311 results about "Magnesium phosphate" patented technology

The invention discloses a preparation method of a curing agent with biological self-healing capability, which comprises the following steps: preparing a bacillus pasteurii bacterial solution, preparing the bacillus pasteurii bacterial solution into an endophytic spore solution, immersing polyvinyl alcohol fibers into a sodium alginate / endophytic spore solution, taking out the polyvinyl alcohol fibers, immediately immersing the polyvinyl alcohol fibers into a calcium acetate solution, drying the polyvinyl alcohol fibers to obtain core fibers with a hydrogel coating, and curing the core fibers with the hydrogel coating to obtain the curing agent with biological self-healing capability. The preparation method comprises the following steps: taking magnesium phosphate cement as a raw material, immediately immersing the magnesium phosphate cement into a chloroform solution of a polystyrene and polylactic acid polymer blend, drying to obtain a coated microbial liquid, premixing urea and glucose, doping the premixed urea and glucose into the magnesium phosphate cement, uniformly stirring, adding the coated microbial liquid, and uniformly stirring to obtain the product. According to the invention, phosphate cement is adopted as the curing agent, has the advantages of high strength, short setting time, strong durability, low alkalinity, good biocompatibility and the like, and compared with the curing agent in the prior art, the curing agent not only has a good curing effect, but also has a crack self-healing function, and is especially suitable for reinforcing foundation soil.

The invention belongs to the field of modified self-repairing calcium aluminate cement 3D printing, and particularly relates to a phosphate modified self-repairing calcium aluminate cement 3D printing material and a preparation method thereof. The phosphate modified self-repairing calcium aluminate cement 3D printing material prepared by the invention is prepared from the following raw materials in parts by mass: 60 to 70 parts of calcium aluminate cement, 3 to 7 parts of silica fume, 2 to 4 parts of metakaolin, 0.5 to 3.5 parts of double-template modified calcium bentonite, 0.8 to 1.5 parts of amino modified sodium polyphosphate and 0.15 to 0.8 part of basalt fiber. The invention relates to a concrete anti-microbial agent, which is prepared from the following raw materials in parts by weight: 20-30 parts of water, 20-30 parts of water, 20-30 parts of water, 20-30 parts of nano calcium carbonate, 20-30 parts of nano calcium carbonate, 20-30 parts of magnesium phosphate cement coated bacteria-loaded porous microspheres, 20-30 parts of a polycarboxylate superplasticizer, 20-30 parts of an organic silicon defoaming agent and 25-35 parts of mixing water. The technical-economic cooperation requirement of building 3D printing under complex working conditions is met, and various indexes of phosphate modified calcium aluminate cement applied to the 3D printing technology are met.

The invention discloses a water and fertilizer management method for transplanted high-yield indica type two-line hybrid rice, and belongs to the technical field of rice cultivation. Comprising the following steps: (1) applying citric acid chelated calcium magnesium phosphate fertilizer to soil before transplanting; (2) applying coated controlled-release urea and a silicon-zinc fertilizer on the third day after transplanting; (3) when the tiller number reaches 2650,000-2750,000 plants / hm < 2 >, starting intermittent light field drying for three times, and deeply applying potassium magnesium sulphate before field drying; (4) laterally and deeply applying urea and a boron-humic acid chelate when tips of two inverted leaves are exposed; (5) spraying an aqueous solution in a full heading stage, wherein the aqueous solution comprises monopotassium phosphate, chelated zinc and brassinolide. Through staged precise fertilization, special chelating / controlled release fertilizer and water and fertilizer-field drying cooperation, the method has the advantages that the fertilizer utilization rate is increased, the nutritional requirements of rice in each growth period are precisely matched, and water and fertilizer cooperative management is optimized.

