Understanding the Differences Between Sulfuric Acid Concentrations: 30%, 70%, 93%, and 96%
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What you will learn
💡 Frequently Asked Questions
Find quick answers to common questions about understanding the differences between sulfuric acid concentrations: 30%, 70%, 93%, and 96%.
Understanding Sulfuric Acid Concentrations: 30%, 70%, 93%, and 96%
A complete comparison of the four most common sulfuric acid grades — physical properties, industrial applications, handling requirements, and which concentration to choose for your process
Quick Answer: Which Concentration Do You Need?
At a Glance
30% — Battery electrolyte, water treatment, pH adjustment. 70% — Fertilizer production, mineral processing, chemical synthesis. 93% — Oil refining, metal pickling, general industrial use (most common). 96% ACS — Laboratory analysis, precision chemical synthesis, reagent-grade applications.
| Property | 30% | 70% | 93% | 96% ACS |
|---|---|---|---|---|
| Specific Gravity | 1.219 | 1.615 | 1.835 | 1.840 |
| Baumé | 26° | 55° | 66° | 66.3° |
| Freezing Point | -36°C | -35°C | -21°C | -15°C |
| Typical Use | Batteries, water treatment | Fertilizers, ore leaching | Oil refining, pickling | Lab analysis, research |
| Grade Available | Laboratory | Laboratory | Technical | ACS Reagent |
For an even more detailed breakdown including 37%, 50%, and electrolyte grades, see our Complete Sulfuric Acid Concentration Guide.
Sulfuric Acid 30% — Dilute Grade
Sulfuric acid 30% contains 30% H₂SO₄ by weight with the balance being water. At a specific gravity of approximately 1.219, it is the least aggressive of the four concentrations but still corrosive and requires proper PPE and handling procedures.
Key Applications
- Battery Electrolyte: Lead-acid batteries use dilute sulfuric acid in the 30–37% range. The electrolyte facilitates the electrochemical reactions for power storage and release. For battery-specific formulations, Alliance Chemical also offers Sulfuric Acid 37% Battery Acid. For a deep dive, see our Battery Acid Deep Dive.
- Water Treatment: Municipal and industrial water facilities dose 30% sulfuric acid to reduce alkalinity, adjust pH, and support flocculation processes. Its controlled acidity helps remove dissolved metals and other impurities.
- Cleaning & Descaling: Used in specialized descalers and rust removers where a less aggressive acid is preferred. Even at 30%, it effectively dissolves mineral deposits and scale.
Sulfuric Acid 30%
CAS: 7664-93-9 | Laboratory Grade | Liquid
From $24.00 — available quart to 55-gallon drum
Shop Now →Though milder than concentrated grades, 30% sulfuric acid can still cause chemical burns. Always follow proper safety measures, use PPE, and consult the Safety Data Sheet (SDS).
Sulfuric Acid 70% — Intermediate Grade
Sulfuric acid 70% is a more potent, intermediate-grade solution with a specific gravity of approximately 1.615. With a higher acid-to-water ratio, it exhibits greater reactivity and a stronger corrosive effect than the 30% variant.
Key Applications
- Fertilizer Production: One of the largest markets for sulfuric acid globally. Phosphate rock is treated with sulfuric acid at concentrations around 70% to liberate phosphate ions, producing superphosphate and ammonium phosphate fertilizers. According to the IFA, approximately 50% of global sulfuric acid production goes to fertilizer manufacturing.
- Mineral Processing & Mining: Mining operations use sulfuric acid to leach metals from ores via hydrometallurgical extraction. Copper heap leaching, zinc extraction, and rare earth processing all rely on sulfuric acid at intermediate concentrations.
- Chemical Synthesis: Intermediate concentrations support detergent production, dye and pigment manufacturing, and general inorganic salt formation.
Sulfuric Acid 70%
CAS: 7664-93-9 | Laboratory Grade | Liquid
From $23.00 — available quart to 55-gallon drum
Shop Now →Due to its elevated acidity and potential for violent reactions with water or incompatible materials, 70% sulfuric acid demands strict adherence to safety protocols. Store in corrosion-resistant containers and ensure a well-ventilated workspace.
Sulfuric Acid 93% — Concentrated / Technical Grade
Sulfuric acid 93% is the standard "concentrated" sulfuric acid used across most heavy industrial applications. At a specific gravity of 1.835 (66° Baumé), it balances high reactivity with manageable handling compared to fuming grades or oleum.
Key Applications
- Oil Refining (Alkylation): Petrochemical refineries use concentrated sulfuric acid as a catalyst in alkylation units to produce high-octane gasoline components. According to the EIA, U.S. refineries consume over 2 million tons of sulfuric acid annually for this purpose.
- Metal Pickling: Steel mills and metal fabricators use 93% acid to remove oxide layers, rust, and scale before galvanizing, painting, or welding. The pickling process becomes rapid and precise at this concentration. See our guide to metal finishing with acids for more detail.
- Pulp & Paper: Used to remove lignin from cellulose fibers, improving paper quality. Concentrated acid efficiently breaks down unwanted organic matter in the pulping process.
- General Industrial Chemistry: Catalyst for esterification, sulfonation, and dehydration reactions across pharmaceutical, agrochemical, and polymer manufacturing.
