Abstract: The present invention relates to crystalline cerium oxide prepared in a simple, economical, and efficient manner, of which crystal structure, shape, and size can be easily adjusted and that exhibits excellent polishing properties, and a preparation method thereof. The crystalline cerium oxide can be prepared as sub-micron crystalline cerium oxide that has a mean volume diameter and a diameter standard deviation within a predetermined range.

Abstract: The present invention discloses to a channel reactor system having a first channel plate assembly in which an exothermic reaction is performed and a second channel plate assembly provided for heat-exchanging and constituted integrally with the first channel plate assembly so as to remove effectively heat, the channel reactor system comprising at least two channel units into which reaction gas and cooling fluid are separately introduced, each channel unit comprising a reaction channel plate assembly into which reaction gas is introduced and a heat-exchanging channel plate assembly into which cooling fluid is introduced; and at least one intermediate plate disposed between the upper and lower channel units, the intermediate plate supplying reaction gas and cooling fluid inflowed from the upper channel unit with new reactant and cooling fluid and supplying reaction gas and cooling fluid to the reaction channel plate assembly and the heat-exchanging channel plate assembly of the lower channel unit, respectively.

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 is a method for preparing cerium carbonate that can prepare cerium carbonate having uniform crystal structure, shape and size with high productivity. The method for preparing cerium carbonate comprises: continuously introducing a reaction solution comprising cerium precursor and urea in a tubular reactor including an inlet, an outlet, and one or more reaction tubes through the inlet; reacting the cerium precursor with urea at an elevated temperature in the reaction tube; and, continuously discharging cerium carbonate formed by the reaction of the cerium precursor and urea to the outlet.

Abstract: The present invention discloses to a chemical reactor with high heat efficiency and small volume, the chemical reaction of the present invention comprises a first unit for performing heat exchange of exothermic reaction products with exothermic reaction raw material fed for exothermic reaction; a second unit including a plate assembly for exothermic reactions and a plate assembly for endothermic reactions; and a third unit for performing heat exchange of endothermic reaction products with endothermic reaction raw material fed for endothermic reactions.

Abstract: The present invention relates to a method for preparing cerium carbonate-based compound, which is capable of easily controlling the crystalline structure, size, shape, or etc. of the cerium carbonate-based compound, and of preparing the cerium carbonate-based compound efficiently at low cost. The method for preparing cerium carbonate-based compound includes comprising the steps of reacting Lanthanite-(Ce) at an elevated temperature to form cerium oxycabonate hydrate (Ce2O(CO3)2.H2O) with orthorhombic crystal structure, or cerium hydroxycarbonate (Ce(OH).(CO3)) with hexagonal crystal structure.

Abstract: The present invention discloses to a channel reactor system having a first channel plate assembly in which an exothermic reaction is performed and a second channel plate assembly provided for heat-exchanging and constituted integrally with the first channel plate assembly so as to remove effectively heat, the channel reactor system comprising at least two channel units into which reaction gas and cooling fluid are separately introduced, each channel unit comprising a reaction channel plate assembly into which reaction gas is introduced and a heat-exchanging channel plate assembly into which cooling fluid is introduced; and at least one intermediate plate disposed between the upper and lower channel units, the intermediate plate supplying reaction gas and cooling fluid inflowed from the upper channel unit with new reactant and cooling fluid and supplying reaction gas and cooling fluid to the reaction channel plate assembly and the heat-exchanging channel plate assembly of the lower channel unit, respectively.

Abstract: The present invention discloses to a chemical reactor with high heat efficiency and small volume, the chemical reaction of the present invention comprises a first unit for performing heat exchange of exothermic reaction products with exothermic reaction raw material fed for exothermic reaction; a second unit including a plate assembly for exothermic reactions and a plate assembly for endothermic reactions; and a third unit for performing heat exchange of endothermic reaction products with endothermic reaction raw material fed for endothermic reactions, the exothermic reaction raw material discharged from the first unit is fed into the plate assembly for exothermic reactions in the second unit and used in the exothermic reactions, the exothermic reaction products are fed into the first unit to pre-heat the exothermic reaction raw material, the endothermic reaction raw material discharged from the third unit is fed into the plate assembly for endothermic reactions in the second unit and used in the endothermic

Abstract: A stack type reactor that can adjust a length of channel (reaction time) to react raw substances with each other for a sufficient time and mix completely raw substances to maximize the reaction efficiency. The stack type reactor comprises an upper block with at least two inlets that introduce different kinds of raw substances and a lower channel fluidly connected to the inlets and formed at a lower surface thereof; a unit block including an upper channel corresponding to the lower channel of the upper block and formed on an upper surface thereof, the unit block including a lower channel formed at a lower surface thereof and fluidly connected with the upper channel via a connecting flow passage. The upper block and unit block form a flow path for the raw substances by connecting to the lower channel of the upper block to the upper channel of the unit block.