Showing papers on "Calcium oxide published in 1977"

Method of preparing a solid animal feed supplement

Abstract: There is disclosed a method for the manufacture of a solid animal feed supplement employing an in-situ reaction between a hydratable metal oxide such as calcium oxide and a water soluble phosphate, such as phosphoric acid to solidify the product. The method comprises the addition of the metal oxide to a concentrated dispersion of a water soluble sugar such as molasses, whey and the like, to hydrate the metal oxide. After sufficient hydration has occurred to provide the desired quantity of reactant metal ions in soluble form, a condition which can be detected by monitoring the pH, temperature, or time following addition of the metal oxide, the soluble phosphate is added to cause solidification of the resultant mixture.

Catalyst and its method of preparation

Abstract: A catalyst comprising 10 to 30 wt.% of nickel as nickel oxide, 20 to 60 wt.% of calcium as calcium oxide, 10 to 70 wt.% of aluminum as aluminum oxide and containing less than 1 wt.% of silicon dioxide. The catalyst is prepared by using: as the starting material for the nickel component, fine particles of nickel oxide obtained by heating a nickel compound which is decomposed to nickel oxide by heating at a temperature in the range of 400° to 800° C in the presence of oxygen; as the starting material for the calcium component, calcium oxide per se or a calcium compound which is decomposed to calcium oxide by heating and; as the starting material for the aluminum component, alumina cement of a high purity. The catalyst is prepared by mixing and kneading the starting materials with water, molding the same, then keeping the catalyst composition under a highly humid atmosphere at a temperature in the range of 5° to 35° C for longer than one day for hydrating and hardening the cement and thereafter sintering the same at a temperature in the range of 550° to 1200° C.

High thermal emittance coating for X-ray targets

Abstract: A high thermal emittance coating for an X-ray tube anode target comprises a high melting point oxide or a mixture of such oxides added to titanium dioxide and another oxide selected from the group consisting of calcium oxide and yttrium oxide.

Recovery of calcium fluoride from phosphate operation waste water

Abstract: Calcium fluoride is produced from pond waters resulting from phosphoric acid processing by treating the pond waters with calcium carbonate and/or calcium oxide in two stages to precipitate out the major part of the fluorine values from the waters as calcium fluoride. After removal of the calcium fluoride the filtrate is treated with calcium oxide to remove a substantial portion of the remaining fluorine values as calcium fluoride. After removal of these calcium fluoride solids, the filtrate is treated with another charge of calcium oxide to produce dicalcium phosphate (dical) which is separated from the aqueous phase. The aqueous phase is treated with an additional charge of calcium oxide to remove a substantial portion of the solids from the aqueous phase leaving waters that can be discharged as waste or recycled as process water.

Process for recovery and separation of nutritious protein hydrolysate and chromium from chrome leather scrap

Abstract: Nutritious water soluble protein hydrolysate having an average molecular weight between about 1500 and 10,000 is obtained by heating to at least about 200° F a mixture of, by weight: 100 parts chrome leather scrap; at least 100 parts water; and at least eight parts calcium oxide, calcium hydroxide, magnesium oxide, or magnesium hydroxide, with the proviso that at least 4.8 of these eight parts be calcium oxide or calcium hydroxide. Simultaneously, chromium is substantially insolubilized and precipitates. The protein is separated from the precipitated chromium compounds and neutralized with acid to provide a nutritious feed or feed supplement. The chromium is washed to remove all protein and dissolved in sulfuric acid to provide a chromium solution useful in tannery operations.

Process for preparing overbased calcium sulfonates

Abstract: Overbased calcium sulfonates and concentrated oily solutions thereof are prepared by reacting a solution of alkylbenzene sulfonic acids with an excess of a calcium oxide having a medium or low activity towards water and with carbon dioxide. Oily solutions of overbased calcium sulfonate obtained from such a calcium oxide are perfectly limpid and are easily filtrable.

