Abstract:
Rare earth metal compounds, particularly lanthanum, cerium, and yttrium, are formed as porous particles and are effective in binding metals, metal ions, and phosphate. A method of making the particles and a method of using the particles is disclosed. The particles may be used in the gastrointestinal tract or the bloodstream to remove phosphate or to treat hyperphosphatemia in mammals. The particles may also be used to remove metals from fluids such as water.
Abstract:
Rare earth metal compounds, particularly lanthanum, cerium, and yttrium, are formed as porous particles and are effective in binding metals, metal ions, and phosphate. A method of making the particles and a method of using the particles is disclosed. The particles may be used in the gastrointestinal tract or the bloodstream to remove phosphate or to treat hyperphosphatemia in mammals. The particles may also be used to remove metals from fluids such as water.
Abstract:
Disclosed is a method for preparing cerium carbonate that can improve yield or productivity of cerium carbonate and enables preparation of cerium carbonate having uniform diameter, cerium carbonate, and a method for preparing cerium oxide.The method for preparing cerium carbonate comprises mixing the cerium precursor with urea; and, elevating the temperature of the mixture to 50° C. or more in the absence of a separate reaction medium to react the cerium precursor with urea in the presence of a polymer dispersant.
Abstract:
Disclosed are cerium oxide powder for an abrasive; CMP slurry including the same; and a shallow trench isolation (STI) process using the CMP slurry. At least two kinds of cerium oxides prepared by using cerium carbonates having different crystal structures are mixed in an appropriate ratio and used as an abrasive for CMP slurry, thereby adjusting required polishing properties of the CMP slurry. Also, in a disclosed method of preparing a cerium carbonate, the crystal structure of the cerium carbonate can be easily controlled. Based on the finding that in a cerium oxide for an abrasive, the kind of improved polishing property depends on the crystal structure of a cerium carbonate, at least one from among polishing properties, such as the polishing rate of a silicon oxide layer, the polishing rate of a silicon nitride layer, the polishing selectivity between the silicon oxide layer and the silicon nitride layer, and WIWNU, can be adjusted by using at least two kinds of cerium oxides selected from the group including (i) a cerium oxide prepared by using a lanthanite-(Ce) crystal structured cerium carbonate, (ii) a cerium oxide prepared by using an orthorhombic crystal structured cerium carbonate, and (iii) a cerium oxide prepared by using a hexagonal crystal structured cerium carbonate, as an abrasive for CMP slurry, and adjusting the mixing ratio of the cerium oxides.
Abstract:
A cerium salt wherein, when 20 g of the cerium salt is dissolved in a mixed liquid of 12.5 g of 6N nitric acid and 12.5 g of a 30% hydrogen peroxide aqueous solution, a concentration of an insoluble component present in the solution is 5 ppm or less by mass ratio to the cerium salt before dissolution and cerium oxide produced by processing the cerium salt at high temperatures. Scratch on a surface to be polished can be reduced when a cerium based polishing slurry containing the cerium oxide particles is used, since an amount of impurities in cerium oxide particles and cerium salt particles, raw material thereof, is reduced for high purification.
Abstract:
In a method for preparing cerium carbonate powder by mixing a cerium precursor solution with a carbonate precursor solution and carrying out a precipitation reaction, wherein cerium carbonate is controlled to have an orthorhombic crystal structure, a hexagonal crystal structure or an orthorhombic/hexagonal mixed crystal structure, by using at least one type of organic solvent comprising at least two hydroxyl groups (OH) in molecular formula as a solvent for either or both the cerium precursor solution and the carbonate precursor solution, and varying a number of carbons or hydroxyl groups (OH) included in the molecular formula of the organic solvent. The method can easily and inexpensively obtain cerium carbonate powder with a desired crystal structure without the danger by high-temperature high-pressure and the need for an expensive system in hydrothermal synthesis.
Abstract:
Method of preparing cerium carbonate powder by mixing a cerium precursor solution with a carbonate precursor solution and subjecting the mixture solution to a precipitation reaction, wherein the concentration of cerium in the cerium precursor solution ranges from 1M to 10M, the molar concentration ratio of the cerium precursor to the carbonate precursor ranges from 1:1 to 1:7, and the cerium precursor solution contains at least one additive selected from the group consisting of carbonate compounds, acrylic compounds, and sulfate ion-containing compounds. The cerium carbonate powder has an orthorhombic crystal structure, a particle size of 0.05 to 1 μm, and an aspect ratio of 1 to 5. Moreover, disclosed are cerium oxide powder prepared from said cerium carbonate powder as a precursor, a preparation method thereof, and a CMP slurry containing said cerium oxide powder as an abrasive.
Abstract:
Disclosed are cerium oxide powder for an abrasive; CMP slurry including the same; and a shallow trench isolation (STI) process using the CMP slurry. At least two kinds of cerium oxides prepared by using cerium carbonates having different crystal structures are mixed in an appropriate ratio and used as an abrasive for CMP slurry, thereby adjusting required polishing properties of the CMP slurry. Also, in a disclosed method of preparing a cerium carbonate, the crystal structure of the cerium carbonate can be easily controlled. Based on the finding that in a cerium oxide for an abrasive, the kind of improved polishing property depends on the crystal structure of a cerium carbonate, at least one from among polishing properties, such as the polishing rate of a silicon oxide layer, the polishing rate of a silicon nitride layer, the polishing selectivity between the silicon oxide layer and the silicon nitride layer, and WIWNU, can be adjusted by using at least two kinds of cerium oxides selected from the group including (i) a cerium oxide prepared by using a lanthanite-(Ce) crystal structured cerium carbonate, (ii) a cerium oxide prepared by using an orthorhombic crystal structured cerium carbonate, and (iii) a cerium oxide prepared by using a hexagonal crystal structured cerium carbonate, as an abrasive for CMP slurry, and adjusting the mixing ratio of the cerium oxides.
Abstract:
A method for treating hyperphosphatemia using lanthanum carbonate, including analytically determining the amount of an impurity in the lanthanum carbonate sample is provided. This X-ray diffraction method preferably uses the Rietveld refinement.
Abstract:
Disclosed are processes and systems for sequestering carbon dioxide from a flue gas effluent from a parent process such as a coal-fired electric power plant. In one non-limiting embodiment of the invention, a mineral having a metal is dissolved with an acid to provide a solution having a predetermined pH. Carbon dioxide from the flue gas effluent and a base are added to the solution to provide a metal carbonate reaction to precipitate a metal carbonate, e.g., magnesium carbonate, from the solution. Heat, which may be supplied by the flue gas effluent, is used to power a base management system for recovering used base form the process.