The invention relates to a method for preparing a silicon-calcium-potassium-magnesium phosphate fertilizer from phosphate tailings, and relates to the technical field of phosphate tailing recycling, the method for preparing the silicon-calcium-potassium-magnesium phosphate fertilizer from the phosphate tailings comprises the following steps: carrying out acidolysis on the phosphate tailings to obtain a leaching residue A and a leaching solution M; an impurity removal agent is added into the leaching slag A, heavy metal elements in the leaching slag A are removed, and leaching slag B is obtained after solid-liquid separation; activating the leaching residue B by hot alkali, and performing solid-liquid separation to obtain a filter residue A; a phosphorus supplement is added into the leachate M, and filter residues B are obtained after solid-liquid separation; and fully mixing the filter residue A and the filter residue B to obtain the silicon-calcium-potassium-magnesium phosphate fertilizer. The method disclosed by the invention is low in energy consumption and high in phosphate tailing recovery rate, and the prepared silicon-calcium-potassium-magnesium phosphate fertilizer has a relatively high adsorption effect on part of main heavy metals.

The invention provides high-bending-resistance injectable magnesium phosphate bone cement. The high-bending-resistance injectable magnesium phosphate bone cement is prepared from solid-phase powder, reinforcing filler and water, the solid-phase powder comprises the following components in parts by weight: 50-70 parts of magnesium phosphate salt and 30-50 parts of hydrogen phosphate, and the magnesium phosphate salt comprises trimagnesium phosphate; the reinforcing filler comprises a polyurethane modified epoxy resin emulsion; based on the polyurethane modified epoxy resin emulsion with the solid content of 30%-50%, the mass fractions of the solid phase powder, the reinforcing filler and the water in the bone cement are 66-70 wt%, 1-7 wt% and 23-33 wt% respectively. The high-bending-resistance injectable magnesium phosphate bone cement is high in bending strength and suitable for bone defect areas bearing multidirectional loads.

The invention discloses a modified magnesium phosphate cement grouting material as well as a preparation method and application thereof. The modified magnesium phosphate cement grouting material comprises magnesium phosphate cement prepared from dead burned magnesium oxide, ammonium dihydrogen phosphate, borax, a polycarboxylate superplasticizer and water; and a water repellent agent added to the magnesium phosphate cement. Further, glacial acetic acid is added during preparation of the magnesium phosphate cement. Furthermore, the modified magnesium phosphate cement grouting material further comprises silane coupling agent modified PVA (polyvinyl alcohol) fibers. The MPC is endowed with excellent compressive and breaking strength, low-temperature toughness, water resistance and controllable setting time by virtue of the synergistic effect of delayed coagulation of glacial acetic acid and the silane coupling agent modified PVA fiber and the effect of the water repellent agent, so that the MPC has high durability and construction feasibility in prestressed duct grouting engineering in severe cold areas; and a reliable solution is provided for engineering application in an extreme environment.

The invention relates to a preparation method of low-carbon magnesium phosphate cement. The low-carbon magnesium phosphate cement is prepared from the following raw materials in parts by weight: 40-50 parts of magnesium oxide, 20-30 parts of phosphate, 1-2 parts of a retarder, 6-8 parts of quartz powder, 1-3 parts of glass fibers, 0.5-1.5 parts of polypropylene fibers, 1-3 parts of steel fibers, 10-20 parts of slag powder, 5-15 parts of silica fume, 1-2 parts of nano silicon dioxide, 0.5-1.5 parts of nano aluminum oxide and 4-6 parts of an additive. According to the preparation method of the low-carbon magnesium phosphate cement, mineral admixtures or industrial waste residues which are lower in price are introduced to serve as partial substitute materials, the requirement for high-cost raw materials is reduced, waste such as fly ash and slag can be used for replacing partial expensive raw materials, the production cost is reduced, cyclic utilization of resources is promoted, and the low-carbon magnesium phosphate cement is suitable for industrial production. Secondly, in order to overcome the problem that the strength of traditional low-carbon magnesium phosphate cement is reduced in water, a special retarder, a stabilizer and other modified materials are added, and dissolution of hydration products in water can be effectively inhibited.

