Showing papers on "Calcium oxide published in 1980"

Method for lime stabilization of wastewater treatment plant sludges

Abstract: A method for the lime stabilization of wastewater sludge, includes the steps of dewatering sludge so as to produce a sludge cake containing from about 10 to 60% by weight of dry solids and rapidly and intimately mixing and reacting the sludge cake with calcium oxide so as to produce stabilized sludge pellets. An apparatus for performing the process is also provided.

Process for the catalytic gasification of coal

Abstract: Carbonaceous solids are contacted in the presence of water with potassium sulfate and a calcium compound selected from the group consisting of calcium oxide, calcium hydroxide, and calcium carbonate thereby producing treated carbonaceous solids which are then gasified. The calcium compound apparently activates the relatively noncatalytic potassium sulfate thereby producing a substantial catalytic effect on the gasification reactions.

Studies on the Acid Resistance of E Glass

Abstract: The acid resistance of E glass was studied by treating the material in HC1. During the acid treatment, nonsiliceous ions were leached out from the glass structure, due to ion exchange. The parameters which govern the removal are the concentration of the acid, time of contact, and acid temperature. At lower acid concentrations (<2N), calcium oxide and aluminum oxide could not be removed completely. By increasing the concentration of the acid to 4N, most of the nonsiliceous ions were leached out. The number of ions removed increases with the increase in treatment time and temperature. When the glass was treated with 4N HCI for a long time, there was a fluctuation in the total number of ions removed. The teachability of E glass is explained using the Muggins formula and the R2O/SiO2 ratio.

Waterproof gypsum molded product

Abstract: The present invention provides a gypsum molded product having excellent waterproof properties without impaired strength by adding alkaline metal alkylsiliconates or phenylsiliconates together with calcium hydroxide or calcium oxide to gypsum; poly(α,β-unsaturated carboxylic acid) may be used in combination with the above, if desired. According to the present invention, the preparation of a gypsum molded product, particularly a gypsum from desulfurization of exhaust gas, is contemplated.

Fixed sulfur petroleum coke fuel and method for its production

Abstract: A fixed-sulfur, solid fuel product is obtained by an improved coking process wherein petroleum fractions are coked in the presence of added alkaline earth metal oxides. The fixed-sulfur, solid fuel product comprises coke and from about 3 to 30 weight percent, preferably from about 5 to 15 weight percent, "ash" (calculated as calcium oxide) derived from the alkaline earth additive. The quantity alkaline earth metal oxide or precursor thereof added to the coking zone is dependent on the sulfur content of the product coke and on the desired ash content of the solid fuel product. The coking zone may comprise delayed, fluid bed, or moving bed cokers.

Solid heat-generating composition

Abstract: A solid heat-generating composition utilizing the heat of hydration of calcium oxide, comprising calcium oxide and a solid substance supplying water capable of reacting with calcium oxide such as a solid substance having water of absorption, adsorption or crystallization, and an organic compound which yields water by an intramolecular or intermolecular reaction at elevated temperature. The composition can be utilized in various applications utilizing heat generation, for example for thawing and heating frozen foods, controlled releasing of agricultural chemicals such as insecticides or repellents, warming human body, etc.

Glass composition for water setting ion-polymer cements

Abstract: A glass composition for effecting crosslinking of a polycarboxylic acid cement and cement compositions formed therefrom. The glass is of the aluminoborate type and comprises 40 to 75 mole % boric oxide, not more than 60 mole % zinc oxide, not more than 50 mole % calcium oxide and not more than 20 mole % alumina. Cements formed from the glasses have a wide range of applications including structural cements, dental filler and orthopaedic cements.

Process for preparing hydroxyapatite, and filter cake, ceramic material and implant material comprising hydroxyapatite

Abstract: Hydroxyapatite is an inorganic component of skeletal tissues, such as bones and teeth. It is known to synthesise hydroxyapatite for use as implant materials, such as artificial bones, by the reaction of calcium hydroxide with phosphoric acid. Known synthetic hydroxyapatite is, however, not sufficiently like the naturally occurring material to be entirely satisfactory for use in providing implant materials. The invention provides a process for synthesising hydroxyapatite which comprises thermally decomposing calcium carbonate, cooling the resultant calcium oxide, slaking the cooled calcium oxide, and reacting the resulting calcium hydroxide with phosphoric acid. A filter cake of the synthetic hydroxyapatite thus produced is porous and contains crystals which can readily be sintered to provide a thermally stable ceramic material which is colorless or semi-transparent and useful in providing implant materials compatible with a living body.

