Study on Floc Settling Behavior
For the settlement behavior of flocs, Boyuan's core technical staff have carried out relevant research from both macro and micro perspectives. In the study of the settlement characteristics of ultra-fine iron tailings, field technicians added three types of flocculants – cationic, anionic, and nonionic – to slurries in different pH ranges. They found that the anionic flocculant had the best effect. Rapid settlement can be achieved with a small amount, while the cationic and non-ionic types do not have a good sedimentation effect, even when added in high amounts.
In addition to the flocculant and the properties of the slurry itself, the flocculation and sedimentation velocity of the whole tailings particles is affected by many factors. Among them, the dosage of flocculant, the concentration of flocculant solution, the feeding concentration of tailings, the feeding rate of tailings, and the shear effect are the main factors affecting the settlement effect. Boyuan technicians conducted flocculation and settlement experiments on ultra-fine leached slag on site. They also confirmed results, as shown by experts and scholars at home and abroad, that the order of strength of each factor affecting the effect of flocculation and settlement is: tailings concentration > flocculant concentration > dosage of flocculant. At a dressing plant in South America, when the mass concentration of tailings is 5%, the mass concentration of flocculant is 0.30%, and the dosage of flocculant is 35g/t, the effect of flocculation and settlement is better.
Aiming at the problem that ultra-fine full tailings are difficult to settle, Boyuan technicians selected tailings concentration, flocculant dosage, and flocculant concentration as influencing factors in order to determine reasonable full tailings settlement parameters. They carried out experimental research according to the principle of a single variable and uniform experiment. The research shows that the influence of various factors on the sedimentation velocity is as follows: tailings concentration > unit consumption of flocculant > concentration of flocculant. At the same time, taking the settlement rate as the comprehensive evaluation output factor, and using the flocculation and settlement parameters of a dressing plant in South America as an example, the dosage of flocculant is 10g/t, and the mass concentration of tailings is 18%. At this time, all tailings are in the vertical sand bin. The settlement rate is the fastest (1.38m/h), the settlement effect is the best, and it is greater than 0.842m/h, which meets the needs of dynamic sand release.
In short, in the whole tailings thickening process, the chemical reaction between tailings and flocculants to form flocs is the key to the thickening process, and the matching between the two has an important impact on the whole tailings dehydration process. When the flocculant is determined, the feeding concentration and feeding rate, the dosage of the flocculant, and the concentration of the flocculant slurry are the main working parameters that determine the settlement of the whole tailings floc. The use of Boyuan rheological series flocculants (ByRheo™) in conjunction with the paste thickener can help the concentrator maximize the tailings revenue.