Showing papers on "Calcium oxide published in 1986"

Cementuous fiber impregnated construction composition and process for formation thereof

Abstract: A construction composition comprising an alkalin earth oxide, such as calcium oxide, a siliceous material having a high surface area to volume ratio such as diatomite, cement, fiber and other additive constituents is disclosed. The material may be formed in place or preferably pressure molded to predetermined structural shapes. A method of making the composition is disclosed wherein a dry concentrate of the alkaline earth oxide, siliceous matter, and additives is formed by ball milling; a slurry embodying additional alkaline earth oxide, siliceous material and fiber is formed with heating; and a final composition is formed by mixing the first two mixtures with additional necessary materials, including fiber, cement and siliceous material, to a paste consistency. The paste is preferably molded under pressure and thereafter cured by heating to form structural shapes. The final composition can replace many conventional building materials, may be shaped and fastened after formation similarly to wood, is thermally and acoustically insulative and fire, rot and vermin resistant.

Low temperature pyrolysis of coal or oil shale in the presence of calcium compounds

Abstract: A coal pyrolysis technique or process is described in which particulate coal is pyrolyzed in the presence of about 5 to 21 wt. % of a calcium compound selected from calcium oxide, calcined (hydrate) dolomite, or calcined calcium hydrate to produce a high quality hydrocarbon liquid and a combustible product gas which are characterized by low sulfur content. The pyrolysis is achieved by heating the coal-calcium compound mixture at a relatively slow rate at a temperature of about 450° to 700° C. over a duration of about 10 to 60 minutes in a fixed or moving bed reactor. The gas exhibits an increased yield in hydrogen and C 1 -C 8 hydrocarbons and a reduction in H 2 S over gas obtainable by pyrolyzing cola without the calcium compound. The liquid product obtained is of a sufficient quality to permit its use directly as a fuel and has a reduced sulfur and oxygen content which inhibits polymerization during storage.

Dental cement composition

Abstract: A dental cement composition consisting of a composition A and a composition B, said composition A comprising at least two powders, (a) 100 parts by weight of a powder containing more than 20 % by weight to 70 % by weight of calcium oxide and 30 % by weight to less than 80 % by weight of aluminium oxide and treated on the surface with 0.01 to 5 % by weight of at least one selected from the group consist-ing organic acids and/or inorganic acids, and (b) 2 to 70 parts by weight of a calcium hydroxide powder, and said composition B comprising of an aqueous solution containing 0.01 to 70 % by weight of a water-soluble high-molecular substance.

Dental aluminate cement compositions

Abstract: A dental cement composition consisting of a composition A and a composition B, said composition A comprising (a) 100 parts by weight of a powder containing 20 to 70% by weight of calcium oxide and 30 to less than 80% by weight of aluminum oxide, said powder being coated on the surface with a water-soluble high-molecular substance, and (b) 2 to 70 parts by weight of a calcium hydroxide powder, and said composition B comprising an aqueous solution containing 001 to 70% by weight of a water-soluble high-molecular substance

Low temperature sintered ceramic capacitor with a temperature compensating capability, and method of manufacture

Abstract: A temperature compensating capacitor of monolithic or multilayered configuration comprising a dielectric ceramic body and at least two electrodes buried therein. The ceramic body is composed of a major ingredient expressed by the formula, {(Sr1-xCax)O}k (Ti1-yZry)O2, where x, k and y are numerals in the ranges of 0.005 to 0.995 inclusive, 1.00 to 1.04 inclusive, and 0.005 to 0.100 inclusive, respectively. To this major ingredient is added a minor proportion of a mixture of lithium oxide, silicon dioxide, and one or more metal oxides selected from among barium oxide, magnesium oxide, zinc oxide, strontium oxide and calcium oxide. For the fabrication of capacitors the mixture of the above major ingredient and additives in finely divided form are formed into moldings of desired shape and size, each with at least two electrodes buried therein. The moldings and electrodes are cosintered in a reductive or neutral atmosphere and then are reheated at a lower temperature in an oxidative atmosphere. The cosintering temperature can be so low that nickel or like base metal can be employed as the electrode material.

Infrared studies of probe molecules adsorbed on calcium oxide

Abstract: Infrared spectra are reported of pyridine, carbon dioxide, methanoic acid, ethanoic acid and carbon monoxide on calcium oxide which had been preheated in vacuum at 1073 K. The oxide surface contains incompletely coordinated weakly Lewis-acidic calcium cation sites and exposed oxide ions with basic character. Pyridine interacts with Lewis-acidic sites whereas carboxylic acids donate protons to oxide ions with the formation of hydroxy groups and adsorbed carboxylate anions. Carbon monoxide undergoes a complex series of reactions involving oxide ions and the availability of vacant ligand sites. The adsorption of carboxylic acids and carbon monoxide is believed to primarily occur on exposed {111} crystal faces or at step and edge sites at which the array of calcium and oxide ions replicates in miniature a (111) face. The chemisorption of hydrogen on calcium oxide is implied by the poisoning effect of hydrogen on carbon dioxide and carbon monoxide adsorption. Oxygen promotes the formation of surface carbonate complexes from adsorbed carbon monoxide.

