96 results about "Anhydrite" patented technology

The invention relates to the technical field of cement mortar compositions, and particularly discloses a double-component anti-freezing early-strength slurry and a preparation method and application thereof. The double-component anti-freezing early-strength slurry provided by the invention is composed of a component A and a component B in a weight ratio of 25: (4-10), the component A is prepared from the following components in parts by weight: 250 to 280 parts of Portland cement, 90 to 100 parts of admixture, 145 to 165 parts of sand and 6.4 to 8.4 parts of water reducing agent; and the component B comprises the following components in parts by weight: 8-10 parts of a sodium nitrite antifreeze agent, 50-58 parts of a reinforcing aid, 32-40 parts of anhydrite, 240-270 parts of an admixture, 155-175 parts of sand and 4.1-6.1 parts of a water reducing agent. By utilizing the technical scheme, the prepared double-component anti-freezing early-strength slurry has the advantages of rapid development of early compressive strength and stable growth of later compressive strength under different ultralow temperature conditions.

The invention relates to the technical field of concrete crack repairing agents, in particular to a triggered precipitation type concrete crack repairing agent as well as a preparation method and application thereof. The repairing agent is prepared from the following raw materials: sulphoaluminate cement, nano anhydrite with a core-shell structure, fluorine-phosphorus composite seed crystal, magnesium oxide, metakaolin and a water reducing agent, wherein the core-shell structure nano anhydrite is prepared by coating mesoporous silica with nano anhydrite, and the fluorine-phosphorus composite seed crystal is prepared from calcium fluoride and monocalcium phosphate through a hydrothermal reaction. According to the trigger precipitation type concrete crack repairing agent prepared by the invention, sulfate ions are slowly released through the core-shell structure nano anhydrite, the crystal form of ettringite is regulated and controlled through the fluorine-phosphorus composite seed crystal, the problems that a traditional repairing agent shrinks and falls off in the later period, the high-temperature strength is suddenly reduced, and the binding power is insufficient are solved, and the trigger precipitation type concrete crack repairing agent is suitable for concrete structure crack repairing and high-temperature environment engineering.

The invention discloses a method for preparing anhydrite through ultrasound-assisted phosphogypsum crystal transformation, which is characterized in that phosphogypsum is used as a raw material, ammonium persulfate is used as an additive, a dilute sulfuric acid solution is used as a crystal transformation agent, and the anhydrite is prepared by adopting a sulfuric acid method under ultrasound-assisted action. The process for preparing the anhydrous gypsum has the characteristics of low sulfuric acid concentration, low equipment corrosion degree, low heating temperature, low energy consumption, high whiteness of the product anhydrous gypsum and small particle size.

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, and discloses a concrete anti-cracking agent and a preparation method thereof.The preparation method comprises the steps that 10-15 parts by weight of zeolite powder, 12-16 parts by weight of anhydrite, 2-3 parts by weight of polymethyl methacrylate microspheres, 1-3 parts by weight of cellulose-based polyurethane and 0.4-0.7 part by weight of graphene oxide are added into a stirrer and stirred for 10-16 min, and a mixture is obtained; and finally, obtaining the concrete anti-cracking agent. The concrete anti-cracking agent disclosed by the invention has relatively good anti-cracking and compression-resistant effects.

The invention belongs to the technical field of grouting materials, and particularly relates to a quick-setting early-strength self-stress functional grouting material and an expansibility testing method. The existing cement-based anchoring agent or mine filling body top-contacting agent and fractured rock mass grouting reinforcing agent have the phenomena of poor coupling effect, volume shrinkage and the like. The grouting material is composed of a component A and a component B, the component A mainly comprises sulphoaluminate cement, a water reducing agent, a retarder, a sodium salt accelerator and fibers, and the component B mainly comprises anhydrite, quicklime, a water reducing agent, an early strength agent, aluminum powder, a retarder and fibers. When in use, the mass ratio of the main components of the component A to the component B is (0.85-1.15): 1, and the water-cement ratio is (0.6-1.2): 1. When the water cement ratio is low (0.6-0.8: 1), the material can be used as an anchoring agent of an anchor rod; when the water-cement ratio is high (0.8-1.2): 1, the grouting agent can be used as a mine filling body top-contacting agent and a fractured rock mass grouting reinforcing agent; the invention further provides a simple testing method for the volume expansion rate and the expansion stress. And the method has obvious engineering application value.

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 relates to a preparation method of type II anhydrous gypsum. The preparation method comprises the following steps: mixing an industrial by-product gypsum raw material with type II anhydrous gypsum seed crystal to obtain a mixture; autoclaving the mixture at the temperature of lower than 200 DEG C to obtain intermediate powder; and drying the intermediate powder at a drying temperature lower than the autoclaved temperature to obtain the type II anhydrite. According to the preparation method, high-temperature calcination or addition of an inducer and a catalyst is not needed, no acidic raw material is added, and the preparation method has the characteristics of low energy consumption, environment optimization and high conversion rate.

Manufacturing lightweight aggregate (LWA) by a sintering technique requires a delicate balance among three conditions: forming sufficient amount of molten liquid phase during sintering; reaching an appropriate viscosity for solid-liquid suspension; and emitting sufficient amount of gas that can be entrapped by the liquid phase to form pores. LWAs were made from low-calcium and high-calcium Waste Coal Combustion Ash (W-CCA) including fly ash and bottom ash. A mass fraction of at least 40% liquid phase for fly ash and 50% for bottom ash is required for a successful entrapment of emitted gaseous phases during sintering. Larger pores were observed in the microstructure of LWA samples made using high-calcium W-CCA in comparison to low-calcium W-CCA. This result was mainly attributed to the high-calcium samples forming liquid phases with lower viscosity values and emitting higher amounts of gaseous phase during sintering than did the low-calcium samples. The gaseous phase was generated by hematite reduction and anhydrite decomposition.

