48results about "Aluminium-carbonate compounds" patented technology

The invention provides a preparation method of LDHs (magnesium-based layered double hydroxides). According to the method, calcium oxides or calcium magnesium oxides are used as an alkali source, calcium oxides or calcium magnesium oxides and a magnesium salt are subjected to a precipitation reaction, magnesium hydroxide precipitates are produced, then the magnesium hydroxide precipitates and divalent and trivalent soluble metal nitrates or chlorides are used as raw materials, LDHs are prepared through a liquid-solid phase reaction, and byproducts, namely, magnesium chlorides or magnesium nitrates, can be used as raw materials. The method has the advantages that the raw materials are rich in source, the price is low, the preparation process is simple, reaction conditions are mild, industrial production is facilitated and the like, and prepared LDHs can be widely applied to fields of catalysis, adsorption, environmental protection, high-polymer plastic and the like.

Disclosed is a clean method for preparing layered double hydroxides (LDHs), in which hydroxides of different metals are used as starting materials for production of LDHs by atom-economical reactions. The atom efficiency of the reaction is 100% in each case because all the atoms of the reactants are converted into the target product since only M²⁺(OH)₂, M³⁺(OH)₃, and CO₂ or H_nAⁿ⁻ are used, without any NaOH or other materials. Since there is no by-product, filtration or washing process is unnecessary. The consequent reduction in water consumption is also beneficial to the environment.

The invention provides a method for preparing a PVC heat stabilizer through the steps that lamellar silica tetrahedrons and a refabricated lamellar alumina octahedron are obtained by taking ore as a raw material, utilizing the lamellar structure characteristic of vermiculite and removing an alumina octahedron layer between two silica tetrahedron layers, layer splitting of the vermiculite is achieved. Particularly, the method comprises the steps that the vermiculite ore is subjected to microwave expansion to obtain expanded vermiculite; a nano-scale vermiculite flake is obtained by means of ion stirring stripping; the solid lamellar silica (silica tetrahedrons) are obtained according to the characteristics that the silica tetrahedrons are insoluble in acid and the alumina octahedron is soluble in acid by splitting the vermiculite through acid dissolving; iron ions in an acid solution are removed through a graded precipitation method, impurities such as salt ions are removed through quick nucleation and water washing, crystal growth is controlled through a hydrothermal method, and the nano-scale lamellar hydroxide (alumina octahedron) is obtained; the obtained silica and hydroxide successfully achieve mixing of a heat stabilizer and PVC through a solvent replacement and dispersion method, and the agglomeration and redispersion problems of the nano-scale silica and hydroxide are solved. According to the method, the PVC heat stabilizer is prepared by selecting the advantageous mineral vermiculite in China as the raw material, and the advantages of being wide in raw material source, low in cost, simple in process, non-toxic, easy to apply and popularize and the like are achieved; in addition, the efficient heat stabilizer is prepared from the original ore vermiculite, the defects of existing toxic heat stabilizers which are high in price or contain lead are overcome.

The present invention is a process for the conversion of aluminum oxide hydroxide (AlOOH) to aluminum oxide. About 30 to 70 wt-% of AlOOH, about 30 to 70 wt-% ammonium hydrogencarbonate NH₄HCO₃ and 0 to 20 wt-% water are combined to produce a mixture. This mixture is then cured at a temperature from about 30° to about 90° C. to convert at least 5% of the AlOOH to a ammonium hydroxycarbonate (dawsonite-type) intermediate and then the dawsonite-type intermediate is decomposed at a temperature from about 130° to 320° C. to produce aluminum oxide. The aluminum oxide can be further calcined at 500° to 800° C. to produce a gamma-theta phase alumina.

