44 results about "Reactive magnesia" patented technology

Novel hydraulic cements are disclosed that include reactive magnesium oxide prepared by low temperature calcination. The cements can be formulated to suit a large number of applications with various setting times, strength and levels of sustainability either by adding iron salts such as ferrous sulfate or blending with other compatible faster setting hydraulic cements such as Portland cement or by using both methods. The compositions are able to incorporate relatively large amounts of low cost pozzolans such as fly ash to advantage as well as wastes. Many excellent properties are exhibited and in particular good comprehensive strength and resistance to sulfates is able to be achieved.

The invention discloses a green low-carbon curing agent for soil curing. The soil curing agent is characterized by comprising granulated blast furnace slag micro powder and exciting agent, wherein the exciting agent comprises active magnesia, the exciting agent is 30 to 5 percent of the total mass of the soil curing agent, and the granulated blast furnace slag micro powder is 70 to 95 percent of the total mass of the curing agent. The exciting agent comprises slaked lime, wherein the slaked lime is 10 to 90 percent of the mass of the active magnesia. The exciting agent comprises calcined lime, wherein the calcined lime is 7 to 66 percent of the mass of the active magnesia.

The invention relates to the technical field of inorganic salts, and provides an activated magnesia, and a preparation method and an application thereof. The preparation method comprises the followingsteps: mixing light burned magnesia powder, magnesium chloride and water, and carrying out a hydrothermal reaction to obtain a magnesium hydroxide precipitate and a calcium chloride solution; soakingthe magnesium hydroxide precipitate in an aqueous ammonium chloride solution for leaching to obtain a magnesium chloride solution, ammonia gas and leaching residues; mixing the magnesium chloride solution, ammonia gas and carbon dioxide, and carrying out a magnesium precipitation reaction to obtain a basic magnesium carbonate precipitate; and sequentially drying and calcining the basic magnesiumcarbonate precipitate to obtain the activated magnesia. Insoluble silicon, calcium and other impurities are left in ammonium chloride leaching residues through magnesium chloride decalcifying and ammonium chloride magnesium leaching, so the improvement of the purity and activity of the final product is benefited. The magnesia obtained through the method is high in purity and activity, the mass content of MgO in the activated magnesia is larger than or equal to 98%, and the activity is larger than 95%.

The invention discloses a method for preparing a modified magnesium hydroxide flame retardant from salt lake produced light-burned active magnesium oxide. The method comprises the following steps: adding a proper amount of deionized water into a reaction kettle, weighing the salt lake produced light-burned active magnesium oxide as a raw material, adding the weighed salt lake produced light-burned active magnesium oxide into the reaction kettle, uniformly stirring, weighing a modifier according to the amount (molar ratio) of 1-3% of magnesium oxide, adding the modifier into the reaction kettle, and reacting for a specified time at a certain temperature and a certain stirring speed; and filtering, washing and drying the reaction product to obtain the hexagonal flaky modified magnesium hydroxide flame retardant. The salt lake produced light calcined magnesia is used as a raw material, stearic acid, sodium stearate, oleic acid, sodium oleate and silane are used as modifiers, the process is simple, the needed raw materials are few in variety, the production cost is low, and the obtained hexagonal flaky oily magnesium hydroxide is high in purity and good in compatibility with high polymer materials and has great application value and market value.

The invention discloses basic magnesium sulfate cement which comprises the following components in parts by mass: 100 parts of active magnesium oxide powder, 30-100 parts of a magnesium sulfate solution, 0.01-0.05 part of an additive and 0.1-5 parts of a magnesium oxysulfate crystal nucleating agent, the magnesium sulfate solution is an aqueous solution of crystallized magnesium sulfate, and the mass fraction of the magnesium sulfate solution is 15-20%; the magnesium oxysulfate crystal nucleating agent is prepared by the following method: step 1, mixing 50-100 parts by mass of light calcined magnesite powder with the active MgO mass fraction of 55%-85%, 70-300 parts by mass of a magnesium sulfate solution with the active MgO mass fraction of 10%-25% and 0.01-0.05 part by mass of phosphoricacid; and 2, putting the paste obtained in the step 1 into a sealed bag, curing at 20+/-3 DEG C for 28 days to promote hardening, and finally grinding the hardened sample into powder through ball milling to obtain the actual magnesium oxysulfide crystal nucleating agent. The basic magnesium sulfate cement has the advantages of short setting time, early strength, high strength and the like.

The invention discloses a negative carbon emission modified immature soil base building block and a manufacturing method thereof, and the negative carbon emission modified immature soil base building block is prepared from active magnesium oxide, cement, fly ash, immature soil and the like. The manufacturing method comprises the following steps: (1) selecting silty soil or clay, silty clay, expansive soil and the like, and passing through a screen with the aperture of 2mm; 2) preparing a mixture of magnesium oxide, cement, fly ash and immature soil according to a mass ratio of 7: 7: 6: 80, uniformly stirring, adding water, and stirring again to obtain a modified immature soil-based material; (3) putting the modified raw soil base material into a customized mold to be pressed into raw soil building blocks; and 4) putting the pressed building blocks into a carbonization box for carbonization treatment. The obtained modified raw soil building block has the characteristics of negative carbon emission, early strength, high performance, recyclability and the like. And the negative carbon emission modified immature soil base building block is environment-friendly, contributes to realizing carbon peak reaching and carbon neutralization, and can be widely applied to the fields of using local materials for earthwork, saving energy, protecting environment and the like.