Additive for use in refining iron

Abstract: Disclosed is an additive in a molded form for use in refining iron. The additive comprises a mixture of at least one metal selected from magnesium, calcium and aluminum, and at least one metal oxide selected from magnesium oxide, calcium oxide and aluminum oxide.

Desulphurization of an iron melt

Abstract: An iron melt is desulphurized. To this end, the irom melt is admixed with a powder mixture comprising metallic magnesium and at least one calcium compound, the latter being selected from calcium carbide, calcium oxide, calcium carbonate and dolomite, and the said calcium compound being used in the form of particles with a size of 0.06 to 3 mm, wherein the powder mixture contains 0.1 to 2.5 weight % of metallic magnesium in the form of particles having a size of 0.060 to 0.095 mm.

Glass compositions for use in curable compositions

Abstract: A novel calcium fluoroaluminosilicate glass consisting essentially of from 25 to 35% by weight of silicon calculated as silica, from 30 to 40% by weight of aluminum calculated as alumina, from 20 to 35% by weight calcium, calculated as calcium oxide, and up to 9% by weight fluorine (preferably 4-7%) can be associated with a poly(carboxylic acid e.g. as an intimate mixture of glass and acid to constitute a composition curable on contact with water and useful, for example, as a loading on a splinting bandage. Such a bandage preferably has a ratio of set time to gel time from 4:1 to 8:1 with a minimum gel time.

Method for regenerating and recycling catalyst for oxidation of sulfur dioxide

Abstract: In a method for oxidizing sulfur dioxide by contacting a sulfur dioxide-containing gas and an oxygen-containing gas with an aqueous solution containing pentavalent vanadium and divalent manganese as a catalyst, the method for regenerating and recycling the oxidation catalyst which comprises adding at least one calcium compound selected from the group consisting of calcium oxide, calcium hydroxide and calcium carbonate and an oxygen-containing gas as an oxidizing agent to at least a part of the aqueous solution catalyst used in the oxidation reaction, separating the resulting gypsum, and recycling the recovered aqueous solution catalyst for use in the oxidation of sulfur dioxide

Use of high surface area mixed metal oxides of manganese and calcium in electrochemical processes

Abstract: Mixed metal oxides of the formula CaMn3 O6, CaMn4 O8 and CaMn7 O12 are disclosed. They are useful in electrochemical processes. CaMn3 O6 is a mixed valence composition whose formula may be written as Ca[Mn2 3+ Mn4+ ]O6. The compound is stable in H2 to about 400° C. and in oxygen to approximately 925° C. CaMn4 O8 is also a mixed valence composition whose formula may be written Ca[Mn2 3+ Mn2 4+ ]O8. This compound is stable in H2 to about 250° C. and in O2 to about 900° C. CaMn7 O12 is a mixed valence composition whose formula may be written as Ca[Mn4+ Mn6 3+ ]O12. The compound is stable in H2 to about 500° C. and in oxygen to approximately 950° C. These materials may be prepared by a variety of standard ceramic techniques, among them being heating in oxygen a mixture of calcium oxide and manganese oxide or mixed calcium and manganese salts or calcium salt and manganese oxide, or calcium oxide and manganese salt. Alternatively, solid solutions of mixed calcium and manganese carbonates may be decomposed to the compositions. The mixed calcium-manganese carbonate solid solutions are prepared by the precipitation from salt solution of the calcium and manganese by the addition of an excess of an appropriate carbonate ion source such as (NH4)2 CO3. The metal ion ratio in this salt solution is adjusted so that the resulting precipitate has the same stoichiometry as the desired oxide. The precipitate is calcined to yield the mixed metal oxide product described. The compounds described have utility as primary battery cathodes and also find use as oxygen activating catalysts in applications such as partial oxidation; methanol decomposition and oxygen reduction at a fuel cell cathode.

