Mar 24, 2009. /Lesprom Network/. Waste products of the paper industry can be used to make clinker for cement production, according to Portuguese scientists in the International Journal of Materials Engineering Innovation. Chemical processing of wood to make pulp for paper manufacture usually involves a chemical treatment with sodium hydroxide and sodium sulfide, which produces good quality pulp but also releases large volumes of waste materials. Incorporated into construction materials, however, would not represent a health or environmental risk and prevents the need to send millions of tonnes of dregs and grits from the world's paper mills to landfill. The researchers have carried out industrial trials with conventional raw clinker and clinker to which they added grits and dregs at 0.25% and 0.13%. They processed the materials as they would normally be treated for cement production and then tested their chemical composition and leaching behaviour. The resulting products are just as robust as conventional cement and do not degrade to release toxic components. "Our results show that such incorporation could be an effective process for waste management from both the environmental and economic points of view," the researchers conclude.