Abstract: Improved set accelerating mixtures and their use are disclosed to shorten the period after mixing hydraulically setting building materials, for example cement, up to the transition into the solid phase. The improved set accelerating mixtures comprise basic aluminum sulphates of the formula: Al(OH).sub.a (SO.sub.4).sub.b, in which the subscripts satisfy the conditions:a=3-2b and b=0.05 to 0.4.These basic aluminum sulphates are produced by parallel precipitation from solutions containing aluminum at temperatures usually less than 60.degree. C. by mixing dilute acid solutions and alkaline solutions containing sulphates in the pH range from 5.0 to 8.0 to produce an amorphous, basic aluminum sulphate.

Abstract: A cement composition consists essentially of (a) from 50% to 97% by weight (calculated on the total composition) of a Portland cement clinker, the sulfur content of which is from 0.5% to 10% by weight expressed as SO.sub.3 and the fluorine content of which is from 0.13% to 1.00% by weight expressed as F, and (b) from 3% to 50% by weight (calculated on the total composition) of an extender containing a carbonate selected from calcium carbonate, magnesium carbonate, calcium magnesium carbonate and mixtures thereof as its main constituent and having a median particle size (d.sub.50) of below 14 .mu.m. Preferably, the total content of C.sub.3 S and C.sub.2 S in the Portland cement clinker is at least 65%. A preferred carbonate is electrostatic precipitator dust extracted from cement kiln exhaust gases. The cement composition may be mixed with further components such as other extenders, retarding agents and aggregate.

Abstract: Class C fly ash containing cementitious mixtures for producing concretes that are resistant to sulfate-containing environments. Class C fly ash is intergound with portland cement clinker and gypsum to produce a cementitions mixture, which, when combined with water and an aggregate produces a hardened concrete that is resistant to sulfate environments. Alternatively, portland cement clinker and gypsum are first interground and the resultant mixture is admixed with Class C fly ash to produce a cementitious mixture. This cementitious mixture, in combination with water and an aggregate, produces a hardened concrete that has improved resistance to sulfate environments. In other aspects, a concrete that is stable in sulfate environments is produced by admixing portland cement, Class C fly ash and water containing a source of ions selected from the group consisting of sulfate and hydroxyl anions.

Abstract: In a process for accelerating the setting and hardening of a material which contains a hydraulic binder or which consists of a hydraulic binder there is used a setting accelerator mixture which is free of alkali metals and free of chlorides. Said setting accelerating mixture contains at least one water soluble sulfate of a polyvalent cation and a further constituent which is selected from the group consisting of calcium aluminate, calcium sulfoaluminate, basic aluminum salts, mixtures thereof or mixtures containing at least one of said constituents and a further component. If the water soluble sulfate of the polyvalent cation is aluminum sulfate, then said compound has to contain crystal water in order to provide the water solubility of said product.

Abstract: A cementitious composition comprising(a) a cementitious material;(b) a fly ash which has a calcium oxide content of from 15-45% by weight;(c) a hydroxycarboxylic acid; and(d) a water-soluble source of alkali metal ions.The compositions are useful as concretes, grouts and mortars.

Abstract: Lightweight concrete products, useful for example in blocks, wall panels, floor and roof slabs, in which zeolite is a major component, its content in the cementing material of the products exceeding 50 wt. %. Depending on application, zeolite may be non-treated or calcined at a temperature enabling the surface activation of the zeolite and resulting high surface energy. Zeolite thus treated will work as both pozzolanic material and bubble-generating agent. Strengthening agents are used to improve compressive strength of the products. Also, a binding material, useful for hazardous waste stabilization, comprising zeolite as a major component, is proposed.

Abstract: A cement composition comprising 1) a cement containing water-soluble chromate and 2) at least one manganese(II) compound in an amount sufficient to reduce the amount of water-soluble chromate to at the most 2 mg of Cr(VI) per kg of the cement, the determination of the chromate content being carried out by elution of the composition in water for 15 minutes at a water/cement ratio 1, filtration and determination of the chromate content in the filtrate.

Abstract: The present invention pertains to a portland cement clinker containing the following amounts of clinker phases, in wt. %:C.sub.3 S: 30 to 80,C.sub.4 A.sub.3 S: 5 to 30,C.sub.4 AF: <30,C.sub.2 S: <40,C.sub.3 A: <20,and an SO.sub.3 content between 2 and 8 wt. %, obtained by calcining a raw material mixture containing CaO, SIO.sub.2, AL.sub.2 O.sub.3, and Fe.sub.2 O.sub.3 in the presence of an additive containing SO.sub.3 and an additive containing fluorine at temperatures between 1,150.degree. C. and 1,350.degree. C.

