Abstract: A process for producing ammonia and sulfuric acid from a stream comprising ammonium sulfate is provided. The process comprises the steps of heating the stream to produce ammonia and a decomposition product comprising one or more than one of a bisulfate salt, a pyrosulfate salt, or a combination thereof. The ammonia produced is recovered, and water is added to the decomposition product to produce a stream comprising the decomposition product. The stream comprising the decomposition product is processed by acid retardation to obtain a sulfuric acid stream and a stream comprising one or more than one sulfate salt.

Abstract: The invention can be summarized as follows. There is provided a method of bleaching chemical pulp comprising the steps of exposing chemical pulp to a chemical bleaching state to produce a partially bleached pulp and treating the partially bleached pulp with a thermophilic, alkalophilic xylanase in an alkaline extraction stage at pH of 8 to 14. The method may be performed in a mill and may form part of a more complex pulp bleaching process. The invention also relates to the use of a thermophilic, alkalophilic xylanase in an alkaline extraction stage of a pulp bleaching process in a mill.

Abstract: A process for producing ammonia and sulfuric acid from a stream comprising ammonium sulfate is provided. The process comprises the steps of heating the stream to produce ammonia and a decomposition product comprising one or more than one of a bisulfate salt, a pyrosulfate salt, or a combination thereof. The ammonia produced is recovered, and water is added to the decomposition product to produce a stream comprising the decomposition product. The stream comprising the decomposition product is processed by acid retardation to obtain a sulfuric acid stream and a stream comprising one or more than one sulfate salt.