The invention relates to the technical field of cement-based patching materials, in particular to a modified brucite fiber reinforced magnesium phosphate cement-based patching material and application thereof. The repairing material comprises the following components in parts by weight: 60-70 parts of magnesium oxide, 15-20 parts of phosphate, 5-9 parts of a retarder, 3-5 parts of modified brucite fibers and 10-15 parts of water. The modified brucite fiber is prepared by the following method: (1) soaking brucite fiber in a dihydric phosphate solution, separating out the brucite fiber after soaking, washing and drying to obtain pretreated fiber; and (2) placing the pretreated fiber in an absolute ethyl alcohol solution of methyltrimethoxysilane, then reacting under a heating condition, separating out the fiber after the reaction is completed, and drying to obtain the modified brucite fiber. The problem that the fluidity, the bonding strength and the fracture toughness of a magnesium phosphate cement-based thin layer repairing material doped with fibers cannot be considered at the same time is effectively solved.

The invention relates to a water-resistant magnesium phosphate cement-based material which comprises the following components: magnesium oxide, a composite phosphate compound, borax, a sodium silicate solution, water, a polyethylene glycol derivative, polyacrylamide and an ammonium sulfate solution. According to the water-resistant magnesium phosphate cement-based material, precipitation of water can be controlled in the preparation process, so that the speed of a hydration reaction is conveniently controlled, and the situation that phosphate is fixed in a matrix and cannot continue to participate in the reaction due to the fact that the hydration reaction is too fast is avoided; according to the water-resistant magnesium phosphate cement-based material, the fluidity of a mixture can be better in the preparation process, so that the mixture can be stirred and mixed more sufficiently, and the polyethylene glycol derivative can introduce bubbles to block capillary pore channels in concrete; therefore, permeation of external water can be reduced in the using process of the water-resistant magnesium phosphate cement-based material.

The invention discloses a double-liquid magnesium phosphate early-strength high-strength grouting material and a preparation method thereof.The grouting material is composed of a liquid A and a liquid B. The liquid A is composed of powder A and water in parts by weight and comprises dead burned magnesia powder, a defoaming agent, steel slag powder, a retarder I and water, and the liquid B is composed of powder B and water in parts by weight and comprises powder B and water in parts by weight. Wherein the monopotassium phosphate, the superfine powder, the polymer rubber powder, the retarder II and the water have the advantages that the stirring time is shortened, the setting time is controllable, the flowability is good, the repair requirement can be met more quickly, the construction period is shortened, and the cane sugar and the borax are used as the retarders, so that the setting time can be controlled, and the early strength can be improved; surplus phosphate in a grouting material matrix is consumed by using the steel slag powder, so that some amorphous gel products can be generated, and the mechanical property is improved; the redispersible latex powder is utilized to form a polymer film in the slurry to wrap a hydration product, so that the water resistance is improved, and the synergistic modification effect is achieved.

The invention relates to a bi-component magnesium phosphate cement spraying foaming material and a preparation method thereof, the bi-component magnesium phosphate cement spraying foaming material comprises a component A and a component B in a dry powder mass ratio of 100: (70-80), the component A comprises dead burned magnesium oxide, slag, a water reducing agent, a thickening agent, a foam stabilizer and a carbonate foaming agent; and the component B comprises phosphate, fly ash and a retarder. During use, the component A slurry and the component B slurry are atomized and sprayed out through a double-head spray gun and are mixed outside a nozzle, a chemical reaction is immediately carried out, foaming expansion and condensation hardening are completed, and a lightweight porous structure is formed. Compared with the prior art, the problems that a single-component foaming material is out of control in foaming, hardened in advance, difficult to spray and the like are effectively solved, and rapid spraying forming of the inorganic thermal insulation material is achieved. The prepared material is adjustable in dry density and uniform in pore size distribution, has the characteristics of high strength, low heat conductivity, small shrinkage rate, high durability and the like, meets the A-level non-combustible standard, and can be widely applied to building wall and roof thermal insulation engineering.