Glazing paste for bonding a metal layer to a ceramic substrate

Abstract: A glazing paste comprising glass frit, a metal oxide powder selected from the group consisting of aluminum oxide (Al 2 O 3 ), magnesium oxide (MgO), calcium oxide (CaO), and zinc oxide, (ZnO), and an organic vehicle.

On the aluminothermic reduction of calcium vanadate

Abstract: In the aluminothermic reduction of m e t a l oxide, calcium oxide is often used as a flux. The calcium oxide instead of forming an extraneous addition can sometimes be present in chemical combination with the m e t a l oxide. A familiar example is the aluminothermic reduction of calcium tungstate for the production of ferrotungsten. It has been stated1 that good coalescence of ferrotungsten is probably due to calcium oxide being an integral part of the tungsten resource, thus being made available essentially on a molecular basis for combining with alumina reaction product and quickly forming a fluid s lag . This can be considered to be a favorable state of affairs in the aluminothermic reduction of metal oxide as tied up with calcium oxide. In this context, reference can also be drawn t o the aluminothermic reduction of calcium molybdate for the production of ferromolybdehum and of molybdenum reported previously from this laboratory.~'3 This communication is an account of the efforts made for the preparation of vanadium and of ferrovanadium from calcium vanadates. The literature has made reference to the precipitation of calcium vanadate from vanadium bearing aqueous solution.4-7 T h e r e is however no information available on any technical use that has been developed for calcium vanadate. Aluminothermic reduction of vanadium pentoxide for the production of ferrovanadium or of vanadium in the industrial practice is known to be c a r r i e d out in presence of lime serving as a flux. This points towards the possibility for calcium vanadate as an alternative starting material for the aluminothermic reduction. For use in the present investigation the calcium vanadates were prepared in the laboratory. The compounds corresponding t o 2 CaO.V205 and to 4 CaO.V2Os were precipitated from alkaline sodium vanadate colution by treatments with CaC12 and lime respectively essentially in accordance with published work.7 The precipitated vanadium salts were dried, calcined at 1123 K and ground predominantly to -100 m e s h . The 2 CaO.V~Os and the 4 CaO.V2Os compounds, as made ready for use, analyzed 59.18 pct VaO5 and 44 pct V2Os respectively. Aluminum powder (grade ' C ' , 1 2 0 mesh) as received from M/s Indian Aluminium Co. was used as the reductant. The proc e d u r e for carrying out the aluminothermic r e d u c tions in refractory lined open vessels was essentially

Radioactive fission products sealed in glass - which contains silica, boron oxide, sodium oxide and calcium oxide

Abstract: Radioactive fission products are sealed in a solid vitreous material by addg. to the soln. contg. the fission products glass-forming substances at a ratio of 45-52 wt.% SiO2 to 26-32 wt.% B2O3 to 3.0-7.5 wt.% Na2O to 13-20 wt.% CaO. The wt. ratio of total amt. of glass forming substances to amt. of fission products, which are assumed to be in oxide form, is 4 to max. 1. The mixt. is dried and the molten at a temp. of about 1100 degrees C in an inert gas atm. Method requires the addn. of only a low number of glass forming substances, and volatilization of the fission products is minimised.

Method of making lightweight cement slurries and their uses

Abstract: A B S T R A C T A method of making lightweight cement slurry which involves dis-solving sodium metasilicate and an activator in mix water, and there-after mixing Portland cement therewith. The activator may be calcium chloride, calcium formate, calcium oxide, a water soluble calcium com-pound or a mixture thereof. The lightweight cement slurry so formed may be used for cementing well pipe in wells or for casting lightweight structural members, such as board, columns, and the like.

