FeCl₂ (Iron(II) Chloride): Properties, Applications & Price Quotes for 2025
FeCl₂—or iron(II) chloride—is one of the most widely used coagulants in the industrial wastewater treatment sector in Vietnam today. With its competitive price, high flocculation efficiency, and flexible applications—ranging from electroplating and textile dyeing to wastewater treatment using the Fenton reaction—FeCl₂ is gradually replacing many traditional flocculants. In this pillar article, we will provide you —whether you’re an operations engineer, procurement manager, or business owner—comprehensive in-depth technical information, comparison charts, and the most practical FeCl₂ purchasing guide for 2025.
What is FeCl₂?
Iron(II) chloride, with the chemical formula FeCl₂, is the chloride salt of iron in the +2 oxidation state. It is an inorganic compound belonging to the iron salt group, commonly found as a liquid solution in industrial applications and as the hydrated crystalline form (FeCl₂·4H₂O) in the laboratory.
Chemical Identification Information:
| Parameter | Details |
|---|---|
| IUPAC Name | Iron(II) chloride |
| Molecular Formula | FeCl₂ |
| CAS Number | 7758-94-3 (anhydrous form); 13478-10-9 (tetrahydrate form) |
| Other Names | Iron(II) chloride, Ferrous chloride, Iron(II) dichloride |
| Molecular Weight | 126.75 g/mol (anhydrous) |
| Fe²⁺ Content | ~44.1% (by weight of the anhydrous form) |
| Common Sources | China, India, Vietnam |
In industrial practice, FeCl₂ is typically produced by dissolving metallic iron or iron scrap in hydrochloric acid (HCl):
Fe + 2HCl → FeCl₂ + H₂↑
This is also a byproduct of the steel pickling process in the metallurgical industry—an abundant source that keeps the cost of FeCl₂ highly competitive compared to other coagulants such as FeCl₃ or PAC. For this reason, FeCl₂ is increasingly being prioritized by wastewater treatment plants, industrial parks, and electroplating companies. Lộc Thiên Chemicals is currently one of the most reliable and stable distributors of FeCl₂ for the markets in Southern and Central Vietnam.
Physical & Chemical Properties
Understanding the properties of FeCl₂ is essential for operations engineers to control dosage, storage conditions, and compatibility at each treatment stage.
Physical Properties
| Property | Description |
|---|---|
| State | Liquid solution (industrial); solid crystals (laboratory) |
| Color | Pale green to moss green (solution); anhydrous crystals are grayish-white but easily turn green due to moisture absorption |
| Odor | Mild, characteristic odor of hydrochloric acid |
| Density (30% solution) | ~1.30–1.35 g/cm³ at 25°C |
| Solubility in water | Completely soluble, with slight exothermic reaction (~68.5 g/100 mL at 20°C for the anhydrous form) |
| pH (10% solution) | ~2.0–3.0 (weakly acidic) |
| Melting point (anhydrous) | 677°C |
| Boiling point (anhydrous) | 1,023°C |
Commercial FeCl₂ solutions typically have a characteristic green color. If the solution turns yellowish-brown, this indicates that some of the Fe²⁺ has been oxidized to Fe³⁺ (FeCl₃)—a sign that storage conditions need to be reevaluated.
Chemical Properties
FeCl₂ exhibits all the properties of a soluble iron(II) salt:
1. Reducing properties – easily oxidized to Fe³⁺
This is the most important property for industrial applications. Fe²⁺ is easily oxidized to Fe³⁺ upon contact with air or oxidizing agents:
4FeCl₂ + O₂ + 4HCl → 4FeCl₃ + 2H₂O
It is precisely this property that makes FeCl₂ a strong reducing agent, particularly useful in treating wastewater containing Cr⁶⁺ (hexavalent chromium) and other heavy metals.
2. Hydrolysis reaction to form hydroxide
In an aqueous environment, Fe²⁺ undergoes hydrolysis to form a blue-green Fe(OH)₂ precipitate—the primary component responsible for floc formation in wastewater treatment:
FeCl₂ + 2H₂O ⇌ Fe(OH)₂↓ + 2HCl
At pH ≥ 8.0, the hydrolysis process proceeds more thoroughly, producing large amounts of Fe(OH)₂ flocs capable of adsorbing and carrying away suspended solids (SS), heavy metals, and some organic matter.
3. Fenton Reaction (with H₂O₂)
Combining FeCl₂ with hydrogen peroxide (H₂O₂) produces the hydroxyl radical (·OH)—one of the strongest oxidizing agents in wastewater treatment:
Fe²⁺ + H₂O₂ → Fe³⁺ + ·OH + OH⁻
This Fenton reaction is the primary “weapon” for breaking down organic compounds that are difficult to biodegrade (refractory COD) in wastewater from textile dyeing, pesticides, and pharmaceuticals.