Methods of improving the viscosity building properties of colloidal clays

Abstract: Unslaked lime, calcium oxide (CaO) or calcium magnesium oxide, CaO.MgO is post added to a ground, colloidal clay product to obtain a resultant product which exhibits greater stability and yield factors than currently available products. The resultant product exhibits a more uniform viscosity-imparting characteristic to a solution to which it is added, while providing greater stability and hence, longer shelf life.

Confinement of Ruthenium Oxides Volatilized during Nuclear Fuels Reprocessing

Abstract: While many materials have been suggested and employed as trapping agents for gaseous oxides of fission product ruthenium volatilized during nuclear fuels reprocessing, none that is known to form thermodynamically stable compounds with rutheniunm has been utilized. We have employed alkaline earth metal compounds for this purpose because of their ability to form stable mixed metal oxide phases with ruthenium. Results of experiments in which RuO/sub 4/ was volatilized from either a solid source (RuO/sub 2/.xH/sub 2/O) or from solution (Ru(NO)(NO/sub 3/)/sub 3/) in HNO/sub 3/ and passed through beds of alkaline earth metal carbonates and calcium oxide held at 600 to 750/sup 0/C have demonstrated that compounds of formulation MRuO/sub 3/ (M = calcium, strontium, barium) are formed. Under oxidizing conditions, these materials exist as stable ceramic phases, whereas under reducing conditions, they are transformed into intimate mixtures of the alkaline earth metal oxide and nonvolatile ruthenium metal.

Sodium resistant sealing glasses

Abstract: Sodium resistant sealing glasses having borosilicate glass compositions in which glass stability is improved by the incorporation of several percent sodium oxide with a select percentage of the alkali earth oxides of calcium oxide, strontium oxide and barium oxide. The sodium oxide is present in the sealing glass compositions in a total weight percent range from 2 to 6 weight percent. Each of the alkali earth oxides is present in the glass compositions in the range from 2 to 8 weight percent with the total of the three oxides not exceeding 16 weight percent.

Durability of Carbonate Rocks as Function of Their Thermal Expansion, Water Sorption, and Mineralogy

Abstract: A suite of 27 rock specimens from active quarries in Southwestern Ontario was collected, and represents the Paleozoic carbonates used as concrete aggregates. Cores and crushed, sized aggregate were obtained from the specimens and subjected to the following tests: water adsorption at 45 and 92 percent humidity at 30°C; thermal expansion coefficient determination in dry and in saturated states; chemical analyses for major oxide content; and soundness tests by modified freeze-thaw methods. Statistical analysis of the results give a direct, positive correlation matrix of greater than 95 percent confidence level for the following: adsorption at 45 percent and 92 percent relative humidity; alumina + silica (Al 2 O 3 + SiO 2 ) content-expansion coefficient in saturated state; and freeze-thaw loss. Negative significant correlation was obtained between the calcium oxide (CaO) and magnesium oxide (MgO) content and the wet and dry expansion coefficients. No correlation was observed between dry expansion coefficients and freeze-thaw loss. Dry rocks were found to have significantly but nonuniformly higher expansion coefficients than saturated rocks. However, the latter are more indicative of rocks' durability. A model for rock deterioration is presented, based on expansion and contraction during wetting-drying and warming-cooling cycles.

Active anti-corrosion pigments based on calcium oxide, aluminium oxide and iron oxide

Abstract: An anti-corrosion pigment comprising about 30.0 to 2.0 mole % of CaO and about 70.0 to 98.0 mole % of Me2 O3, wherein Me2 O3 is (1-x) Al2 O3 and x Fe2 O3, x is from 0 to 1 and up to about 25 mole % of the Fe2 O3 may be replaced by the corresponding quantity of Mn2 O3, and having a specific surface area according to BET of about 0.1 to 200 m2 /g and a percentage weight loss per gram of pigment, as determined by the Thompson corrosion test, of less than about 0.05% per gram of pigment is produced by calcining the corresponding metal oxides or materials which form the metal oxides on calcination at about 200° to 1100° C. The pigments are especially useful in making up anti-corrosion paints and lacquers.