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 discloses high-temperature phase change regulation and control anhydrite-based self-leveling mortar and a preparation method thereof. The self-leveling mortar is prepared from Portland cement, sulfur aluminum cement, modified fine sand, modified coarse sand, modified heavy calcium carbonate, ash calcium, anhydrite, cellulose, a water reducing agent, a defoaming agent, rubber powder and lithium sulfate. The preparation method comprises the following steps: S1, carrying out solid phase change on calcined phosphogypsum to prepare anhydrous gypsum, S2, preparing modified fine sand and modified coarse sand, S3, preparing modified coarse calcium carbonate, and S4, mixing all the components to obtain the anhydrous gypsum-based self-leveling mortar. Through the synergistic effect of all the raw materials, the modified fine sand, the modified coarse sand and the modified coarse calcium carbonate form a tight filling structure, the structural strength of the dried mortar is enhanced, in the alkaline environment of the self-leveling mortar, polyethylene glycol monomethyl ether on the surface of the modified coarse calcium carbonate reacts with silane coupling agents on the surfaces of the modified fine sand and the modified coarse sand to form a cross-linked structure, and the self-leveling mortar has the advantages that the self-leveling effect is good; the structural strength and the stability of the self-leveling mortar are further improved.

The invention relates to a system for flash production of anhydrite from phosphogypsum. The system comprises a chimney, an induced draft fan, a bag collector and a vertical cylinder furnace, the vertical cylinder furnace is composed of a furnace body, a furnace cover, a furnace bottom and a material scattering device. The furnace body comprises a green electric heating body, a heat insulation material and a furnace body shell. The green electricity is used as an energy source, the anhydrous gypsum is produced by adopting a vertical suspension calcination technology, and the carbon neutralization of the anhydrous gypsum industry is favorably realized.

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 invention discloses gypsum plastering mortar with gradient aggregate enhanced cohesion strength and a preparation method thereof.The gypsum plastering mortar is prepared from anhydrite, modified glass beads, modified quartz sand, ash calcium, modified heavy calcium carbonate, cellulose, starch ether, an air entraining agent, a retarder and a thixotropic lubricant, and the preparation method comprises the steps of S1, preparing the modified glass beads, S2, preparing the modified heavy calcium carbonate, S3, preparing the modified quartz sand, S5, preparing the modified quartz sand, S6, preparing the modified quartz sand, and S6, preparing the gypsum plastering mortar. S4, all the components in the formula are mixed, through gradient particle size design of the modified glass beads, the modified quartz sand, the modified heavy calcium carbonate and the ash calcium, a close packing structure is formed, the compactness of the mortar is improved, and therefore the structural strength of the gypsum plastering mortar is effectively improved; and the interface bonding force with a gypsum matrix can be enhanced, a three-dimensional network is formed with cellulose and starch ether, and the cohesion strength of the gypsum plastering mortar is effectively improved, so that the structural strength of the gypsum plastering mortar is further improved.

The invention relates to the technical field of phosphating waste residue treatment, in particular to a construction method of a high-performance phosphorus II type anhydrite-based tile adhesive. The ceramic tile glue is prepared from the following raw materials in parts by weight: 45 to 60 parts of phosphorus II type anhydrite, 30 to 40 parts of quartz sand, 3 to 5 parts of cement, 3 to 5 parts of metakaolin, 2 to 5 parts of mineral powder, 2 to 5 parts of silica fume, 0.6 to 1.8 parts of latex powder, 0.05 to 0.12 part of a water reducing agent, 0.1 to 0.25 part of cellulose ether, a waterproof agent and 0.10 to 0.15 part of a retarder. During construction, a thick layer is not needed to be smeared, only a thin layer is needed, and if the construction process reaches the standard, the ceramic tiles are very firmly adhered. And the construction steps are simple, the brick can be used by adding water and stirring on site, and the brick can be tiled without soaking the brick and wetting the wall. In addition, hollowing and cracking can be eliminated, the reworking possibility is reduced, and the bonding strength is very high.

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 provides a method for preparing high-purity anhydrous calcium sulfate powder from electrolytic manganese residues. The preparation method comprises the following steps: drying the electrolytic manganese residues and preparing the electrolytic manganese residues into electrolytic manganese residue powder; mixing the electrolytic manganese residue powder with an ammonium chloride solution, and reacting to obtain a mixed solution; carrying out solid-liquid separation on the mixed solution to obtain a first filtrate; adding sulfuric acid into the first filtrate to adjust the pH value to 2-4, aging to obtain a solid-liquid mixture, and performing solid-liquid separation to obtain a filter cake and filtrate; washing and drying the filter cake to obtain high-purity anhydrous calcium sulfate powder; wherein the phase of the high-purity anhydrous calcium sulfate powder is an anhydrite phase, the purity of the anhydrous calcium sulfate powder is greater than 99%, the whiteness of the anhydrous calcium sulfate powder is greater than 90, and the microscopic morphology of the powder comprises a particle shape and / or a plate shape. According to the method, the high-purity and high-whiteness anhydrous calcium sulfate powder can be prepared by taking the electrolytic manganese residues as the raw material without adding a crystal form control agent.

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.