Paper & Pulp Industry Chemicals — NaOH, H2O2, PAC, ClO2
Table of contents
TL;DR: The paper & pulp industry uses 4 main chemical groups: NaOH (CAS 1310-73-2) for Kraft pulping at 155–175°C, H₂O₂ (CAS 7722-84-1) for ECF/TCF bleaching with no dioxin formation, PAC (CAS 1327-41-9) for wastewater coagulation meeting QCVN 12-MT:2015, and ClO₂ for disinfection. Loc Thien supplies all 4 groups, delivering to 6 warehouses across 3 regions with batch CoA/MSDS.
What Chemical Groups Does the Paper Industry Use?
Chemicals used in paper and pulp production are divided into 4 main groups by process stage:
Group 1 — Pulping chemicals: NaOH (caustic soda), Na₂S (sodium sulfide). Breaks down lignin from cellulose fibers in the Kraft process.
Group 2 — Bleaching chemicals: H₂O₂ (hydrogen peroxide), ClO₂ (chlorine dioxide), NaOCl (sodium hypochlorite). Removes residual lignin and chromophores, raises ISO brightness.
Group 3 — Wastewater coagulation chemicals: PAC (polyaluminium chloride), PAM polymer. Treats paper mill wastewater to meet QCVN 12-MT:2015.
Group 4 — pH adjustment and auxiliary chemicals: H₂SO₄ (sulfuric acid), Na₂CO₃ (soda ash), CaCO₃ (calcium carbonate), dyes, sizing agents.
According to the Vietnam Pulp & Paper Association (VPPA), the paper industry consumes over 200,000 tons of chemicals annually, of which NaOH accounts for ~35%, H₂O₂ ~15%, and PAC with other coagulants ~12%.
NaOH — Kraft Pulping Chemical
NaOH (Sodium Hydroxide, CAS 1310-73-2) is the foundational chemical in the Kraft process — accounting for 90% of global pulp production. NaOH combines with Na₂S to form “white liquor,” hydrolyzing lignin-carbohydrate bonds at 155–175°C, pressure 700–1000 kPa.
Mechanism: OH⁻ ions break ether linkages in lignin, releasing long cellulose fibers → increased mechanical strength of finished paper.
NaOH specifications for the paper industry:
| Parameter | NaOH flakes | NaOH liquid 32% | NaOH liquid 50% |
|---|---|---|---|
| NaOH content | ≥99.0% | 32.0 ± 0.5% | 50.0 ± 0.5% |
| Na₂CO₃ | ≤0.5% | ≤0.2% | ≤0.3% |
| NaCl | ≤0.03% | ≤0.01% | ≤0.02% |
| Fe₂O₃ | ≤0.005% | ≤0.001% | ≤0.002% |
| Packaging | 25kg/bag, 1 MT pallet | IBC 1000L, 20 MT tank | IBC 1000L, 20 MT tank |
Reference dosage — Kraft pulping:
- Softwood: 16–20% Active Alkali (AA) based on dry wood weight
- Hardwood: 12–16% AA
- Bamboo, straw: 10–14% AA
- Cooking temperature: 155–175°C, retention time 2–4 hours
- Target H-factor: 800–1200 depending on raw material type
“Control of Active Alkali (AA%) and H-factor are the two parameters that determine Kraft pulp quality. A 1% deviation in AA can change paper tear strength by 5–8%.” — Tech. Specialist Phan Cam Thuy, CGHT, HCLT
Figure: On-site chemical dosing, storage tank operation, and batch COA inspection — Source: Loc Thien Chemical.
H₂O₂ — Chlorine-Free Pulp Bleaching
H₂O₂ (Hydrogen Peroxide, CAS 7722-84-1) is a next-generation bleaching agent replacing Cl₂, recommended by WHO and the EU for ECF/TCF processes. H₂O₂ generates no dioxins or furans (AOX), meeting export label requirements for EU and Japanese markets.