Production of magnesium oxide

Abstract: PURPOSE: An inert magnesium oxide calcined at temperature higher than 1,400°C is hydrated in the presence of a certain amount of an acid and the resultant magnesium hydroxide is calcined to produce a magnesium oxide with uniform particle size and high activity. CONSTITUTION: Magnesium oxide calcined at temperature higher than 1,400°C, preferably by higher than 96% MgO purity and less than 250mμ particle size is combined with water to form a slurry of about 200W300g/l concentration. Then, an acid is added in such an amount as corresponding to more than 0.5% equivalent of the magnesium oxide as a starting material, and to the equivalent number of calcium oxide in the starting material or its magnesium salt is added to effect hydration of magnesium oxide. Obtd. magnesium hydroxide is calcined. COPYRIGHT: (C)1982,JPO&Japio

New Accelerated Methods for Predicting Durability of Cementitious Materials

Abstract: Miniature specimens of different configurations have been used to study the durability of cementitious materials. The tests involved monitoring the dimensional change or mechanical property in the following studies under specified rigorous conditions: (a) unsoundness of lime, (b) failure of white coat plasters, (c) unsoundness of cement containing magnesium oxide (MgO) and calcium oxide (CaO), (d) durability of cement mortars exposed to chloride solutions, (e) resistance of sulfur-impregnated cement systems to high humidities, and (f) drying shrinkage of cements with and without admixtures. The results indicate that the tests are not only applicable for the prediction of durability of materials but that they also may be used to study the mechanisms of material deterioration. (TRRL)

Process for detoxifying coal tars

Abstract: A process for treating liquid hydrocarbons to remove toxic, mutagenic and/or carcinogenic aromatic hydrocarbons comprises feeding the hydrocarbons into a reactor where vapors are thermally treated in contact with a catalyst consisting essentially of calcium oxide or a calcium oxide containing mineral. Thermally treating liquid hydrocarbons in contact with calcium oxide preferentially increases the cracking of aromatics thus producing a product having a reduced amount of aromatic compounds.

Oxide magnetic material

Abstract: PURPOSE:To obtain a high density and highly wear-resistant oxide magnetic material by adding the specified quantity of zirconium oxide and calcium oxide as auxiliary constituents to an oxide magnetic material constituting of ferric oxide, manganese oxide, and zinc oxide in a specified composition as principal constituents and sintering and pressing the material by the specified method. CONSTITUTION:At the same time, 0.01-0.4 wt.% of zirconium oxide and 0.005-0.2 wt.% of calcium oxide are added to an oxide magnetic material consisting of 50-56 mol.% of ferric oxide, 20-40 mol.% of manganese oxide, and 6-27 mol.% of zinc oxide. The material is sintered at 1,100-1,350 deg.C in a nitrogenous atmosphere containing a very small amount of oxygen and shaped by hot hydrostatic pressing at 1,000-1,300 deg.C and 600-1,600kg/cm in an argon gas atmosphere. A composition of over 56 mol.% of ferric oxide, under 2 mol.% of manganese oxide, or under 6 mol.% of zinc oxide has a characteristic not suitable for practical use because its effective initial relative magnetic permeability is not higher than 1,500 when zirconium oxide and calcium oxide are added. A composition of under 50 mol.% of ferric oxide, over 40 mol.% of manganese oxide, or over 27 mol.% of zinc oxide has a characteristic not suitable for practical use because its magnetic transformation temperature is not higher than 100 deg.C.

