Process for pulping and cleaning of papermaking raw materials containing impurities

摘要

The procedure for suspending and cleaning of fibrous material containing waste paper, comprises mixing the waste paper with water and dissolving the mixed paper to the fibrous material suspension, supplying unsorted partial flow of this suspension into a depositing device (4) and into a closed sieve apparatus (7) by a pumping apparatus (2), and enriching the fibrous materials held back at a sieve (3) in the sieve apparatus. The partial flow in the closed sieve apparatus is sorted with the sieve, by which accepted material leads through. The procedure for suspending and cleaning of fibrous material containing waste paper, comprises mixing the waste paper with water and dissolving the mixed paper to the fibrous material suspension, supplying unsorted partial flow of this suspension into a depositing device (4) and into a closed sieve apparatus (7) by a pumping apparatus (2), and enriching the fibrous materials held back at a sieve (3) in the sieve apparatus. The partial flow in the closed sieve apparatus is sorted with the sieve, by which accepted material leads through. The fibrous material is led from sieve apparatus continuously or in adjustable time intervals. A recirculation flow is led back from the pressure pipeline of the pumping apparatus into the depositing device. The dissolving is accomplished in a pulper (1). The accepted material is continuously removed from the pulper by a pulper sieve (12). The partial flow is not removed by the pulper sieve defined for the accepted material. The partial flow in its solid composition is rougher than the accepted material of the pulper. The sieve apparatus is used with even sieve, which is held freely by a central rotor. The fibrous material is removed from sieve apparatus as rejection in time intervals. The rejection is rinsed out by gush-like water addition into the sieve apparatus. The recirculation flow is separated at the position of the pressure pipeline, which is distanced from an intake in the sieve apparatus in maximum 1 m. The sieve apparatus is operated with vertically standing axis and that the accepted material chamber is arranged above the sieve. The pipeline between the rejection outlet in the sieve apparatus and the sorting device contains no pressure increasing apparatus. The sorting device stands geodetically 3 m higher than the sieve apparatus.