274 results about "Calcium carbonate crystals" patented technology

Disclosed is a method for soft soil foundation treatment through microorganism grouting sand drain. The method comprises the steps that a, a pile hole 1 is formed in a soft soil foundation to be treated, and sand is poured into the pile hole 1 to form a sand pile; b, a urease-producing microorganism solution 9 and a nutritive salt solution 10 are sequentially and evenly injected into the sand pile through a grouting tube 6, sand cementation is achieved through the microorganism induction calcium carbonate crystal technology, the concentration of the urease-producing microorganism solution 9 and the concentration of the nutritive salt solution 10 are controlled, sand in the pile body forms a specific cementation mode, and the good water permeable characteristic is ensured; c, after the microorganism grouting solidification sand pile is formed, a flexible water permeable sand cushion 4 is laid on the top of the foundation jointly formed by the sand oil and pile space soil 2, prepressing loads 5 are exerted on the top of the flexible water permeable sand cushion 4, pore water in the pile space soil 2 is made to be drained along a drainage channel formed by the sand pile and the sand cushion, the pile space soil is solidified, and the composite foundation with the high bearing capacity is formed jointly through the soft soil obtained after drainage and solidification are carried out on the microorganism grouting sand pile and the flexible water permeable sand cushion covering the soft soil.

The invention relates to a single-distributive micron short fiber-typed vaterite calcium carbonate and its preparing method. The calcium carbonate crystal is needle short fiber-typed, its length is 2-8 micron and width is 0.3-1.5 micron, the ratio of length and diameter is 5-10, its content of vaterite calcium carbonate is larger than 90% with small particle on the surface of. The preparing method includes mix the aqueous solution of carbonate containing water soluble organic solvent with aqueous solution of calcium salt also containing that, make use of the different dissolubility of carbonate and calcium salt in water soluble organic solvent and water, and the different solvation to calcium ion, compound the product. The calcium carbonate has remarkable single distribution, large ratio of length and diameter, high activity of surface, suitable for coating on paper, filling plastic, coating, printing ink and paper, as well as the raw material for calcium preparations.

Method for producing nanosized calcium hydroxide crystals or particles, according to which method the calcium oxide-bearing initial material is brought into contact with carbon dioxide in the aqueous phase. Calcium carbonate crystals or particles are produced in a mixture, the pH of which is below 7. Using the present invention, it is possible to combine the two stages of producing CaCO₃ particles into one entity, in which case the overall processing time is shortened and the use of external energy is minimized.

Through carbonization in Ca(OH)2 suspension by leading-in kiln gas containing CO2; controlling the nucleation rate of calcium carbonate crystal nucleus by the temperature of Ca(OH)2 suspension and the CO2 flow rate; controlling the growth rate of crystal faces by adding crystal form regulator; adding dispersant to regulate surface charge; and liquid phase surface coating dispersed cubic nanometercalcium carbonate grains, transparent nanometer calcium carbonate material for ink is prepared, which has size of 15-40 nm, GSD of 1.57, specific surface area greater than 35 sq m/g, ink oil absorption of 0.4 g/g and no coagulation. The calcium carbonate material may be used to produce transparent ink for high grade lithography.

The invention relates to a surface modified product of an acicular wollastonite crystal and a production method thereof. The product is micro-nano composite powder by coating a nanometer calcium carbonate crystal on the surface of the acicular wollastonite fiber crystal. The method comprises the following steps: firstly, preparing an active lime milk solution and an acicular wollastonite fiber solution; compounding the two solutions into a suspension; adding a crystalline directing agent to the suspension and filling CO2 gas for a coating reaction so that the nanometer calcium carbonate crystal gradually grows on the surface of an acicular aedelforsite fiber, and the micro-nano composite powder by coating a nanometer calcium carbonate crystal on wollastonite is obtained; and coating a layer of coupling agent on the surface of the micro-nano composite powder to obtain the acicular wollastonite fiber crystal-nanometer calcium carbonate crystal-coupling agent composite powder material. The product keeps the superior characteristics of the acicular wollastonite crystal and the nanometer calcium carbonate crystal, improves the surface energy and the chemical activity of wollastonite composite particles and can be well stuck with organic polymers so as to form a favorable interface and improve the bonding force between fillings and basal bodies, such as plastics, pulp, and the like.