Pressureesensible recording material

Abstract: PURPOSE:To obtain a pressure-sensible recording paper of good preserving and stabilizing capability by providing it with a high density in such a manner as to add metallic oxide and alcoholic hydroxyl compound to a coloring agent layer with fragrant carbonic acid as the coloring agent. CONSTITUTION:To obtain a pressure-sensible material, for a pressure-sensible paper, by providing a coloring agent layer, with fragrant carbonic acid (such as benzonic acid, anise acid and chlorine benzonic acid, etc.) as a coloring agent, with preferably 50-500wt% of metallic oxide (such as calcium oxide, barium oxide and zinc oxide, etc.) and preferably 50-150wt% of alcoholic hydroxyl compound (such as 2-hydroxybenzyl alcohol and, m-trildiethanolamine).

Lime addition to heavy crude oils prior to coking

Abstract: The sulphur emissive capability, on combustion, of coke which is formed during upgrading of sulphur-containing heavy crude oils, including oil sands bitumen, or residua is decreased by the addition of slaked lime or calcium oxide to the heavy crude oil prior to coking. The presence of the slaked lime or calcium oxide leads to an increased yield of liquid distillates at coking temperatures of about 450° to about 500° C. Ash remaining after combustion of the coke may be leached to recover nickel and vanadium values therefrom.

Method of aquifer restoration

Abstract: A method is disclosed for restoring a clay rich aquifer which has been solution mined with ammonium ions. Calcium carbonate is precipitated from a solution pumped through the aquifer by the addition of calcium oxide, calcium hydroxide, or a mixture thereof in quantities sufficient to raise the pH to at least about 9.5. The precipitated calcium carbonate is separated from the solution and the ammonium ion is then removed from the solution by standard techniques. The solution is recycled through the aquifer and these steps are repeated until the bicarbonate ion concentration has been reduced to such an extent that the addition of at least one soluble salt of calcium, magnesium, or potassium to the solution does not result in precipitation of calcite underground, plugging the aquifer. Recycling with the addition of the soluble salt is continued until the ammonium ion concentration is reduced to a desired level. Finally, residual amounts of the salt are removed from the aquifer using standard techniques.

Removal of titanium dioxide from a filter element

Abstract: Titanium dioxide is removed from contaminated workpieces by immersing them in an alkaline solution containing calcium ions at approximately 30° C. The cleaning solution is made from a concentrated aqueous alkaline hydroxide solution and a calcium salt or from a basic calcium salt, e.g., calcium oxide.

Desulfurizer for molten iron

Abstract: PURPOSE:To accelerate the reactivity of carbide and achieve the improvement in desulfurization efficiency by adding the specific metal fluorides in the desulfurizer for molten iron composed primarily of calcium carbide. CONSTITUTION:Metal fluorides such as MgF2, LiF, NaF, KF, Na2SiF6, etc. are added to the desulfurizer base material containing calcium carbide (purity 60% or over, grain sizes normally 1mm or under) or calcium carbide and calcium oxide, calcium carbonate and carbon material or other, whereby the desulfurizer for molten iron is obtained. The amount of addition of the metal fluorides is 0.1-10%, preferably 0.3-1%. In the case of compounding calcium oxide, calcium carbonate, etc. to the carbide, they are compounded at 80-20% based on 20-80% of the carbide.

Effect of iron oxide on the phase composition of zirconia refractories

Abstract: It has been established that in the compositions ZrO2∶Y2O3∶Fe2O3 and ZrO2∶Nd2O3∶Fe2O3 the processes of formation of rare earth ferrites and ZrO2 cubic solid solutions occur simultaneously. At temperatures of up to 1300°C the ferrite-formation process is fastest; with a further increase in the temperature the synthesis of ZrO2 cubic solid solutions is significantly intensified. In the mixture of CaO, ZrO2, and Fe2O3, the calcium oxide reacts only with ZrO2. The greatest stability in relation to the action of Fe2O3 is clearly found in the case of the zirconia-calcium oxide solid solutions. In the mixtures of cubic solid solutions of Nd2Zr2O7-ZrO2 or ZrO2-Y2O3 and Fe2O3, an interaction is only possible in the case where the synthesis of ferrites is not accompanied by the restructuring of the crystal lattice of ZrO2, i. e., by destabilization of the material. The presence of Fe2O3 prevents the decomposition of zirconia-calcium oxide and zirconia-neodymium oxide solid solutions under conditions of prolonged heating in air at 1300°C. The zirconia-yttria cubic solid solution is the most stable and does not decompose, regardless of the concentration of Fe2O3, after a dwell of 250 h at 1300°C.

