In flotation processes, the dangers of excessive reagents are often overlooked. Practical experience has shown that a decline in flotation indicators is often caused by excessive flotation reagents. The dangers of excessive flotation reagents mainly include the following:

(1) Dangers of excessive collectors. 1) Disruption of the selectivity of the flotation process. Extensive production practice and experiments have shown that when the amount of collector exceeds a certain range, the concentrate grade will decrease significantly. Even if the recovery rate increases slightly, it is still not worth the loss. 2) Excessive collectors will make it difficult to further refine frothy concentrates and separate mixed concentrates. In this case, the method of adding more modifiers is often used to remedy the situation. Due to the addition of more modifiers, the middlings containing excessive reagents return to the process, causing chaos in the flotation process, reducing flotation indicators, and forming a vicious cycle. In addition, excessive collectors require increased inhibitor dosage (e.g., excessive xanthate requires increased cyanide inhibitor dosage), which not only wastes reagents but also increases the toxic reagent content in tailings, causing pollution. 3) Excessive collectors can reduce the floatability of certain minerals. For example, excessive fatty acid collectors can reduce the floatability of oxidized minerals. This is because the collector forms a multi-layered reverse adsorption layer on the mineral surface, with polar groups facing outwards, making the mineral surface hydrophilic. 4) Excessive collectors can also form a large amount of foam, making it difficult to dewater concentrates and tailings, causing difficulties in concentration and filtration.

(2) Harm of excessive inhibitors. When inhibitors are excessive, the minerals to be floated may also be inhibited simultaneously with the inhibited minerals, leading to a decrease in recovery rate. In this case, in order to improve the floatability of the minerals to be floated, the amount of collector must be increased.

(3) Harm of excessive activators. This not only disrupts the selectivity of the flotation process but may also react with collectors to form precipitates, consuming large amounts of collectors. For example, when activating sphalerite, excessive copper sulfate can cause excess copper ions to react with xanthate in the pulp to form copper xanthate precipitate, increasing unnecessary consumption.

(4) Harmful effects of excessive frother. Excessive frother will create numerous sticky, fine bubbles, easily causing gangue minerals to adhere to the bubbles and reducing concentrate grade. If the raw ore contains a lot of mud, it will form a large amount of sticky foam, easily causing “foam overflow” accidents, resulting in a large amount of concentrate overflowing the froth tank and causing production chaos.

Strict control of reagent dosage is an important factor in improving flotation process indicators. Excessive reagents disrupt the selectivity of the flotation process, increase beneficiation costs, and directly or indirectly make it difficult to adjust the flotation process.