The invention discloses inflaming retarding high-temperature-resisting foam concrete and a preparation method thereof. The concrete is prepared by mixing a gel material, heat-resisting aggregates, a liquid-state composition, an admixture and a foaming agent, wherein the gel material is slag silicate cement and grade-I fly ash; the heat-resisting aggregates comprise vitrified micro-beads, crushed clay clinkers, nano clay and corundum sand; the liquid-state composition comprises a water reducing agent, water and acrylic resin; and the admixture comprises phosphate, an inorganic fire retardant, glass fibers and calcium carbonate crystal whiskers. The inflaming retarding high-temperature-resisting foam concrete prepared by the preparation method has the advantages of small density, relatively high strength, low heat conductivity coefficient, good heat insulation performance and the like; and the combustion performance is grade A, and the fireproof limit can reach 4 hours so that the inflaming retarding high-temperature-resisting foam concrete is a fireproof heat-insulation material with a good comprehensive performance.

The invention relates to a composite foundation with a discrete material pile restrained through microorganism soil solidification and a construction method. The construction method includes the steps that a, a pile pipe is pressed into a foundation body; b, meanwhile, microorganism bacterium liquid is injected into a gap between an inner steel sleeve and an outer steel sleeve and diffused into the foundation body around the pile; c, the microorganism bacterium liquid is pumped out, a cementing solution is injected and diffused into the foundation body around the pile and reacts with the microorganism bacterium liquid to generate calcium carbonate crystals, and loose sandy soil or floury soil is cemented; d, the step b and the step c are repeated until the soil around the pile meets reinforcement requirements; e, discrete materials are poured into a hole of the inner steel sleeve; and f, a bed course is laid, so that the composite foundation is formed. According to the composite foundation with the discrete material pile restrained through microorganism soil solidification, the microorganism bacterium liquid and the cementing solution react to generate calcium carbonate so as to solidify the soil around the pile, so that the strength of the soil around the pile is improved, and the discrete material pile is protected against the problems of different pile diameters, bulging damage, pile hole caving and the like; the microorganism solidified soil and the pile can be combined to bear loads, and thus the bearing capacity of the single pile is improved.

The invention discloses a calcium carbonate surface modifying method, which comprises the following steps of: adding a surface treatment agent into slurry obtained after the carbonation reaction of light calcium carbonate or precipitated calcium carbonate, wherein the treatment agent consists of unsaturated long carbon chain plant oil and a cosolvent; stirring at a high speed of 500 to 1,200rpm for 0.5 to 2h to perform surface treatment on the calcium carbonate; and obtaining the finished product of modified calcium carbonate by dewatering, drying, crushing and packaging the calcium carbonate emulsion after the reaction. The surface treatment agent of the invention has high dispersion in water at normal temperature, uniformly acts on the surfaces of calcium carbonate grains under the action of a high-speed shearing force, physical absorption and the hydroxyl on the calcium carbonate surface and restrains the crystal growth and secondary aggregation of the calcium carbonate, so that the modified calcium carbonate has uniform aperture, high dispersion, high affinity with organic high polymer and high filling property. In the invention, when the liquid surface treatment agent is used, the modification reaction process of the calcium carbonate needs no heating and is low in energy consumption and environmentally-friendly.

The invention discloses a microorganism soil-reinforcement cement fly-ash gravel (CFG) pile composite foundation and a construction method. The construction method comprises the steps that a, a pile pipe is pressed into a foundation; b, microorganism bacterium liquid is injected into the pile pipe at the same time, and the microorganism bacterium liquid is made to diffuse towards the foundation around the pile pipe; c, the microorganism bacterium liquid is pumped out, and a cementing solution is injected into the pile pipe and made to diffuse to the foundation around the pile pipe and reacts with the microorganism bacterium liquid to generate calcium carbonate crystals, and incompact sandy soil or floury soil is cemented; d, the step b and the step c are executed repeatedly till the soil around the pile pipe meets the reinforcement requirement; e, pipe-drawing pile formation is conducted while cement-ash stabilized aggregates are poured; and f, a bed course is laid, so that the CFG pile composite foundation is formed. According to the microorganism soil-reinforcement CFG pile, the soil around the pile pipe is reinforced through calcium carbonate generated through reaction between the microorganism bacterium liquid and the cementing solution, so that the strength of the soil around the pile pipe is improved, and the quality problems of necking, pile breakage, soil carrying and the like in the pile forming process are solved; in addition, a reinforced soil body can be combined with a pile for bearing, and the bearing capacity of the single pile is effectively improved.