The invention relates to a preparation method and an application of a hydrotalcite-like compound for adsorbing and reducing heavy metals. The preparation method concretely comprises the following steps: a) weighing all raw materials according to the stoichiometric ratio of an object having a general formula of Mg6-xFexAl2(OH)16CO3.4H2O (x = 0.3-1.2), adding deionized water into a magnesium raw material, an iron raw material and an aluminum raw material to form a solution A, and adding deionized water into alkali metal and carbonate raw materials to form a solution B; b) dropwise adding the solution A to the solution B, pouring the formed mixed suspension into an autoclave, heating the autoclave to 120-180 DEG C, performing heat treatment, and performing suction filtration, washing and drying to form a Mg6-xFexAl2(OH)16CO3.4H2O sample; and c) adding the sample into a potassium dichromate solution, taking the obtained supernatant and testing the adsorption rate of the supernatant every 2h, and detecting the Cr (VI)reduction degree of the material. Iron magnesium aluminum hydrotalcite prepared in the invention has good adsorption capability to heavy metals, and can be recycled through the reduction and separation of Fe<2+> on the heavy metals. The method has the advantages of simplicity in operation, high adsorption and reduction efficiency, low cost and no secondary pollution.

A dry material is synthesized by alkali metal (Li, Na and K) promoted calcium aluminate carbonates to obtain a CO₂ sorbent used at a temperature higher than 600 Celsius degrees (° C.). The key composition of the sorbents is 52˜69% of CaO, which is beneficial to capture CO₂ at 400˜800° C. A breakthrough result is achieved by using this sintering-resistant sorbent, which includes the features of 50% initial carbonation capacity and 20 folds CO₂ capturing performance maintained after 40˜60 hours. Besides, alkali bearing material provides good velocity in CO₂ capturing/releasing cycles; for example, by using Li and K series sorbents, 40 hours is required for 40 cycles only.

Wide mesoporous alumina composites are produced by an “in situ reaction” route comprising agglomeration of an alumina powder that is capable of rehydration together with a second reactive powder such as carbonate. In one method of production, the powders are fed to a rotating forming device that is continuously sprayed with liquid under conditions to form particulates. The discharging beads are then subjected to curing and thermal activation to produce the final catalyst or adsorbent. The alumina participates in a pore altering process involving the carbonate component upon formation of hydroxycarbonate intermediates such as Dawsonite. Large fraction of the pore volume of the final product consists of wide mesopores in the 15-50 nanometers range. The alumina composites exhibit a characteristic trimodal pore structure that includes also small micro-meso pores and macropores larger than 200 nanometers.

The invention provides a preparation method for carbonate type hydrotalcite compound powder. The method comprises the following steps: taking divalent metal oxide or hydroxide and trivalent metal hydroxide as main raw materials; compounding with divalent metal carbonate (normal salt or subcarbonate) of the same metal of the divalent metal oxide or hydroxide, for supplying carbonate; directly compounding the hydrotalcite compound with regular structure and uniform grain size through one-step ultrasonic-assisted hydrothermal reaction. The preparation method belongs to atom economy reaction; thereaction speed is high; no waste is discharged during the process; the product can be directly dried without washing, so that water resource can be greatly saved; the method has the characteristics ofsimple technological process, environmental protection and easiness in industrial production.

The present invention belongs to the synthesis technology field of inorganic functional materials, and particularly provides a self-balanced high-pressure and high-shear autoclave and its application in the preparation of layered double hydroxides (LDHs). In this invention, by imbedding the handpiece of emulsification mill into the autoclave, and by taking the motor driving system outside of the autoclave, the pressure of the autoclave can be highly stable by the use of self-balanced seal gland. These characters solve the problem that the typical emulsification mill cannot be used in high-pressure system, and ensure the crystallization under the high-pressure and high-shear conditions. Such autoclave takes the advantages of additional equipment, and eliminates the volume effect in the amplification process. By the use of this new autoclave, the reaction time can be shorten from 24 hours to 2-6 hours, the reaction temperature can be reduced from 180° C. to 140° C. The LDHs products with small particle size and narrow size distribution are obtained. These results are better than those prepared at the laboratory level.

