A strategic alliance between Sika AG, Switzerland, and fly ash beneficiation specialist Ash Improvement Technology, New York, will support development of binder products that reduce carbon dioxide emissions tied to portland cement milling. It is the latest in a series of ventures—Calera Corp., Ceratech Inc., Flyanic LLC, Solidia Technologies—inside or outside the concrete industry aimed at a) maximizing coal combustion byproducts’ aggregate-binding capability; or, b) commercializing low-carbon alternatives to ASTM C150 product.
“Construction markets worldwide are demanding innovation for more environmentally sustainable cement and concrete,” says Sika Senior Vice President, Concrete Producers, Phillippe Jost. “Technologies such as CleanCem are an inherent part of Sika’s strategy towards the future.”
The proprietary CleanCem process converts coal ash into a high-value substitute for cement, AIT officials note. It treats ash as it is formed during power plant coal combustion, they add, netting a cost-effective material offering production flexibility and meeting performance levels equal to a number of end uses. The process reduces a key indicator for concrete-grade fly ash, LOI (loss on ignition) or carbon content, partly through the introduction of sorbent into the boiler. That fosters comminution, or grinding through particle collisions, and better coal-combustion efficiency, which in turn affects the ash’s LOI level.
CleanCem was developed by AIT co-founder Wayne Fried, a structural engineer from New York who had previously worked on Ceratech’s binder technology, combining fly ash and liquid admixtures. His idea was based on the simple recognition that a cement kiln and coal-fired power plant boiler have two common elements, both fundamental building blocks in powder production: a source of intense heat, and minerals rich in metal oxides such as calcium, aluminum and silica. The AIT process aims at complementing these elements, which are already present in the boiler, with missing materials that facilitate mineralogy changes and yield ash of more cementitious quality than conventional ASTM C618 product.
“Coal ash is a perfect material to substitute [portland cement] clinker, hence reducing CO2 emissions inherent to cement production and the environmental toll of large ash disposal sites,” says AIT CEO Marc Zacharias. “Sika’s innovative strength and [global] footprint will help accelerate implementation of our technology and satisfy pressing demand we are seeing in multiple markets.” AIT has a sub-scale CleanCem process demonstration at Western Research Institute in Laramie, Wyo., he adds, and is in discussion with utilities on full-scale installations.
Zacharias joined Fried in co-founding AIT after 10-plus years in cement and concrete industry executive marketing posts. As Grace Construction Products business director, he developed a new unit serving markets related to sustainable building products, including extensive research and strategic investments in fly ash beneficiation technologies. Prior to Grace, he was Lafarge Group director of marketing. He holds a Harvard MBA and master’s degrees in Industrial Engineering from Ecole Centrale Paris and Universidad Politecnica de Madrid.