Abstract: A composition for binding environmentally-harmful substances in solid or semi-liquid state contains caustic magnesium oxide, non-ferrous metal salts as a hardener, non-ferrous metal oxides catalyzing formation of radial crystalline structures, and optionally water and other additives. A method of stabilization of environmentally-harmful substances binds these substances in the solid state or semi-liquid state in the composition containing caustic magnesium oxide, wherein the environmentally-harmful substances are supplemented by the composition containing caustic magnesium oxide, non-ferrous metal salts as hardener, non-ferrous metal oxides catalyzing formation of radial crystalline structures, and optionally water and other additives. A form of paste is obtained, followed by leaving the mixture for solidification and stabilization of the product.

Abstract: A grouting material which contains a fine particle material having a Blaine specific surface area of 5000 cm2/g or more, containing 30 to 60% by mass of cement clinker, 40 to 70% by mass of and blast-furnace slag and 0.5 to 3 parts by mass of gypsum in terms of SO3 based on 100 parts by mass of the total amount of cement clinker and blast-furnace slag, and further contains (i) 4 to 8 parts by mass of calcium-aluminate-based rapid-hardening admixture, (ii) 0.05 to 0.2 parts by mass of setting retarder and (iii) 0.5 to 1.7 parts by mass of high-performance water-reducing agent, based on 100 parts by mass of the fine particle material.

Abstract: A lime independent cementitious mixture including: an iron oxides constituent comprising one or more oxides of iron; and an activator. The activator is selected from one or more metal non-chloride salts, including metal phosphates and nitrates, or non-alkaline earth metal salts. The activator is also selected from those which may form one or more megalithic molecules with the iron oxides constituent when co-activated with water. A lime independent cementitious mixture including an iron oxides constituent comprising one or more oxides of iron; a silicates constituent comprising one or more calcined metal silicates; and an activator selected from one or more metal non-chloride salts which may form one or more megalithic molecules with the iron oxides and/or silicates constituents when co-activated with water.

Abstract: A method of servicing a wellbore comprising placing in the wellbore a cement composition comprising light-burned magnesium oxide, water and an alkaline metal chloride, and allowing the composition to set. A method of cementing comprising preparing a cement composition comprising a light-burned magnesium oxide, water and an alkaline metal chloride, and allowing the composition to set.

Abstract: A cementitious material having improved resistance to water, increased strength, increased resistance to deteriorating processes and which is toxic to certain microorganisms and repellent to certain roach species, said material comprising on a dry mix basis, in % by weight, about 2% to 5% copper oxide, about 1% to 5% condensed silica fume, about 1.5% siloxane coated calcium hydroxide, about 53.5% to 60.5% dolomitic limestone and effective amounts of pigments and fillers.

Abstract: A process for producing a hard material from a cementitious mixture, the process including the steps of blending together a cement constituent and a filler constituent whilst in a dry condition to provide a compactable homogeneous mixture containing a predetermined volume of voids defined between filler particles up to a predetermined size, laying the dry mixture onto a substrate, sparingly applying water to the surface of the mixture to dampen the surface layer of the mixture for causing setting of the cement in said surface layer and subsequently applying more water for causing setting and hardening of the remainder of the cement.

Abstract: The present invention relates to the use of manganomanganic oxide particles containing at least 90% by weight of manganomanganic oxide, said particles having a density of 4.50 to 4.75 g/cm.sup.3 and a particle size of at least 98% below 10 .mu.m, as a weight material for drilling mud fluids and for cement slurries for cementing oil wells.The manganomanganic oxide particles which are used are preferably recovered from off-gases which evolves during refining of ferro-manganese melts.