FeCl3 for wastewater treatment This is the coagulation-flocculation step using ferric iron: neutralizing negative colloids, removing SS/turbidity/color, and precipitating phosphate before sedimentation. The "correct dose on paper" is only meaningful afterwards. jar-test on factory samples.
FeCl3 (ferric chloride / iron trichloride / iron III chloride, CAS 7705-08-0) common form of commerce Liquid 36–40% (FECL3-40L) or solid ~96% for dilution. Also known in the water industry. ferric sulfate / ferric sulfate IIIB2B orders with COA/MSDS per batch — do not replace the plant SOP with the lab number.
- Fe³⁺ is a strong coagulant; the pH and alkalinity window of the water determines the floc — not just "adding more iron sulfate".
- Liquid form 36–40% with rapid ETP; solid form 96% when stored/mixed on-site — concentration converted according to COA.
- Jar testing is mandatory when changing color, season, or batch of chemicals; lab ≠ fixed injection dose.
Trade name and form of supply
In catalogs and RFQs, the same substance may appear under multiple names. The table below helps engineers/procurement managers map synonyms before comparing the COA.
| Name / alias | Commercial Notes | Common forms |
|---|---|---|
| FeCl3 / FeCl₃ | Formula symbols on COA and RFQ | Liquid or solid |
| Iron(III) chloride / iron(III) chloride | Vietnamese technical name | Liquid 36–40% · Solid ~96% |
| Ferric chloride | Common EN names for B2B | Solution / solid |
| Iron trichloride / iron(III) chloride | Alias EN / SDS | According to grade |
| Iron alum / ferric alum | Water-based coagulant industry name (not a separate brand) | Usually attached to FeCl3 or other iron salts — read COA |
Loc Thien money path for priority wastewater treatment plant Liquid FeCl3 36–40%When purchasing and comparing price quotes, request that the COA clearly state "ferric chloride solution" or "iron(III) chloride alum" to avoid confusion with FeSO4 or mixtures with different percentages of Fe. For a broad definition of an entity, see the article. What is FeCl3 (iron(III) chloride)?.
Mechanism of Fe³⁺ coagulation in XLNT
When added to water, FeCl3 hydrolyzes to form Fe³⁺/hydroxo-iron species. These electrical neutral The coagulant is negative, then Fe(OH)₃ flocs up to "sweep" the suspended particles. Phosphate can precipitate into iron phosphate salts — this is why many ETPs use FeCl3 when the phosphorus requirement is tight.
In parallel, FeCl3 can partially reduce the color of the colloid and aid in the separation of unstable emulsion oils, but Dissolved COD This often requires advanced biological or oxidative processes. Engineers should differentiate the objectives: water quality (SS/turbidity) is different from "achieving outlet COD".
The effectiveness depends on pH, alkalinity, initial SS, stirring time (fast/slow), and the flocculant polymer (if any). Incorrect pH → "chemicals are added but the water remains cloudy" even after increasing the dosage.
Applications in the wastewater industry
With its ability to coagulate Fe³⁺ and phosphate, FeCl3 (ferric chloride) is found in many industrial ETPs in the South — textile, paper, food, and mixed industrial parks. The actual effectiveness still depends on the input characteristics and jar-test results, not on the name on the invoice.
- Textile dyeing/coloring: Color-correcting agent + SS; usually combined with pH and polymer; do not expect FeCl3 alone to treat all dissolved COD.
- Paper, food, and mixed industrial zones: Reduces turbidity/TSS, supports pre- or post-settling biological settling.
- Phosphate / Nutrition: When the lab showed high P and the jar-test Fe outperformed alum/PAC in that sample.
- Leachate/Difficult-to-treat waste: This may be part of the pre-processing chain — mandatory jar-test, do not copy doses from other factories.
FeCl3 is not a "cure for all wastewater". When Fe²⁺ (reduction/Fenton/Cr6+) is needed, see FeCl2 and compare performance; see also Advantages and disadvantages of FeCl2 vs FeCl3.
Is it 36–40% liquid or 96% solid?
- Liquid 36–40%: Dosing pump fill, suitable for continuous ETP; check for pipe/pump corrosion; concentration according to batch COA.
- Snake ~96%: Save on transportation/storage costs in some cases; stock must be mixed correctly to avoid moisture absorption and clumping; convert to actual mg/L FeCl3 before comparing doses.
RFQ B2B: clearly state the form + % + packing (can/drum/IBC/tank) + COA/MSDS — avoid vague comparisons of "iron sulfate" between FeCl3 and FeSO4.
