Abstract: A plant for producing chain-type ammonium polyphosphate from ammonium orthophosphate and phosphorus pentoxide in the presence of gaseous ammonia comprises a reactor having rotatable mixing, kneading and comminuting tools in its interior and a feed pipe for the solid starting materials, an introduction pipe for ammonia, a gas discharge pipe and a discharge line for the reaction product, all of which are flow-connected to the interior of the reactor. The discharge line of the reactor is also connected for material flow to a mixing apparatus. A discharge device, which is controlled by the power consumption of the drive motor of the reactor, is arranged in the discharge line.

Abstract: In a continuous process for the preparation of phosphorous acid with simultaneous production of hydrochloric acid, a reaction zone is provided which is in open communication with a first scrubbing zone. A portion of the reaction product is recycled from the bottom of the reaction zone into the top of the scrubbing zone and phosphorous acid is removed from the circulation. Hydrogen chloride gas escaping from the top of the first scrubbing zone is brought into contact, in a cooled, second scrubbing zone, with an overstoichiometric amount of water. Hydrochloric acid is obtained which is passed as starting material into the reaction zone or into the top of the first scrubbing zone. The external cooling of the second scrubbing zone is controlled such that the temperature in the reaction zone is kept constant at a desired value between 90.degree. and 130.degree. C. without adding any external cooling or heating energy. Pure hydrochloric acid is recovered in an absorption zone.

Abstract: For the preparation of dicalcium phosphate dihydrate stabilized with dimagnesium phosphate trihydrate and sodium pyrophosphate, an aqueous suspension of calcium carbonate is introduced into a reactor and recirculated by pumping through a high-speed mixer at 3,500 to 8,000 rpm which is in flow connection with the lower and upper portion of the reactor. Into the mixer an amount of phosphoric acid is introduced which is at least sufficient for the quantitative formation of dicalcium phosphate dihydrate and then an oxygen-containing magnesium compound is introduced into the reactor. Finally, lime milk is metered into the reactor up to a maximum pH of 6.9, before the sodium pyrophosphate is added to the reactor. The resulting suspension which has a stabilized dicalcium phosphate dihydrate content of 20 to 33% by weight is spray-dried.

Abstract: A coated valve, in particular an inlet valve for internal combustion engines, is provided, which is provided with a deposit preventing layer containing cerium (IV) oxide. A process for coating a valve with the deposit preventing layer containing cerium (IV) oxide is also provided.

Abstract: A method for manufacturing an iron-containing sintered electrode for alkaline accumulators as well as the product obtained by such method, in which iron powder and at least one reducible iron compound are intimately mixed with each other; the powder mixture is sintered into a stable body and the reducible iron compound is reduced to highly active iron.

Abstract: A hydrogen-storing material of known type, e.g. Mg, Ti, V, Nb, and alloys such as La-, Ti- and Co- alloys, is made form retaining without significant loss of hydrogen absorption and desorption properties by binding with a plastic having sufficient adhesion or binding strength. The hydrogen-storing material in granular form is mixed with the plastic in powder, emulsion, solution or melt form and then molded into the desired shape.