The invention belongs to the technical field of soil curing materials, and relates to a salinized soil curing agent and a preparation method thereof. The composite material comprises the following components in parts by mass: 20-40 parts of a bio-based polymer cementing material; 10 to 20 parts of modified bentonite; 15 to 30 parts of superfine slag powder; 1 to 5 parts of nano silicon dioxide; 5 to 15 parts of magnesium phosphate cement; 3-8 parts of a plant fiber reinforced material; 0.5 to 2 parts of a dispersant; and 2-6 parts of a composite slow-release salt-resistant additive. The problems that a traditional curing agent is weak in salt corrosion resistance and poor in durability in salinized soil are solved, the mechanical property and long-term stability of cured soil are remarkably improved, and the environment-friendly, efficient and high-adaptability salinized soil reinforcing effect is achieved.

The invention relates to the technical field of building materials, in particular to light water-resistant phosphogypsum-based cement concrete mortar and a preparation process thereof. The phosphogypsum-based cement concrete mortar comprises the following components: activated phosphogypsum, sulphoaluminate cement, magnesium phosphate cement, modified zeolite powder, lightweight aggregate, modified nano silicon dioxide, a core-shell toughening agent, a polycarboxylate superplasticizer and water, and the preparation method comprises the following steps: respectively preparing the activated phosphogypsum, the modified zeolite powder, the modified nano silicon dioxide and the core-shell toughening agent; the water resistance of the ardealite is improved through activating treatment, the interface bonding force and the structural compactness are enhanced through multi-component synergism by means of selective adsorption of the modified zeolite powder, the mechanical property of the lightweight aggregate is optimized, the toughness is improved through the core-shell toughening agent, and lightweight, high water resistance, stable performance and durability improvement of the mortar are achieved; the requirements of complex building scenes are met, and environment-friendly and practical values are achieved.

The invention relates to the technical field of culture substrates, in particular to a culture substrate and a preparation process thereof. The culture medium sequentially comprises a perlite particle layer, a first fiber base material layer, an ammonium magnesium phosphate slow-release fertilizer layer, a temperature-sensitive water-retaining agent layer and a second fiber base material layer from bottom to top, the thickness ratio of the perlite particle layer to the first fiber base material layer to the ammonium magnesium phosphate slow-release fertilizer layer to the temperature-sensitive water-retaining agent layer to the second fiber base material layer is (5-10): (20-40): (1-2): (0.1-1): (10-30); the raw material of the perlite particle layer is perlite particles with the particle size of 2-4 mm. Synergistic longitudinal permeation and transverse diffusion of water can be effectively achieved, water can be locked at low temperature and high humidity, water can be released at high temperature and low humidity, the porosity is enlarged, the system stability is excellent, nutrient substance loss can be effectively avoided, and the substrate state can be stably maintained even if the substrate is used for a long time.

The invention discloses a high-strength low-immunoreaction bone bonding material and a preparation and application method thereof. The bone binding material comprises tetracalcium phosphate, serine phosphate, magnesium phosphate and a sodium citrate solution. According to the preparation method, tetracalcium phosphate, phosphoserine, magnesium phosphate powder and a sodium citrate solution are fully mixed and reacted by utilizing a hedging device consisting of a screw injector and a connecting pipe. And extruding the mixed liquid material through a filter membrane to complete the preparation of the bone adhesive material. The bone binding material can be used for preparing bionic sclerotin, binding broken bones in comminuted fractures or smearing the bone binding material to bone gaps, and in the decomposition process, the bone binding material can continuously release magnesium ions, so that the immune environment of early bone repair is regulated and controlled, the bone repair process is accelerated, and bone healing is promoted. Meanwhile, experimental data prove that the bone adhesive material provided by the invention can provide stable supporting strength, has no potential toxicity to fibroblasts, and is good in biocompatibility.

