EFFECT OF DEINKING ON OPTICAL AND PHYSICAL-PROPERTIES OF SECONDARY FIBER AFTER PULPING AND FLOTATION

furnishes of mixed magazines and newsprint and all magazines and all-n ewsprint were used to investigate changes in properties of secondary f ibre during deinking. In most cases, optical and physical properties s howed reverse trends after pulping and flotation stages. These differe nces can be explained by the change in proportions of mechanical and c hemical fibres, filler, fines and ink during flotation. After the pulp ing stage, trends in strength properties were influenced by detrimenta l effects of filler from magazines. However, after the flotation stage , due to loss of most of the filler and fines, an enhancement in all s trength properties occurred. Brightness and light absorption coefficie nt appeared to be more influenced by ink content, then large amounts o f filler are present. The light scattering coefficient was dominated b y the fibre type. After flotation, despite the highest brightness valu e, the all-magazine furnish had the highest ink speck count. Extended periods of flotation (greater than ten minutes) had no significant eff ect on properties of the waste paper investigated.