Sulfuric Acid (H₂SO₄) Complete Guide — 98%/75%/50% Concentration, ZDHC Level 1 | Lộc Thiên Chemicals

Sulfuric Acid (H₂SO₄) Complete Guide — Properties, 98%-75%-50% Concentrations & Applications

TL;DR: Sulfuric acid (H₂SO₄, CAS 7664-93-9) is the highest-volume industrial chemical globally at ~260 million tons/year. Lộc Thiên supplies H₂SO₄ at 10%–98% concentrations, ZDHC Level 1 certified (TÜV Rheinland), lot-wise COA, same-day delivery to Industrial Parks via 20 dedicated tanker trucks.

What is Sulfuric Acid (H₂SO₄)?

Sulfuric acid (chemical formula H₂SO₄, molar mass 98.08 g/mol, CAS 7664-93-9) is a strong inorganic acid produced in the largest volume of any chemical worldwide — approximately 260 million tons annually. This viscous, colorless to slightly yellow liquid is also known as oil of vitriol or battery acid at 33–37% concentration. As a raw material input for countless critical production processes, H₂SO₄ is known as the “king of chemicals” — its production and consumption levels directly reflect the health of the chemical industry and the broader industrial economy. In Vietnam, Lộc Thiên supplies H₂SO₄ at concentrations from 10% to 98% for battery manufacturing, wastewater treatment, steel pickling, and chemical synthesis. Products are officially imported, COA-certified per lot, and meet ZDHC Level 1 standards — a mandatory requirement for export-oriented textile dyeing and leather-footwear factories.

Molecular Structure and Physicochemical Properties of H₂SO₄

The H₂SO₄ molecule has a tetrahedral structure with a sulfur atom in sp³ hybridization, bonded to two hydroxyl groups (-OH) and two double-bonded oxygen atoms (S=O). Sulfuric acid dissociates in two stages: complete first-stage dissociation (H₂SO₄ → H⁺ + HSO₄⁻), and partial second-stage dissociation (HSO₄⁻ ⇌ H⁺ + SO₄²⁻) with Ka₂ = 1.0 × 10⁻², yielding pH < 1 at all commercial concentrations. The most notable property of concentrated H₂SO₄ (≥93%) is its extremely strong dehydration capability — it absorbs moisture from the air and can carbonize organic compounds (sugar, cellulose, fabric) by removing H and O elements as water. At high temperatures, concentrated H₂SO₄ exhibits strong oxidizing properties, capable of oxidizing copper, silver, and many nonmetals; when diluted with water, the reaction is violently exothermic (ΔH = -880 kJ/mol), reaching temperatures above 100°C without proper control. Therefore, the absolute safety rule for dilution is to add acid to water, never the reverse.

Detailed H₂SO₄ Technical Specifications — Lot-wise COA

H₂SO₄ supplied by Lộc Thiên is COA-certified per lot with precise technical parameters. Technical grade 98% (UN 1830, Class 8) has H₂SO₄ content ≥ 97.5%, specific gravity ~1.84 g/mL, iron (Fe) ≤ 60 ppm, chloride (Cl⁻) ≤ 20 ppm, APHA color ≤ 30. Grade 75% has specific gravity ~1.67 g/mL, content ≥ 75%, suitable for fertilizer production and electroplating. Grade 50% (electrolyte grade, UN 2796) has specific gravity ~1.40 g/mL, content ≥ 50.9%, used in battery electrolyte and pH adjustment for water treatment. Each Lộc Thiên shipment comes with complete COA verifying all parameters, inspected and certified by QC Technicians Phan Cẩm Thủy and Võ Thị Như Hòa before dispatch. Iron (Fe) content is a critical parameter: high Fe causes yellow discoloration in end products, affecting aluminum sulfate quality and equipment lifespan. Chloride (Cl⁻) content is tightly controlled at ≤ 20 ppm since Cl⁻ causes additional corrosion on stainless steel and carbon steel in piping systems.

Analytical methods: ASTM E223 (assay), ASTM D891 (specific gravity). Actual lot data may vary within allowable limits — refer to specific lot COA upon receipt.

H₂SO₄ Concentration Comparison — Choosing the Right Concentration for Your Application

Each H₂SO₄ concentration has different specific gravity, freezing point, and transport costs that directly affect factory selection. H₂SO₄ 98% (specific gravity 1.84 g/mL) contains 980 kg of pure H₂SO₄ per ton of product — lowest logistics cost, but freezing point ~10°C (at 100%) requires heating consideration in winter. H₂SO₄ 75% (specific gravity 1.67 g/mL) has a very low freezing point at -39°C, no freezing concerns, suitable for factories without storage tank heating. H₂SO₄ 50% (specific gravity 1.40 g/mL, freezing point -33°C) has lower acid content, higher transport cost per kg of pure H₂SO₄, but is safer to handle and suitable for mild pH applications like wastewater treatment and batteries.

