13 results about "Reactive magnesia" patented technology

The application relates to the technical field of cement-based material admixtures, in particular to a magnesium oxide-based low-temperature expansion agent and a preparation method and application thereof. The magnesium oxide-based expansion agent prepared by using active magnesium oxide as a main component, using a small amount of calcium oxide, adding modified starch, aluminum sulfate and sodium carbonate as promoting components can be used for low-temperature construction of cement-based materials.

This invention discloses a retarder for magnesium silicate cementitious materials and its preparation and application methods, belonging to the field of green building materials technology. The retarder of this invention is composed of sodium hexametaphosphate, citric acid, and tartaric acid in a mass ratio of (1-3):(2-4):(0.5-2). The retarder of this invention forms a three-level gradient synergistic retarding effect by using sodium hexametaphosphate to inhibit the rapid dissolution of active magnesium oxide, citric acid to chelate and regulate the magnesium ion concentration in the liquid phase, and tartaric acid to inhibit the nucleation and growth of hydration products, covering the entire hydration process of magnesium silicate cementitious materials. This invention also discloses the preparation and application methods of this retarder. Compared with existing technologies, the retarder of this invention can significantly extend the setting time of magnesium silicate cementitious materials while maximizing the preservation of their mechanical properties and improving slurry fluidity. Furthermore, the raw materials are widely available, the preparation process is simple, and the cost is controllable, showing good prospects for industrial application.

The application discloses a kind of water purifying agent waste residue-magnesium-aluminum ternary synergistic flow state solidified soil for bridge head backfill and preparation method, the flow state solidified soil includes: soil material, water purifying agent waste residue, aluminate cement, active magnesium oxide, magnesium sulfate heptahydrate, water-resistant modifier, reinforcing modifier and additional water.The application constructs water purifying agent waste residue-aluminate cement-magnesium sulphoaluminate cement three synergistic excitation mechanism, utilizes the chemical synergistic effect of aluminate cement and water purifying agent waste residue in magnesium sulphoaluminate cement environment, in combination with water-resistant modifier and reinforcing modifier, in situ induced magnesium-aluminum-calcium-based composite crystalline network.The network is inserted and wrapped in the interface transition zone between waste residue micro-particles and matrix, effectively repairs the crystal defects of traditional magnesium cement, significantly enhances the water resistance and chemical stability of the material, improves its strength retention rate in long-term immersion environment, ensures that backfill body has excellent long-term durability when bearing road load.

The systems and methods include a method. The method can include mixing, for a first time period, salt water with reactive magnesium oxide cement (RMC) at a first ratio to create a first mixture. The method can include mixing, for a second time period, the first mixture with an aggregate at a second ratio to create a second mixture. The method can include hydrating, for a third time period, the second mixture by molding and covering the second mixture. The method can include curing, for a fourth time period, the second mixture in a chamber to create an RMC-based composite, the chamber having a temperature value, a humidity value, and a CO2 concentration value.

The invention provides a low-shrinkage high-adhesion concrete crack repairing agent and a preparation method thereof, and relates to the field of concrete crack repairing, the low-shrinkage high-adhesion concrete crack repairing agent comprises inorganic dry powder and a microbial liquid agent, the mass ratio of the inorganic dry powder to the microbial liquid agent is 100: (20-30); wherein the inorganic dry powder comprises 60-75 parts of active magnesium oxide, 9-16 parts of monopotassium phosphate or ammonium dihydrogen phosphate, 10-20 parts of fly ash or silica fume and 5-15 parts of a boron compound; the microbial liquid agent is prepared from 10-25 parts of bacterial strain liquid, 1.2-3 parts of a nutrient source, 1.7-5 parts of a calcium source and 0-25 parts of distilled water; according to the invention, the induced mineralization ability of microorganisms is combined with the rapid hardening and early strength characteristics of an inorganic cementing material, so that the concrete crack repairing agent which has the characteristics of rapid plugging, high early strength, good cohesiveness, excellent environmental protection property and the like is developed.

The invention discloses a cementing material for a green low-carbon component and a preparation method, and relates to the technical field of green low-carbon building materials. The material comprises the following components in percentage by mass: 30-60% of a silicon-aluminum solid waste based gelling precursor, 3-12% of an alkaline activator, 5-20% of active magnesium oxide, 1-5% of a cationic biopolymer, 1-5% of an anionic biopolymer, a blending filler and water. The inorganic phase is composed of aluminosilicate gel formed by alkali excitation and a MgO carbonized product, and the organic phase is a complementary charged biopolymer composite network. The preparation method comprises the following steps: dry-mixing the powder, sequentially adding the alkaline excitation liquid and the cationic and anionic biopolymer solution, stirring to form slurry, and combining wet curing and CO2 curing after forming. The composite material has high strength, toughness, high temperature resistance, corrosion resistance and carbon sequestration performance, and is suitable for the fields of buildings, traffic and maritime work.

