Mining experts EP4: Process control in the flotation circuit

Posted on Wednesday, 11 November 2020 at 02:11

In the fourth episode of our series “mining experts talking”, we continue our interview with Sandro Marino and talk about process control in the flotation circuit. In this video he explains why measurement of slurry density in the flotation feed is important.

Flotation is about recovery of valuable materials. The pulp density is on the hands of the operator to make the decision on having a maximum recovery or to lose valuable materials to the tailings (waste). Operators need to set a target for the slurry density feeding the flotation to keep the process operating at its optimal conditions. If the slurry density target is not matched then the operator has to correct the density. This can be done by adjusting the water addition for example, since major changes cannot take place in a short term.

The volume (of slurry) in the tank could increase in minutes when the slurry density or particle sizes are changing, affecting the efficiency of the collection process. If the pulp density is not corrected in time, the amount of (valuable) material that can possibility be “lost” is huge. By adjusting the pulp density, particles are made easily available to be collected by the air. The goal is to recover desired particles.

Generally, the larger particles are considered waste (tailings) and the finer particles are valuable materials that need to be collected (product). Finer particles are collected by the air + reagents (collectors) and are sent to the overflow. After being attached to the air bubbles + reagents, these particles also need to detach. The larger particles are sent to the underflow with the help of reagents too (depressors).

By measuring the flow and density on the flotation feed and underflow, you can calculate the mass balance and determine the throughput. In this way, you can measure the collected amount of valuable particles.

Learn more about process control in the flotation circuit by watching our fourth episode: “Process control in the flotation circuit”.