Abstract: A method and composition for making concrete includes an antifreeze admixe which is added to the concrete to prevent the freezing of water in the concrete when the concrete is cured during the winter or other cold conditions. The concrete admixture includes sodium nitrate and sodium sulfate combined with one another in a predetermined ratio. In a preferred a embodiment the ratio of sodium nitrate to sodium sulfate equals 3:1. A dosage of greater than 2% by weight of cement of the above described admixture was found to significantly increase the compressive strength of concrete cast of cold (below freezing, or 0 degrees celsius) temperatures, and dosages of 6% and 8% by weight of cement of the specified admixture were found to be particularly effective.

Abstract: A thixotropic preflush fluid is employed in a well drilling operation to prevent loss of cement slurry to an air zone penetrated during the drilling operation. The preflush fluid comprises water, a cement, calcium sulfate, and a quick-hardening accelerator. Optionally, the preflush fluid also comprises a thickening agent.

Abstract: A mixed gypsumless Portland cement of high initial and long-lasting strengths which contains 60-96.7 weight percent gypsumless Portland cement clinker with the specific surface of 350-550 m.sup.2 /kg and 3-40 weight percent of ground latently hydraulic matter, such as granulated blast-furnace slag, light ash, and the like, which two components have been ground in the presence of 0.01-0.1 weight percent of a liquid milling admixture, advantageously with a synthetic surface active matter with wetting properties, and containing 0-20 weight percent of fine amorphous SiO.sub.2 and/or 0.1-3 weight percent sulphonated polyelectrolyte or ligninsulphonate and 0.5-6 weight percent alkaline carbonate, hydrogen carbonate, or alkaline hydroxide.

Abstract: An improved modified sulfur concrete product is provided in the form of discrete, self-sustaining pellets of modified sulfur concrete which can be shipped and stored for indefinite periods and remelted to yield useable concrete. The pellets are preferably formed by first preparing a quantity of hot modified sulfur concrete (74), followed by passing such concrete (74) into a pelletizing chamber (12) equipped with an elongated auger-type, axially rotatable mixing element (14) and apparatus (16) for the introduction of pressurized air and water into the chamber (12) in the form of a spray. Supplementary pressurized air may advantageously be added at spaced points along the length of the chamber (12).

Abstract: A method of disposing of wastes containing heavy metal compounds by neutralizing the wastes, oxidizing the neutralized wastes, then solidifying the oxidized wastes using conventional mineral binding agents such as Portland cement. This method is of particular interest in treating arsenic sulfide containing aqueous sludges produced in the manufacture of phosphoric acid.

Abstract: A procedure for the treatment of filter cakes obtained during the purification of chemical substances in liquid form, especially during the purification of phosphoric acid obtained by wet methods, whereby a filter cake is dried and heated in the presence of a melt of inorganic material.

Abstract: A process and apparatus are disclosed for the treatment of a substance contained in a solution or a slurry.The solution or slurry can be treated to give a fusible dried product by use of microwave radiation.The fusible dried product can be heated and fused by use of microwave radiation.

Abstract: Radioactive substances are disposed of by incorporating glass particles containing the radioactive substance in molten metal, heat treating the molten metal containing the glass particles to convert the glass to glass ceramic, and cooling the resulting composite to solidify the metal and provide the glass ceramic particles embedded in a matrix of the metal.

Abstract: A foamed ceramic product and method for making same is disclosed. The foamed ceramic is characterized by a high compressive strength, high insulating properties and low fluid permeability when compared against conventional materials. This foamed ceramic is made by mixing a clay mineral with a foaming agent comprising a combination of sulfate and sulfide compounds, heating to a temperature of about 1,000.degree. C. where controlled foaming occurs and then cooling the resulting foamed product.Additionally, there is disclosed a foamed ceramic product and method for making same which is characterized by its fire resistant properties as a result of creating micro cracks therein which permit controlled fluid permeability. This foamed ceramic product is made by controlling the phase constituents and heating and cooling temperatures to induce stresses which result in such micro cracks.

Abstract: Glass pellets for use in producing glass for the manufacture of glass fibers are described in which a significant portion of the pellets are made up of fiber glass cullet. The pellets of glass fiber batch contain quantities of fiber glass cullet from 5 percent by weight to 35 percent or more by weight. The glass fiber cullet employed is in the form of ground glass or short glass fibers, 0.0625 to 0.5 inch (0.158 to 1.27 centimeters).

Abstract: A method for the production of synthetic wollastonite material. The treatment involves slag melt which is obtained during the thermal production of phosphorous from crude phosphate. This slag is then treated with water under a preferred embodiment and burned at a certain temperature in an oxidizing atmosphere.

Abstract: A high sodium oxide composition suitable for use in the manufacture of glass and fiber glass is prepared by heating a sodium carbonate ore with a silicate or other source of glass making oxides such as clay or oil shale. The product obtained is rich in sodium, calcium and magnesium oxides and contains less than 35 weight percent SiO.sub.2. It may be substituted for soda ash in a glass batch and will reduce the fuel required in glass manufacturing.

