Process for making wood composite employing blast-furnace slag as the

Abstract

A novel method of making a wood composite employing cellulosic material as the wood component and pulverized blast-furnace slag as the binder component and the product produced thereby is disclosed. A settable mixture of the wood component, binder component and water is prepared and thereafter subjected to a forming pressure within a confined space. While in its confined condition, the mixture is also subjected to heat and carbon dioxide (CO.sub.2) for a time and at a temperature sufficient to cause accelerated and early setting of the mixture. Optionally, calcium-rich compounds can be added to the settable mixture as a slag cement binder enhancer and sodium silicate can also be used as a mineralizer. The cellulosic material can also be pre-treated with a fire retardant resulting in a cementatious wood composite exhibiting improved fire resistance and in situ fire load bearing strength. Slag cement is plentiful, being a by-product of steel mills, but as a binder, is significantly less expensive than Portland cement. Employing CO.sub.2 injection, comparable set times for slag and Portland cements can be obtained, but the wood composite employing a slag cement binder has superior final strength.