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a fire brick, firebrick, or refractory brick is a block of refractory ceramic material used in lining furnaces, kilns, fireboxes, and fireplaces. a refractory brick is built primarily to withstand high temperature, but will also usually have a low thermal conductivity for greater energy efficiency.
natural hydraulic lime nhl is made from a limestone which naturally contains some clay. artificial hydraulic lime is made by adding forms of silica or alumina such as clay to the limestone during firing, or by adding a pozzolana to pure lime. hydraulic limes are classified by their strength: feebly, moderately and eminently hydraulic lime. feebly hydraulic lime contains 5-10% clay, slakes in minutes, and sets in about three weeks.
a fire brick, firebrick, or refractory brick is a block of refractory ceramic material used in lining furnaces, kilns, fireboxes, and fireplaces. a refractory brick is built primarily to withstand high temperature, but will also usually have a low thermal conductivity for greater energy efficiency .
silica fume is similar to fly ash, but has a particle size 100 times smaller. this results in a higher surface-to-volume ratio and a much faster pozzolanic reaction. silica fume is used to increase strength and durability of concrete, but generally requires the use of superplasticizers for workability.
the same effluvial deposition of bentonite clay onto beaches accounts for the variety of plasticity of sand from place to place for building sand castles. beach sand consisting of only silica and shell grains does not mold well compared to grains coated with bentonite clay.
the section on the history of portland cement duplicates thatin the 'portland cement' article, but has a different emphasis, giving greater credit to the aspdins. ideally the general history should be in the cement article, and the complicated evolution of modern portland cement in the more specialised article. i missed an explanation of how .
this gives a c/a ratio of 15.6%, and a sand/stone ratio of 67%. —preceding unsigned comment added by 184.108.40.206 talk contribs 04:19, 26 july 2007 utc a rule of thumb for home made concrete, i call it the '1, 2, 3 rule' by volume : 1 part cement 2 parts sand 3 parts stones 0.6 water add a bit of washing up liquid to improve workability.
fire clay is a range of refractory clays used in the manufacture of ceramics, especially fire brick.the united states environmental protection agency defines fire clay very generally as a 'mineral aggregate composed of hydrous silicates of aluminium al 2 o 3 ·2sio 2 ·2h 2 o with or without free silica.'
but i have seen a definition by daniel rhodes clay and glazes for the potter, p.54 . during the vitrification in the kiln the wares becomes soft and have a tendency to come out of shape. to overcome this some manufactures choose to fire the wares to maturing temperature while supporting them by special supports or by settling them in silica .
to counter this hazard, silica sand for blasting is often coated with resins to control the dust. using silica as an abrasive is not allowed in germany, belgium, russia, sweden and united kingdom for this reason. silica is a common abrasive in countries where it is not banned. another common mineral abrasive is garnet. garnet is more expensive than silica sand, but if used correctly, will offer equivalent production rates while producing less dust and no safety hazards from ingesting the dust.