The invention relates to a preparation method of morphology controllable calcium carbonate based on temperature control. The preparation method of the morphology controllable calcium carbonate based on the temperature control comprises the following steps: introducing a solution containing carbonate or gas such as CO2 which can generate carbonate or a gas mixture containing CO2 into a solution containing calcium ions at the temperature of 10-100 DEG C, initiating precipitation reaction, obtaining a precipitate mixture several minutes later, and drying at room temperature, so that micron-sized calcium carbonate crystals with specific morphology are obtained. The calcium carbonate obtained by adopting the preparation method is good in correspondence between morphology and reaction temperature, and the correspondence is independent of type of a reactant; the obtained calcium carbonate crystals are well dispersed and uniform in sized; meanwhile, control of crystal form is efficient and stable; besides, by adopting a temperature control process, one-step synthesis, simplicity and practicability are realized, and industrial cost is low, so that the preparation method of the morphology controllable calcium carbonate based on the temperature control can be widely applied to batch preparation of calcium carbonate in different morphologies.

Production of high-purity spherical calcium carbonate is carried out by taking calcium chloride as chlorine source, taking mixture of calcium hydroxide and polyacrylamide as impurity remover, reacting it with sodium hydroxide, bubbling while carburizing by pure carbon dioxide, growing calcium carbonate crystal grain fast and enlarging. It has excellent purity, activity and dispersion, it simplifies and optimizes process, shortens reactive time and saves energy resources, it costs low and has no environmental pollution.

The invention discloses a method for fixing CO2 in industrial waste gas by using calcium-based bulk industrial solid waste phosphogypsum through strengthening and carbonating. The method comprises the following steps of: firstly, washing phosphogypsum with hot water to remove water-soluble impurities; secondly, adding the phosphogypsum cleaned in the first step in ammonia water for carrying out alkali-dissolved reaction to leach part of calcium ions; thirdly, adding a solid-liquid mixer generated in the second step into an airtight reactor, introducing CO2 waste gas for carrying out a gas-liquid-solid multi-phase CO2 carbonated fixing reaction to generate a calcium carbonate crystal, filtering, separating, washing and drying to obtain crystalline calcium carbonate; and fourthly, adding crystallized mother solution obtained in the third step in sulfuric acid and neutralizing to neutral and carrying out evaporating, concentrating, slurry spraying and granulating, drying and screening to obtain a granular ammonium sulfate product. According to the method disclosed by the invention, two valuable products are generated by using two wastes, so that the production cost of raw materials is reduced and the value of products is improved; and the method has the advantages of easiness in industrialization, better economic benefit, social benefit and industrial application prospect.

Into calcium hydroxide emulsion of 10-12 wt% concentration and at 20-25 deg.c, compound crystal form controlling agent is added while stirring, and then the mixture is transferred into a bubbling carbonating tower for carbonization for 50-70 min while introducing CO2 gas in the rate of 50-80 1/min. Kg calcium hydroxide and cold water to control the temperature not higher than 60 deg.c until the pH value being reduced to 7-8. Through the one-step carbonization process, cubic calcium carbonate of 80-100 nm size is prepared. The said process is suitable for use in industrial production and has low production cost and high production efficiency, and the product has excellent dispersant characteristic and may be widely used, especially in producing silicon rubber product.

A process for preparing the light active calcium carbonate includes such steps as before or during carbonating reaction in the process for preparing light or precipitated calcium carbonate, adding the surfactant prepared from water-insoluble salt of fatty acid, alcohol or ether type surface wetting agent and water, carbonating reacting to obtain calcium carbonate emulsion, dewatering, drying and pulverizing. Its advantages are high granular uniformity, dispersity and thermal stability, and good affinity to organic high polymer.