Bleaching mechanism: At pH 10–11, H₂O₂ dissociates into the perhydroxyl anion (HO₂⁻):
H₂O₂ + OH⁻ → HO₂⁻ + H₂O
HO₂⁻ + chromophores (lignin) → colorless productsOptimal operating parameters:
- pH: 10.0–11.0 (adjust with NaOH)
- Temperature: 60–70°C
- Retention time: 2–3 hours
- Dosage: 15–40 kg H₂O₂/ton dry pulp (depending on target brightness)
- Stabilizer: MgSO₄ 0.5–1.0 kg/ton pulp
Typical results with OQP (Ozone-Quebracho-Peroxide) sequence:
- Inlet ISO brightness: 50–60%
- Outlet ISO brightness: 80–90%
- AOX: ≤0.1 mg/L (meets QCVN)
Industrial H₂O₂ specifications:
| Parameter | H₂O₂ 27.5% | H₂O₂ 50% |
|---|---|---|
| Content | 27.5 ± 0.5% | 50.0 ± 1.0% |
| Active oxygen | ≥13.0% | ≥23.5% |
| Fe | ≤0.5 ppm | ≤1.0 ppm |
| Stability | ≥97% | ≥97% |
| Packaging | IBC 1000L, 25 MT tank | IBC 1000L, 25 MT tank |
PAC — Paper Mill Wastewater Coagulation
Paper mill wastewater has COD 800–2000 mg/L and TSS 500–1500 mg/L, primarily from dissolved lignin, fine cellulose, and residual bleaching chemicals. PAC (Poly Aluminium Chloride, CAS 1327-41-9) with its Al₁₃ polycation structure neutralizes the negative charge of these colloidal particles, forming fast-settling flocs.
Coagulation mechanism:
- Neutralizes negative charge of cellulose and lignin → loss of dispersion stability
- Forms bridges between particles → Al(OH)₃ floc precipitation
- Mechanical entrapment of suspended solids during settling
PAC operating parameters for paper mill wastewater:
| Parameter | PAC 10% | PAC 17% |
|---|---|---|
| Al₂O₃ content | 10 ± 1% | 17 ± 1% |
| Basicity | 45–65% | 45–65% |
| Solution pH | 3.5–5.0 | 3.5–5.0 |
| Dosage | 150–300 mg/L | 100–250 mg/L |
| Optimal pH range | 6.5–7.5 | 6.5–7.5 |
| Packaging | IBC 1000L | 25 kg bag, 25 L pail |
Typical treatment performance:
- TSS reduction: 85–95%
- COD reduction: 40–60%
- Color removal: 60–80%
- Settling time: 20–30 minutes
PAC note: Unlike conventional aluminum sulfate, PAC 10% and 17% have a pre-hydrolyzed Al₁₃ polycation structure, enabling effective coagulation even at low temperatures (5–15°C) without increased dosage. This is a major advantage for paper mills operating in cold seasons or using surface water from rivers and lakes.
Combined with aerobic biological treatment post-coagulation, treated effluent meets QCVN 12-MT:2015 Column A: COD ≤75 mg/L, TSS ≤50 mg/L, AOX ≤0.1 mg/L.
ClO₂ — Final-Stage Bleaching and Disinfection
ClO₂ (Chlorine Dioxide, CAS 10049-04-4) is a selective strong oxidizing agent used in final-stage ECF bleaching and paper mill feed water disinfection. ClO₂ has oxidation potential E° = 0.95V (reduction to Cl⁻) and selectively attacks lignin aromatic rings while preserving cellulose fiber structure.
Mechanism: ClO₂ oxidizes lignin aromatic rings into colorless carboxylic acids, preserving cellulose fiber structure. Unlike Cl₂, ClO₂ does not undergo substitution halogenation reactions, resulting in extremely low AOX generation.