The invention belongs to the technical field of preparation of hydrotalcite-like compounds, and particularly relates to calcium-aluminum hydrotalcite and a preparation method thereof. The preparationmethod of calcium-aluminum hydrotalcite provided by the invention comprises the following steps: step (1) mixing a calcium source, an aluminum source, a stabilizer and water to obtain mixed liquid, and carrying out a reaction to obtain intermediate slurry, wherein anions in the mixed liquid contain OH<-> and complex anion; the complex anion contains one or more of Cl<->, F<->, SO4<2->, NO3-, PO4<3-> and HPO4<2->; and step (2) mixing and crystallizing the intermediate slurry and an alkaline salt solution to obtain the calcium-aluminum hydrotalcite. The preparation method provided by the invention follows a 'rapid nucleation mechanism'; and an intermediate is generated during preparation to avoid CaCO3 and other impurities generated by direct contact of calcium ions and aluminum ions and anions of an alkali solution, so that the prepared calcium-aluminum hydrotalcite has uniform crystal phase and high purity.

A process is provided for preparing calcium carbonate hydroxodialuminates which have a hexagonal platelet-shaped crystal habit and are of the formula (A):

Ca_mAl₂(OH)_6+2(m−1)An*nH₂O   (A)

where m=3.5 to 4.5 and An=carbonate which may be partly replaced by perchlorate and/or trifluoromethanesulfonate (triflate) and n=0 to 6, comprising the steps of reacting calcium oxide or calcium hydroxide with optionally activated aluminum oxohydroxide or aluminum hydroxide and simultaneously or subsequently with a carbonate source consisting of carbon dioxide or alkali metal (bi)carbonate and optionally further reacting the product obtained in step (a) with perchloric acid and/or trifluoromethanesulfonic acid or optionally calcining the product obtained in step (a) at 200° C. to 900° C. and subsequently exchanging ions in the presence of a perchlorate and/or triflate salt, optionally in the presence of alkali metal (bi)carbonate, in water. The present invention further relates to the aluminates thus obtained in compositions and stabilizer systems and to the use thereof.

The present invention discloses a green technology for synthesizing ammonium aluminum carbonate hydroxide and a pyrolysis thereof to prepare high specific surface alumina. The green technology comprises the following steps: a, ammonium salts (ammonium carbonate and ammonium hydrogencarbonate) or amide compounds (formamide, acetamide, urea, etc.) are used as a modifier to prepare a clarified solution; b, pseudo-boehmite is added to the clarified solution in the step a at a certain molar ratio, the materials are stirred until the solution is uniform, then the solution is transferred to a crystallization kettle, crystallized solids are washed and dried to obtain the ammonium aluminum carbonate hydroxide (AACH), and obtained mother liquor is recycled for use; c, after the mother liquor obtained in step b is cooled, a certain amount of the modifier is supplemented for use, and the step b is repeated; and d, the ammonium aluminum carbonate hydroxide is pyrolyzed to obtain the high specific surface alumina. The AACH synthesized by the provided method for synthesizing the ammonium aluminum carbonate hydroxide has a specific surface as high as 812.5 m<2>g, after high temperature calcinations, the obtained alumina still has a relatively high specific surface (681.8 m<2>/g), and the green technology realizes the recycling of the mother liquor after reaction, and is free of waste liquid discharge, energy-saving and environmentally protective.

The present invention relates to the field of solid materials for adsorption of lithium. In particular, the present invention relates to a novel method for preparing a crystallized and shaped solid material, preferably as extrudates, of formula LiX_x.2Al(OH)₃, nH₂O with n being comprised between 0.01 and 10, x being equal to 1 when X is an anion selected from among chloride, hydroxide and nitrate anions, and x being equal to 0.5 when X is an anion selected from among sulfate and carbonate anions, comprising a step a) for precipitation of boehmite under specific temperature and pH conditions, at least one shaping step, preferably by extrusion, said method also comprising a final hydrothermal treatment step, the whole giving the possibility of increasing the adsorption capacity for lithium as well as the adsorption kinetics of the materials obtained as compared with the materials of the prior art when the latter is used in a method for extracting the lithium from saline solutions.

