【摘要】 笔者取长江口铜沙浅滩的沉积物,配制成浓度为7.5克/升的悬浊液,利用沉降天平观察,分析了不同盐度下絮凝临界粒径、临界盐度即絮凝体峰值粒径达最大的临界盐度和絮凝体沉速达最大的临界盐度。絮凝体的沉速和在静水环境下絮凝趋于完全所需要的絮凝时间。更多还原

【Abstract】 Based on the sediment samples from the Tongsha Shoal in Changjiang estuary which were prepared with a turbidity of 7.5 g/l, the critical grain size and critical salinity for the fine-grain sediment to flocculate were studied with a settling balance. The critical grain size is about 32μm, above which the sediments do not flocculate obviously and below which the sediments flocculate markedly. There are two kinds of critical salinity as presented in the paper. One is about 3.00×10-3 above which the floc mode grain size no longer gets coarser with the increase of salinity, The other is about 13.00×10-3 at which the floes settling speed reaches maximum. The settling speed of floes is three to seven times faster than in distilled water and the time for the finegrain sediments to flocculate completely is about 173 seconds.更多还原