Technical specifications:
- Form: dissolved gas solution (unstable above 9%, must be used same day)
- pH: 2–4
- Bleaching dosage: 5–15 kg ClO₂/ton pulp
- Temperature: 50–70°C
- Retention time: 60–120 minutes
ClO₂ vs. other bleaching agents:
| Parameter | H₂O₂ | ClO₂ | NaOCl |
|---|---|---|---|
| AOX generation | None | Very low | Yes |
| Maximum brightness | ≤88 ISO | ≤92 ISO | ≤85 ISO |
| Equipment corrosion | Low | Medium | High |
| Cost per kg | Low | High | Low |
Technical Specification Comparison Table
| Chemical | CAS | Density | Solution pH | Common packaging | Main application |
|---|---|---|---|---|---|
| NaOH flakes | 1310-73-2 | 2.13 | 13–14 | 25kg/bag | Kraft pulping |
| NaOH liquid 32% | 1310-73-2 | 1.328 | 13–14 | IBC 1000L | Pulping, pH adjustment |
| H₂O₂ 50% | 7722-84-1 | 1.195 | 3–4 | IBC 1000L | ECF/TCF bleaching |
| PAC 17% | 1327-41-9 | 1.32 | 3.5–5.0 | IBC 1000L | Wastewater coagulation |
| ClO₂ (solution) | 10049-04-4 | — | 2–4 | On-site generation | Bleaching + disinfection |
Reference Dosage by Process Stage
| Process stage | Chemical | Dosage | Conditions |
|---|---|---|---|
| Kraft pulping | NaOH + Na₂S | 12–20% AA/ton wood | 155–175°C, 2–4h |
| Pulp washing | H₂SO₄ | 5–10 kg/ton pulp | pH 5.5–6.5 |
| ECF bleaching | H₂O₂ | 15–40 kg/ton pulp | pH 10–11, 60–70°C |
| Final bleaching | ClO₂ | 5–15 kg/ton pulp | pH 2–4, 50–70°C |
| Wastewater treatment | PAC 17% | 150–300 mg/L | pH 6.5–7.5 |
| Settling aid | Anionic polymer | 1–5 mg/L | After PAC |
QCVN 12-MT:2015 Standard and Documentation
Paper mill wastewater must meet QCVN 12-MT:2015/BTNMT (Column A for environmentally sensitive areas):
| Parameter | Column A | Column B |
|---|---|---|
| COD | ≤75 mg/L | ≤150 mg/L |
| TSS | ≤50 mg/L | ≤100 mg/L |
| AOX | ≤0.1 mg/L | ≤0.3 mg/L |
| pH | 6.0–8.5 | 5.5–9.0 |
| Color | ≤20 Pt-Co | ≤70 Pt-Co |
Loc Thien provides complete legal documentation for ISO 14001 audits and periodic environmental inspections: batch CoA (lot code, manufacture date, expiry), 16-section bilingual EN-VN MSDS/SDS under GHS, CO/CQ for imported goods, Chemical Business License (Decree 113/2017/ND-CP), and fire safety inspection certificate.
Buy Paper Industry Chemicals from Loc Thien
Loc Thien supplies all 4 groups of paper industry chemicals — from pulping chemicals, bleaching agents to wastewater coagulation chemicals. 6 strategic warehouses in Ba Ria – Vung Tau, Dong Nai, Binh Duong, Da Nang, Can Tho and Bac Ninh. Tank trucks 5–30 tons, delivery to industrial zones (HCMC 4h, Southern IZs 24–48h).
Need bulk paper industry chemicals? Get a quote for paper & pulp chemicals — NaOH, H₂O₂, PAC, ClO₂, with batch COA/MSDS, nationwide delivery to industrial zones. Hotline 0979 891 929.
Technical Support & B2B Procurement Hotline
Loc Thien Chemical specializes in direct manufacturing of FeCl₂ / FeCl₃ and direct industrial supply of basic chemicals (NaOH, HCl, H₂SO₄, PAC, NaOCl, H₂O₂, FeSO₄) with direct B2B pricing and dedicated 5–30-ton tanker delivery across Vietnam.
