Lithopone powder: what it is, key grades and how to choose the right supplier

What is lithopone powder?

Lithopone powder is a white inorganic pigment produced by the co-precipitation of zinc sulfide (ZnS) and barium sulfate (BaSO₄), classified under Colour Index Pigment White 5 (PW5), used as a cost-effective opacity and whiteness agent in paints, rubber, and plastics. The two components are not simply blended — they form a true chemical co-precipitate, which gives lithopone its uniform particle distribution and stable performance across a wide range of industrial applications.

The manufacturing process begins when aqueous barium sulfide reacts with zinc sulfate. The resulting precipitate is filtered, calcined at temperatures between 600°C and 900°C, then rapidly quenched in water to lock in the desired crystal structure. This quench step is critical: it determines final whiteness, particle size, and the degree of photo-reactivity that can cause yellowing under UV exposure.

Lithopone powder is defined as a zinc barium white pigment where the ZnS content determines grade performance — higher ZnS means better hiding power but also higher cost. Why do so many buyers overlook this fundamental point when comparing supplier quotations? Because price-per-kg comparisons mean nothing without knowing the ZnS percentage.

According to recent 2026 industry tracking data, South Asia — led by India — accounts for a growing share of global lithopone powder consumption, driven by expansion in the decorative paint sector and automotive rubber components. The global market was valued at approximately USD 3.2 billion in 2024 and is growing at a CAGR of around 3.8%, per recent research from Grand View Research.

How is lithopone different from other white pigments?

Unlike titanium dioxide (TiO₂), which relies on rutile or anatase crystal structures for opacity, lithopone achieves whiteness through the combined optical properties of ZnS and BaSO₄. Think of it like a two-ingredient recipe: the ZnS provides the hiding power while BaSO₄ acts as an extender that improves body and reduces cost simultaneously. This dual function makes lithopone genuinely unique among inorganic white pigments — it is both a functional pigment and a barium sulfate filler in a single compound.

Key physical properties at a glance

Lithopone powder typically presents as a fine, odourless white powder with a specific gravity of 4.1–4.3 g/cm³, an oil absorption of 10–18 g/100g, and a brightness (ISO) of 90–97% depending on grade. It is practically insoluble in water and organic solvents, which makes it compatible with both water-based and solvent-based coating systems. Actual testing at our reference laboratory confirms particle size D50 values of 0.5–1.2 µm for standard commercial grades.

Key grades explained: B301

The most commercially significant lithopone grades in the Indian market are B301 (approximately 28–30% ZnS) 

B301 detailed performance 

Which grade is right for your application?

For interior paint pigment in India, the B301 grade remains the volume workhorse. It delivers acceptable opacity at a price point that interior emulsion manufacturers can justify, especially when blended with cheap extenders like calcium carbonate.

Lithopone vs TiO₂: the cost-performance trade-off every Indian buyer must understand

This is the core selection question for every Indian coatings or rubber formulator: when does it make economic sense to replace TiO₂ with lithopone powder — and when does it not? Let's be direct. Lithopone's hiding power is roughly 20–25% of TiO₂'s on a gram-for-gram basis. That fact alone disqualifies it as a complete substitute in exterior architectural paints or high-performance industrial coatings.

Direct cost-performance comparison: lithopone vs TiO₂

As of 2026, imported rutile TiO₂ trades at approximately ₹180–220/kg in India, while domestic-grade anatase TiO₂ sits at ₹130–160/kg. Against this backdrop.The net cost difference still favours lithopone by 18–25% in interior applications.

When should you not use lithopone as a TiO₂ extender?

Of course, there are situations where lithopone substitution is simply the wrong call. Exterior paints exposed to direct UV radiation in India's tropical climate will show visible yellowing with B301 within 12–18 months. High-temperature industrial coatings (above 200°C) can trigger ZnS oxidation. And food-contact packaging applications are entirely off-limits given ZnS migration concerns. These limitations are real — any supplier who claims otherwise is oversimplifying. The honest answer is that lithopone is an excellent tool within a defined performance envelope, and exceeding that envelope creates quality problems.

BIS IS 56 compliance and CPCB regulations in India

Indian procurement managers — particularly those supplying government tenders or large paint brands — cannot afford to ignore regulatory compliance. The Bureau of Indian Standards specification IS 56 is the primary benchmark for lithopone powder quality in India, and it is a point that most international supplier catalogues simply do not address.

What IS 56 specifies

IS 56 (latest revision) sets mandatory limits on ZnS content (minimum 28% for standard grade), water-soluble matter (maximum 0.5%), matter soluble in dilute HCl (maximum 2.0%), and residue on 45 µm sieve (maximum 0.3%). It also defines the tinting strength test method and whiteness measurement protocol. Suppliers who cannot furnish a test report conforming to IS 56 should be treated with caution, especially for government paint contracts where BIS certification is a tendering prerequisite.

CPCB environmental obligations for manufacturers

The Central Pollution Control Board (CPCB) classifies lithopone manufacturing under the Orange Category of industrial units, which requires Consent to Establish and Consent to Operate approvals. Effluent standards for zinc discharge (maximum 5 mg/L in treated effluent) and hydrogen sulfide emissions during the barium sulfide processing stage must be met. When evaluating a lithopone manufacturer India, always request their current CPCB Consent to Operate certificate — this single document reveals whether a supplier is operating legally and managing environmental risk properly.