The invention relates to a method for preparing a flaky calcite calcium carbonate crystal, which comprises the following steps of: according to the substance amount ratio of calcium chloride to sodium carbonate as 1.4-1.8:1, adding boric acid or oxalic acid as a crystal shape control agent accounting for 0.8-4.2 percent of the mass of the sodium carbonate into 0.52-3.96mol/L of sodium carbonate solution, and controlling the solution temperature to be 40-90 DEG C; taking 1.24-6.32mol/L of calcium chloride solution, and controlling the solution temperature to be 40-90 DEG C; dropwise adding the calcium chloride solution into the sodium carbonate solution, stirring as dropwise adding, then stirring at constant temperature for 0.5-2 hours, settling at room temperature for 12-36 hours, and filtering to obtain precipitates; and repeatedly washing the precipitates with water to be neutral, removing adsorbed chloride ions, then filtering, and carrying out vacuum drying at the temperature of 40-80 DEG C to prepare the flaky calcite calcium carbonate crystal. A product is confirmed as a calcite crystal through X-ray diffraction analysis; and a scanning electron microscope result shows that the crystal is regularly flaky. The method has the advantages of low cost, simple process and regular product appearance.

Whiskers of calcium carbonate are prepared by: slaking, reactive liquid preparing, carbonating, finishing and recovering. The process is of easy control and operation with short preparing period, low cost and quality products.

The invention relates to a preparation method of hydroxyapatite nanosheets, which comprises the following step: by using shell powder or egg shells as a calcium source, ammonium phosphate as a phosphorus source and water as a solvent, reacting at 30-70 DEG C to obtain the hydroxyapatite nanosheets. According to the method, the reaction occurs at lower temperature, the prepared shell calcium carbonate crystal grains have favorable crystallinity and obvious oriented preferential growth shape, are sheet-shaped, and have low solubility in the water solution. In the reaction process, calcium carbonate crystal grain dissolution, hydroxyapatite recrystallization and hydroxyapatite grain growth are performed, the calcium carbonate sheet-like crystal grains gradually grow into the hydroxyapatite nanosheets. The method has simple requirements for reactors, and can perform production only by using a glass container, a stirrer, a thermostatic water bath box and other low-temperature reactors; and the production process is easy to operate and does not need any high-temperature high-pressure apparatus, thereby effectively lowering the production cost of hydroxyapatite.

The invention discloses a preparation method for rice-grain-shaped light calcium carbonate. The preparation method comprises the following steps: calcining lime stones with natural gas, adding digesting water to complete digesting reaction, performing screening, impurity-removal and ageing, adding a crystal form controller, introducing lime kiln kiln-gas to perform carbonization, pumping into a homogenizing tank to perform re-aging, and introducing purified, cooled and compressed lime kiln kiln-gas to perform secondary carbonation reaction, thereby preparing calcium carbonate slurry; and adding a modifying agent into the calcium carbonate slurry and stirring, and performing filter-pressing and dehydrating, drying, crushing and grading, thereby obtaining the rice-grain-shaped light calciumcarbonate. The light calcium carbonate crystal form prepared by the preparation method is rice-grain-shaped, has a long diameter of 150-200 nm, a short diameter of 30-50 nm, a BET specific surface area of 20-22 m<2>/g, a small length-diameter ratio, a high specific surface area and good dispersion, and can be used for manufacturing food and cosmetics; and moreover, the process is simple and feasible, the cost is low, the price is low, and the economic benefits are relatively good.

The invention relates to a process for preparing light magnesium oxide and calcium carbonate powder by utilizing a dolomite acid method, which comprises: dolomite is crushed and pulverized into powder; the powder is dissolved by utilizing hydrochloric acid to be prepared into a solution with key components of MgCl2 and CaCl2; the pH value is adjusted, the ions of Fe3<+>, Al3<+> and the like in the solution are eliminated, and the solution becomes a pure MgCl2 and CaCl2 solution; ammonia is introduced into the solution to react so that Mg2<+> is converted into Mg(OH)2 precipitations, and the light magnesium oxide powder is prepared through filtering, washing, drying and calcining; the filtrate is prepared into calcium carbonate crystals through continuous ammonia introduction and carbonization; and the calcium carbonate crystals are dried to prepare the light calcium carbonate powder. The process has the advantages that the design is reasonable; the energy consumption is low; the purities of the prepared light magnesium oxide and the calcium carbonate are above 98%; the resource utilization ratio of the dolomite is larger than 95%; and the process is worthy of being popularized and implemented.

