Improving of deinking technology of printing recovered paper

Abstract

The possibility of improving the efficiency of deinking «МС-7Б» grade recovered paper from toner applied on a laser printer by dry two-stage dispersion before flotation was investigated. Recovered paper was used with a different level of toner print on one side of the paper: 2.5%; 3,9%; 8,2%; 60%. The degree of toner prints of office recovered paper was determined by the program «lpSquare v5.0 for Windows» as the ratio of the area of the printed area to the total area of the sheet in %. The level of cleaning recovered paper from toner embossments was determined using a graphic program that made it possible to establish the area of the black area. It has been that the developed recovered paper stock preparation technology involving two-stage dry dispersion and subsequent flotation effectively removes toner print area in paper samples. Toner print area in samples of paper obtained from floated recovered paper with preliminary two-stage dry dispersion are practically absent, unlike samples of paper from recovered paper ennobled with standard flotation. Assessment of mechanical properties of paper samples was carried out by changing the values of bursting and tinsel strength. It is shown that preparation of recovered paper stock by method of flotation with preliminary dry dispersion contributes to small increase of mechanical indices of paper samples. The mechanical properties of paper samples practically does not depend on the level of toner print area of recovered paper.