In the mining industry, chemicals used in dewatering primarily aid in solid-liquid separation processes. They help aggregate fine particles in slurries or tailings, speed up settling, improve water clarity in thickeners, reduce moisture in filter cakes, and enhance overall efficiency in tailings management, concentrate dewatering, and wastewater treatment.
These chemicals are most commonly applied in mechanical dewatering (e.g., thickeners, filter presses, centrifuges, belt filters) and tailings handling—key for water recovery, safer storage, and environmental compliance in Indonesian mining operations (nickel, coal, copper, gold).
Main Categories of Chemicals for Dewatering
1. Flocculants (Most Widely Used)
High-molecular-weight polymers that bridge fine particles into larger flocs for faster settling and better dewatering.
- Anionic flocculants — Common for negatively charged particles (e.g., in coal or clay tailings).
- Cationic flocculants — Effective for positively charged or organic-rich slurries.
- Non-ionic flocculants — Versatile for various conditions. They dramatically improve thickener performance and filter cake dryness.
2. Coagulants
Inorganic or organic compounds that neutralize particle charges to form small aggregates (microflocs), often used before or with flocculants.
Common examples:
- Ferric chloride (FeCl₃)
- Poly aluminum chloride (PACl)
- Ferrous sulfate
- Alum (aluminum sulfate)
- Magnesium chloride They work well in low-pH or variable slurries.
3. Dewatering Aids / Filter Aids / Surfactants
Surface-active agents that reduce surface tension, improve water release from particles, and lower residual moisture in cakes.
- Surfactants (e.g., non-ionic alcohol ethoxylates, cationic fatty amines)
- Specialty polymers or blends
- Sulfonates or sulfates in some cases These enhance filtration efficiency and reduce energy needs in presses or centrifuges.
4. Other Supporting Chemicals
- pH adjusters (e.g., lime, sulfuric acid) — Optimize conditions for flocculants/coagulants.
- Rheology modifiers / viscosity reducers — For easier pumping of thickened slurries.
- Antiscalants — Prevent scaling in pipes during dewatering circuits.
How These Chemicals Are Applied in Mining Dewatering
- In thickeners: Add flocculants (and sometimes coagulants) to promote rapid settling.
- In filter presses/centrifuges: Use dewatering aids or flocculants to achieve low-moisture cakes (10-30%).
- In tailings: Polymers enable thickened or paste tailings for dry stacking.
- Dosage is optimized via jar tests—too much can cause poor settling or high costs.
Challenges and Best Practices
- Overdosing flocculants can lead to “pin flocs” or carryover.
- Match chemistry to slurry type (e.g., anionic for coal tailings, cationic for some mineral slimes).
- Monitor residual chemicals in recycled water to avoid impacts on downstream processes (e.g., flotation).
How Reliable Piping Complements Chemical Dewatering
Chemical-treated slurries can be more viscous or corrosive—durable HDPE pipes resist abrasion from aggregated solids, handle pressure in feed lines, and minimize buildup during transport to/from dewatering equipment.
Aiko Indonesia supplies premium HDPE pipes optimized for dewatering and slurry applications. They provide long service life, flexibility for remote sites, and reliable performance when paired with chemical-assisted systems.
Conclusion: Chemicals Boost Efficient Dewatering in Mining
The primary chemicals for dewatering are flocculants, coagulants, and dewatering aids/surfactants, with polymers leading modern tailings and process dewatering for better water recovery and safety.
Selecting and dosing the right ones maximizes throughput and sustainability.
At Aiko Indonesia, our HDPE pipes support chemical dewatering systems—abrasion-resistant and ideal for Indonesian mining challenges. Contact us today to discuss solutions that enhance your dewatering processes, improve water management, and reduce operational risks.
AUTHOR BIO:
Endy Gunawan is the Director at Kharisma Group and holds a degree in Engineering, which provides the technical foundation for his expertise in complex infrastructure. He specializes in providing integrated solutions for industrial piping, prefab steel structures, and water storage systems. Endy is dedicated to driving innovation and excellence across Indonesia’s industrial landscape, ensuring that engineering precision meets strategic growth. For project inquiries or professional networking, connect with Endy Gunawan on LinkedIn