Techniques for growing crystalline calcium carbonate solids such that the crystalline calcium carbonate solids include a volume of 0.0005 mm³ to 5 mm³, include a slaker to react quicklime (CaO) and a low carbonate content fluid to yield a slurry of primarily slaked lime (Ca(OH)₂); a fluidized-bed reactive crystallizer that encloses a solid bed mass and includes an input for a slurry of primarily slaked lime, an input for an alkaline solution and carbonate, and an output for crystalline calcium carbonate solids that include particles and an alkaline carbonate solution; a dewatering apparatus that includes an input coupled to the crystallizer and an output to discharge a plurality of separate streams that each include a portion of the crystalline calcium carbonate solids and alkaline carbonate solution; and a seed transfer apparatus to deliver seed material into the crystallizer to maintain a consistent mass of seed material.

The invention discloses whisker reinforcement-based self-leveling cement mortar. The whisker reinforcement-based self-leveling cement mortar comprises the following components in parts by weight: 10 to 20 parts of ordinary Portland cement, 50 to 150 parts of slag powder, 3 to 20 parts of special cement, 10 to 20 parts of gypsum, 5 to 10 parts of metakaolin, 100 to 160 parts of quartz sand, 1 to 10 parts of a crystal whisker and 1 to 1.5 parts of a water-reducing agent, wherein the special cement adopts sulphoaluminate cement or aluminate cement; the gypsum adopts one of or a mixture of more than two of high-strength gypsum, fluorgypsum, desulfurized gypsum and citric acid gypsum; and the crystal whisker adopts one of or a mixture of more than two of gypsum crystal whiskers, a magnesium hydroxide crystal whisker, a magnesium oxide crystal whisker, an ettringite crystal whisker and a calcium carbonate crystal whisker. A terrace prepared from the whisker reinforcement-based self-leveling cement mortar has high surface hardness and high anti-compression and anti-bending strength, and can meet the wear-resistant requirement of most occasions.

The invention discloses a preparation method of nano calcium carbonate for MS glue, which comprises the following steps: removing impurities from calcium hydroxide (Ca (OH) 2) slurry obtained after the digestion reaction of quicklime (CaO) and water (H2O), preserving heat and aging, adding a crystal form control agent, performing primary carbonization synthesis reaction with the washed kiln gas containing carbon dioxide (CO2), adding a post-treatment agent, aging for a certain time, performing secondary carbonization synthesis reaction with the washed kiln gas containing carbon dioxide (CO2) to obtain calcium carbonate (CaCO3) cooked slurry, adding a modifier into the cooked slurry, performing filter pressing dehydration, drying, crushing and grading after the reaction is finished to obtain the nano calcium carbonate for MS glue. The nano calcium carbonate crystal prepared by the method is a standard cube, and the crystal is mono-disperse, and the average particle diameter is only 100-150nm, and the specific surface area is 16-18m <2 >/g, and the nano calcium carbonate crystal is used for MS glue, and the thixotropy is good, and the extrusion property is good, and the storage stability is good, and the surface finish after gluing is good, and the tensile strength is high, and the elongation is high and the bonding property is also good. The preparation method of nano calcium carbonate for MS glue has the advantages of simple and feasible process, low cost, low price and better economic benefit.

The invention discloses a method for regulating growth of calcium carbonate crystal grains by using pulping black liquor lignin. According to the biological mineralization principle, by softwood pulping black liquor lignin as an organic matrix, the lignin concentration, system temperature, system pH value, crystallizing time and other technological parameters are changed and regulated to prepare calcium carbonate crystal grains with different shapes and sizes to satisfy the application demands of different technical fields. The technique disclosed by the invention is quick, efficient and environment-friendly; the softwood pulping black liquor lignin is introduced into the raw materials for preparing calcium carbonate crystal grains with different shapes and sizes as the organic regulation matrix, thereby sufficiently and reasonably utilizing the waste resources in paper making industry, and reducing the pollution load of the pulping black liquor onto the natural environment and the treatment cost of the paper making enterprise; and the prepared calcium carbonate crystal grains can be widely used in industries of paper making, rubber and the like, and has important environmental benefit and economic value.