The invention discloses a rare earth doped humic acid-based retarder, a preparation method and application thereof in grouting materials, and belongs to the technical field of inorganic non-metal building materials. The invention discloses a rare earth doped humic acid-based retarder, which is prepared from the following raw materials in parts by weight: 35 to 50 parts of rare earth modified humic acid, 10 to 15 parts of amphiphilic phosphonate dispersing agent, 5 to 8 parts of magnesium phosphate corrosion inhibition reinforcing agent, 8 to 12 parts of nano silicon dioxide and 3 to 5 parts of function regulator. The loading capacity of rare earth oxide in the rare earth modified humic acid is 8-12wt%. The retarder provided by the invention realizes effective retarding through an innovative hydration inhibition mechanism, and has significant advantages in temperature response characteristics, hydrolysis resistance and diversified regulation performance. The effects are synergistic, so that the grouting agent is particularly suitable for grouting construction under severe conditions such as high temperature and the like, and a more stable, reliable and flexible solution is provided for engineering.

The invention discloses a high-reflection magnesium phosphate / aluminum phosphate radiation refrigeration material and a preparation method thereof, and relates to the technical field of radiation refrigeration materials. The preparation method of the high-reflection magnesium phosphate / aluminum phosphate radiation refrigeration material comprises the following steps: (1) mixing aluminum sec-butoxide and deionized water to prepare a solution A; mgCl2. 6H2O and deionized water are mixed to prepare a solution B; mixing the solution A and the solution B to obtain a solution C; (2) adding 3-sulfopropyl tetradecyl dimethyl betaine into the solution C to obtain a solution D; (3) stirring sodium pyrophosphate and deionized water into a solution E; mixing the solution E and the solution D to obtain a solution F; and (4) reacting the solution F at 150-180 DEG C, cooling, freeze-drying and grinding to obtain H, heating H to 300-400 DEG C at the rate of 3-4 DEG C / min, then heating H to 800-1300 DEG C at the rate of 7-10 DEG C / min, and keeping the temperature for 1-3 hours to obtain the product. The material prepared by the invention has excellent sunlight reflectivity and excellent mid-infrared emissivity, and shows excellent performance in the field of radiation refrigeration.

To provide a soil improvement method utilizing urea and urease, allowing reduction of ammonia generated in the course of soil improvement.SOLUTION: The present invention provides a soil improvement method in which calcium carbonate is generated from carbon dioxide produced through urea and urease to solidify soil, the method characterized by further adding a phosphorus compound and a magnesium compound to produce magnesium ammonium phosphate from at least a part of the ammonia generated through urea and urease.SELECTED DRAWING: None

The invention belongs to the field of biomedical materials, and relates to a chitosan calcium sulphoaluminate-potassium magnesium phosphate composite bone material as well as a preparation method and application thereof. The calcium sulphoaluminate-potassium magnesium phosphate composite bone material is formed by curing a calcium sulphoaluminate-potassium magnesium phosphate composite bone material and a chitosan solution, the calcium sulphoaluminate-potassium magnesium phosphate composite bone material comprises the following components in percentage by mass: 5-40% of calcium sulphoaluminate, 0.01-3.0% of boric acid and the balance of dead burned magnesium oxide and monopotassium phosphate, and the molar ratio of magnesium in the dead burned magnesium oxide to phosphorus in the monopotassium phosphate is (1-4): 1. The material provided by the invention has remarkable mechanical property, biological activity, cytotoxicity, injectability, non-transmissivity, coagulation property, degradability, absorbability and the like. Meanwhile, the bone material contains unreacted and degradable monopotassium phosphate, magnesium oxide and other substances, and due to the reasonable degradability and absorbability design of the bone material, the material can be gradually degraded in vivo and can grow along with bone tissue, and the treatment effect is further improved.

The invention discloses a lithium slag based salt corrosion resistant concrete pole and a preparation method thereof. The pole is made of lithium slag based geopolymer concrete. The concrete comprises the following components in parts by mass: 20-30 parts of dealkalized red mud, 15-25 parts of activated lithium slag, 10-15 parts of slag, 5-8 parts of silica fume, 6-10 parts of magnesium phosphate cement, 12-18 parts of a composite alkali activator, 25-35 parts of machine-made sand, 40-50 parts of gravel, 0.4-0.6 part of a polycarboxylic acid water reducer, 0.8-1.2 parts of composite fibers, 2-3 parts of a salt corrosion-resistant corrosion inhibitor and 25-35 parts of water. The outer surface of the electric pole is coated with an organic silicon-fluorosilicone resin hydrophobic coating; the salt-corrosion-resistant corrosion inhibitor is prepared by compounding nano silicon dioxide, a hydrotalcite precursor and a triphosphonic acid-based corrosion inhibitor, the concrete pole is obtained through the processes of red mud and lithium slag pretreatment, raw material mixing, centrifugal forming, curing and surface treatment, and has excellent salt corrosion resistance and mechanical property.