4. Complexation Reaction
Fe²⁺ can form complexes with various ligands such as cyanide (CN⁻), sulfide (S²⁻), EDTA, and citrate—applications found in electroplating and chemical industry wastewater treatment.
Common Concentrations and Corresponding Applications
In the Vietnamese market, FeCl₂ is primarily supplied as a liquid solution with the following common concentrations:
| Concentration | Product Form | FeCl₂ Content (w/w) | Density ~ | Main Applications |
|---|---|---|---|---|
| 15% | Solution | ≥15% | 1.12–1.14 | Small-scale treatment systems (under 100 m³/day); medium-scale textile dyeing; small electroplating facilities |
| 25% | Solution | ≥25% | 1.22–1.25 | Medium-sized wastewater treatment plants (100–500 m³/day); industrial parks |
| 30% | Solution | ≥30% | 1.30–1.35 | Large wastewater treatment systems (over 500 m³/day); recycling plants; high-capacity Fenton systems |
Which concentration should you choose?
- Small systems, low flow rates: A 15% concentration is typically preferred because it is easier to measure, causes less equipment corrosion, and is safer for operators.
- Medium-sized plants: A 25% concentration offers a balance between shipping costs (logistics savings compared to 15%) and treatment efficiency.
- Large-capacity systems, industrial parks: A 30% concentration is optimal in terms of cost per unit of active FeCl₂, reduces the frequency of shipments, and is suitable for large storage tanks.
At Loc Thien Chemicals, we offer a full range of concentrations—15%, 25%, and 30%—with clear Certificates of Analysis (COA) for each batch, ensuring customers can trust the quality of their raw materials.
Main Applications of FeCl₂
1. Wastewater Treatment – Highly Effective Coagulant
This application accounts for over 70% of total FeCl₂ consumption in Vietnam. FeCl₂ acts as a coagulant through the following mechanism:
Coagulation Mechanism:
When added to wastewater, Fe²⁺ is rapidly oxidized to Fe³⁺ (under conditions with dissolved oxygen or aeration). Fe³⁺ then hydrolyzes to form iron hydroxide complexes:
Fe³⁺ + 3H₂O → Fe(OH)₃↓ + 3H⁺
The Fe(OH)₃ precipitate forms a gel-like floc with a very large specific surface area, capable of:
- Adsorption of suspended solids (TSS), colloidal solids, and microorganisms
- Co-precipitate with heavy metal ions such as Pb²⁺, Cu²⁺, Zn²⁺, and Cd²⁺
- Neutralize the surface charge of negatively charged colloidal particles (flocculation mechanism)
- Reduce COD and BOD by 30–55% (depending on wastewater characteristics)
Advantages of FeCl₂ over aluminum sulfate:
- Fe(OH)₃ flocs are heavier than Al(OH)₃, settle faster, and reduce retention time in the settling tank
- Performs well over a wider pH range (pH 5–9 compared to pH 6.5–7.5 for aluminum sulfate)
- Leaves no aluminum residue in the effluent (an issue subject to stricter regulations under QCVN)
- Cost per cubic meter of wastewater is 20–35% lower
2. Electroplating – Chromium (Cr⁶⁺) Removal
In electroplating wastewater, hexavalent chromium (Cr⁶⁺) is a highly toxic, carcinogenic substance that is strictly regulated under QCVN 40:2011/BTNMT (discharge limit ≤ 0.1 mg/L for Cr⁶⁺).
FeCl₂ is the most common Cr⁶⁺ reducing agent in the electroplating industry due to the following reaction:
3Fe²⁺ + Cr⁶⁺ → 3Fe³⁺ + Cr³⁺
Cr³⁺ is then precipitated as Cr(OH)₃ when the pH is raised to 8–9 using NaOH or Ca(OH)₂:
Cr³⁺ + 3OH⁻ → Cr(OH)₃↓
Advantages of FeCl₂ over NaHSO₃ (sodium bisulfite):
- Does not produce toxic SO₂ gas during the reduction process
- Lower chemical costs
- Simultaneously reduces Cr⁶⁺ and forms flocs for the subsequent settling stage
3. Fenton Reaction – Treatment of Hard-to-Degrade COD
For wastewater containing organic compounds that are difficult to biodegrade (azo dyes, phenols, pesticides, pharmaceuticals, surfactants), conventional biological treatment systems are often ineffective. The Fenton reaction, which uses the FeCl₂/H₂O₂ system, is a widely applied advanced oxidation process (AOP).
Principle:
Fe²⁺ catalyzes the decomposition of H₂O₂ to form hydroxyl radicals (·OH) with an oxidation potential of 2.80 V—second only to fluorine in oxidizing power. The ·OH radical non-selectively attacks organic bonds, breaks aromatic rings, cleaves polymer chains, and mineralizes pollutants into CO₂ and H₂O.
