray, and stirring to obtain a fine mixed powder; mixing and aging in a homogenization chamber to obtain the slow-release high-efficiency expansive agent. The slow-release high-efficiency expansive agent of the present invention gradually generates calcium hydroxide and ettringite crystals to provide efficient compensation when the cement hardened body begins to shrink, and achieves continuous micro-expansion throughout the process by relying on later expansion sources such as periclase.