According to the low-temperature high-durability magnesium phosphate cement and the preparation method thereof, dead burned magnesia powder serves as a core gelling base material and can provide a large amount of active Mg < 2 + >, ammonium dihydrogen phosphate can provide an acid environment and PO4 < 3->, the dead burned magnesia powder and the ammonium dihydrogen phosphate are subjected to an acid-base neutralization reaction in the presence of water to generate ammonium magnesium phosphate hydration products, and the magnesium phosphate hydration products are subjected to a low-temperature high-durability magnesium phosphate cement. The products are interwoven to form a hardened body framework, and a strength foundation is laid for cement; borax is adopted as a key retarder, borate ions generated after the borax is dissolved in water can be adsorbed on the surfaces of dead burned magnesia powder particles, a magnesium borate complex film is formed, the dissolution of Mg < 2 + > and the reaction of PO4 < 3-> are hindered, the cement setting time is effectively delayed, and the construction requirements are met; and the borax can also refine the crystal structure of a hydration product, reduce the porosity, improve the impermeability and the volume stability of a hardened body, and avoid shrinkage cracking.

The application discloses a magnesium phosphate-based cement grouting material and a preparation method and application thereof. The raw materials of the magnesium phosphate-based cement grouting material include A component and B component; the raw materials of the A component include, in parts by weight, calcined magnesium oxide 140-200 parts, bentonite 0-30 parts, hydroxypropyl methylcellulose 0.2-0.5 parts, an additive 1-10 parts and water 70-140 parts; the raw materials of the B component include a first dihydrogen phosphate 70-100 parts, pretreated high-molecular water-absorbing resin 20-50 parts, sodium polyacrylate 0.5-2 parts and water 30-70 parts; the pretreated high-molecular water-absorbing resin is obtained by soaking the high-molecular water-absorbing resin in an aqueous solution of a second dihydrogen phosphate. The magnesium phosphate-based cement grouting material has the characteristics of low shrinkage, short and adjustable setting time, high compressive strength, simple construction, low cost, green environmental protection, good grout injection, good water dispersion resistance, good durability in a long-term soaking environment and the like.

The invention discloses high-crack-resistance and corrosion-resistance marine mass concrete based on an aluminoferrite-magnesium phosphate composite gel system and a preparation method thereof. The method comprises the following steps: 1, pretreating 35-50 parts by mass of aluminoferrite cement, 25-40 parts by mass of magnesium phosphate cement, 5-15 parts by mass of phosphorus slag powder and 10-20 parts by mass of lithium slag powder; 2, premixing the iron aluminate cement, the magnesium phosphate cement, the phosphorus slag powder and the lithium slag powder which are pretreated in the previous step; 3, 1-3 parts by mass of an ion erosion inhibitor and 2-4 parts by mass of a hydration heat regulating agent are added into the slurry obtained through premixing in the previous step, 0.5-2.0 parts by mass of temperature shrinkage fibers are doped, and concrete slurry is obtained after ultrasonic dispersion is conducted for 15 min or above; 4, after the slurry obtained in the previous step is poured, the high-crack-resistance and corrosion-resistance marine mass concrete is obtained. By adopting the method disclosed by the invention, the marine mass concrete with high crack resistance and corrosion resistance can be prepared.

