Abstract: A method for reducing the leachability of granular material which consists essentially of an inorganic binder and a filler containing contaminants, in which individual particles of the granular material are coated with a closed coating of a water-insoluble and water-repellent polymer composition. The coating is preferably a bituminous material.

Abstract: Described is the process for forming a hardenable mixture of a coal ash comprising free CaO and free CaSO.sub.4.0 H.sub.2 O.In order to remove all free CaO the coal ash is mixed with a fly-ash comprising essentially no free CaO and no free CaSO.sub.4.0 H.sub.2 O and water and subsequently subjected to a heat treatment.By removal of free CaO it is found that the strength of hardened granules formed from such ash mixture does not deteriorate as is the case from granules formed with a coal ash comprising free CaO.Also a process for forming hardened granules and a building component formed with use of a hardenable mixture according to the invention are described.

Abstract: Described is the process for forming a hardenable mixture of a coal ash comprising free CaO and free CaSO.sub.4 .OH.sub.2 O.In order to remove all free CaO the coal ash is mixed with a fly-ash comprising essentially no free CaO and no free CaSO.sub.4.OH.sub.2 O and water and subsequently subjected to a heat treatment.by removal of free CaO it is found that the strength of hardened granules formed from such as mixture does not deteriorate as is the case form granules formed with a coal ash comprising free CaO.Also a process for forming hardened granules and a building component formed with use of a hardenable mixture according to the invention are described.

Abstract: A process for manufacturing hardened granules produced by mixing at least fly ash obtained from combustion of a material selected from a coal product and lignite, a binder and water, forming granules of said mixture, hardening said granules in an embedding material at a temperature between 85.degree. and 212.degree. F. by applying heat and separating the hardened granules from the embedding material, said embedding material being used for forming new granules, including the step of embedding the non hardened granules after granulation in a hardening reactor in a fine grained material with a water absorption capacity of at least 8% and being free from a compound generating heat by contacting water, and supplying heat to the mixture of granules and embedding material in said hardening reactor by introducing steam into the mixture of granules and embedding material as present in the hardening reactor to raise and maintain the temperature at a value comprised between 85.degree. F. and 212.degree. F.

Abstract: The pozzolanic properteis of a pozzolanic material, such as a fly ash, are improved by mixing the pozzolanic material with a calcium oxide or calcium hydroxide containing material and water in such a way that at the time of associating or bringing together the abovementioned components the mixture has or immediately attains a temperature of more than 50.degree. C., preferably at least 80.degree. C., most preferably 85.degree. to 100.degree. C.A mixture of pozzolanic material and calciumoxyde and/or calcium hydroxide may be preheated, water subsequently is added to said mixture.Hot water may be used and is preferably added as one mass at one moment.The pozzolanic material obtained from the process of the invention is suitable as cement substitute, as material for manufacturing building articles and a binder for occluding one or more fillers to be introduced into a chemical process or one or more fillers presenting noxious properties.

Abstract: A method is described for producing a building element in which a hardenable binder-material is mixed with a coarse particles comprising material after which the mixture is used for forming unhardened building elements. The building elements are subsequently hardened at a temperature up to 100.degree. C. and at atmospheric pressure in a water-vapor containing atmosphere. The hardenable binder material is constituted by a separately prepared mixture of fly ash; Ca(OH).sub.2 or a substance which may be converted into Ca(OH).sub.2, and water.Optionally the hardenable mixture may be partially granulated before use.

Abstract: The pozzolanic properties of a pozzolanic material, more particularly a fly ash, are improved by mixing the pozzolanic material with a calciumoxyde or calciumhydroxide containing material and water in such a way that at the time of associating or bringing together the abovementioned components the mixture has or immediately attains a temperature of more than 50.degree. C., preferably at least 80.degree. C., most preferably 85.degree. to 100.degree. C.A mixture of pozzolanic material and calciumoxyde and/or calciumhydroxide may be preheated, subsequently, water being added to said mixture.Water as used may be hot water and said water is preferably added as one mass at one moment.The pozzolanic material obtained from the process of the invention is suitable as cement substitute, as material for manufacturing building articles and a binder for occluding one or more fillers to be introduced into a chemical process or one or more fillers presenting noxious properties.