硅含量及苛化方法对竹浆绿液苛化白泥的影响

Effects of Silicon Content and Causticization Method in Bamboo Pulping Green Liquor on the Property of Lime Mud

碱回收白泥是造纸行业的主要污染物之一,白泥是带有残碱的高碱性二次污染物。以非木材纤维为原料的制浆造纸企业,由于白泥的硅含量高,碱回收有严重的硅干扰,白泥不能全部再生回用。若对白泥进行填埋或堆放,其中的有害成分,特别是碱会对环境造成严重污染。本研究利用铝盐改性膨润土获得铝基膨润土(AlMB)吸附除硅,通过调节AlMB的用量,得到不同硅含量的竹浆绿液,再将不同硅含量的绿液分别采用两种苛化方法进行苛化,得到不同硅含量、不同苛化方法的白泥。实验对比分析了白泥白度、粒径和晶体形貌、硅含量以及苛化方法对白泥性能的影响。结果表明,硅的存在对竹浆绿液苛化效率、苛化所得白泥的白度和匀整性不利,而经过AlMB除硅并结合间歇式苛化法则能有效地改善绿液苛化效率及苛化白泥的质量。

In this paper,the silicon in the green liquor from bamboo pulping chemical recovery was removed by adding aluminum salt modified bentonite.Through controlling the dosing amount of Al-based bentonite,the bamboo green liquor containing different silicon contents was obtained.Then,the green liquor with different silicon contents was causticized by two kinds of causticization processes i.e.rapid causticization and batch causticization respectively,the lime mud calcium carbonates with different contents of silicon prepared by using different causticization processes were obtained.The whiteness,particle size and crystal morphology of the obtained lime mud calcium carbonate were measured,and the influence of the silicon content and the causticization process on the properties of the lime mud calcium carbonate was analyzed.The results indicated that the presence of silicon was detrimental to the causticization efficiency of bamboo pulping green liquor,and the whiteness and uniformity of lime mud calcium carbonate.The batch causticization method could effectively improve the causticizing efficiency of green liquor and the quality of the corresponding lime mud calcium carbonate.