Abstract: A solidification and curing accelerator for hydraulic binders produced by a process including providing a reaction mixture composed of constituents (a) - (e) as follows: (a) at least one of basic aluminum salts which are substantially water insoluble and aluminum hydroxide; (b) at least one of aluminum sulfate which is substantially water soluble and sulfuric acid; (c) at least one of an organic carboxylic acid or mixtures of at least two organic carboxylic acids; (d) aluminum salts of organic carboxylic acids; and (e) at least one organic and inorganic substance selected from the group consisting of sulfates, hydrogen-sulfates, carbonates, hydrogen-carbonates, alkaline earth metal oxides, and alkaline earth metal hydroxides; adding water to the reaction mixture and reacting at a temperature ranging up to 150 ° C. for a time effective to provide a reaction product which is a solution in water.

Abstract: A process for purification by multistage countercurrent extraction of wet-process phosphoric acid includes the steps of (a) preparing an aqueous phosphoric acid by decomposition of crude phosphates with sulfuric acid and prepurification thereof; (b) providing an organic solvent mixture consisting of one of (A) a water immiscible solvent and a fully water-miscible solvent or (B) a partially water-miscible solvent and a fully water-miscible solvent; (c) extracting water from the acid by contacting with the solvent mixture in a volumetric ratio of acid to solvent mixture of 1:1 to 1:10 at a temperature of 5 to 90° C.; (d) recovering the fully water-miscible solvent by distillation and washing; (e) recycling the fully water-miscible solvent to step (b) to provide a recycled solvent mixture; and (f) repeating steps (c), (d) and (e) with the recycled solvent mixture to provide a phosphoric acid having a preselected degree of purity.

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: The present invention relates to a novel process for the production of low viscosity copolymers of maleic acid monoalkyl ester and vinyl alkyl ethers characterized in that the copolymerization of alkyl vinyl ether is performed with a mixture composed of maleic acid anhydride and maleic acid monoalkyl ester. The specific viscosity is controlled by the setting of a certain maleic acid anhydride to maleic acid monoalkyl ester ratio.

Abstract: A process of manufacturing powdered copolymers of maleic anhydride with methyl vinyl ether in a mole ratio of 1:1 and a specific viscosity in a range from 2 to 5 by copolymerization of maleic anhydride with methyl vinyl ether in the presence of radical initiators to initiate polymerization. The process includes mixing maleic anhydride with an excess of about 3 to about 20 mol methyl vinyl ether per mol maleic anhydride and initiating a polymerization reaction with a radical initiator added in a quantity of from about 0.001 to about 1 weight % with respect to the maleic anhydride. The polymerization reaction takes place in the absence of other solvents.

Abstract: In the manufacture of phosphoric acid by treatment of phosphate ores with excess phosphoric acid and precipitation of calcium ions as calcium sulfate, the purity and quality of the byproduct calcium sulfate is substantially improved by subjecting the monocalcium phosphate extract of the ore before precipitation of calcium sulfate to one or more preliminary treatments, whereby contaminent ions are substantially and preferentially removed from the extract while the calcium remains substantially in solution. These preliminary treatments may include separation of fluoride by reaction with silicon compounds, separation of radium by reaction with barium compounds in the presence of sulfate ions, and separation of strontium as strontium sulfate.