Page 340 - Design for Environment A Guide to Sustainable Product Development

Materials Pr oduction Industries 315

• Nitrous gas emissions are lower than many U.S. coals,
particularly the high-sulfur coals.
To monitor the eco-efficiency of clinker production, Holcim (US)
uses four key performance indicators:

1. Clinker factor—the percentage of clinker in cement
2. Thermal energy efficiency—energy consumed per ton of
clinker produced
3. Thermal substitution rate—percentage of fossil fuels
replaced by alternative, waste-derived fuels
4. Cement kiln dust disposal rate—kg of CKD not recycled
per ton of clinker

Envirocore™ Family of Products
In addition to process improvements, Holcim has introduced product
innovations aimed at improving both the functional and environ-
mental performance of its cement products. Envirocore™ Blended
Cements are designed to meet all general construction uses, to incor-
porate eco-efficiency strategies, and offer additional benefits, such
as sulfate attack resistance, reduced heat evolution, alkali-silica reac-
tion resistance, and high early strength. The following are examples
of these products.
Holcim Performance Cement (HPC ) is a family of blended
®
cements designed to meet the increasing performance demands,
higher standards and specifications, and environmental constraints
being placed on today’s construction industry. They are manufac-
tured by intergrinding or interblending a pozzolanic substance (typi-
cally fly ash from power plants) with conventional clinker. The
primary ingredients in HPC are Portland Cement clinker, fly ash
®
and gypsum ground to a fine powder. Fly ash is primarily silicate
glass containing silica, alumina, lime, and iron, and certain fly ashes
exhibit both pozzolanic and cementitious properties. A by-product of
cement hydration is calcium hydroxide, which is water soluble, and
pozzolans react with the calcium hydroxide to form other cementi-
tious compounds, creating a denser, more durable concrete.
®
Enviroset is a family of dry blended alkaline reagents for solidi-
fication and stabilization, designed specifically for the environmental
remediation industry. Alkaline reagents have been generally recog-
nized as the preferred products for remediating sludges containing
®
heavy metals, oils, and solvents. Enviroset is unusual in that the cus-
tomer plays a major role in designing the final product. Samples of
components are sent to the customer’s lab for bench testing with the
actual waste stream to be remediated. After evaluation, Holcim will
dry blend the reagents in the proportions required by the customer,
and in the quantities needed for successful completion of the project.