What is the role of lime in the flotation of sulfide ore?

Lime is a commonly used regulator for sulphide ore flotation. It can be adjusted alkaline pulp, to suppress iron sulfide ore, slime and having coagulating function. It is widely used and cheap, and is one of the main agents for sulfide ore flotation.

When using xanthate to collect sulfide ore, it is often required that the slurry is alkaline, and lime is generally used to adjust the pH of the slurry.

Lime is an inhibitor of iron sulfide ore (pyrite, pyrrhotite, pyrite). Associated copper sulfide, lead sulfide, zinc ores often include pyrite, sulfur, arsenic, iron, in order to better floating copper, lead and zinc minerals, lime necessary to suppress iron sulfide minerals.

When the inhibited iron sulfide mineral content is relatively small, the slurry can be adjusted to pH = 9 or more with lime. If the content of the iron sulfide ore is relatively high, the pH of the slurry should be adjusted to 11 or more with lime.

It should be noted that the lime lead ore, especially the slightly oxidized galena on the surface, also has a certain inhibitory effect. Thus, when the metal sulphide ore flotation more gold from galena, generally adjusting the pH with sodium carbonate instead of limestone. If it is necessary to use lime to suppress due to high pyrite content, care should be taken to control the amount of lime and minimize the influence of the lead.

Lime itself is a kind of coagulant, which can make the slime gather and, to a certain extent, eliminate the harmful effect of the slime on the ore cover. In addition, due to this coagulation, when the amount of lime is appropriate, the foam can be maintained at a certain viscosity with appropriate stability. However, if the dosage is too large, the fine particles are condensed in the foam, the foam is viscous and expanded, and even the tank is sagged, causing confusion in operation and lowering the sorting index, so the usage is controlled.

In production, lime is usually added as lime milk, and it can also be added in powder form. The pH of the slurry is generally controlled to control its amount. However, when the amount of lime is large, it is necessary to reflect the amount of free CaO in the slurry to reflect its amount.

It is used primarily for small-scale compaction work, such as pavements, cycle paths, small roads and small parking areas, and places that need compaction but are difficult to reach with a large roller.