Production of agent for desulfurizing crude iron and steel melts

Abstract: The invention relates to the production of an agent for desulfurizing crude iron and steel melts, the desulfurizing agent being based on calcium carbide containing calcium oxide. To this end, a calcium carbide/calcium oxide/starting melt mixture with a CaO-content within the range 20 to 80 weight % is produced from lime and coke and allowed to solidify to a block. While the solidified block still has an average temperature of more than 400° C., it is crushed to particulate material with a size of less than 150 mm. Next, the hot crushed material of at least 400° C. is admixed with a quantity of calcium oxide necessary to have in the resulting mixture an overall content of CaO corresponding to that desired for the final product. The whole is thoroughly mixed and crushed with exclusion of moisture at temperatures higher than 100° C. to particulate material with a size of less than 10 millimeters.

Manufacturing method for highhalkali type lubricating oil composition

Abstract: PURPOSE:To obtain a lubricating oil composition having good clean dispersiveness, high heat resistance, and high total basicity by making higher the basicity of acid anhydride calcium salt and calcium naphthenate with calcium carbonate. CONSTITUTION:Calcium hydroxide and calcium oxide are suspended in an alcohol, and alcohol-inorganic compound complex obtained by the action of carbon dioxide on the suspension is then reacted with an acid anhydride. The mixture is then heated at 200-300 deg.C in an organic solvent containing a mineral oil and naphthenic acid or calcium naphthenate, or the mixture containing acid anhydride, calcium hydroxide, calcium oxide, organic solvent, alcohol, mineral oil, and naphthenic acid or calcium naphthenate is heated at 200-300 deg.C while being treated under the action of carbon dioxide. Thus, the basicity of acid anhydride calcium salt and calcium naphthenate can be made higher by calcium carbonate.

Solid heat-generating compositions comprising calcium oxide, method of generating heat using such compositions, and use of such compositions in the generation of heat

Abstract: A solid heat-generating composition utilizes the heat of hydration of calcium oxide, and comprises calcium oxide and a solid substance supplying water capable of reacting with calcium oxide. The use of a solid substance makes possible greater control over the rate and extent of the heat-generating hydration reaction than the use of liquid water. The solid substance can be one having water of absorption, adsorption or crystallization, or an organic compound which yields water by an intramolecular or intermolecular reaction at an elevated temperature. The composition can be utilized in various applications requiring heat generation, for example for thawing and heating frozen foods, controlled releasing of agricultural chemicals such as insecticides or repellents, and warming the human body.

Studies on the acid resistance of e glass

Abstract: The acid resistance of E glass was studied by treating the material in HC1. During the acid treatment, nonsiliceous ions were leached out from the glass structure, due to ion exchange. The parameters which govern the removal are the concentration of the acid, time of contact, and acid temperature. At lower acid concentrations (<2N), calcium oxide and aluminum oxide could not be removed completely. By increasing the concentration of the acid to 4N, most of the nonsiliceous ions were leached out. The number of ions removed increases with the increase in treatment time and temperature. When the glass was treated with 4N HCI for a long time, there was a fluctuation in the total number of ions removed. The teachability of E glass is explained using the Muggins formula and the R2O/SiO2 ratio.

Preparation of calcium base alloy

Abstract: PURPOSE:To obtain the calcium base alloy, suitable for removing non-alloy metal contained in molten steel, molten ferro alloy etc., by reducing calcium oxide with fused aluminum and obtaining calcium as alloy of calcium and aluminum. CONSTITUTION:Calcium oxide is reduced by fused Al and Ca-Al base alloy is obtained, no occasion demands, under the existence of specific gravity regulating agent composed of metals or alloys of Fe, Cr, Mn, etc. Quantity of fused aluminum is made 0.5-30 times of chemical theoretical quantity to satisfy the mentioned formula and more than 5% of Ca content in the product is preferably. Reaction temperature is 1350-1800 deg.C, preferably 1450-1650 deg.C and pressurized inactive atmosphere is preferable.