Patent ID: 8268119

Claim:
A method of manufacturing cellulose fibers having reduced chemical oxygen demand (COD) components adapted for use in fiber-reinforced cementitious products, said method comprising: processing a fibrous material in a reactor to form a brown stock pulp; washing said brown stock pulp through a series of aqueous solutions at elevated temperatures, wherein the temperature of each of said aqueous solutions is greater than 65° C.; removing said washed brown stock pulp from the series of aqueous solutions; soaking said washed brown stock pulp in a series of diffusion solutions at elevated temperatures, wherein the temperature of each of said diffusion solutions is greater than 65° C., wherein the individual retention time of the washed brown stock pulp in each of said diffusion solutions is between about 30 minutes to 2 hours, wherein the cumulative retention time of the washed brown stock pulp in the series of diffusion solutions is greater than 7.5 hours and less than 36 hours; and processing said washed brown stock pulp to form cellulose fibers having a COD content of less than about 5 kg/ton of oven dried pulp.