• Commercial H₂SO₄ 98% has actual freezing point ranging -1.1°C to 10°C depending on water content.

Choosing the right H₂SO₄ concentration depends on storage infrastructure, application purpose, and logistics costs. Factories with 316 stainless steel or FRP-lined tanks and heating systems can choose 98% for cost optimization. Wastewater treatment plants needing small-dose pH adjustment typically use 50% or 30% to avoid overdosing and improve handling safety.

Distinguishing UN 1830, 1831 and 2796 — Logistics Significance

H₂SO₄ is classified under different UN numbers depending on concentration and properties: UN 1830 applies to H₂SO₄ above 51% concentration (technical grade 98%, 75%), Class 8 — corrosive substance, Packing Group II. UN 1831 is for fuming sulfuric acid (oleum) at very high concentrations containing free SO₃, with higher hazard level — requiring specialized transport vehicles and stricter permits. UN 2796 applies to H₂SO₄ at ≤ 51% (battery grade 30–50%, electrolyte grade), also Class 8 but Packing Group III — with less stringent packaging and vehicle requirements. Distinguishing UN numbers directly affects logistics costs: tanker trucks carrying UN 1830 require passivated carbon steel tanks and corrosion-resistant safety valves; vehicles carrying UN 2796 may use HDPE tanks or lined IBCs with lower equipment costs. Lộc Thiên maintains a fleet of specialized tanker trucks for both UN numbers, fully licensed for hazardous chemical transport.

Industrial Applications of H₂SO₄ (8+ Industries)

H₂SO₄ is present in nearly every modern industrial production chain. Fertilizer production accounts for approximately 60% of global output — H₂SO₄ reacts with phosphate ore to produce superphosphate, DAP, MAP, and ammonium sulfate. In wastewater treatment, H₂SO₄ is used for pH adjustment and alkali neutralization — dosage depends on inlet alkalinity (e.g., a 50 m³/h plant with Alk 150 mg/L requires approximately 7–9 L/h of H₂SO₄ 98%). The metallurgy industry uses dilute H₂SO₄ 5–15% for steel pickling (rust removal) before galvanizing or painting, operating at 60–80°C, with FeSO₄·7H₂O as a crystallizable and recoverable byproduct. Lead-acid batteries use 33–37% H₂SO₄ solution as electrolyte — the most familiar application to end users. In intermediate chemical production, H₂SO₄ 93–98% is the main raw material for producing phosphoric acid (H₃PO₄), hydrochloric acid (HCl), aluminum sulfate Al₂(SO₄)₃, and detergents. The electroplating industry uses H₂SO₄ for metal surface cleaning before plating. Textile dyeing and leather-footwear industries use H₂SO₄ for pH adjustment in dyeing and washing processes — requiring ZDHC Level 1 chemicals. In organic synthesis, concentrated H₂SO₄ is used as a drying agent and catalyst for alkylation and esterification reactions.

Related: See also HCl (hydrochloric acid) — properties and applications for comparison of the two main industrial acids. Or check NaOH liquid caustic soda 50% — acid neutralization chemical for wastewater treatment processes.

ZDHC Level 1 — H₂SO₄ for Export Textile Dyeing Factories

ZDHC (Zero Discharge of Hazardous Chemicals) is a global initiative to eliminate hazardous chemicals from the textile, apparel, and footwear supply chain. H₂SO₄ is included in the ZDHC MRSL (Manufacturing Restricted Substances List) requiring suppliers to have compliance certification at one of three levels (Level 1–3). H₂SO₄ supplied by Lộc Thiên achieves ZDHC Level 1, certified by TÜV Rheinland — meaning the product contains no restricted chemicals per the ZDHC MRSL V3.1 list. This is mandatory for textile dyeing and leather-footwear factories exporting to the EU, USA, and Japan — they must use ZDHC-compliant chemicals to maintain export certifications (OEKO-TEX, GOTS, bluesign). Lộc Thiên provides lot-specific COA for each H₂SO₄ shipment clearly indicating ZDHC status, enabling full traceability when customers audit. Beyond H₂SO₄, Lộc Thiên also supplies a range of textile dyeing chemicals meeting ZDHC standards, serving complete needs for garment and tannery factories.

Safe Handling Guide for H₂SO₄

Sulfuric acid is an extremely corrosive chemical requiring strict safety procedures. Rule number one when diluting: always slowly add acid to water while stirring, never the reverse — the violent exothermic reaction can cause localized boiling and acid splashing. Required Personal Protective Equipment (PPE): chemical splash goggles, face shield, acid-resistant gloves (butyl rubber or thick nitrile), PVC or chemical-resistant apron, rubber boots. H₂SO₄ is incompatible with strong alkalis (NaOH, KOH) — violent exothermic neutralization; with active metals producing flammable hydrogen gas; with organic compounds causing carbonization and fire. For spill response: isolate the area, use inert absorbent materials (sand, vermiculite, chemical absorbent granules) to contain spread, then neutralize with controlled Na₂CO₃ or Ca(OH)₂. If H₂SO₄ contacts skin or eyes, flush continuously with clean water for at least 15 minutes and seek immediate medical attention. In laboratory settings, 316 stainless steel resists dilute H₂SO₄ at room temperature; high concentrations and high temperatures require PTFE, PVDF, or borosilicate glass.