The invention relates to the technical field of microbial fertilizers, in particular to a low-cost compound microbial fertilizer and a preparation method thereof. The low-cost compound microbial fertilizer comprises the following raw materials in parts by mass: 20-40 parts of a fermented organic fertilizer, 10-20 parts of urea, 5-10 parts of ammonium magnesium phosphate, 5-15 parts of a potassium fertilizer, 1-4 parts of sodium humate, 1-4 parts of trehalose, 1-3 parts of gelatin, 0.1-1 part of a stabilizer, 7-19 parts of a mineralized microbial agent load and 1-3 parts of a coating solution, the mineralized microbial inoculum load comprises the following raw materials: 5-15 parts of bamboo charcoal powder, 1-3 parts of a composite microbial inoculum, 1-2 parts of calcium chloride and 1-2 parts of disodium hydrogen phosphate. The fertilizer has the advantages of obviously increasing the fertilizer utilization rate, improving the physical and chemical properties of soil, promoting the formation of granular structures and repairing hardened and ill-conditioned soil, has obvious soil repairing effect and obvious yield increasing, value increasing and quality improving effects, and is suggested to be suitable for large-scale popularization and application when being popularized and applied in production.

The invention discloses magnesium phosphate cement paste based on low-temperature calcined phosphate tailings and a preparation method of the magnesium phosphate cement paste, and relates to the technical field of magnesium phosphate cement materials. Uniformly mixing soluble phosphate, low-temperature calcined phosphate tailings, light calcined magnesia and a delayed coagulation substance to obtain a mixed dry material; adding the calculated water reducing agent into water, and fully and uniformly mixing for later use; the mixed dry material and the water reducing agent mixed solution are mixed, magnesium phosphate cement paste is obtained, the dry material mixing time is not less than 1 min, and the stirring time is not less than 150 s when the mixed solution is added. The phosphate tailings are used for replacing dead-burnt magnesium oxide, so that a large amount of consumption of the existing accumulated phosphate tailings can be realized, the value of the phosphate tailings is improved, effective elements in the phosphate tailings are fully utilized, cyclic utilization of resources is realized, meanwhile, the manufacturing cost of the magnesium phosphate cement can be remarkably reduced, and impurities such as silicon and aluminum in the phosphate tailings possibly form a compact structure; the acid corrosion resistance and the salt corrosion resistance of MPC are improved.

The invention discloses magnesium phosphate cement-based concrete mechanical property detection equipment, and relates to the technical field of magnesium phosphate cement-based concrete mechanical property detection equipment.The magnesium phosphate cement-based concrete mechanical property detection equipment comprises a workbench, a support is fixed to the top of the workbench, and a driving motor is fixed to the top of the support; a threaded rod is fixed to the output end of the driving motor, and the bottom of the threaded rod is rotationally installed on the top of the workbench. According to the magnesium phosphate cement-based concrete mechanical property detection equipment, through the arrangement of a protection device, when a pressure block moves downwards, a roller extrudes a concrete block and a placement plate to move downwards, so that a connecting column drives an extrusion block to move downwards, and through the cooperation of a rotating block and a rotating rod, a protection plate can be turned over; and the front face of the containing box can be shielded and protected through the protection plate, and the situation that when concrete blocks are crushed, broken stone is splashed to the body of a worker, and safety risks are brought to the worker is prevented.

The invention discloses a nano-modified fiber reinforced 3D printing magnesium phosphate cement-based material as well as a preparation method and application thereof. The material is prepared from the following components in parts by weight: 40 to 70 parts of dead burned magnesium oxide, 10 to 25 parts of basic hydrogen phosphate, 5 to 25 parts of silica fume, 30 to 60 parts of fine aggregate, 10 to 30 parts of water, 0.1 to 1 part of fiber dispersing agent and 0.5 to 5 parts of nano modified fiber, the surface activity of the fiber is remarkably improved through a nano modification process, active SiO2 sites attached to the surface of the fiber are activated by using an alkali solution, and a hydration product is generated in situ, so that the interface bonding strength between the fiber and a cement matrix is enhanced, and the surface strength of the fiber is improved by relying on the high-rigidity characteristic of the fiber. The yield stress, thixotropic property and constructability of the material are effectively improved, structural deformation in the printing process is remarkably inhibited, and the 3D printing material has excellent rheological property, strengthened mechanical property and tough fiber-matrix interface bonding property.