Evaluation of the Potential for Expansion and Cracking of Concrete Caused by the Alkali-Carbonate Reaction

Abstract: Alkali-carbonate reactive rock was inadvertently used in the Cornwall and Ottawa areas of Ontario between 1978 and 1982. The excessive expansion and cracking caused by this reaction resulted in the need to replace concrete within three years of construction. This reaction of dolomitic limestone with the alkalies from cement is well known in the Midland-Kingston areas of Ontario. It had not been expected in the Cornwall and Ottawa areas. In an effort to prevent further occurrences of this reaction, 17 quarries in the Gulf River Formation were studied. Aggregate durability tests, chemical analysis, and concrete prism expansion tests were conducted on 26 bulk aggregate samples. Concrete prism expansion tests were conducted at alkali contents of 1.25 and 3.0% sodium oxide (Na2O) equivalent. Results showed that the current Canadian Standards Association specifications are inadequate for recognizing some alkali-carbonate reactive aggregates. This was due to the occurrence of delayed expansive aggregate. It is recommended that the concrete prism expansion test be conducted using cement with an alkali content of 1.25% Na2O. Those aggregates that exceed 0.025% expansion at one year should not be used in highway structures exposed to deicing salt. A rapid chemical screening test is proposed. The determination of the calcium oxide to magnesium oxide (CaO:MgO) ratio and alumina content or insoluble residue can be used to screen potentially alkali-carbonate expansive rocks from those that are nonexpansive.

Process for treating waste water containing phosphorus compounds and/or organic cod substances

Abstract: The specification discloses a novel calcium silicate water-treating agent exhibiting a superior ability to remove various kinds of phosphorus compounds or other environmental pollutants contained in wastewater, the calcium silicate water treating agent comprising a burned product which is prepared by burning a mixture containing as main constituents calcium compound, thermally decomposable to calcium oxide (CaO), and SiO2 -containing compound at a temperature of 1300° to 1600° C., the molar ratio of CaO/SiO2 of the resultant burned product being in the range of 1.5 to 5.0, preferably 2.0 to 4.0. In this water treating agent, SiO2 component may be partially replaced by Al2 O3 and/or Fe2 O3. A further water treating agent is prepared by heating the hydrate of the burned product prepared above at a temperature of 50° to 700° C. By using the thus obtained water treating agents, water treatment can be carried out with a high efficiency, thereby the treatment time, labor and cost can be considerably saved.

Solvent-free coating composition and process for protecting a surface from corrosion

Abstract: A solvent-free coating composition useful for increasing the corrosion resistance of a surface is provided. The composition comprises a solvent-free coating material and an anti-corrosive agent comprised of a calcined mixture consisting essentially of magnesium oxide and zinc oxide with or without calcium oxide. The composition may also include a defined compound which can improve the corrosion resistance and fillers.

A process for causticizing of an aqueous solution containing alkali carbonate

Abstract: Process for causticizing a water solution containing alkali carbonate with calcium oxide and hydroxide by bringing the water solution containing alkali carbonate into contact with the calcium oxide or hydroxide and by separating the alkali hydroxide solution arisen in the causticizing from the calcium carbonate precipitate. The water solution containing alkali carbonate is conducted through a bed which has been formed by mixing calcium oxide and calcium carbonate in the causticized alkali solution and by removing the excess alkali solution.

Magnesium phosphinates and calcium phosphinates and basic refractory raw materials bound therewith

Abstract: Magnesium and calcium salts of phosphinic acids of the general formula in which R and R denote different or identical functional groups, and their preparation are described. These phosphinates are outstandingly suitable as binders in basic refractory raw materials such as magnesium oxide, calcium oxide, dolomite, olivine, forsterite and mixtures thereof.

The preparation of polysiloxanes from halosilanes

Abstract: @ This invention relates to a process for the preparation of polysiloxanes by reacting halosilanes in the presence of metal oxides and sulfolane. Preferred metal oxides include antimony (III) oxide, antimony (V) oxide, cadmium oxide, calcium oxide, copper (II) oxide, indium oxide, iron (II) oxide, iron (III) oxide, magnesium oxide, manganese (II) oxide, mercury (II) oxide, nickel (II) oxide, thallium (III) oxide, tin (II) oxide, and zinc oxide. Improved yields and rates of reaction can be observed with the process of this invention.

