Two recent developments at Queens Carbon Inc. (Pine Brook, N.J.; www.queenscarbon.com), a spinoff company from Rutgers University (New Brunswick, N.J.; www.rutgers.edu), illustrate the potential for reducing the high carbon-dioxide emissions that result from cement and concrete production. Both are results of the company’s Q-System technology platform (diagram).
“The Q-System uses thermochemical pathways driven by steam, pressure and moderate industrial heat, rather than direct combustion and extreme industrial heat,” explains Daniel Kopp, Queens Carbon CEO. “By carefully controlling the reaction environment, we’re able to drive phase-transformation reactions that typically occur in a rotary kiln [for traditional cement production], but at less than half the temperature. This makes the process fundamentally electrifiable, economically attractive and substantially lowers the barriers to decarbonizing cement,” he explains.
The first product from the Q-System is a zero-CO2 engineered supplementary cementitious material (SCM) that the company calls Q-SCM. SCMs are finely ground solids added to concrete to enhance its properties and reduce the amount of Ordinary Portland Cement (OPC) needed as a concrete binder. The company is now operating a small pilot plant for Q-SCM at its R&D facility in N.J. A larger (10 ton/d) pilot plant is planned for late 2026 at Buzzi Unicem USA’s cement production facility in Stockertown, Pa.
The Q-SCM process starts with cement raw-meal — a mixture of limestone and sand/clay feedstocks. “Q-SCM is a synthetic pozzolan made of a mixture of activated limestone, sand and clay,” explains Kopp. “Initially, the low-carbon Q-SCM will replace OPC at rates of 20–30%, and we are working toward 50% substitution of cement with Q-SCM,” he says.
“Uniquely, the Q-System co-produces a pure stream of CO2 without requiring additional purification, avoiding the costly and complex chemistry of traditional post-combustion carbon capture,” Kopp continues. The CO2 from limestone is locked inside the chemical structure of Q-SCM (the CO2 never leaves the Q-System, although there is a chemical transformation that occurs), he says.
A second product is also planned on Queens Carbon’s Q-System. Known as Q-Cement, the second product is a low-carbon, hydraulic cement substitute for OPC that can be made on the same platform. “The feedstocks, conditions and outputs are tuned differently depending on whether the product is a hydraulic cement or SCM,” Kopp points out.
The company aims to partner with the cement industry, providing advanced technology and equipment that will enable producers to continue making cementitious materials — now with zero CO2 emissions.