233 results about "Ettringite" patented technology

The invention belongs to the technical field of building materials and relates to a high-performance concrete expansion agent which is composed of calcium clinker, aluminium material and calcium sulfate by mixing and matching, the calcium clinker contains magnesium oxide which is not more than 5 percent of the total weight, calcium oxide and magnesium oxide of 7 to 12 percent; the aluminium material and the calcium sulfate form ettringite. The high-performance expansion agent of the invention adopts the mutual action of three expansion sources of the CaO, the ettringite and the MgO and simultaneously carries out the utilization, the expansion of the three are appropriately combined to make up for deficiencies of each other, thereby obtaining the most appropriate expansion amount and the expansion exertion, better compensating the concrete shrinkage, improving the anti-crack effect of a product, overcoming the shortcoming of volumetric shrinkage and improving the durability of a building and the safety of the use.

The invention provides an internal curing process for improving the performance of high strength and slight expansion concrete, which comprises: mixing and stirring sand and stones, adding a gelled material, an expanding agent and a super absorbent resin; stirring the mixture for 30 seconds, adding water and a water reducer and stirring the mixture for 120 seconds; and filling the mixture into a mold. The water absorption of the super absorbent resin is between 150 and 300 times, the salt solution absorption capacity of the super absorbent resin is between 15 and 40 times, and the added amount of the super absorbent resin is 0.15 to 0.30 percent based on the mass of the gelled material. The process solves the problems of insufficient expansion rate, contraction, cracking and damages of later-stage secondary ettringite generation to the internal structure of the concrete, which are caused by curing. The internal curing technique effectively improves the moisture field in the concrete, the internal moisture content of the concrete and the hydration degree of the concrete, contributes to the full generation of the ettringite in the slight expansion concrete and improves the internal porous structure and compactedness of the concrete.

Provided is a method for preparing mine fill by utilizing Bayer process red mud. The method belongs to the technical fields of construction materials and solid waste resource utilization. The technical scheme of the method for preparing the mine fill is that the Bayer process red mud, coal ash, lime and gypsum are adopted to serve as raw materials and are evenly mixed according to a certain weight percentage to form the mine fill. The method for preparing the mine fill by utilizing the Bayer process red mud has the advantages that due to the fact that after the Bayer process red mud is hydrated, large amount of ettringite is produced and has high strength in an early period, the ettringite has an function of micro-expansion without shrinkage, and a goaf of a mine can be filled. Compared with cement used for the fill, cost can be saved by more than 60%. The method for preparing the mine fill by utilizing the Bayer process red mud facilitates saving of land source, avoids causing severe pollution to peripheral water bodies, atmosphere and soil, and facilitates environment protection.

The invention relates to a resource pretreatment technology for desulfurization waste water hardness ions. The resource pretreatment technology includes the following steps that desulfurization waste water from a flue gas desulfurization unit is conveyed into a pre-coagulating precipitate unit, suspended matter, SO4<2-> and F<-> in the desulfurization waste water are removed after coagulation, and then the waste water sequentially passes through a first softening precipitate group to remove Mg<2+> and generate magnesium hydrate, passes through a second softening precipitate group to remove Ca<2+> and generate ettringite and passes through a third softening precipitate group to remove Ca<2+> and generate calcium carbonate which is recovered as a desulfurizing agent. Compared with the prior art, various hardness ions can be effectively removed, precipitates such as magnesium hydrate, ettringite and calcium carbonate are recovered and used, the resource degree of pollution ions is high, and waste water and sludge are hardly discharged.

The invention discloses an early-strength polycarboxylate superplasticizer and a preparation method thereof. The water reducer is prepared from raw materials in parts by weight as follows: 200 parts of unsaturated polyether, 10-30 parts of acrylic acid, 1-3 parts of an amide derivative, 0.1-0.5 parts of mohr's salt, 0.5-1.5 parts of a chain transfer agent, 0.2-0.8 parts of L-ascorbic acid, 0.8-4 parts of an oxidizing agent, 230 parts of deionized water and 12-20 parts of a 30% sodium hydroxide solution. The unsaturated polyether with a larger molecular weight is used, that is, a long side chain is introduced into a polycarboxylate superplasticizer molecule, quaternary amine and amide functional groups exist on a main chain, early hydration of hydration products, namely C3A and C3S, can be promoted, crystallization of Ca(OH)2 and forming of ettringite can be accelerated, the concrete setting time can be effectively shortened, the compactness of an early microstructure is improved, the early mechanical property of cement grout can be substantially improved, and the polycarboxylate superplasticizer promotes early-strength development of concrete and shows excellent early-strength performance from a macroscopic view.