- Hotline / Zalo: +84 979 891 929
- Official Email: [email protected]
- Direct Manufacturer: Ferrous Chloride (FeCl₂ 30%) & Ferric Chloride (FeCl₃ 38–40%)
- Primary Supplier: NaOH 32%/45%/50%/99%, HCl 32%, H₂SO₄ 98%, PAC 30–31%, NaOCl 10–12%, H₂O₂ 35%/50%
- Compliance & Quality: FeCl₂ ZDHC MRSL v3.1 test report (Smart testing, 5 substance groups, TUV Rheinland Vietnam), ISO 9001:2015, Quatest 3, Full COA & GHS SDS
Frequently Asked Questions
What types of chemicals does the paper industry use?
4 groups: (1) NaOH for Kraft pulping, (2) H₂O₂ and ClO₂ for bleaching, (3) PAC for wastewater coagulation, (4) H₂SO₄, Na₂CO₃ for pH adjustment and auxiliary processes.
What concentration of NaOH is used for pulp cooking?
NaOH flakes ≥99% or liquid 32–50%. Dosage calculated as AA%: softwood 16–20%, hardwood 12–16%, bamboo/straw 10–14%. Cooking temperature 155–175°C.
What advantage does H₂O₂ have over chlorine for pulp bleaching?
No dioxin or AOX generation, achieves ISO brightness 80–90%, environmentally friendly. Meets EU and Japanese standards for paper export.
What is the PAC dosage for paper mill wastewater?
PAC 17% at 100–300 mg/L at pH 6.5–7.5, reducing TSS by 85–95% and COD by 40–60%. Combined with biological treatment to meet QCVN 12-MT:2015 Column A.
How does ClO₂ differ from H₂O₂ in paper bleaching?
ClO₂ achieves higher brightness (≤92 ISO) and is more selective, but has higher cost and requires on-site generation equipment. H₂O₂ is more common for ECF/TCF bleaching.
What documentation comes with paper industry chemicals?
Batch CoA, 16-section GHS MSDS, CO/CQ certificate of origin, Chemical License under Decree 113, and fire safety inspection certificate. Sufficient for ISO 14001 audits.
Can paper chemicals be delivered to Binh Duong IZs, and how long does it take?
Yes — warehouses in Ba Ria – Vung Tau, Dong Nai, Binh Duong, Da Nang, Can Tho and Bac Ninh. Estimated delivery time: within 4 hours in inner-city Ho Chi Minh City, 24–48 hours to industrial parks in the South and Mekong Delta, 2–3 days to Northern and Central Vietnam. Specialized hazardous material vehicles.
Hotline 0979 891 929 — quote within 15 minutes, nationwide delivery from 200 kg to 20 tons per shipment.
Industrial Field Operation & Batch Quality Verification
1. Incoming Batch COA Verification & Regulatory Compliance (Law on Chemicals 69/2025/QH15)
When operating industrial water treatment, surface finishing, or textile dyeing lines in Vietnam, engineering teams must verify every chemical delivery against its batch-specific Certificate of Analysis (COA) and 16-section GHS Safety Data Sheet (SDS). Under the Vietnam Law on Chemicals No. 69/2025/QH15, Decrees 24/2026/ND-CP, 25/2026/ND-CP, and 26/2026/ND-CP, and QCVN 40:2025/BTNMT on industrial wastewater discharge:
- Specific Gravity & Assay Verification: Upon arrival of a 5–30-ton tanker or IBC tote shipment, plant QA technicians measure specific gravity at 20 °C using a calibrated hydrometer and cross-check active concentration against the batch COA issued by Loc Thien Chemical and verified via Quatest 3 (ISO/IEC 17025).
- Impurity & Heavy Metal Control: Trace heavy metals (Fe, Pb, As, Hg, Cd, Cr⁶⁺) and insoluble matter are strictly controlled to prevent catalyst poisoning in Fenton reactors, membrane fouling in RO/UF systems, or shade deviations in reactive textile dyeing.
