Chelating agents in eucalyptus kraft pulps: II. Different chelant agents addition in brown stock washing

FELISSIA, F.E.; AREA, M.C.

Campinas, Sao Paulo, Brasil

Congreso; Congreso Ibero Americano de Investigación en Celulosa y Papel , CIADICYP 2002; 2002

RIADICYP-USP

Adding chelants in brown stock washing is a valid alternative to remove harmful ions before the oxygen stage. This work studied chelating agents application during Eucalyptus spp. kraft brown stock washing. Pulps were therefore prepared to be bleached by a TCF procedure afterwards. Phosphonates known as DTPMPA (diethylene triamine penta(methylene phosphonic acid)), SPAP (Sodium salt solution of Polyaminophosphonic acids), HEDP (1-Hydroxy ethylidene diamine (1, 1-diphosphonic acid), EDTA (ethylene diamine tetraacetic acid), and an acid washing, were evaluated in the brown stock washing step. When DTPMPA and SPAP were added, Mg, Cu and Fe levels did not show significant differences while Mn reduced to very low levels. HEDP did not produce any difference in metallic ions content as contrasted with pulp without treatment. Results evidence great advances in Mn remission before the oxygen stageand without any Q separate step.