Flocculation (flocculant) is the phenomenon of small particles coming together to form larger particles that are more easily separated from the liquid substrate.
Also known chemically as polyacrylamide, flocculants are formed by the combination of acrylamides and other chemicals (or monomers).
The raw material acrylamide is obtained from crude oil. In the first step, propylene is formed, then propylene is converted to acrylonitrile, from which acrylamide is formed. All other monomers are somehow produced from petroleum, which is why oil prices are a very important factor in cost.
What are the Physical Variations in Flocculants:
- Powder or Particle
- Liquid Emulsions
- Liquid Dispersions
Chemical Diversity in Flocculants:
- Polymer type obtained from monomer combination
- Polymer type obtained from the final polymer structure
- Ionicity (Charge) – anionic, cationic or non-ionic
- Molecular Weight (between 5 and 26 million)
Type of Polymer Obtained from Monomer Combination:
Acrylamide (AM) is always the starting monomer and can combine with monomers such as:
- Sodium Hydroxide hydrolyzes acrylamide to form anionic polyacrylamide.
- Acrylic acid copolymerizes acrylicamide to form anionic polyacrylamide.
- Dimethylaminoethyl acryl copolymerizes acrylamide to form cationic polyacrylamide.
End Polymer Type of Polymer Obtained from Its Structure:
- Cross Linked
- High molecular weight-acrylamide based
- water soluble
- Molecular weight5 – 20 x 106
- Visible chain length: 10 – 50 μm
- Charge density: cationicànonionicàanionic
- Physical forms: powder, porous, dispersion, emulsion
Ionicity or Charge (Charge):
- Anionicity, charge varying between 5 -50% (mol/mol)
- Cationicity, charge ranging from 4-80% (Weight/wt)
Molecular Weight of Flocculants
- Anionic powders 6 -26 million
- Cationic powders4 -12 million
- Nonionic powders 4 -12 million
- Anionic/Cationic/Nonionicliquids4 -20 million
Powder Flocculants or Liquid Flocculants?
- Powders have lower production costs
- The shipping cost of powders is lower
- Powders are completely stable and can be stored for 2 years or more.
- Dusts are not affected by extreme heat and cold during storage.
- Powders are richer in ionicity and molecular weight diversity.
- Solutions of liquids are easier to prepare.
- Low cost of equipment used for liquid