Sulfuric Acid 93% Technical Grade
CAS: 7664-93-9 | Technical Grade | Liquid
From $25.00 — available quart to 55-gallon drum
Shop Now →Safety Warning
93% sulfuric acid is a powerful dehydrating agent. It can cause severe burns on contact with skin, eyes, and mucous membranes. Always wear a face shield, acid-resistant gloves, and a chemical apron. Use in a fume hood or well-ventilated area. When diluting, always add acid to water slowly — never water to acid.
Sulfuric Acid 96% ACS Grade — Reagent / Analytical
Sulfuric acid 96% ACS Grade is among the most concentrated commercial forms, meeting American Chemical Society (ACS) Reagent Grade specifications for maximum impurity limits. Its high purity makes it indispensable for precision work.
Key Applications
- Laboratory Reagent: Standard reagent for titrations, dehydration reactions, and analytical procedures. ACS-grade purity ensures reproducible, accurate results — trace metal impurities are controlled to <0.5 ppm for critical contaminants.
- Chemical Synthesis: Nitration, sulfonation, and forming certain sulfates depend on near-anhydrous sulfuric acid. The low water content shifts reaction equilibria in ways that weaker concentrations cannot achieve.
- Catalyst for Esterification: The acid's potent proton-donating ability accelerates esterification, polymerization, and other acid-catalyzed reactions to near-completion.
- Quality Control & Assay: Used as a primary standard in wet chemistry labs for acid-base titrations and Karl Fischer moisture analysis.
Sulfuric Acid 96% ACS Grade
CAS: 7664-93-9 | ACS Reagent Grade | Liquid
From $26.00 — available quart to 55-gallon drum
Shop Now →How Sulfuric Acid Compares to Other Mineral Acids
Beyond sulfuric acid, industrial operations frequently use other strong mineral acids. Understanding the differences helps you select the right acid for each application. For a broader overview, see our Professional's Guide to Industrial Acids.
| Property | Sulfuric (H₂SO₄) | Hydrochloric (HCl) | Nitric (HNO₃) |
|---|---|---|---|
| CAS Number | 7664-93-9 | 7647-01-0 | 7697-37-2 |
| Type | Diprotic, dehydrating | Monoprotic, non-oxidizing | Monoprotic, oxidizing |
| Max Concentration | 96–98% | 37–38% | 68–70% |
| Primary Use | Fertilizer, refining, pickling | Metal pickling, pH control | Fertilizer, etching, explosives |
| Residue/Anion | Sulfate (SO₄²⁻) | Chloride (Cl⁻) | Nitrate (NO₃⁻) |
Hydrochloric Acid (HCl)
Hydrochloric acid (CAS 7647-01-0) is a strong monoprotic acid widely used for metal pickling, pH control, and chemical production. It generates chloride residues rather than sulfates, which can be advantageous for certain processes but may cause corrosion concerns with specific equipment alloys.
Nitric Acid (HNO₃)
Nitric acid (CAS 7697-37-2) is an oxidizing acid essential for fertilizer manufacturing (ammonium nitrate), explosives, and semiconductor etching. Its oxidizing nature makes it uniquely capable of dissolving noble metals when combined with hydrochloric acid (aqua regia). See our Introduction to Nitric Acid Uses for a detailed guide.
Safety Precautions & Handling Guidelines
Regardless of concentration, sulfuric acid must be handled with rigorous safety protocols. The higher the concentration, the more severe the consequences of mishandling.
- Personal Protective Equipment (PPE): Acid-resistant gloves (nitrile or butyl rubber), splash-resistant face shield, chemical apron, and closed-toe shoes. For concentrated grades (>70%), consider respiratory protection — use a fume hood or NIOSH-approved acid gas respirator.
- Ventilation: Use fume hoods or local exhaust systems. Concentrated sulfuric acid fumes at elevated temperatures, and mist from dilution can irritate the respiratory tract.
- Storage: Store in HDPE containers (up to 93%) or glass/fluoropolymer-lined steel for 96%. Keep tightly sealed in a cool, dry, well-ventilated area. Separate from bases, oxidizers, organic materials, and reactive metals.
- Safe Dilution: Always add acid to water, never water to acid. Add slowly while stirring. The dilution reaction is strongly exothermic — adding water to concentrated acid can cause violent boiling and splashing.
- Spill Response: Neutralize small spills with soda ash (sodium carbonate) or lime. Large spills require trained hazmat response. Chemical showers and eyewash stations must be within 10 seconds of any handling area per OSHA 29 CFR 1910.151.
- Disposal: Follow EPA and local regulations. Spent acid may be neutralized before disposal or handled by licensed chemical waste contractors.
Alliance Chemical Quality Assurance
Every sulfuric acid product shipped by Alliance Chemical includes a Certificate of Analysis (COA) documenting lot-specific concentration, specific gravity, and trace impurity levels. Safety Data Sheets (SDS) are provided with every order. Our products meet the purity requirements demanded by industrial processors, laboratories, and water treatment facilities nationwide.
Frequently Asked Questions
Shop Sulfuric Acid — All Concentrations
Alliance Chemical stocks sulfuric acid in 30%, 37%, 50%, 70%, 93%, and 96% concentrations. Available from quart bottles to 55-gallon drums with COA and SDS for every order.
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