改性硅灰石在新闻纸造纸业中的双重环境效应

介绍了一种新型矿物填料——改性硅灰石在新闻纸中的应用。样品采自云南省腾冲县，加工成1250目的超细纤维，其长径比为15左右，经化学改性处理，添加到脱墨纸浆中制作新闻纸。实验室手抄片和工业试验结果表明，改性硅灰石能极大地改善再生新闻纸的白度、不透明度和适印性。加入有10％～15％改性硅灰石的新闻纸(定量44～47g／m^2)具有高白度(58％～60％)、高强度(裂断长3800～4000m)和高不透明度(95％～97％)，属高质量新闻纸。另一方面，由于改性硅灰石具有对油墨粒子、细小纤维和有机物有良好的吸附性，添加改性硅灰石的新闻纸在造纸过程中排出的废水易于处理，废水经简单沉淀后所含BOD和COD，以及重金属元素含量极低，达到综合排放国家一级标准。改性硅灰石在造纸业方面显现出保护森林和水体的双重环境效应，是造纸业中一种性能优秀的新型功能填料。

DUAL ENVIRONMENT EFFECTS OF MODIFIED WOLLASTONITE ON PAPERMAKING OF NEWSPRINT

Newsprint is indispensable in human being's life but the papermaking produces negative dual (environment) effects. The production of newsprint needs voluminous woods and this may destroy forests. Meanwhile, the processing of pulp preparation discharges voluminous waste water which remains one of the most troublesome problems in the pulp and paper industry. As environment and ecology problems (become) more and more severe, the papermaking enterprises are faced with or will be faced with a shortage of wood pulp supply and a difficulty of treatment of waste water. More and more waste newspapers have been used through de-ink processing. However, due to the brightness of de-ink pulp attains only 80% of its original newsprint and the brightness of recycling newsprint is usually less than 45% (ISO) if chemical blanching processing is not used. This limits the addition amount of de-ink pulp and the quality of recycling newsprint (mainly made up of de-ink pulp), and thus limits the debasement of production cost. Filler (utilization) in newsprint is a solution. However, addition of traditional filler (calcite, kaolin, talc, for (example)) into newsprint would result in a serious problem in debasement of strength and not be accepted for the high-speed newspaper printer. In this article, the results of application of a chain silicate mineral wollastonite in the newsprint papermaking are presented. Wollastonite from Tengchong County of Yunnan Province has been grinded into 1250 mesh powder with a length/width ratio of 15. And then the powder has been modified with some chemicals. The addition of the modified wollastonite into the de-ink pulp has been made just like the ordinary fillers. The hand sheet and industrial experiments showed that the modified wollastonite has greatly ameliorated the brightness, opacity and printbility of newsprint made up of de-ink pulp. The newsprint (44~47 g/m~2) containing wollastonite (10%~15%) shows remarkable properties: high brightness (58%~60%), high strength (3800~4000 m of breaking length) and high opacity (95%~97%), ranging in the newsprint in good quality. On the other hand, as the modified (wollastonite) has a good adsorption for the fine fibers and ink particles, the waste water discharged from the papermaking processing of newsprint containing wollastonite showed very low content of BOD, COD and heavy elements after a simple precipitation. This gives an economic way of producing high quality newsprint with de-ink pulp. The modified wollastonite displays significant dual environment effects in the protection of forests and water and can been used as a remarkable new filler in the newsprint papermaking industry.