Apparatus for treating sumps

Abstract: Lime, preferably as calcium oxide, is mixed with the contents of sumps, such as oil well sumps, and these generally have a pasty or plastic consistency. The calcium oxide reacts with the materials present and also dehydrates the contents of the sump, causing the sump contents to stiffen. This mixing is performed by a drag line scoop that carries calcium oxide through the sump contents, mixing and blending the oxide and contents as it moves because of the unique construction of the mixing scoop. Once the mixing and blending is complete and reaction of the calcium oxide and the contents is complete, the sump contents are dredged and deposited on high ground to dry by the combined action of sun and air. Drying periods may range from several days to several weeks and the material thereupon becomes a dry, hard and stable type of soil suitable for fill purposes and which, when neutralized with acid, also may be suitable for agricultural purposes.

Stabilization of calcium oxide sulfate trapping materials

Abstract: Sulfate absorbent calcium hydroxide is dispersed in a binder and pelletized. The pellets are exposed to carbon dioxide at elevated temperatures to convert at least a portion of the calcium hydroxide to calcium carbonate. Pellets so treated are suitable for prolonged use in fixed volume sulfur oxide and sulfate scrubber vessels.

Pressure-sensitive recording sheet

Abstract: A pressure-sensitive record sheet material comprising a supporting web material having adhesively bound on the surface thereof a coating composition comprising kaolin clay, a zinc-modified alkyphenol-formaldehyde resin and a metallic compound selected from the group consisting of calcium oxide, calcium hydroxide and magnesium oxide, said resin and metallic compound combining to produce an improved color response when contacted with a color-producing material.

Production of high purity calcium thiosulfate

Abstract: A process for the production of high purity calcium thiosulfate by a metathesis reaction of ammonium thiosulfate and calcium hydroxide or calcium oxide is disclosed. Aqueous solutions of high purity calcium thiosulfate, in concentrations up to about 30% by weight, are prepared by removing substantially all of the co-product ammonia under conditions which minimize the decomposition of the thiosulfate ion. Heating the reaction mixture to a temperature of about the boiling point at atmospheric pressure is used to prepare aqueous solution of about 10% by weight calcium thiosulfate, and lower reaction temperatures are employed to prepare more concentrated aqueous solutions of calcium thiosulfate up to about 30% by weight, which is the saturation point.

Thermodynamics of mixing in molten sodium-potassium silicates at 1100°C: The effect of a calcium oxide addition

Abstract: A Knudsen cell-mass spectrometer technique has been used to study the thermodynamics of mixing of liquid sodium and potassium metasilicates containing calcium oxide at the composition 0.15 CaO:0.85 (K2O + Na2O). It is shown that the CaO addition reduces the maximum excess free energy of mixing of the metasilicates from about 1.9 kJ to about 1.1 kJ per mole of alkali cations. Measurements have been made at the tetrasilicate composition in the absence of CaO, and these results have been combined with previous measurements and a recent thermodynamic relationship due to Wagner to yield the variations in the activities of silica and the alkaline oxides across the disilicate section. All the results are considered to be consistent with cation size effects being the principal cause of positive deviations from ideal silicate mixing in these systems.

Hot nitrogen generator containing calcium oxide

Abstract: A solid propellant gas generator consisting of 45-65 weight percent calcium oxide, 25-45 weight percent calcium azide, and 8-11 weight percent calcium nitrate which produces pure nitrogen gas at temperatures above 2200° K in the complete absence of other gaseous products and metallic vapors.

Recovery of lactose from aqueous solutions: precipitation in the presence of calcium hydroxide and ammonium chloride additions

Abstract: The use of calcium hydroxide instead of calcium oxide for recovery of lactose from solutions was studied. With lactose concentrations of less than 10%, recovery was unsatisfactory. Addition of NH4Cl increases the solubility of calcium hydroxide, and at an adequate concentration of NH4Cl it is possible to solubilize part of the Ca(OH)2 without decreasing the amount of lactose in the precipitate. Then, NaOH addition improved lactose recovery markedly, precipitating more than 90% of total lactose. Acetone addition also proved effective.

