In the practice of flotation, in order to overcome the deterioration of the flotation process by fine mud and to eliminate the harmful effects of fine mud, the following measures are often adopted.
1 When the fine mud is not too much, add a dispersant to reduce its impact.
Generally be added to the water glass, phosphate, sodium hexametaphosphate. The dispersant is a pure electrolyte that acts to increase the electromotive force on the surface of the fine mud. When the fine muds are close to each other, they are mutually repelled due to the same electrical properties, so that the slime acts as a dispersion to prevent non-selective agglomeration of the fine mud.
The method of adding a dispersing agent is relatively simple, and is suitable for a case where the mud is less. However, this method still cannot solve the shortcomings such as poor selectivity and large dosage of chemicals caused by the fine mud, so it is often necessary to strengthen the selection operation in production practice.
2 remove the slime before flotation
There are two ways to remove mud beforehand: flotation de-sludge and mechanical de-sludge. Flotation de-slurry is to use a small amount of foaming agent and collector to float a part of the slime and then carry out coarse flotation. Mechanical desilting is the use of a classifier (such as a hydrocyclone) to remove a portion of the fine mud prior to flotation. The particle size of the general deliming is 10.20 microns. Deslimation grade is mainly determined by the performance of the classification equipment . After de-sludge, the effect of coarse flotation can also be improved. The main problem is difficult to deal with fine mud, fine mud useful if very little mineral content can be discarded, but often useful in fine clay minerals in ore grade and almost, if it abandoned on the Slimes metal lost in vain.
3 mud sand sorting
Process requirements for fine flotation of fine mud:
a. It is advisable to use a longer flotation time. According to the data, the flotation time of less than 10 micron size is as long as 40-60 minutes;
b. High concentration of pulp (up to 60%-70% pulp concentration), low concentration flotation (generally less than 20%);
c. Sub-dosing, increase the amount of collector, reduce the amount of foaming agent;
d. Large amount of inflation, small bubbles, weakening the rise of slurry flow.
In actual production, it is difficult to meet the above-mentioned fine mud flotation process requirements, so the index of fine mud flotation is not high. Although the above method of treating fine mud is used for production, it does not solve the special process of fine mud flotation. From the current research trend, there are two ways to increase the flotation speed of fine particles: one is to increase the particle size of fine flotation; the other is to reduce the particle size of flotation bubbles.
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