Catalyst for steam reforming of hydrocarbon

Abstract: PURPOSE:To perform the steam reforming of hydrocarbons with high efficiency, by using a catalyst which is prepared by baking a mixture consisting of a calcium compound an an aluminum compound while supporting ruthenium by the baked mixture in a specific ratio. CONSTITUTION:A mixture consisting of a calcium compound and an aluminum compoun is baked to obtain a solid baked substance comprising calcium/alumina spinnel or consisting of said spinnel and calcium oxide and/or alumina and containing 10-50wt% of calcium oxide and 0.02-10wt% of ruthenium is supported by said baked substance. Thus obtained catalyst is a reforming one prevented from the deposition of carbon or sintering within a wide temp. range of 300-900 deg.C under a condition of low steam/carbon ratio and having high activity and durability.

Method of producing an iron; cobalt and nickel base alloy having low contents of sulphur, oxygen and nitrogen

Abstract: A method of producing an alloy containing at least one major ingredient selected from the group consisting of iron (Fe), cobalt (Co), and Nickel (Ni) and having low contents of sulphur, oxygen, and nitrogen, comprises steps of: (a) holding a molten alloy in a container selected from the group consisting of a lime crucible, a lime crucible furnace, a converter and a ladle lined with a basic refractory consisting of 15-85% of calcium oxide (CaO), and 15-75% of magnesium oxide (MgO), wherein said alloy consists essentially of at least one major ingredient selected from the group consisting of iron (Fe), nickel (Ni), and cobalt (Co); (b) adding at least one additive, based on the molten alloy, into said molten alloy in an atmosphere selected from the group consisting of a non-oxidizing atmosphere and a vacuum, wherein said additive is selected from the group consisting of aluminum (Al), aluminum alloys, silicon and silicon alloys; (c) desulphurizing, deoxidizing and denitrifying said molten alloy under an atmosphere selected from the group consisting of a non-oxidizing atmosphere and a vacuum, whereby the molten alloy contains 0.005 to 7.0% of residual aluminum, 0.0001 to 0.02% of residual calcium, and 0.0005 to 0.03% of residual magnesium; and (d) casting said molten alloy into a mold.

Preparation of absorbent for desulfurization and denitration

Abstract: PURPOSE:To obtain a desulfurization and denitration absorbent having high capacity, by using calcium oxide, calcium sulfate, silicon dioxide and aluminum oxide as main stock materials and applying moistened air aging and steam aging thereto CONSTITUTION:Dilute sulfuric acid is added to coarse particulate coal ash to be sufficiently reacted therewith and, after slaked lime is compounded with the reaction mixture according to a table, steam aging is performed at 100 degC or less under atmospheric pressure to obtain a cured substance calcium sulfate may be used in place of sulfuric acid, and coal ask and Portland cement may be compounded Coal ash contains a large amount of silicon dioxide and alumi num oxide (eg, SiO2 60%, Al2O3 23%) In place of coat ash, a pure substance may be compounded Thus obtained cured substance is crushed and screened to obtain an absorbent This absorbent can simultaneously perform desul furization and denitration and can keep a high desulfurization rate and a high denitration rate

Snow-melting agent

Abstract: PURPOSE:To obtain a snow-melting agent free from secondary pollution due to calcium chloride, with high spreading efficiency, especially suitable for orchard, gold course, etc., by grinding ash discharged from coal combustion unit or coal gasifier into size below a specific level followed by sieving treatment. CONSTITUTION:The objective snow-melting agent can be obtained by grinding dried granular and/or bulk product(s) from the ash discharged from coal combustion unit or coal gasifier into size <=2.5mm followed by sieving treatment. Preferably, the content of granules with a size <=88mum is <=10wt% in the above processes. This agent is incorporated with such ingredient(s) as ammonium sulfate, ammonium phosphate, urea, calcium carbonate powder or calcium oxide powder to apply to crops, orchard, roadside trees, etc.

Process for preparing magnesium oxide and/or its hydration products

Abstract: A process for preparing magnesium oxide and/or its hydration products from predominantly magnesium- and/or magnesium/calcium-containing raw materials, in general with simultaneous preparation of calcium carbonate in a purity of over 99% by weight of CaCO3 is proposed. The starting material, optionally present as carbonate, is thermally decomposed. Calcium oxide and/or its hydration products are selectively extracted at a temperature of from 0 to 100 DEG C with a solution which contains at least one organic, optionally nitrogen-containing, base and at least one salt of these bases with an organic and/or inorganic acid in a total amount which corresponds to the desired degree of extraction of the calcium-containing component from the, optionally roasted, starting material. The residual magnesium oxide and/or its hydration products, optionally with impurities, are separated off from the solution and the calcium carbonate is precipitated at a pH of from 7 to 12 with carbon dioxide and/or ammonium carbonate.

