Polymer Adsorption
Adsorption measurements on all the solids were carried out by the methods described above. Figure 2 shows a typical isotherm for the adsorption of polymer A on coal. The adsorption density rises monotonically until an apparent plateau is reached. For the case shown in Figure 2, the plateau occurs at an adsorption density of about […]
Flocculation & Lewis Acid-Base Theory
The use of synthetic polymers such as polyacrylamide and its derivatives to dewater mineral-processing waste streams has become commonplace. The use of polymers often solve many of the solid-liquid separation problems encountered by the industry. However, using polyacrylamides to dewater clay containing minerals such as montmorillonite and kaolin often produces a dewatered material containing a […]
Thickener Operation and Flocculant Application
At start-up, the relatively high level of feed solids, 17-20%, called for in design led to difficulties in achieving the degree of flocculation necessary to meet required settling rates. It was recognized that decreasing feed solids would improve thickener performance while reducing flocculant consumption (Figure 2). This was accomplished by recycling thickener overflow to the feed […]
How to Determine Flocculant Density
The density of a Flocculant is usually evaluated by measuring its buoyant density while settling in a quiescent column. An equation of the general form (Matsumoto and Mori, 1975) is used to calculate the buoyant density (pa), from settling rate (U) and diameter of floc (Df). The constants Kf, α, β and γ depend on shape, porosity […]
Electrodewatering of Muds
Research was conducted by the Bureau of Mines to determine the feasibility of using electrokinetic densification to dewater Bayer process red mud, magnetic black mud prepared by pressure digestion of red mud in the presence of ferrous sulfate, and magnetic black mud formed by simulated Bayer digestion of Jamaican bauxite with added ferrous sulfate. Tests […]
Calcium Montmorillonite Flocculation
The flocculation process involving fine particles and organic polymers can be depicted by the following sequence: adsorption of the polymeric species on particles, conformational changes in the adsorbed polymer molecules, and collisions between particles to form flocs through bridging. Flocculation is the result of mixing the polymer with the particle slurry in some device, e.g., […]
Thickener Performance Optimization
The results of this study can be shown as counter plots. Due to the variety of experimental runs and generation of numerous plots it would be beyond the limits of this paper to discuss all of the cases. Therefore, the discussion will be based on the plots given in Ghalambor (1980), and only a few […]
Laboratory Continuous Dynamic Thickening Tests
Dynamic tests were conducted in a laboratory continuous thickening system. This system, shown in Figure 1, consists of a 3½ in. (89 mm) ID and 20 in. (508 mm) height lab thickener/clarifier equipped with feed, polymer and underflow pumps, bed level sensor and controller. Rake speed, the gap between the deflector plate and feed pipe, […]
Flocculant Mixing System & Dosage Strength Dilution
Sludge Dewatering by Pressure Filtration
Pilot test results with 30% refuse slurry suggested the installation of two (2) Passavant Pressure Filters, Model 20 with 150 chambers each and a cake thickness of 40 mm. Each filter plate is 2m x 2m in size and the total cake capacity of each filter is 762 cu. feet. The sludge pumping requirements, per […]