Description

Thiourea dioxide (TDO) is a strong reductant which re-arranges under alkaline conditions to form formamidine sulphinic acid. This product is used in leather processing industry, paper, pulp and board industry, photographic industry, textile processing industry, bleaching and reducing agents. This product is also a component of decolorisation agents. TDO bleaching has recently come to be spotlighted as a substitute for NaClO bleaching in bleaching of waste wood-free or mechanical paper and as a substitute for Sodium Hydrosulfite bleaching in post-bleaching after hydrogen peroxide deinking/bleaching of waste newspaper, from the viewpoint of the problem of waste water pollution by organic chlorine compounds represented by dioxins, demand for energy conservation, decoloring effect on dye type coloring materials, etc. TDO bleaching has a considerable decoloring effect on dye type coloring materials, like Sodium Hydrosulfite bleaching, and TDO has a property of reacting with oxygen in air slowly as compared with Sodium Hydrosulfite. Even when a presently used NaClO bleaching equipment is diverted as it is, a loss due to oxidative decomposition is relatively small and a bleach brightness equal to that attained by NaClO bleaching can be attained by choosing a suitable using amount of TDO. TDO undergoes relatively rarely oxidative decomposition by oxygen in air. TDO bleaching is suitable for bleaching pulp having a high consistency by usual equipment while achieving a saving in energy. TDO has been very effective on a wide variety of pulp sources as a reductive bleaching aid in the pulp and paper industry. The application of TDO is crucial to achieve optimal brightness gain in the deinking process. Handling and Storage