Disclosed in the present invention are a biochar-based alkali-activated containment material, a preparation method therefor, and the use thereof. The biochar-based alkali-activated containment material comprises 50-70% by mass of in-situ soil and 30-50% by mass of a cementitious material, wherein the cementitious material comprises an ash material and a composite alkali activator, and the composite alkali activator is obtained by ball milling activated magnesium oxide and biochar together. The biochar-based alkali-activated containment material of the present invention has better early compressive strength under a low cement-to-sand ratio and the 7d compressive strength thereof can reach 9.33 MPa; in addition, because of the presence of biochar, the containment material can better adsorb and trap soil contaminants and has better anti-seepage performance, and the permeability coefficient can reach 2.4×10-10 m / s. When being applied to rapid emergent containment for contaminated sites, the containment material can be quickly spread and quickly shape and achieve a lower seepage concentration of contaminants, thereby having a great application prospect.

The invention discloses a method for preparing magnesium oxysulfate cement by using high-activity magnesium oxide, and relates to a method for preparing the magnesium oxysulfate cement, which is characterized in that the hydration process of the high-activity magnesium oxide is regulated and controlled by adding a modifier, and the magnesium oxysulfate cement with good performance is prepared by controlling the feeding proportion of raw materials and process conditions. The invention aims to research and develop a preparation process of a green building material, and mainly aims to solve the problems of too short setting time, low mechanical strength, poorer water resistance and the like of magnesium oxysulfate cement prepared from high-activity magnesium oxide produced by new technologies such as flash light burning and the like due to too high content of the active magnesium oxide. The development of the high-activity magnesium oxide for preparing the environment-friendly magnesium oxysulfate cement is beneficial to expanding the wide application of the high-activity magnesium oxide, further promotes the popularization of a new technology for obtaining magnesium oxide such as flash light burning and the like, and provides a necessary technical support for energy conservation and carbon reduction of an industrial chain.

The invention relates to the technical field of building materials, and discloses an environment-friendly sand brick and a preparation method thereof.The environment-friendly sand brick is prepared from aggregate and raw materials of a gelling and functional system; the gelling and functional system comprises a sodium silicate solution, active magnesium oxide, glycerol triacetate and calcium formate; the preparation method comprises the following steps: carrying out dry mixing on the aggregate, the active magnesium oxide and the calcium formate, premixing a sodium silicate solution and glycerol triacetate, and then carrying out wet mixing, compression molding and maintenance. Sodium silicate gel is controlled by glycerol triacetate to provide early strength, and calcium formate is utilized to construct a substance transmission channel to drive active magnesium oxide to generate mineralization reaction in the later stage; an expansive product generated by the reaction can fill pores and microcracks, so that the long-term strength and water resistance of the material are remarkably improved, and damage self-repairing is realized; the sand brick prepared by the invention has excellent comprehensive mechanical property, durability and self-repairing function.

This application provides a method for preparing magnesium-based cementitious materials from phosphate rock flotation tailings and the magnesium-based cementitious materials themselves, relating to the field of mineral processing. The method includes: drying and first homogenizing phosphate rock flotation tailings, followed by calcination to obtain a first material; homogenizing the first material with activated magnesium oxide to obtain a second material; and mixing the second material with a conditioning agent to obtain a magnesium-based cementitious material; wherein the conditioning agent includes at least one of magnesium chloride and magnesium sulfate. The resulting novel magnesium-based cementitious material possesses excellent physicochemical properties such as short setting time and high compressive strength. Furthermore, the phosphorus-containing minerals remaining in the phosphate tailings can improve the water resistance of the magnesium-based material within the novel cementing system.

The invention discloses a quick-setting high-viscosity high-strength road cold patch material, which is prepared from the following ingredients in parts by weight: 40 to 50 parts of sulphoaluminate cement, 20 to 30 parts of modified slag, 4 to 6 parts of active magnesium oxide, 2 to 4 parts of slaked lime, 2 to 3 parts of EVA latex powder, 1 to 2 parts of nanometer silicon dioxide, 20 to 40 parts of basalt, 15 to 25 parts of quartz sand, 0.8 to 1.2 parts of polycarboxylic acid water reducing agents and 0.3 to 0.5 part of boric acid retarders. The preparation method comprises the following steps: S1, preliminarily pre-mixing the EVA latex powder and the quartz sand, the modified slag and the nano silicon dioxide, and the sulphoaluminate cement and the boric acid retarder in proportion respectively; s2, adding basalt, the three premixes, active magnesium oxide and slaked lime into a stirrer in proportion, and stirring step by step to obtain a dry mixture; s3, dissolving a polycarboxylic acid water reducer and water in proportion to obtain mixing water, adding the mixing water into the dry mixture, and stirring to obtain a finished product. The prepared quick-setting high-viscosity high-strength road cold patch material is short in initial setting time and high in compressive strength and bonding strength.

The invention relates to the technical field of cement-based material admixtures, in particular to a magnesium oxide-based low-temperature expanding agent and a preparation method and application thereof. Active magnesium oxide is adopted as a main component, a small amount of calcium oxide is used in cooperation, and modified starch, aluminum sulfate and sodium carbonate are added as promoting components; the magnesium oxide-based expanding agent can be used for low-temperature construction of cement-based materials.