Targeted dose and jar-test
| Objective / Context | FeCl3 dosage (expressed as active ingredient, ppm) — for guidance only. | Inspection |
|---|---|---|
| Reduces turbidity/TSS in mild to moderate CN water. | Typically wide range of 50–300+ (according to jar-test) | pH before and after, sedimentation rate |
| Textile dyeing/coloring + SS | Or higher; 100–500+ depending on color and alkalinity. | Color after settling, remaining COD |
| Phosphate | Based on moles of P and jar-test — the “general formula” is not fixed. | Output pressure, pH |
| Change furnace / season / batch of new chemicals | Re-test; do not keep the old records. | COA %, solution color |
Disclaimer: The number in the table is refer to the labThis is not the factory SOP. Plant scale depends on G-value, injection point, and retention time. When converting from a 36–40% solution to ppm “as in the catalog 100%”, engineers must use the correct % COA lot — incorrect conversion is a common reason why the plant consumes more than the lab. Detailed jar-test procedure: Jar-test guide for wastewater treatment.
pH, polymer, and comparison with PAC
FeCl3 typically "absorbs" alkali and can lower the pH — many pH adjustment stations use alkali/acid around the coagulation window before or after dosing. Anionic/cationic polymers help create larger flocs that settle faster when the Fe flocs are small. PAC (aluminum) sometimes produces different flocs and a more pH-friendly solution; choose accordingly. parallel jar-test, not following the vendor's usual practice.
Short checklist before scaling plant dose: (1) COA % of the lot being used, (2) pH meter calibration, (3) sufficiently wide jar range, (4) observe the sediment at the bottom of the jar, (5) record the sample temperature. Missing any of these steps can easily turn "cheap" OPEX into expensive OPEX.
If sufficient chemicals have been added but the outlet is still failing, check the operating sequence (probe pH, sludge, mixing): The acupuncture system still failed — the pain of ETP..
Safety and storage
- Corrosive to metal / skin / eyes — PPE: gloves, goggles, face mask, chemical protective clothing.
- Store in a cool, airtight, moisture-free place for solids; acid-resistant tanks/tubes for solutions.
- Do not mix indiscriminately with incompatible chemicals; spill according to the batch MSDS.
- ETP personnel: rinse eyes/skin immediately if contact occurs; first aid kit available at acupuncture site.
Top Q&A
How does FeCl3 differ from "iron sulfate" and aluminum sulfate?
"Iron alum" is a technical term — it may refer to FeCl3, FeSO4, or other iron salts. Aluminum alum (alum/PAC) is based on Al³⁺. Always read the COA: formula, %, CAS. FeCl3 = ferric chloride CAS 7705-08-0.
Should you choose 36–40% liquid or 96% solid FeCl3?
ETP is typically a liquid at 36–40% concentration when continuous ETP dosing is required. It is 96% solid when logistics/warehouses require stock dilution. Convert concentrations before comparing ppm dosages.
What is the optimal pH for FeCl3 coagulation?
Dependent on wastewater. Many cases work well in neutral-slightly acidic/mildly alkaline zones, but jar-test Just close the window for your sample. Measure pH before and after dosing.
Where can I get the FeCl3 dose if I haven't done a jar test yet?
Use guide strips only to design the lab cup array. Don't use "150 ppm forever" for every case. Change oven color / season / COA → retest.
When should FeCl3 be used instead of FeCl2 or PAC?
FeCl3 is used when Fe³⁺ is needed for coagulation/phosphate/color according to jar-test. FeCl2 is used when Fe²⁺ is needed (reduction, Fenton...). PAC is used in labs to stabilize aluminum floc/pH/sludge. There is no single chemical formula for all ETPs.
What are the COA, MSDS, and B2B packaging requirements?
Requires a batch COA (% FeCl3 or Fe³⁺, visual inspection) and MSDS. Packing cans/drums/IBCs/tanks depending on quantity. Price quoted on request — no publicly listed retail prices.
Does FeCl3 increase sludge production and pressing costs?
Possibly. TCO = chemical + sludge + polymer + machine shutdown. Jar-test should observe the volume of sludge at the bottom of the cup, not just the clarity.
Need FeCl3 / iron III chloride / ferric chloride 36–40% For XLNT: see Loc Thien products
https://hoachatlocthien.com/san-pham/fecl3-sat-iii-chloride
· COA/MSDS + support for reading jar-testing according to B2B policy · Hotline (+84) 979 891 929.
Please include the slip parameters (SS, turbidity, P, color) and the chemical currently in use for comparison with the appropriate liquid form.
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