The present invention is related to the process and composition for the manufacture of cement expansion additive. The process comprises a blending step, a reaction step, and a calcination step. The blending step is to incorporate soluble calcium sulfate, soluble calcium oxide, and soluble aluminum compounds such as aluminum dross. The addition of water with the above incorporated materials to from ettringite is so-called reaction step. The calcination step is to calcine the products which are produced from reaction step at a temperature range between 60° C. and 900° C. by transforming ettringite from amorphous to calcium sulfoaluminate respectively. After calcinations, the final products can be used as expansive additives for cement or concrete. Further, this manufacturing method can effectively decrease raw material cost and production cost due to the raw material coming from recycling and no need to calcine at high temperature than other relative arts.

This invention describes a simple and effective method, through introducing fluoride ion releasing agent/salt(s), such as sodium fluoride, for preventing, reducing or eliminating the undesirable construction heave/expansion/distresses/damage, characterized by loss of dimensional stability and integrity of expansive soil layers or concrete structural elements, primarily caused by the formation of ettringite or similar minerals. We demonstrated the technology that can be easily applied to new construction sites and to the sites where repair/retrofit of the existing or potential distresses in soil subgrade, base, subbase, or construction materials is needed. Experiments have demonstrated the effectiveness and efficiency of the technology with applications to stabilization of soils with all range of aluminum and sulfate contents including more than 3000 ppm of sulfate, and to treating cementitious construction materials. This invention can also extend the application of lime to stabilization of sulfate-rich soils and remedy of foundation movement or tilting of buildings caused by the formation of ettringite.

A phosphate-containing mud-resistant polycarboxylate water reducer is provided and has a general chemical formula shown as a formula (I), wherein R1 is -H or -CH3, R2 is -CH2- or -CH2CH2-, R3 is -H, -COOH or -CH2COOH, R4 is -H or an alkali metal ion, and x, y, z, m and n are non-zero integers. The provided polycarboxylate water reducer has higher adsorption capacity than existing polycarboxylate water reducers, can effectively resist sulfates in cement, has greatly improved dispersion capability, and can change crystal morphology formed in the initial period of ettringite, thus improving slump loss resistance. The invention further provides a preparing method of the phosphate-containing mud-resistant polycarboxylate water reducer.

The invention discloses a preparation method of a concrete artificial fish reef material, and belongs to the technical field of artificial fish reef preparation. The preparation method comprises the steps that firstly, pretreated coal slag and clay are mixed and calcined; then, obtained materials are mixed with gypsum and the like; then, the mixture is added into a mold and is subjected to primary maintenance in solution cavity environment; carbon dioxide in a solution cavity takes a reaction with sodium hydroxide generated in the materials to generate calcium carbonate, so that the alkalinity is reduced; calcium hydroxide and ettringite are reduced; the materials are demolded to obtain fish reef concrete; then, a mixed solution prepared by chitosan and the like is sprayed and coated on the surface of the concrete; maintenance is performed again to obtain the concrete artificial fish reef material. The preparation method solves the problems of low artificial fish reef intensity, poor durability, short service life and the like. The obtained concrete artificial fish reef material has high intensity and higher durability; the hardened concrete artificial fish reef material has good compactness; the finally coated chitosan and mussel mucoprotein can be used as microorganism growth nutrient substances; the microorganism attachment quantity is increased.

The invention discloses an accelerator auxiliary material based on a composite polymerized flocculating agent and a preparation method thereof. The accelerator auxiliary material includes the components of poly aluminum ferric silicate-sulfate (PAFSS), an early-strength type reinforcing agent, a rear age reinforcing agent and the balance of water. The preparation method includes the steps that a poly ferric-aluminous-sulphate solution is prepared, a polymeric silicic acid solution is added into the poly ferric-aluminous-sulphate solution to be subjected to polymerization reaction for 30 minutes according to the (Al+Fe)/Si molar ratio, the early-strength type reinforcing agent, the rear age reinforcing agent and the water are mixed and stirred, and then the accelerator auxiliary material is obtained. With an aluminous component, a rich-silicon component and a sulfuric acid component being main components, a stabilizer and inorganic acid are added, and the aluminous coagulation accelerating component makes cement slurry rapidly condensed and hardened; the rich-silicon reinforcing component snatches C-S-H gel in the slurry, and under the joint flocculating interaction of the rich-silicon reinforcing component, hydrated calcium aluminate and ettringite, the slurry forms a remote coagulation structure more easily, and therefore the early and late period strength of a cement-based binding material is improved. The preparation technology is simple, and adaptability is good.

