Solid-liquid separation of colloidal suspensions by use of gelation of natural polymers

提出了一种利用天然高分子的凝胶化反应对难滤性胶体悬浮液进行固液分离的新技术。将胶体悬浮液与海藻酸钠溶液混合，并将该混合物滴在氯化钙溶液上。产生包括胶体颗粒的藻酸钙凝胶。研究了海藻酸钠凝胶的制备条件。以膨润土颗粒作为难滤胶体的实验材料。使用均高于1000 ppm的海藻酸钠溶液和氯化钙溶液，可以得到具有足够强度用于重力排水的球形海藻酸钙凝胶。根据压缩渗透性测试，凝胶网络的网孔尺寸估计为亚微米尺寸：网孔尺寸足够小以捕获胶体颗粒。膨润土-藻酸盐凝胶，含有钙。10 - 20wt%的藻酸盐显示最大表达率，因为膨润土-藻酸盐凝胶的比流体动力学阻力是原始膨润土污泥的百分之一。

A novel technique for solid-liqued separation of difficult-to-filter colloidal suspensions has been proposed by use of gelation reaction of natural polymers. Colloidal suspensions are mixed with a sodium alginate solution and this mixture are dropped on a calcium chloride solution. resulting in calcium-alginate gels including colloidal particles. Gel suspensions are then drained gravitationally, followed by mechanical expression of gels.Preparation conditions of colloid-inclusion alginate gels are studied. Bentonite particles are used as experimental materials of difficult-to-filter colloids. Using sodium alginate solutions and calcium chloride solutions of both above 1000 ppm, one can get spherical calcium-alginate gels with sufficient strength for gravitational drainage. The mesh size of gel network was estimated as a size of sub-micro meters from the compression-permeability test : the mesh size is small enough to trap colloidal particles. Bentonite-alginate gels which contain ca. 10 - 20wt% of alginate show the maximum expression tate, since the specific hydrodynamic resistance of the bentonite-alginate gels is one hundredth of original bentonite sludge.