- ZDHC MRSL v3.1 Level 1 Portfolio Boundary: For export-oriented textile and footwear FDI factories, Loc Thien Chemical maintains official ZDHC MRSL v3.1 Conformance Level 1 documentation for exactly 9 core products: four products certified by TUV SUD Product Service GmbH (
NaOH,H2O2,Na2SO4,Na2CO3) and five products verified via Conformance Summary Report (CSR) and Analytical Test Report by TUV Rheinland Vietnam (H2SO4,FeCl2,HCl,Javel/NaOCl,PAC 31%).
| Control Stage | Inspection Parameter | Test Method / Standard | Operational Target |
|---|---|---|---|
| Pre-Unloading Check | Seal integrity, UN/GHS hazard placards, batch COA & SDS | Visual & Document Audit | 100% match with delivery manifest |
| On-Site Sampling | Specific gravity (20 °C), visual clarity, pH / assay | ASTM / TCVN / Hydrometer | Within ±0.5% of COA specification |
| Dosing Skid Calibration | Metering pump stroke & frequency, back-pressure valve, ORP/pH probe | 2-Point Buffer Calibration | Dosing accuracy ±1.5%, stable effluent |
| Storage Safety Audit | HDPE/FRP tank vents, secondary containment dike (110% volume), eyewash | OSHA / Vietnam EHS | Zero vapor leak, immediate emergency readiness |
2. Dosing Optimization, Storage Materials & Preventive Maintenance
- Compatible Wetted Materials: Use cross-linked high-density polyethylene (XLPE / HDPE), polypropylene (PP-H), fiberglass-reinforced plastic (FRP with vinyl ester resin), or PTFE/PVDF-lined piping depending on corrosive and thermal conditions. Avoid unlined carbon steel or incompatible elastomers.
- Automated Dosing Control: Integrate diaphragm metering pumps with real-time pH, ORP (mV), turbidity, or conductivity sensors. Always perform a 5-beaker Jar Test whenever raw water COD, TSS, or alkalinity shifts by more than 15%.
- Secondary Containment & PPE: Storage tanks must sit inside an acid/alkali-resistant bund wall holding at least 110% of the largest tank volume. Operators handling unloading hoses must wear splash-proof chemical goggles, acid/alkali-resistant nitrile or neoprene gloves, face shields, and emergency respirators.
3. Multi-Role B2B Value Matrix (Procurement · QA/EHS Engineer · Plant Director)
- For Procurement Managers: Loc Thien Chemical is the direct manufacturer of FeCl2 30% solution and FeCl3 38–40% wastewater grade (3,000+ tons/month capacity), and a Tier-1 bulk commercial supplier of NaOH, HCl, H2SO4, PAC, NaOCl, H2O2, FeSO4, and Na2SiO3. Pricing is transparently structured around 5 technical cost drivers (active assay, packaging format, delivery distance from our 6 warehouses, order volume, and scheduled contract cadence) with a 15-minute technical quotation SLA.
- For Environmental & Process Engineers: Full technical support for Jar Test optimization, stoichiometry calculation, sludge minimization, and QCVN 40:2025/BTNMT compliance auditing.
- For FDI Plant Directors: Guaranteed supply continuity via 6 regional warehouses (Ba Ria - Vung Tau, Dong Nai, Binh Duong, Da Nang, Can Tho, Bac Ninh) and a dedicated 5–30-ton tanker fleet (4 hours in inner HCMC, 24–48 hours across Southern & Mekong Industrial Parks, 2–3 days in Northern & Central Vietnam).
4. Related Technical Resources & 15-Minute Quotation Gateway
- Explore our full industrial catalog: Industrial Chemical Catalog | Technical Knowledge Hub | Request a 15-Minute Technical Quote
- Legal Head Office: 452/6B Tinh Lo 10, Binh Tri Dong Ward, Binh Tan District, Ho Chi Minh City, Vietnam (Head Office only — all physical stock is dispatched from our 6 regional industrial park warehouses).
- 24/7 Technical Hotline: 0979 891 929 (Please contact hotline 0979 891 929 for detailed delivery procedures) | Official Email: [email protected]