The invention provides a magnesium oxysulfate cementing material adopting silicon dioxide aerogel, a preparation method of the magnesium oxysulfate cementing material and a building component. The magnesium oxysulfate cementing material adopting the silicon dioxide aerogel comprises a component A and a component B, wherein the component A comprises, by mole, 1 part of magnesium sulfate heptahydrate, 8-12 parts of light calcined magnesia and 15-22 parts of water, and the content of active magnesium oxide in the light calcined magnesia ranges from 55% to 65%; the component B comprises a modifier and aerogel; the modifier is one of citric acid, tartaric acid and sodium malate or a mixture of the citric acid and the tartaric acid, the citric acid accounts for 0.7%-0.8% of the mass of the light calcined magnesia, and the tartaric acid and the sodium malate both account for 1.3%-1.8% of the mass of the light calcined magnesia; and the mass of the aerogel is 6% or less of that of the light calcined magnesia. According to the magnesium oxysulfate cementing material adopting the silicon dioxide aerogel, the mechanical property and the thermal insulation property of the magnesium oxysulfate cementing material can be improved.

The invention relates to the technical field of concrete, and particularly discloses a preparation method of modified coral aggregate and basic magnesium sulfate cement gradient composite coral aggregate concrete. The preparation method comprises the following steps: firstly, soaking original coral aggregate in a weak acid aqueous solution for micro-corrosion to obtain acid-treated coral aggregate, and then soaking the acid-treated coral aggregate in a basic magnesium sulfate cement-based slurry coating material prepared from active magnesium oxide, magnesium sulfate heptahydrate, citric acid and water to obtain modified coral aggregate; and preparing the basic magnesium sulfate cement-based coral aggregate concrete from the aggregate, active magnesium oxide, magnesium sulfate heptahydrate, citric acid and water as raw materials. Based on a core admixture and a gradient composite technology, the invention provides a method for enabling basic magnesium sulfate cement whiskers to grow in communicated pores of coral aggregate, and external pores of the coral aggregate are fully filled with gradient composite basic magnesium sulfate cement. The effects of reducing the overall porosity of the coral aggregate concrete, optimizing the concrete interface transition area and improving the working performance and the mechanical property of the concrete are achieved.

Methods of using micronized particulate, reactive magnesium oxide or magnesium hydroxide to treat hazardous waste having high zinc content and hazardous levels of cadmium and lead. The reactive magnesium oxide or magnesium hydroxide has a median particle size in the range of 2-3 μm. The hazardous waste material is generated by a foundry or steel mill.

According to the present disclosure, a method of producing a hydrated magnesium carbonate based cement composite (HMCs) is provided. The method comprising providing an aqueous solution comprising a hydration agent and hydrated magnesium carbonate seed particles; contacting the aqueous solution with a magnesium oxide based cement to form magnesium hydroxide from the hydration agent and the magnesium oxide based cement, and on the hydrated magnesium carbonate seed particles; and exposing the magnesium hydroxide to carbon dioxide to form the hydrated magnesium carbonate based cement composite. The use of hydration agent and seed particles not not only increases formation of HMCs but also improves the mechanical performance of RMC based concrete formulations.

The invention discloses a method for preparing active magnesium oxide from carbide slag and a preparation method of magnesium cement. The method for preparing the active magnesium oxide from carbide slag comprises the following steps of: S1, preparing carbide slag and magnesium chloride into slurry, and carrying out reaction to generate a precursor; and S2, calcining the precursor at 500-900DEG Cfor less than 60min to obtain a calcined product, wherein the activity of magnesium oxide in the calcined product is 80% or more. The preparation method of magnesium cement comprises the following steps of: conducting the above steps of preparing the active magnesium oxide from the carbide slag; then mixing the calcined product, magnesium chloride and water according to a certain ratio to obtain magnesium cement; wherein the mass ratio of the active magnesium oxide to the magnesium chloride is 5-8:1, and the mass ratio of the magnesium chloride to water is 1:8-19. The two processes have greatsignificance in solving the treatment problem of salt lake by-products magnesium chloride and carbide slag.

Herein discloses a method of carbonating reactive magnesia cement, which includes: (i) providing an aqueous suspension including a carbon dioxide-producing bacteria; (ii) mixing the aqueous suspension with a precursor which the carbon dioxide-producing bacteria generates carbon dioxide from for a duration to form an aqueous mixture sufficient for substantially carbonating the reactive magnesia cement; (iii) mixing the aqueous mixture with the reactive magnesia cement to form a blend; wherein a nutrient is provided in the aqueous suspension of step (i) or in the reactive magnesia cement of step (iii) to sustain the carbon dioxide-producing bacteria in the reactive magnesia cement; and (iv) curing the blend to carbonate the reactive magnesia cement. A reactive magnesia cement composite formed by the method is also disclosed.

The invention discloses composite thermal insulation mortar initiated by soluble phosphate and a preparation method of the composite thermal insulation mortar. The composite thermal insulation mortarcomprises the following components in parts by mass: 1-10 parts of soluble phosphate, 20-70 parts of active magnesium oxide powder, 5-55 parts of fly ash, 2-10 parts of magnesium cement layer EPS particles and 10-70 parts of magnesium salt crystal filled expanded perlite. The magnesium cement layer EPS particles comprise EPS particles and a magnesium cement layer coating the EPS particles, and themagnesium cement layer is a magnesium oxychloride cement layer or a magnesium sulfate cement layer; the expanded perlite filled with the magnesium salt crystals comprises expanded perlite and the magnesium salt crystals filled in open pores of the expanded perlite, and the magnesium salt crystals are magnesium chloride salt crystals or magnesium sulfate salt crystals. During construction, in themixing process of the thermal insulation mortar and water, the soluble phosphate is subjected to hydrothermal reaction to release heat, the reaction process of the magnesium cement is accelerated, andthe construction efficiency is improved.