Date of Award


Degree Name

Master of Science


Chemical and Paper Engineering


Paper Engineering, Chemical Engineering and Imaging

First Advisor

Dr. John Cameron

Second Advisor

Dr. David Peterson

Third Advisor

Dr. Peter Parker

Access Setting

Masters Thesis-Open Access


Borate autocausticizing can replace - total autocausticizing, or supplement the kraft lime cycle- partial autocausticizing. Partial autocausticizing is undergoing trials in several mills and has been recently commercialized in one mill. One common observation in the on-going trials is that the causticizing efficiency increases. The primary objectives of this research are to study the effect of metaborate on the causticizing rate, equilibrium and rate controlling parameters such as the temperature, concentration and sulfidity. The aim is to define the conditions that resulted in the increase of the causticizing efficiency.

The major findings of the research are that when the causticizing reaction is rate limited, which is true in commercial operations, partial borate autocausticizing can increase causticizing efficiency due to the higher initial hydroxide content, temperature is a critical factor and has to be monitored and maintained to achieve good causticizing efficiencies, and the effect of sulfidity on the causticizing reaction rate and equilibrium is less pronounced with the presence of borate in the system.