A cement mix based on an inorganic hydraulic cement, for example, Portland Cement, an air-cooled blast furnace slag and silica fume produces concretes having strength characteristics superior to those achieved by the cement alone; furthermore this cement mix is superior to a corresponding mix based on the inorganic hydraulic cement, and the air-cooled slag without the silica fume, and to a corresponding mix based on the cement and silica fume without the slag; additionally a cost saving in the e...

The yield of cement clinker recovered from a kiln assembly is enhanced by feeding a particulate material comprising silica and an oxide of at least one of calcium and aluminum, for example, fly ash into contact with hot cement clinker; the fly ash melts to a partially fused material which chemically reacts with the hot clinker to produce a pyroprocessed cement clinker of crystalline hydraulic silicates; the extruder is added to the hot cement clinker downstream of the formation of the cement cli...

A binder for mine tailings and aggregate used as a backfill for an underground void comprises ferrous slag, and cement kiln dust, optionally with lime kiln dust; the binder displays strength characteristics better than or comparable to those achieved with conventional binders based on Portland cement and slag.

A source of free lime is introduced into a cooling zone of a cement kiln in an amount to elevate the free lime content to a content of 0.6 to 2.0%, by weight. This addition is made without altering the normal or standard process operating parameters of the kiln for cement clinker production. The free lime content of 0.6 to 2.0%, by weight, provides advantageous characteristics in cement produced with the cement clinker.

A drain tank for installation underground has a longer life than steel and fibreglass tanks and has a leak detection system to identify leaks. The drain tank comprises a sealed concrete chamber having at least one opening at the top thereof with a collar integral therewith, a manway connected to the collar extending upwards, the manway having a top lid with a vent and pump out exit. Inside the concrete chamber is an impervious bag liner which is sealed to the collar; an entry pipe passes through...

A synthetic slag is produced by melting the mineral content of an organic carbon-containing mineral, for example, oil shale or tar sands, with a source of lime such as cement kiln dust. The organic carbon, especially hydrocarbon, content of the mineral is oxidized by oxygen gas, which typically is derived from air or an air/oxygen combination, in an exothermic reaction and the heat generated provides the thermal energy for the reaction between the mineral content and the source of lime. In this ...

Ground bottom ash, a waste material derived from combustion of coal, which presents a disposal problem, replaces part of the cement in a cementitious material useful in concretes and mortars and provides compressive strengths in concretes comparable with or better than corresponding cements in which there is no replacement of cement by ground bottom ash and cements containing fly ash.

Contaminated coal ash, for example flyash contaminated with carbon is introduced to hot clinker in a cooler downstream of a cement kiln; the carbon is combusted in the cooler to provide a cement clinker having an effective content of flyash free of carbon; this permits use of flyash contaminated with carbon without the need for separate special steps for carbon removal; volatile contaminants or contaminants having a volatile component, for example adsorbed ammonia are similarly removed in the co...

A combination of a class C fly ash having a high analytical content of CaO, and a silica fume, with a hydraulic cement, such as Portland cement, produces concrete with alkali-silica reactive aggregate having acceptable low expansion such as by ASTM C 1260; and also produces sulphate resistance with mineral aggregates generally.

Concrete's durability to freeze-thaw cycles is dependent on its level of air entrainment, the appropriate level of which is achieved with the aid of surface active or air entraining agents. These agents promote the fragmentation of large air voids into smaller ones and stabilize air voids in the concrete. The carbon matter found in fly ash when used as a pozzolanic component of concrete, adsorbs the air entraining agents, reduces the air voids and concrete's ability to withstand many freeze-thaw...