Search results
Results from the WOW.Com Content Network
Concrete is a composite material consisting of aggregate (gravel and sand), cement, and water. As a construction material, concrete can be cast in almost any shape desired, and once hardened, can become a structural (load bearing) element. Concrete can be used in the construction of structural elements like panels, beams, and street furniture ...
A raw mill is the equipment used to grind raw materials into "rawmix" during the manufacture of cement. Rawmix is then fed to a cement kiln, which transforms it into clinker, which is then ground to make cement in the cement mill. The raw milling stage of the process effectively defines the chemistry (and therefore physical properties) of the ...
In 2013, 70.8 percent of portland cement was sold as ready-mix concrete, such as is delivered in cement-mixer trucks. 11.5 percent was sold dry to contractors and construction materials stores; 11.3 percent was sold to manufacturers of concrete products; 4.6 percent was sold for oil and gas wells, and 1.8 percent was sold to government agencies ...
In this process, the steps of raw material processing, fuel preparation, clinker burning and cement grinding constitute major emission sources for particulate components. While particulate emissions of up to 3,000 mg/m 3 were measured leaving the stack of cement rotary kiln plants as recently as in the 1960s, legal limits are typically 30 mg/m ...
Scrap automobile and truck tires are useful in cement manufacturing as they have high calorific value and the iron embedded in tires is useful as a feed stock. [84]: p. 27 Clinker is manufactured by heating raw materials inside the main burner of a kiln to a temperature of 1,450 °C. The flame reaches temperatures of 1,800 °C.
Concrete recycling is the use of rubble from demolished concrete structures. Recycling is cheaper and more ecological than trucking rubble to a landfill. [1] Crushed rubble can be used for road gravel, revetments, retaining walls, landscaping gravel, or raw material for new concrete
Portland cement is usually made from cheap, quarried raw materials, and these usually contain substantial amounts of Cr, Mn and Fe. For example, limestones used in cement manufacture usually contain 0.3-1% Fe 2 O 3, whereas levels below 0.1% are sought in limestones for white manufacture. Typical clays used in gray cement rawmix may contain 5 ...
The second raw material (materials in the rawmix other than limestone) depend on the purity of the limestone. Some of the second raw materials used are: clay, shale, sand, iron ore, bauxite, fly ash and slag. Portland cement clinker is made by heating a homogeneous mixture of raw materials in a rotary kiln at high temperature. The products of ...