The present invention relates to an improved process for treating high sulphate waters. In particular, the present invention relates to an improved process by which ettringite is used to treat high sulphate waste waters by controlled precipitation of sulphate and metal ions.

The invention relates to a cement mortar body (2) made up of an aggregate (4) with silica content of around 99.5% which is formed by particles with a rounded surface and particle size between 0.1 and 1 mm The existing interstices of the body are filled with an ettringite binder (6) derived from hydrating cement particles (5) with particle size of around 5 microns, and with the actual cement particles (5), perfectly hydrated. The body (2) can include microparticles (7) and colloidal materials in the interstices formed between the particles of aggregate (4), the ettringite binder (6) and the cement particles (5). The interstices created between the particles of aggregate (4), the cement particles (5) with ettringite binder (6), the microparticles (7) and the colloidal materials can include nanoparticles (8). The invention also relates to a method for manufacturing said mortar body.

The invention belongs to the field of building materials and particularly relates to superfine ettringite, a preparation method and application of the superfine ettringite to a cement-based grouting material. An aluminum salt solution, a calcium salt solution to which a surfactant is added, and a caustic soda solution are prepared respectively and poured into a full-backmixing explosive nucleating reactor at the same time, a nucleating reaction is carried out for 2-3 min, the materials are subjected to backflow crystallization for 2-20 h at the temperature of 20-50 DEG C, the materials are centrifugally washed to be neutral and then dried, and the superfine ettringite is obtained. According to the prepared superfine ettringite, the preparation method is simple, synthesis conditions are mild, operation is easy, good repeatability is achieved, and industrial production is easy. The superfine ettringite is applied to the cement-based grouting material, the strength of sulphate aluminium cement at all ages can be remarkably improved, especially, the early strength of the cement material can be remarkably improved, and later strength is not subjected to backward shrinkage.

The invention provides a pervious concrete self-crystallization multi-lacuna gel material, which adopts Portland cement as a main body, and forms the gel material with automatic expansion and shrinkage functions through compositing a micro-expanding agent, a crystallizing agent and fine elastic colloidal particles. When being applied to pervious concrete, the gel material is self-crystallized to form multi-lacuna ettringite with flexibility, and not only has favorable adhesion with coarse and fine aggregates, but also forms multi-lacuna pervious channels. When being used, the self-crystallization gel material and porous fine aggregates are used cooperatively, and micro pores of the porous fine aggregates cannot be blocked. Therefore, a large amount of porous fine aggregates can be used in the pervious concrete, the adhesion interface area between the coarse aggregates is increased, and the strength of the pervious concrete is improved. The pervious concrete self-crystallization multi-lacuna gel material can be applied to concretes for high-load roads such as urban roads and highway roads.

The invention discloses a method which uses steel slag, mineral slag or electric power plant slag as the materials of a self-hydrating activation type pavement basic layer to activate the potential hydrating activation of the mineral slag or the pozzuolana activation of the electric power plant slag by the corresponding interlocking effect of each waste and the self-hydrating activation of the steel slag to form hydrated C-S-H, C-S-A-H, or C-S-A-F-H, ettringite, and calvital hydration product, form the initial strength of the pavement basic layer and ensure the continuous increasing of the later strength; counted by weight portions, the mixture ratio of each material is as follows: 40 to 65 portions of steel slag, as well as 35 to 60 portions of mineral slag and/or electric power plant slag. The pavement basic layer is a non-cement basic layer with excellent performance, and the preparation method thereof is as follows: the materials after being mixed are transported to a constructionfield, paved, rolled, and maintained by moisture retention to a regulated age. The invention uses industrial wastes, can save land and resources and reduce the cost, is beneficial to protecting environment, is simple to be constructed, and is suitable for building the basic layers and the foundation layers of common roads and advanced roads.

