Flotation reagents are mainly used to regulate the floatability of minerals. The purpose of reasonably adding flotation reagents is to ensure that the optimum concentration of the flotation reagents is maintained in the pulp for maximum efficacy. In actual production, it is necessary to reasonably select the addition location and method of flotation reagent according to the nature of the ore and the characteristics of the flotation reagents.

Addition location of the flotation reagents

The choice of the addition location of flotation reagents is usually related to the usage and solubility of the flotation reagents. In order to fully utilize the action of the flotation reagents, the selection of the addition location is usually the following.

Add flotation conditioners, inhibitors and part of collectors to the ball mill to create a suitable flotation environment as early as possible.

The flotation collectors and foaming agents are typically added to the first agitation tank of the flotation process. If there are 2 agitation tanks in the flotation process, then the activators should be added to the first agitation tank and the collectors and foaming agents should be added to the second agitation tank.

Depending on the role of the flotation reagents in the flotation cell, the addition location of the flotation reagents is different. For the three flotation reagents of copper sulfate, xanthate and pine oil, the general order of addition is that copper sulfate is added to the center of the first agitation tank, xanthate is added to the center of the second agitation tank, and pine oil is added to the outlet of the second agitation tank.

Addition method of flotation reagents

The way in which flotation reagents are added is usually divided into one-time additions and phased additions.

One-time addition means that all the flotation reagents are added to the slurry at one time before the flotation is carried out, which is beneficial to increase the initial speed of the flotation process and is convenient to add. But, as the flotation process progresses, the flotation speed will slowly decrease. However, the overall flotation time is still short, which can improve the efficiency of flotation to a certain extent. The method of adding flotation reagents is mainly applicable to the flotation reagents which is easily soluble in water and which is not easily carried away by the foam, and which does not fail in the slurry due to the reaction, such as xanthate, Sodium bicarbonate and lime.

Phased addition means that the flotation reagents is added to the slurry multiple times during the flotation process. Generally, 60%-70% of the total amount of flotation reagents is added before the flotation, and the remaining 30%-40% of the flotation reagents is added to the appropriate place during the flotation process. Such a flotation reagents addition method is beneficial to improve the quality of the concentrate. However, due to the low speed of the initial reaction during the flotation process, the entire flotation time will increase. Phased addition is mainly applicable to the following types of flotation reagents:

(1) The flotation reagents that are difficult to dissolve in water and are easily carried away by mechanical foam, such as oleic acid and fatty amine collectors, which require phased additions to ensure their effectiveness.

(2) The flotation reagents that are easily decomposed during the reaction with the slurry, such as carbon dioxide and sulfur dioxide. If it is added only once, it will soon be ineffective with the reaction of the slurry, so it is necessary to add in batches to achieve the effect of continuous reaction.

(3) The flotation reagents whose dosage requires strict control, such us sodium sulfide. When the local concentration is too large, the selection effect of the flotation reagents will be weakened. Therefore, it is necessary to add in batches to ensure that the concentration of the flotation reagents is maintained to a certain level.

The above describes the selection of the addition location and method of the flotation reagents. It is necessary to choose the appropriate addition location according to the use and reaction sequence of the flotation reagents. First, a part of the medicine is added to the ball mill to create a flotation environment in advance, and then add other flotation reagents in suitable place of the flotation cell according to the effect of each kind of flotation reagents, ensure that it can play its biggest role.

At the same time, it’s necessary to select the appropriate addition method according to the nature of the flotation reagents. If the flotation reagents is readily soluble in water and does not fail in the reaction, one-time addition method can be adopted. On the other hand, if the flotation reagents is hardly soluble in water and is easily decomposed, it is more advantageous to adopt the method of phased addition. Except that, the addition method should also be adjusted according to the nature of the ore. For example, in some preferential flotation processes, in order to reduce the side effects of the inhibitor on the floating minerals, the collector is usually added in stages to improve the flotation efficiency.