Cement Manufacturing
The manufacturing of Cement is a large scale energy intense process that operates 24/7. The process typically involves the operation of Rotary Kilns at high temperatures to achieve the Calcination (roasting or oxidization) of the raw feedstocks.
Cement is made primarily from a Limestone base (Calcium carbonate CaCO3) with a blend of alumina, silica, gypsum, other minerals, and iron.

Although, traditionally, the combustion of fossil fuels have been used as a source of heat for the kilns in the cement industry (oil, natural gas & coal) there has been a shift towards the use of Alternative Fuels.

Cement production is a significant generator of CO2 as an essential part of the oxidization process, traditionally these CO2 Emissions have been released to the atmosphere.

Concrete Products
Cement is blended with Aggregates (sand and gravel) to form Concrete Products. The cement component acts as a binder that hardens concrete into resilient shapes. Concrete is one of the most commonly used building products used worldwide. The recovery of end of life concrete structures makes Concrete Recycling one of the highest volume commodities reclaimed and reused.

Fuel Requirements
A major cost in the production of cement is the fuel to operate the kiln. In order to be economically competitive cement manufactures are constantly seeking cheaper alternatives. Traditional fossil fuels (oil, natural gas & coal) are shifting to the use of Alternative Fuels due to the appetite for calorific values in both the preheating stage and in the primary kiln burner.

Solid Recovered Fuel SRF
Solid Recovered Fuel SRF, also known as Specified Recovered Fuel (SRF), processes waste materials into specified sizing, calorific value and moisture content and may be pelletized or semi-densified.
RDF Refuse Derived Fuel, ash or residues and residual minerals may be directly incorporated into the Cement Clinker

Cement Clinker
Calcination (which is the process of heating a substance to a high temperature, but below its melting point, in the absence of air, to bring about thermal decomposition) takes place within a rotary kiln. This process produces an intermediary nodular material called clinker which is then further blended and pulverized to produce a particular recipe or quality of cement.

A wide number of minerals may be included in the mix of raw kiln feedstock to produce cement clinker, in addition, other minerals may be blended into the post kiln clinker. These minerals may include a mix of both virgin or recycled materials that contain lime, calcium, alumina, silica, gypsum and other materials that are acceptable within the tolerance for critical specifications for cement production.
In addition burner fuel ash or residues and residual minerals may be directly incorporated into the clinker. The potential exists to consume Non~Metallic Inorganic Content Composite Wastes.

Slag Cements
One common source of materials used as a feedstock in the manufacturing of cement is Blast Furnace Slag (BFS) generated as a by-product of the Steel Making process.

CO2 Emissions
A combination of high temperature Combustion and the kiln roasting process releases CO2 as a by-product from the reduction (oxidation) of limestone in the production of Cement Clinker.
In Traditional Cement Manufacturing it has been an acceptable practice to release the CO2 Emissions into the atmosphere. In an effort to become carbon neutral the industry is moving towards a closed loop emission capture and collection of the off gasses.
Some schemes propose the sequestration of the captured emissions, other methods utilize the captured CO2 as a primary raw feedstock in a Bio-Refining process.

Thermal Waste Destruction
Some Cement Kilns are used for High Temperature Thermal Waste Destruction for the neutralization of biological or pathological medical wastes as well as general and hazardous chemical wastes.
Cement Kilns may also be utilized as a waste treatment or disposal method for municipal solid waste and commercial wastestreams that are sorted and processed into Solid Recovered Fuel SRF as a kiln combustion heat source.