The invention discloses a method for recovering valuable elements in phosphorite step by step through gradient acid leaching, which comprises the following steps: firstly, mixing high-magnesium phosphorite and high-silicon phosphorite in proportion for ore blending, and carrying out crushing, grading and ball milling until the particle size is less than or equal to 200 meshes; then, adopting a gradient acid leaching process: (1) leaching with low-concentration inorganic acid (1-3wt%), and preferentially and selectively removing dolomite and calcite to obtain phosphate concentrate and leachate rich in calcium and magnesium; (2) leaching the phosphate concentrate by using medium-concentration inorganic acid (5-8wt%), and dissolving the phosphate concentrate to obtain a phosphate concentrate leachate and residues mainly containing iron, aluminum and silicon; and (3) leaching the residues by using high-concentration inorganic acid (30-40wt%) to obtain silicon-rich residues and a leaching solution rich in iron and aluminum. (4) neutralizing and carbonizing the calcium-magnesium leaching solution, and respectively precipitating and recovering magnesium hydroxide and calcium carbonate; (5) carrying out fractional precipitation on the phosphate concentrate leachate to obtain rare earth enrichment and calcium hydrogen phosphate; (6) carrying out alkali dissolution and carbonization reaction on the silicon-rich slag to prepare high-purity white carbon black; and (7) carrying out iron powder reduction, neutralization aluminum removal and oxidation iron precipitation on the iron and aluminum lixivium to prepare the battery-grade iron phosphate. The method is simple and convenient to operate, energy-saving and environment-friendly, various valuable elements in the phosphorite are efficiently recycled, and the economic added value of phosphorite resources is increased.

The application discloses a magnesium phosphate cement-based concrete mechanical property detection equipment and relates to the technical field of magnesium phosphate cement-based concrete mechanical property detection equipment.The magnesium phosphate cement-based concrete mechanical property detection equipment comprises a workbench, a support is fixed to the top of the workbench, a driving motor is fixed to the top of the support, a threaded rod is fixed to the output end of the driving motor, and the bottom of the threaded rod is rotatably installed at the top of the workbench.The magnesium phosphate cement-based concrete mechanical property detection equipment is provided with a protection device.When the pressing block moves downward, the roller extrudes the concrete block and the placing plate to move downward, so that the connecting column drives the extrusion block to move downward, and through cooperation of the rotating block and the rotating rod, the protection plate can be turned over, the protection plate can shield the front face of the placing box, and the safety risk of workers caused by flying stones when the concrete block is crushed is avoided.

The invention relates to the technical field of building materials, in particular to an energy-saving and environment-friendly recycled concrete pipe pile and a preparation method thereof. The recycled concrete is prepared from the following raw materials in parts by weight: 35 to 45 parts of recycled aggregate, 22 to 28 parts of P.O42.5 Portland cement, 6 to 9 parts of magnesium phosphate cement composite admixture, 18 to 22 parts of river sand, 1.0 to 1.3 parts of hydroxylated graphene-chitosan-nano zinc oxide ternary composite modifier, 6 to 8 parts of modified waste tire rubber powder, 0.5 to 0.8 part of basalt fiber and the like. The rubber powder is soaked in a sodium hydroxide solution and then treated with a maleic anhydride grafted polyethylene solution; the metakaolin is prepared by calcining coal gangue; the ternary modifier is prepared by grafting, crosslinking and dispersing; the magnesium phosphate admixture contains light calcined magnesia, ammonium dihydrogen phosphate and borax. The tubular pile is excellent in mechanical and durable performance and high in solid waste utilization rate, carbon emission and production energy consumption are reduced, the cost is reduced, the problems that a traditional regenerated tubular pile is low in strength and poor in environmental protection performance are solved, the tubular pile is suitable for multiple engineering scenes, and economic and environmental benefits are remarkable.