Digitalfire Ceramic Materials Database

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Portland Cement

Chemistry %

CaO	62.27
MgO	2.21
Al2O3	7.54
SiO2	22.64
Fe2O3	2.11

Volatiles %

LOI

3.20

Manufactured using limestone and shale. Powder is mixed and fired in a rotary kiln to near-stoneware temperatures. The clinker is finely ground to produce a grey powder that reacts with water to form a hydrous calcium silicate with some CaO left over.

Acids do attack cement however as soluble materials are removed less reactive remaining materials are quite stable.

Richard Willis

A relatively high-temperature calcinated mix of clay and lime which hardens quickly after wetted with water and left to air-dry. Unlike most “natural” clay cements, however, Portland’s bonding deteriorates under time, stress and weathering. Like all clay cements, Portland, behaving as a calcined calcareous earth, will fuse readily when fluxed and will melt at much lower temperatures than its required high calcinating temperatures. A simple brown glaze, for example, can be obtained at 900º ;C from a thick solution comprising equal parts of Portland and hydroboracite or minium.
typical analyses of compositions, after calcinated at 1300-1500ºC
“limestone”; 52% lime, 3% silica, 1% slumina, 0.5% iron, 0.5% magnesia, 42% burned away
“chalk”; 54% lime, 1% silica, 0.5% alumina, 0.2% iron, 0.3% magnesia, 43% burned away
“cement rock”: 43% lime, 11% silica, 3% alumina, 1% iron, 2% magnesia, 36% burned away
“clay”: 1% lime, 57% silica, 16% alumina, 7% iron, 1% magnesia, 14% burned away
“slag”: 42% lime, 34% silica, 15% alumina, 1% iron, 4% magnesia, 0% burned away

XML for Import into INSIGHT

<?xml version="1.0" encoding="UTF-8"?>
<material name="Portland Cement" descrip="" searchkey="" loi="3.20" casnumber="">
<oxides>
<oxide symbol="CaO" name="Calcium Oxide, Calcia" status="U" percent="62.275" tolerance=""/>
<oxide symbol="MgO" name="Magnesium Oxide, Magnesia" status="U" percent="2.215" tolerance=""/>
<oxide symbol="Al2O3" name="Aluminum Oxide, Alumina" status="" percent="7.549" tolerance=""/>
<oxide symbol="SiO2" name="Silicon Dioxide, Silica" status="" percent="22.647" tolerance=""/>
<oxide symbol="Fe2O3" name="Iron Oxide, Ferric Oxide" status="" percent="2.113" tolerance=""/>
</oxides>
<volatiles>
<volatile symbol="LOI" name="Loss on Ignition" percent="3.200" tolerance=""/>
</volatiles>
</material>