The invention discloses a method for preparing bar-shaped ammonium aluminum carbonate without a template agent. According to the method, an ammonium aluminum carbonate micron bar is hydrothermally synthesized without the template agent by taking Al(NO3)3 as an aluminum source and urea as a precipitator; and the ammonium aluminum carbonate micron bar prepared through hydrothermal reaction without the template agent is high in length-diameter ratio, regular in shape and good in crystallization performance. The bar-shaped micron bar prepared by virtue of the method is high in length-diameter ratio, the average length is about 15 microns, the average diameter is about 200nm, and the length-diameter ratio is about 75 to 1. The shape of the product is not controlled by virtue of a surfactant inthe preparation process, so that the preparation cost is lowered, the preparation process is simplified, a series of environmental pollution problems in the preparation process and the later-period cleaning process are avoided, the preparation process adopted in the method is an environment-friendly preparation process and is accordant with the environment-friendly development idea nowadays, and the preparation method is simple and convenient, the cost is low and the environmental friendliness is high.

A method of making silica-layered double hydroxide microspheres having the formula I : (i) wherein, Mz+ and M'y+ are two different charged metal cations; z = 1 or 2; y = 3 or 4; 0 < x < 0.9; b is 0 to 10; c is 0 to 10; P > 0, q > 0, Xn- is an anion; with n > 0 a = z(1-x) + xy-2; and the AMO-solvent is an 100% aqueous miscible organic solvent; comprises the steps: (a) contacting silica microspheres and a metal ion containing solution containing metal ions Mz+ and M'y+ in the presence of a base and an anion solution; (b) collecting the product; and (c) optionally treating the product with AMO-solvent and recovering the solvent treated material to obtain the silica-layered double hydroxide microspheres. Preferably, M in the formula I is Li, Mg, Ni or Ca. Preferably, M' in formula I is Al. The invention further provides silica-layered double hydroxide microspheres having the formula I. The silica-layered double hydroxide microspheres may be used as catalysts and/or catalyst supports.

The present invention relates to the field of solid materials for the adsorption of lithium. In particular, the present invention relates to a new method for the preparation of a crystallized and shaped solid material, preferably in extruded form, of formula LiX_x.2Al(OH)₃,nH₂O, wherein n is between 0.01 and 10, x is 1 when X is an anion selected from among chloride, hydroxide and nitrate anions, and x is 0.5 when X is an anion selected from among sulfate and carbonate anions, comprising a boehmite precipitation step a) under specific temperature and pH conditions, at least one basic mixing shaping step, wherein the method also comprises a final hydrothermal treatment step, all to increase the lithium adsorption capacity and the kinetics of adsorption of the materials obtained, compared with the materials of the prior art when it is used in a method for lithium extraction from saline solutions.

The invention discloses an intelligent aluminum magnesium carbonate crystallization system, belonging to the technical field of aluminum magnesium carbonate production. The aluminum magnesium carbonate crystallization system comprises a reaction kettle, a filtering device and a drying device connected in sequence, and the reaction kettle comprises a kettle body, The top of the kettle body is provided with a feeding port and the outer surface is provided with a jacket, and the jacket is provided with a heat medium inlet and a heat medium outlet for the entry and exit of the heat medium; the bottom of the kettle body is provided with a discharge port, so the The kettle body is provided with a driving mechanism, an upper and lower pushing mechanism and a stirring mechanism, and the driving mechanism is located above the top of the kettle body and is used to drive the upper and lower pushing mechanism and the stirring mechanism, and the stirring mechanism It is used for stirring the materials in the kettle, and the upper and lower pushing mechanism is used to push the materials in the kettle up and down. The present invention can make the material react sufficiently and rapidly in the reaction kettle.