Influence of Fine Mud on Flotation Process And Solution
In the flotation practice, in order to overcome the deterioration of the flotation process by the fine mud and eliminate the harmful effects of the fine mud, the following measures are often used.
Fine mud can be divided into primary fine mud and secondary fine mud. The primary fine mud is the fine mud formed by the natural weathering of minerals in the deposit, such as fine mud as kaolin and clay. Secondary fine mud refers to the fine mud produced in the process of mining, handling, crushing and grinding. Generally, the primary fine mud is more difficult to float than the secondary fine mud. In order to reduce the harm of fine mud to the flotation process, it is necessary to reduce the secondary fine mud as much as possible. In the flotation practice, in order to overcome the deterioration of the flotation process by the fine mud and eliminate the harmful effects of the fine mud, the following three measures are often used.
1. Add a dispersant to reduce the impact
When the fine mud is not too much, add a dispersant to reduce its influence. The dispersant is a pure electrolyte, and its function is to increase the electrodynamic potential of the fine mud surface. When the fine muds are close to each other, they repel each other due to the same electrical properties, so that the mineral muds play a dispersing role and prevent the non-selective agglomeration of the fine muds.
The method of adding dispersant is relatively simple, and is suitable for mineral flotation with less mud. However, this method still cannot fundamentally solve the shortcomings of poor selectivity and a large dosage of chemicals caused by fine mud, so it is often necessary to strengthen the selection operation in production practice.
2. Pre-slime removal before flotation
There are two main methods for pre-sliming: flotation desliming and mechanical desliming. Flotation desliming is to use a small amount of foaming agent and collector to first float a part of the sludge, and then carry out coarse flotation. Mechanical desliming is to use a desliming bucket to remove a part of fine mud before flotation, and the general particle size is 10-20 microns. The desliming grade is mainly determined by the performance of the classification equipment. After desliming, the effect of coarse flotation can also be improved.
3. Sediment sorting
The flotation of fine mud alone can effectively improve the influence of fine mud on the flotation process. The flotation of fine mud alone should follow the following four principles:
A. Use longer flotation times. The flotation time for fractions smaller than 10 microns is 40-60 minutes.
B. High-concentration pulping (up to 60%-70% pulp concentration), low-concentration flotation (generally below 20%).
C. Dosing in stages, increasing the amount of collector and reducing the amount of foaming agent.
D. Large air volume, small air bubbles, weaken the rising slurry flow.