Abstract: A method of repairing refractory walls, especially coke-oven walls is disclosed. The invention utilizes a refractory repair material selected in accordance with the wall to be repaired and not less than 5.5 nor more than 20% binder. The repair material is sprayed onto a hot wall to be repaired and the binder adheres thereto by sintering with at least the boundary surfaces of the binder undergoing vitrification.

Abstract: A method of utilizing sewage and/or industrial, e.g. poisonous sludges for making bricks or other ceramic articles. Sludge is mixed with clay to form a mixture of approximately 30 to 50% sludge. The mixture may then be stored, and is extruded by conventional means. After extrusion and cutting or shaping, the articles are dried in a dryer and fired in a kiln. Preferably, the exhaust gases from the dryer are vented into the kiln as combustion gases, where odors or poisonous compounds of the exhaust air are destroyed. Also, used or waste oil may be added during mixing to lessen odors and to supply extra heat during firing in the kiln. The products so produced are substantially indistinguishable from conventional products, except that their insulating properties are enhanced.

Abstract: A method for the strengthening of glasses, glazes, cement, gypsum board, wood fiber board, mineral fiber board, lime or gypsum by adding fly or filter dust to the starting material after which the mixture is heated or not heated depending upon the product being manufactured. For glasses, glazes and other vitreous products (besides porous ceramic products) and cement the starting material is heated to above 1000.degree. C. For gas concrete, gypsum board, wood fiber board and mineral fiber board the starting material is heated to from 100.degree.-1000.degree. C. For cement, lime and gypsum it is possible that no heating take place to the starting material.

Abstract: If cemented carbide products such as hot rolling-mill rolls, plugs and dies can be made of the powder reclaimed from scrapped cemented carbide products and the virgin powder of cemented carbide, it is possible to obtain cemented carbide products lower in price and capable of meeting the requirements of severe working conditions.

Abstract: A method for manufacturing porous ceramic products by mixing ceramic material with a fly dust containing silica and metal oxides and having a large specific surface area of at least 20 m.sup.2 /g. The mixture is heated to at least 800.degree. C to convert it into a porous ceramic material. The process is carried out so as to result in either products having mainly closed pores by heating at sintering temperatures or products having mainly open pores by heating at consolidation temperatures. The admixture may be wrapped in a sheet of material which upon heating the admixture to form pores in the material encloses the gases formed at low temperatures but which ruptures at high temperatures to expose the clay to an oxidizing atmosphere.

Abstract: Process for recovery of glass from municipal waste, comprising shredding the waste, subjecting the shredded waste containing the glass to treatment in an air classifier, recovering the overhead including glass from the air classifier, the latter being operated under conditions such that the major portion of the glass particles contained in such overhead are of a fineness smaller than about 6 mesh, and usually of a size such that a substantial portion of such glass particles are less than about 20 mesh, screening such overhead fraction and recovering an enriched glass fraction of the aforementioned fineness, subjecting the screened glass-enriched material to treatment on an air table, and recovering a fine glass product of substantially reduced organic content, and having a particle size less than about 6 mesh, with a substantial portion less than about 20 mesh.

Abstract: Production of building bricks utilizing as an ingredient thereof, advantageously in substantial or in major proportion of brick-forming compositions or mixtures of ingredients, ore residues obtained from the extraction of lithium values from beta-spodumene. The said residues so utilized result from a process in which beta-spodumene is subjected to a sulfuric acid roast, the lithium values are then extracted from the acid-roast product by an aqueous extraction liquid, followed by neutralization with lime or limestone, and separation of the formed lithium sulfate by filtration, leaving the ore residues which are then utilized in admixture with other ingredients to produce bricks possessing excellent strength and other desirable properties.

Abstract: Bauxite waste red mud is treated with hydrochloric acid to dissolve only the sodium content. The treated material is mixed with kaolinitic clay and formed into construction bricks.

Abstract: Structural clay products such as bricks, tile and blocks are made using waste soda lime glass, other inorganic materials and ball clay. The products are produced at the relatively low firing temperatures between 1300.degree. and 1900.degree.F and are of minimum porosity.

Abstract: A method for the manufacture of foamed ceramics from a starting composition containing at least one component, which, when heated, forms a viscous, sintered and porous mass and a relatively difficultly oxidizable pore-forming agent for producing the porous structure, characterized by using as the starting composition a composition containing (1) at least one waste product rich in silica and containing readily oxidizable substances which, when heated, are themselves capable of producing uncontrollable pore formation and/or an undesirable melt, and (2) a strongly oxidizing agent, the quantity of oxidizing agent being such that the oxidizable substances are oxidized to eliminate or to reduce the uncontrollable pore formation and/or the melting and wherein the desired pore structure is obtained by oxidation of the difficultly oxidizable carbonaceous pore-forming agent.