Guest Lecture

Question 1

Flotation Factors:

Answer 1

machine (used for process, ex. agitators), physics (of the solid-liquid interactions), circuits (pathway to separate), chemistry (of compounds)

Together make up whole system

Question 2

Chemistry of flotation

Answer 2

hydrophobic vs hydrophilic (want hydrophobic)

• if necessary will change surface chemistry to make hydrophobic
• to change surface chemistry, will use a compound with a reactant end and a hydrophobic end

Question 3

Physics of flotation

Answer 3

need interaction with the bubble for the solid to attach to bubble
- to increase interactions, will change size, number, and coallesion of bubbles (can do this by adding a frother)

• need small particles and larger bubbles (roughly 10-300 microns of particles)

Question 4

Flotation steps

Answer 4

1. collision (bubble and particles collide)
2. attachment (particle attaches to bubble)
3. detachment (particles release from bubbles)

Question 5

Flotation collison

Answer 5

• larger particles have less deviation from path due to low affect of water movement - increases collision probability

Question 6

How to improve flotation recovery?

Answer 6

• increase gas rate (increase number of bubble)
• decrease bubble size (with agitator)

Question 7

Flotation attachment

Answer 7

-particle slides along bubble for certain length of time
- if sliding time > attachment time then particle attaches
- Tsliding = Length of bubble sliding over/velocity of particle)

Question 8

Flotation examples

Answer 8

• Mining (iron flotation, rare earth flotation)
• Li-Ion battery recycling (recovery graphite instead of using leaching)