Method of preparing phosphoric acid

Abstract: FIELD: preparation of extracting phosphoric acid from natural phosphates. SUBSTANCE: method comprises sulfuric phosphoric acid decomposition of phosphate stock, defluorination of the resulting suspension with sodium-containing reactants, separation and washing off precipitate of calcium sulfate, sodium silicon fluoride and calcium fluoride from phosphoric acid, desulfurization of the latter with precipitate of dicalcium phosphate and calcium fluoride which result from treatment of circulating water with calcium oxide or hydroxide to pH values of 6-8, and separation of said precipitate from circulating water, filtration of precipitate of calcium sulfate and fluoride recovered from desulfurization of precipitate of calcium sulfate and fluoride and recycling said precipitate to decomposition stage, additional washing of precipitate of calcium sulfate, sodium silicon fluoride and calcium fluoride with 5-10 parts of circulating water per 1 part of calcium sulfate to leach sodium silicon fluoride, remove precipitate of calcium sulfate and calcium fluoride for processing or storage. EFFECT: reduced specific consumption of stock for phosphoric acid production and no discharge of toxic water soluble fluorine-containing compounds into environment. 3 cl, 3 ex, 1 dwg

Manufacture of maleimides via cyclizing dehydration

Abstract: The invention relates to a process for the manufacture of maleimides by cyclic dehydration of corresponding maleamic acids in the presence of acetic anhydride and a calcium, barium or strontium oxide, acetate or alcoholate (catalyst). Compared to known catalysts, especially nickel salts, these alkaline earth metal compounds used as catalysts according to the invention have the advantage that the manufacturing process gives substantially greater kettle yields, and that the compounds are non-toxic. Preferably, calcium oxide and calcium acetate are employed according to the invention. Corresponding barium compounds are also very suitable for use.

Process for preparing sulfinyl chlorides from penicillin sulfoxides

Abstract: A penicillin sulfoxide ester is reacted with an N-chloro halogenating agent at a temperature of from about 75° C. to about 135° C. and in the presence of an alkylene oxide and calcium oxide to produce a 2-chlorosulfinylazetidin-4-one intermediate. The intermediate, upon separation from the alkylene oxide, calcium oxide, and any conversion products of both the alkylene oxide and calcium oxide, can be treated with stannic chloride to produce a 3-exomethylenecepham sulfoxide.

Process for the digestion of goethite-containing bauxites

Abstract: The present invention provides for an improvement in the Bayer Aluminum manufacturing process wherein the digestion of goethite-containing bauxite is effected in higher yields, at lower temperatures and in a single step by carrying out said digestion in a wet caustic solution containing both calcium oxide and sodium chloride.

Calcium oxide or hydroxide to improve the charge acceptance of electrographic dielectric resins

Abstract: The charge accepting capacity of electrographic dielectric coatings is improved by dispersing in an organic solvent-soluble thermoplastic insulating resin having carboxyl functionality providing an acid value of from 5-100, from 0.05-3% by weight of calcium oxide or calcium hydroxide.

Simple field controls for soil-lime construction

Abstract: Tests are suggested for field control which are designed to ascertain the relative amounts of reactive lime after mixing and prior to soil compaction The methods discussed involve end points, the plastic limit leveling off, and the pH increasing towards that of free lime with increasing precentages of lime The Eades method for determination of a lime retention point involves preparing a series of soil-water suspensions with successively higher proportions of hydrated lime The use of phenolphthalein pH indicator with soil suspensions is described A plastic bottle of about one liter capacity equipped with a pump-type spray is used in the field Such techniques are used in the resolution of questions regarding the minimum levels of lime treatment required for stabiization The phenolpthalein indicator test is also used to detect a lime deficiency during mixing, compaction, or at any other time until the cure membrane is applied to the lime-treated layer Mention is made also of the clarification of suspensions Observations using the dirty palm test are useful where it is not possible to use either indicator or Sedimentation The use of these field tests will determine whether or not a soil is reactive to lime, which is valuable information in predesign sampling, development of design studies and economic evaluations