Optimal Operating Conditions:
| Parameter | Optimal Range |
|---|---|
| pH | 2.8–3.5 |
| H₂O₂ : Fe²⁺ molar ratio | 2:1 to 10:1 (depending on input COD) |
| Reaction time | 30–120 minutes |
| Temperature | 20–40°C |
The COD removal efficiency of the Fenton process typically reaches 60–85% and can increase to 90%+ when combined with UV (photo-Fenton) or electrolysis (electro-Fenton).
4. Textile Dyeing
The textile dyeing industry is the second-largest consumer of FeCl₂ after wastewater treatment, with two main applications:
a) Mordant in fabric dyeing:
Fe²⁺ forms complexes with dye molecules and fabric fibers, helping to fix the dye to cellulose and protein fibers. Iron(II) chloride produces characteristic deep, gray, and moss-green tones—which are highly favored in the dyeing of cotton, linen, and silk fabrics.
b) Textile dyeing wastewater treatment:
Textile dyeing wastewater has high color intensity (thousands of Pt-Co units), high COD, and contains many refractory reducing dyes. FeCl₂ both coagulates and decolorizes the wastewater (with a decolorization efficiency of 70–90%) and participates in the Fenton reaction to oxidize any remaining colored compounds.
5. Recycling – Dual Environmental Benefits
One of the lesser-known advantages of FeCl₂ is its sustainability within the supply chain:
- Recycled Source: Most commercial FeCl₂ is a byproduct of the steel pickling process (pickling liquor). Instead of being neutralized and landfilled as hazardous waste, this FeCl₂ solution is recovered, refined, and reused as a water treatment chemical—creating an economic cycle.
- Reduced carbon emissions: Compared to producing FeCl₃ from iron ore and chlorine, producing FeCl₂ from steel scrap consumes significantly less energy.
- Less sludge: Fe(OH)₃ sludge from the FeCl₂ flocculation process can be dewatered and reused as raw material for the production of unburned bricks or construction pigments.
Comparison of FeCl₂ vs. FeCl₃ vs. FeSO₄ vs. PAC
Below is a comprehensive technical comparison table to help procurement managers and engineers make the right choice for each wastewater treatment application:
| Criterion | FeCl₂ (Iron(II) Chloride) | FeCl₃ (Iron(III) Chloride) | FeSO₄ (Iron(II) Sulfate) | PAC (Poly aluminum chloride) |
|---|---|---|---|---|
| Form | Liquid solution | Liquid solution | Crystals/solution | Powder/solution |
| Active Ingredient Content | 15–30% | 38–42% | 18–22% (dry form: ≥98%) | Al₂O₃ ~10% (solution); ~28–30% (powder) |
| Flocculation mechanism | Hydrolysis of Fe²⁺ → Fe³⁺ | Direct hydrolysis of Fe³⁺ | Hydrolysis of Fe²⁺ → Fe³⁺ | Hydrolysis of Al³⁺ |
| Optimal pH range | 5.0–9.0 | 4.5–8.0 | 7.0–9.0 | 6.0–7.5 |
| Ability to reduce Cr⁶⁺ | ✓ Yes | ✗ No | ✓ Yes | ✗ No |
| Fenton (with H₂O₂) | ✓ Very good | ✗ No | ✓ Good | ✗ No |
| Floc settling rate | Fast (heavy flocs) | Very fast | Moderate | Slow (light flocs) |
| Equipment corrosion | Moderate–High | High | Moderate | Low |
| Cost (VND/kg) | 4,000–7,000 | 7,000–12,000 | 3,500–5,500 | 8,000–15,000 |
| Residues after treatment | Fe (safe) | Fe (safe) | Fe (safe) | Al (subject to stricter limits) |
| Water Color After Settling | Clear, slightly yellowish | Brownish-yellow | Clear | Very clear |
Quick Selection Conclusion:
- Requires Cr⁶⁺ removal + flocculation: Choose FeCl₂ – the most cost-effective 2-in-1 solution.
- Requires treatment of difficult COD + flocculation (Fenton): Choose FeCl₂ – superior Fenton efficiency.
- Requires rapid flocculation, low pH wastewater: Consider FeCl₃.
- Low budget, alkaline wastewater pH: Consider FeSO₄.
- Requires extremely clear effluent, with no concern for aluminum residue: Consider PAC.
Purchasing Guide: Specifications, Shipping & Pricing
Packaging Specifications
At Loc Thien Chemicals, FeCl₂ is available in flexible packaging options to suit all scales:
| Specification | Volume | Suitable for |
|---|---|---|
| HDPE plastic can | 30 liters | Small facilities, laboratories, pilot tests |
| HDPE Plastic Drum | 200 liters | Medium-sized plants, systems with a capacity of 50–200 m³/day |
| Tank Truck (ISO Tank) | 5,000–15,000 liters | Industrial parks, large plants, recurring orders |
All containers and drums meet chemical-resistant HDPE standards, feature leak-proof lids, and are fully labeled with GHS labels in accordance with Decree 113/2017/NĐ-CP.
