柔印报纸电浮选脱墨技术

从含有电解池的半连续浮选机,用于从报纸纸浆中收集油墨。一般情况下,制浆时间过长不利于柔印旧报纸或新闻纸印刷品100%脱墨,但升温有助于脱墨。然而,当施加电场后,延长制浆时间,如从5min到25min,通过测定有效残余油墨浓度（ERIC）百分比变化发现,制浆效率提高了5%。在电场的作用下,温度增加,从25℃到40℃,脱墨效率将提高5%。本文通过以下变量进一步讨论了施加电场对浮选脱墨的影响：碱量（氢氧化钠含量）,悬浮物的浓度（纸浆悬浮液固体百分比）,非离子表面活性剂和阴离子表面活性剂含量,以及柔印报纸在混合纸浆中的比例。与100%柔印报纸不同,由48%的柔印报纸、30%的胶印报纸和22%旧杂志（OMG）组成的混合废纸中因包含柔印和胶印两种油墨,具有不同的粒径和化学成分,施加电场可使脱墨效率平均提高3%。在氢氧化钠、非离子表面活性剂和阴离子表面活性剂与电场共同作用下,浮选浓度达到1%时脱墨效率最高。通过热重分析（TGA）验证了脱墨效率。根据脱墨选择性参数（即加权系数Z）对脱墨效率进行了讨论。

Electroflotation Combined with Flotation Deinking of Flexographic Newsprint

A semicontinuous flotation cell,which incorporates an electrolytic cell,was used to collect inks from newsprint pulp slurry.In general,longer pulping time has an adverse impact on deinking of 100%flexographic old newspaper or newsprint （flexo-ONP） while temperature has a positive impact on deinking.However,the use of electric field improved deinking efficiency -measured by the percent reduction in effective residual ink concentration（ERIC）-by as much as 5%at longer pulping time （25 min compared to 5 min）.Higher temperature（40℃compared to 25℃） combined with the use of electric field further improved deinking efficiency by 5%.Furthermore,the impact of electric field assisted flotation is discussed in the context of the following variables：alkali charge（sodium hydroxide）,float consistency（percent solids in the pulp suspension）,surfactant and soap concentration,and the amount of flexo newsprint in a mixture of newspaper（or furnish）-newsprint.Unlike 100%flexo-ONP, the mixture of 48%flexo-ONP,30%offset-ONP and 22%old magazine（OMG） contains both flexographic and offset inks,which have different ink sizes and chemistries.On average,considering all the variables,the use of electric field improved deinking efficiency by 3%.The best deinking efficiency was achieved at 1%consistency,when sodium hydroxide and surfactant and soap were added,combined with electric field.The deinking efficiency was corroborated with thermogravimetric analysis （TGA）.Deinking efficiency is also discussed in terms of a deinking selectivity parameter called the Z-weighted factor.