90 results about "Cerium hydroxide" patented technology

The present Invention relates to a method for preparing single crystalline cerium oxide nanopowder capable of easily controlling the shape and granularity of particles. The method includes preparing cerium hydroxide by precipitating a cerium salt in the presence of a solvent mixture of organic solvent and water and hydrothermally reacting the prepared cerium hydroxide. The prepared single crystalline cerium oxide has a particle size of not less than about 30 nm and an excellent degree of dispersion.

The invention discloses a preparation method for cerium oxide. The preparation method comprises the following steps: step 1, mixing a precipitating agent, a cerium source and an oxidizing agent, wherein the precipitating agent is added into a solution of the cerium source while stirring at first, then addition of the precipitating agent is stopped when the pH value of precipitate mixed liquor reaches 7.0 to 10.0, and then adding a solution of the oxidizing agent into the precipitate mixed liquor for precipitation so as to obtain cerium hydroxide; and step 2, subjecting cerium hydroxide to hydro-thermal synthesis reaction so as to prepare cerium oxide particles. The cerium oxide synthesized in the invention does not need other special treatment, has good dispersibility and polishing activity and can be used as an abrasive for STI polishing.

The invention relates to cerium dioxide nanosheets as well as a preparation method and application thereof. The preparation method comprises the following steps: (1) precipitating a cerous nitrate solution with an alkali solution so as to obtain a cerium hydroxide nanosheet precursor; (2) drying and roasting the cerium hydroxide nanosheet precursor obtained in the step (1), thereby obtaining cerium dioxide nanosheets, wherein the alkali solution of the step (1) comprises a sodium hydroxide solution and / or a potassium hydroxide solution, and the mole ratio of hydroxide ions in the alkali solution to cerous nitrate in the cerous nitrate solution is (8-27):1. The cerium dioxide nanosheets provided by the invention can be used as multiple nano metallic carriers and have very good application prospects in fields of energy, environment protection and catalysis. The cerium dioxide nanosheets has the advantages of being free of high-temperature high-pressure equipment for hydrothermal reactions and the like, free of organic modifier or organic solvent, good in environment protection, gentle in reaction condition, low in cost, and the like, and is beneficial to industrial amplified production.

The present invention relates to cerium oxide powder and a process for producing the same. The cerium oxide powder of the invention, which is produced by mixing a cerium source such as cerium oxide, cerium hydroxide and cerium carbonate with an alkali metal compound, as flux, and performing high temperature treatment, may have a variety particle size while having spherical shape.

The invention provides a preparation method of a cubic Nb-CeO2 material. The preparation method comprises the following steps: absorbing niobium oxalate by virtue of cerium hydroxide, directly roasting, dispersing sodium cerium hydroxide prepared in a hydrothermal method in a niobium oxalate solution, completely evaporating the solvent, roasting in a muffle furnace to obtain Nb-CeO2 composite oxide. The prepared material contains 1 to 10 percent of Nb2O5 and 90 to 99 percent of CeO2 and has cubic morphology. By adopting the method disclosed in the invention, the niobium oxide can more sufficiently form the composite oxide with cerium oxide, so that the modification effect for the cerium oxide can be improved, and the preparation method is further applied to various catalytic reactions.

The invention provides a method for efficiently removing fluorine ions in a manganese sulfate solution. The method is characterized in that a certain quantity of to-be-processed manganese sulfate solution is added into reaction equipment, the content of the fluorine ions in the solution is measured, solid cerium hydroxide with a certain fluorine ion content proportion is added under the conditionsthat the temperature is 30-50 DEG C and the pH value is 2-6, the material is stirred for 8-12 h at the rotational speed of 150-350 r / min, then stirring is stopped, the material is left to stand for 12-18 h and then transferred into filtering equipment for filtration, the filtrate is a fluorine-removed qualified manganese sulfate solution, filter cake is added into reverse osmosis water at a solid-liquid mass ratio of 1:(1-6), stirring and washing are performed for 0.5 h, and filtering is performed to obtain fluorine-containing cerium hydroxide which is then fed into a regeneration procedure.According to the method, lots of residual fluorine ions in a manganese sulfate solution system can be removed, the content of a fluoride in the processed solution can be reduced to 100 ppm or below, and the fluorine removal agent cerium hydroxide can be recycled after being regenerated, so that the production cost is greatly lowered.

The invention relates to a pearlescent pigment comprising a metal oxide-containing, platelet-shaped substrate and having a first and a second protective layer, wherein the metal oxide has a refractive index greater than 1.8, and in which the first protective layer comprises cerium oxide and / or hydrated cerium oxide and / or cerium hydroxide, the second protective layer consists substantially, preferably completely, of SiO2, wherein the second protective layer is disposed on top of the first protective layer, and between the first and second protective layers there can be disposed metal oxide layers which differ from cerium oxide and / or hydrated cerium oxide and / or cerium hydroxide and SiO2, wherein the second protective layer has an organochemical aftercoat and the organochemical aftercoat comprises at least one silane bonded to the second protective layer by means of at least one oxygen atom, said α-silane having the formula—O(4-n-m)—Si(—R1)m(—CH2—Y)n  (I),in which 1≦n+m≦3; m=0 to 2; n=1 to 3 andR1 is a hydrogen atom or an Si—C-bonded C1-C20-hydrocarbon radical or a C1-C15-hydrocarbonoxy radical, in which in each case one or more methylene units not adjacent to one another can be replaced by the groups —O—, —CO—, —COO—, —OCO—, or —OCOO—, —S—, or —NRx— and in which one or more methine units not adjacent to one another can be replaced by the groups —N═, —N═N—, or —P═, wherein R1 can independently be the same or different, Rx can be a hydrogen atom or a linear, branched and / or cyclic C1-C15-hydrocarbon radical or aryl radical, and Y is a functional binding group reactive with a binder system.

The present invention is one electrolytic process of reducing Yb, enriching Tu and Lu, and oxidizing Ce simultaneously. The electrolytic process reduces Yb into bivalent Yb ion in the cathode chamber so as to separate out Yb from the enriched Yb, Tu and Lu; oxidizes Ce into four-valent ion so as to separate out Ce. The electrolytic equipment has cathode of metal mercury or amalgam, anode of inert metal, anion exchange membrane to separate the anode chamber from the cathode chamber, cathode solution of sulfuric acid solution of pH 0.1-4.0 with enriched Yb, Tu and Lu, and anode solution of sulfuric acid solution of acidity 0.01-3.0 mol / L with enriched Ce. The present invention has low production cost, best utilization of electrolytic current and other advantages.