Sulfate anions and divalent metal ions in water are removed by treating sulfate-containing water, at a pH of 11-12.5, with aluminum chloride and calcium chloride, optionally together with lime, to form solid ettringite and similar crystalline species. Sulfate is removed as part of the ettringite or ettringite-like materials, but calcium content can be reduced at the same time even though calcium chloride is used as an additive to the treated water. Lime may be used also as a supplemental source of calcium and to help raise the pH. Iron may also be removed by oxidation in a variation of the process. In well treatment, divalent metal ions in flowback fluids can reduce the amount of calcium otherwise necessary to form the solid materials, thus further facilitating recycling of the fluid.

The invention relates to a composition for preparing dry-mixed mortar. The composition comprises aggregate, cellulose ether, latex powder, cement and a buffer material composed of calcium hydroxide, sodium sulfate and calcium sulfate, wherein with the buffer material, a relatively great quantity of ettringite can be generated after the dry-mixed mortar is mixed with water, the mortar has ideal rigidity, and the mass of the added cement can be reduced.

The invention discloses a high-moisture content soft soil consolidating agent and application thereof. The high-moisture content soft soil consolidating agent is composed of an expanding component anda gelatinizing component, wherein the expanding component is composed of sulphoaluminate cement clinker, gypsum and lime, and the gelatinizing component is ordinary Portland cement; the weight ratioof the expanding component and the gelatinizing component is 0-100:100-0, and the weight ratio of the sulphoaluminate cement clinker, the gypsum and the lime of the expanding component is 40-60:32-48:8-12. The high-moisture content soft soil consolidating agent can be applied to consolidating muddy soil, sandy soil or silty soil with a moisture content as high as 50-150%; the construction processof the high-moisture content soft soil consolidating agent comprises construction methods of deep mixed piles, high-pressure jet grouting piles of a double-slurry grouting system. The high-moisture content soft soil consolidating agent solves coordination of production amount and speed of ettringite and C-S-H (calcium silicate hydrate) gel, makes full use of water absorbency of the expanding component, pore filling of the ettringite and bonding effects of compaction clay and the C-S-H gel.

The invention relates to a sulfoaluminate cement composite early strength agent and early strength sulfoaluminate cement. The sulfoaluminate cement composite early strength agent is prepared from the following components in parts by weight: 0.15 to 0.3 part of a promoter, 1 to 3 parts of a dense agent and 0.05 to 0.1 part of a conditioner. The early strength sulfoaluminate cement is prepared from sulfoaluminate cement and the sulfoaluminate cement composite early strength agent, and is particularly prepared from the following components in parts by weight: 100 parts of the sulfoaluminate cement, 0.15 to 0.3 part of the promoter, 1 to 3 parts of the dense agent and 0.05 to 0.1 part of the conditioner. By the synergistic action of the three components, the sulfoaluminate cement composite early strength agent promotes early hydration of the sulfoaluminate cement and rapid formation of ettringite and maintains the compactness of the structure of hardened paste, so that the sulfoaluminate cement obtains relatively high hour strength, and the later strength cannot be reduced or is slightly reduced.

The invention relates to efficient expansion clinker for cement concrete, a preparation method of the efficient expansion clinker and application of the efficient expansion clinker. The efficient expansion clinker is composed of, by weight, 30-60wt% of f-CaO, 5-40wt% of Fe2O3, 3-10wt% of C2S, 2-10wt% of C4AF, 3-15wt% of SiO2, 3-12wt% of Fe and 1-8wt% of C4A3S. The preparation method of the efficient expansion clinker includes: grinding 60-80wt% of limestone, 15-30wt% of pyrite cinders and 5-10wt% of rice husk ash, and well mixing to obtain raw materials; calcining the raw materials for 30-120min at the temperature of 1100-1350 DEG C to obtain the efficient expansion clinker. The expansion clinker can be mixed with dispersive carriers (such as blast furnace slag and copper slag) to form an efficient expanding agent for cement concrete. The expansion clinker and the expanding agent integrate three expanding sources including calcium hydroxide, ferric hydroxide and ettringite and are greatly promoted in expanding performance as compared with an ettringite type expanding agent with a single expanding source; due to a hydraulic binder component, later-stage mechanical properties of the cement concrete can be enhanced to some extent.