Transportation
Loc Thien Chemicals operates an extensive network of warehouses:
- Main Warehouse: Ho Chi Minh City (serving the Southeast region)
- Satellite Warehouses: Ba Ria–Vung Tau, Dong Nai, Da Nang, Can Tho, Bac Ninh
Thanks to this network, we deliver quickly within 24–48 hours to areas with local warehouses and within 3–5 days to more distant provinces. We transport goods using specialized chemical-carrying trucks, fully licensed for the transport of hazardous materials in accordance with ADR regulations.
FeCl2 Price Quote – 2025
The price of FeCl2 depends on concentration, specifications, and order quantity. Below is a reference price range:
| Concentration | Reference Price (VND/kg) | Notes |
|---|---|---|
| FeCl2 15% | 4,000 – 5,500 | Retail price per can/drum |
| FeCl₂ 25% | 4,500 – 6,000 | Retail price per can/drum |
| FeCl₂ 30% | 5,000 – 7,000 | Wholesale price per drum/tanker truck |
📞 Contact our Hotline immediately at 0979 891 929 to receive an accurate quote based on actual quantities and discount policies for large orders. We guarantee competitive prices, complete COAs, and on-time delivery.
FAQ – Frequently Asked Questions About FeCl2
1. Is FeCl2 a hazardous substance? What precautions should be taken during storage?
FeCl2 is classified as a corrosive chemical (Group 8 under GHS); it is non-flammable and non-explosive but is acidic and can irritate the skin and eyes. It must be stored in sealed cans or drums in a dry, cool, well-ventilated area, away from direct sunlight and high temperatures. Storage tanks should be made of HDPE plastic, PVC, or FRP—never use unlined carbon steel. Operators must wear full PPE: rubber gloves, safety goggles, and an acid-resistant respirator.
2. How can you distinguish high-quality FeCl₂ from low-quality FeCl₂?
High-quality FeCl₂ has a uniform green color, is clear, and has no sediment at the bottom. If the solution turns yellow-brown or develops a reddish-brown scum on the surface, this indicates that Fe²⁺ has been oxidized to Fe³⁺—reducing the efficiency of Cr⁶⁺ reduction and the Fenton reaction. Loc Thien Chemicals provides a Certificate of Analysis (COA) for each batch, allowing you to accurately verify the FeCl₂ content and Fe³⁺ impurity levels.
3. Can FeCl₂ be mixed with PAC or polymers?
FeCl₂ should not be mixed directly with PAC in the same mother tank, as this may cause premature precipitation and clog the pipes. However, they can be dosed separately at different points in the flow: FeCl₂ first (primary flocculation), followed by PAC or anionic polymer (flocculant aid, to increase floc size). Always conduct a jar test before implementing on a large scale.
4. Does the use of FeCl₂ in wastewater treatment affect activated sludge?
At typical flocculation doses (100–500 ppm), FeCl₂ is not toxic to activated sludge. Fe²⁺, after being oxidized to Fe³⁺, will precipitate and be removed in the settling tank before the water enters the biological reactor. However, if FeCl₂ is used in a Fenton system, the pH must be neutralized and excess H₂O₂ removed before the water is fed into the biological reactor.
5. Can I purchase small quantities of FeCl₂ for testing?
Yes. At Lộc Thiên Chemicals, we offer 30-liter drums for customers to conduct pilot tests or jar tests before deciding to purchase in bulk. Call our Hotline: 0979 891 929 now for consultation and prompt sample delivery.
Conclusion
FeCl₂ (Iron(II) Chloride) is not just an affordable flocculant—it is a versatile chemical that simultaneously addresses multiple challenges in industrial wastewater treatment: from flocculating suspended solids and removing heavy metals (especially Cr⁶⁺), to the advanced oxidation of hard-to-degrade organic compounds. With a supply chain sourced from sustainable recycling and the most competitive prices on the market, FeCl₂ is a strategic choice for any plant seeking an effective and cost-efficient wastewater treatment solution.
Loc Thien Chemicals is proud to be a trusted partner, providing FeCl₂ of consistent quality with fast delivery from our network of warehouses across Ho Chi Minh City, Dong Nai, Ba Ria–Vung Tau, Da Nang, Can Tho, and Bac Ninh.
📞 Contact us today: 0979 891 929
🌐 Website: hoachatlocthien.com
✉️ Email: [email protected]
Loc Thien Chemicals – A trusted chemical partner for Vietnamese businesses.