Manganese-zinc system ferrite material and magnetic core for high frequency power supply transformer

Abstract: PURPOSE:To obtain high permeability and low loss characteristic by forming a manganese-zinc system ferrite material through inclusion of calcium oxide, silicon oxide, niobium oxide, bismuth oxide and/or indium oxide and potassium oxide. CONSTITUTION:A manganese-zinc system ferrite material is formed through inclusion of calcium oxide, silicon oxide, niobium oxide, bismuth oxide and/or indium oxide and potassium oxide. Calcium oxide is 0.03-0.2wt% in terms of CaCO3, silicon oxide is 0.001-0.05wt% in terms of SiO2, niobium oxide is 0.001- 0.1wt% in terms of Nb2O5, bismuth oxide and/or indium oxide is 0.001-0.1wt% in terms of Bi2O3 and/or In2O3 and potassium oxide is 0.3wt% or less in terms of K2CO3.

Heat store system

Abstract: A method of storing and releasing heat energy uses a reversible chemical reaction in which heating causes dissociation of a chemical compound, the components formed by dissociation being exothermically reactable. An example is calcium hydroxide, which dissociates to calcium oxide and water (in the form of steam) when heated to about 580 DEG C. Apparatus is provided for carrying out the reaction, the apparatus comprising a chamber (22) in which the compound is heated, and separating means (27, 28, 29 and 31) for removing one of the components formed by dissociation (water). On reintroducing the water to the chamber, heat is evolved, which is recovered by a heat exchanger.

Use of cement kiln dust and red mud to produce hydraulic cement

Abstract: A high iron content cement is formed principally from two industrial by-products which are available in very large quantities, (1) cement kiln dust, or CKD, and (2) the Red Mud which is a by-product of the extraction of alumina from bauxite ore. Smaller quantities of lime (calcium oxide) and gypsum (calcium sulfate) and aluminum oxide as needed, are added to the CKD and Red Mud, and the mixture is heated to between about 1250 degrees C. and 1400 degrees C., substantially lower than the kiln temperature for Portland cement. The resultant clinker is pulverized to form a lightweight, fast setting, strong, hydraulic cement.

Chemically heating medium

Abstract: PURPOSE:To provide a chemically heating medium capable of giving sequential exothermic reaction by adding water, for use in domestic water heater, comprising alkaline earth metal element compound, metallic aluminum powder and alkali metal element compound. CONSTITUTION:The objective chemically heating medium comprising (A) an alkaline earth metal element compound [pref., a blend calcined matter from =70wt% of calcium oxide or calcium hydroxide], (B) metallic aluminum powder with a size pref. 30-100 mesh, and (C) (i) an alkali metal element compound [pref. sodium or potassium bromate or chlorate powder or particulates, or its anhydrous salt] or (ii) another metal element compound (pref., ferric chloride powder or its anhydrous salt particulates).

Volume-reducing solidification treatment process for radioactive waste water containing boron

Abstract: After evaporating and concentrating the radio-active waste water, caustic soda and a soluble calcium compound such as calcium hydroxide or calcium oxide are added to precipitate insoluble calcium borate, the precipitate is aged, liquid and solid portions are separated, the precipitate is mixed with cement and solidified, and the liquid portion, after evaporation and concentration, is recycled to the step in which insoluble calcium borate is precipitated.

Formation and Crystallization of Yttrium Aluminosilicate Glasses Containing Calcium Oxide

Abstract: Formation of yttrium aluminosilicate glasses containing calcium oxide from batches melted at 1550°C was investigated. Densities and thermal expansion coeflcients were measured for some glasses. In a specific compositional region, crystals with a needlelike habit were observed in the glass matrix. A crystal in the form of a tubular hexagonal prism was identified as Ca4Y60(Si04)6.

Drug-release controlling agent composed of phosphate glass

Abstract: PURPOSE:To obtain a phosphate glass useful as a drum release-controlling agent, easily and economically, by using phosphorus pentoxide or polyphosphoric acid as a main component, adding calcium oxide thereto and vitrifying the composition. CONSTITUTION:A phosphate glass having high chemical stability and capable of arbitrarily selecting the rate of release of a drug can be produced by adding a proper amount of calcium oxide in the production of a glass composed mainly of phosphorus pentoxide or a polyphosphoric acid having a molecular weight of about 1,000-2,000. The above phosphate glass can be produced easily by pulverizing and mixing the components, putting the mixture in a crucible, heating and melting the mixture in an electric furnace at about 300-1,000 deg.C and quenching the molten mixture in cold water. The rate of drug release can be adjusted by changing the amount of the calcium oxide added to the glass. In the case of using the above glass as a drug release controlling agent, a necessary amount of the drug is added to the mixture in the vitrification process.