Storage and Transport of H₂SO₄

H₂SO₄ is stored in specialized tanks of carbon steel (for concentrations >70% — steel is passivated forming a protective FeSO₄ layer) or corrosion-resistant FRP-lined tanks (for all concentrations). Tanks must be sealed with a desiccant vent cap since H₂SO₄ strongly absorbs moisture from the air — water ingress causes dangerous localized heating and acid dilution. The freezing point of H₂SO₄ 98% at ~10°C is a factor to consider for storage in northern Vietnam during winter or cool southern nights — requiring tank heating systems or selecting 75% concentration (freezing point -39°C) to avoid solidification. H₂SO₄ transport requires dedicated tanker trucks: passivated carbon steel tanks (for 98%), corrosion-resistant safety valves, and UN 1830/UN 2796 hazardous goods signage. Vehicles must have Class 8 hazardous chemical transport permits and drivers trained in chemical incident response. Lộc Thiên owns 20 tanker trucks and 6 warehouses nationwide (HCMC, Đồng Nai, BR-VT, Cần Thơ, Đà Nẵng, Bắc Ninh), ensuring same-day H₂SO₄ delivery within HCMC and Southern Industrial Parks.

Pricing & Purchasing H₂SO₄ at Lộc Thiên

Lộc Thiên supplies H₂SO₄ across a concentration range from 10% to 98%, with flexible packaging options — jerry cans, drums, 1000L IBC tanks, and tanker trucks. Lộc Thiên’s technical staff advises on optimal concentration based on storage infrastructure, application purpose, and customer consumption volume — helping factories optimize logistics costs and reduce inventory risk. Each shipment includes full COA and MSDS, traceable by lot code. Products are officially imported, ZDHC Level 1 certified (TÜV Rheinland), suitable for textile dyeing, leather-footwear export factories, and industries requiring strict environmental certification. A fleet of 20 tanker trucks and 6 warehouses nationwide ensures uninterrupted large-volume supply and same-day delivery to Industrial Parks in the Southern region.

🛒 Need industrial H₂SO₄? Request a quote for Sulfuric Acid H₂SO₄ 10%-98% — Lot-wise COA/MSDS, ZDHC Level 1, nationwide Industrial Park delivery. Hotline 0979 891 929.

Frequently Asked Questions (FAQ)

Can H₂SO₄ 98% be diluted to 50%?

Yes. Slowly add acid to water while stirring, with full PPE. The reaction is strongly exothermic — never reverse the order.

What’s the difference between H₂SO₄ and HCl?

H₂SO₄ is more dehydrating and has stronger oxidizing properties than HCl. HCl fumes heavily and corrodes reinforced concrete. H₂SO₄ has a high boiling point (≥327°C), less evaporation — safer in workplace conditions.

Does H₂SO₄ 98% freeze?

The freezing point of 100% H₂SO₄ is ~10°C, but commercial 98% H₂SO₄ freezes at -1.1°C. Heating is needed if storage falls below 0°C.

What is ZDHC Level 1 for H₂SO₄?

Certification that H₂SO₄ contains no hazardous chemicals per the ZDHC MRSL V3.1 list, certified by TÜV Rheinland. Mandatory for textile dyeing and leather-footwear export factories.

How do UN 1830 and 1831 differ?

UN 1830 for H₂SO₄ concentration >51%. UN 1831 for fuming H₂SO₄ (oleum) — more hazardous, stricter transport requirements. UN 2796 for concentrations ≤51%.

Does H₂SO₄ corrode stainless steel?

316 stainless steel resists dilute H₂SO₄ at room temperature. High concentrations and high temperatures require PTFE, PVDF, or passivated carbon steel.

Where to buy H₂SO₄ 75%?

Lộc Thiên — officially imported, lot-wise COA, ZDHC Level 1, nationwide Industrial Park delivery. Hotline 0979 891 929.

What is the H₂SO₄ dosage for wastewater treatment?

Depends on inlet alkalinity. Reference: 50 m³/h plant, Alk 150 mg/L → approximately 7–9 L/h H₂SO₄ 98%. Jar-test required for optimal dosage determination.

See also: PAC water treatment chemical — primary coagulant and FeSO₄ (ferrous sulfate) — applications in water treatment.

Article by Hồng (Content Writer). Quality review: QC Technician Phan Cẩm Thủy — Lộc Thiên QC Department. Approval: Võ Thị Như Hòa.

Updated: 05/09/2026 — COA data referenced from actual shipments; refer to specific lot COA upon receipt.