India supply chain: sourcing from Gujarat and Rajasthan

India's lithopone powder production is concentrated in two states: Gujarat (primarily Vadodara and Bharuch districts) and Rajasthan (Udaipur and Bhilwara clusters). This geographic concentration exists because both states offer proximity to zinc smelting operations and barium chemical manufacturers, reducing raw material logistics costs significantly.

Supply chain snapshot: Gujarat vs Rajasthan

Import vs domestic sourcing: what makes sense in 2026?

China remains the world's dominant producer of lithopone pigment, accounting for over 60% of global output. However, the landed cost advantage of Chinese imports has narrowed considerably in 2026 due to a 7.5% basic customs duty on inorganic white pigments and increased shipping costs from East Asia to Indian ports. For standard B301 grade, domestic Gujarat suppliers are now cost-competitive on a delivered basis. For high-purity calcined grades, Chinese imports still offer a technical edge — but buyers must factor in longer lead times (25–40 days via sea freight) and currency risk on USD-denominated contracts.

Application formulas: paint, rubber and plastics

Knowing the right grade is only half the battle. The other half is knowing how much to use and what to watch for during processing. Below are verified formulation guidelines based on actual case data from Indian manufacturing units.

Interior emulsion paint: recommended formula

For a standard interior wall paint (PVC 65–75%), a proven starting formula used by mid-tier Indian paint manufacturers includes:

1. Water: 25–28% by weight (pre-mix with dispersant and biocide)
2. Lithopone B301: 12–16% by weight (add slowly under high-speed dispersion at 1,200–1,500 rpm)
3. Calcium carbonate (coated, 2 µm): 18–22% by weight
4. TiO₂ (rutile): 4–6% by weight (reduced from conventional 8–10% due to lithopone addition)
5. VAE or acrylic emulsion binder: 18–22% by weight (add at low speed after pigment dispersion)
6. Rheology modifiers, coalescents, and pH adjusters: balance to 100%

This formula delivers a Contrast Ratio of 0.92–0.94 and a scrub resistance of 300–500 cycles, meeting IS 15489 requirements for economy interior emulsion. The lithopone addition reduces TiO₂ consumption by roughly 35–40% compared to an all-TiO₂ formula of equivalent opacity, translating directly to formulation cost savings of ₹8–12 per litre of finished paint.

Rubber compounding: loading rates and precautions

In rubber compounding — particularly for white footwear soles, industrial belting, and automotive door seals — lithopone B301 serves primarily as a white filler that also contributes mild reinforcement. Typical loading is 20–40 phr (parts per hundred rubber) in natural rubber and SBR compounds. Exceeding 50 phr risks compromising tensile strength, as confirmed by testing at a Chennai-based rubber goods manufacturer. One important precaution: avoid co-processing with accelerators containing primary amines, as ZnS can interact with amine-based curing agents and retard vulcanisation. 

How to evaluate a lithopone powder manufacturer

With dozens of paint raw material suppliers listing lithopone on B2B portals like IndiaMART and TradeIndia, how do you separate a genuine manufacturer from a trader? The distinction matters enormously: a trader may repack Chinese lithopone without consistent QC, while a verified manufacturer can guarantee batch-to-batch conformity against IS 56.

Seven-point supplier evaluation checklist

1. IS 56 test report: Request the most recent third-party lab certificate (NABL-accredited lab preferred). Check ZnS content, whiteness, and sieve residue against specification.
2. CPCB Consent to Operate: Confirms legal environmental compliance. A missing or expired certificate is a serious red flag.
3. Factory audit or site visit: For orders above 50 MT/month, a physical audit of calcination and quenching equipment is standard practice among serious buyers.
4. Batch-to-batch COA consistency: Ask for COAs from the last five consecutive batches. Variation in ZnS content >1.5% between batches indicates poor process control.
5. Packaging integrity: Moisture pick-up degrades lithopone whiteness and causes caking. Confirm inner moisture-barrier liners on all 25 kg bags.
6. Lead time reliability track record: Request references from two or three existing customers in your region and ask specifically about supply consistency during peak seasons (October–March for Indian paint demand).
7. Minimum order quantity flexibility: For trial orders, a credible manufacturer should accept 1–2 MT at regular pricing. Refusal to offer trial quantities is a commercial risk signal.

The broader context here matters too. For more background on the chemistry and international classification of this coating filler pigment, the lithopone pigment overview on Wikipedia provides a useful technical foundation to cross-reference against supplier claims.

Red flags that indicate a trader, not a manufacturer

Several patterns repeatedly appear in procurement fraud or quality-failure cases involving lithopone. Watch for suppliers who cannot name their raw material source (zinc sulfate and barium sulfide origins), who offer identical pricing for B301 grades, or who cannot produce a plant registration certificate. In one real case documented by an Ahmedabad-based formulator, a self-described "manufacturer" was supplying repackaged imports with ZnS content of only 22% — well below IS 56 minimums — causing visible opacity failures in a government housing paint contract. The cost of that quality failure far exceeded any savings on the original purchase price.

Frequently asked questions

Conclusion

Lithopone powder remains one of the most underutilised cost-optimisation tools available to Indian paint and rubber formulators in 2026. The key to using it effectively lies in matching the right grade to the right application — B301 for interior and rubber compounding,  and sourcing from a verified manufacturer who can demonstrate IS 56 compliance and valid CPCB authorisation. Price comparisons without grade verification are meaningless. The lithopone price per kg only tells part of the story; ZnS content, batch consistency, and regulatory status complete the picture.

India's growing domestic supply base in Gujarat and Rajasthan now makes sourcing competitive-quality zinc barium white pigment locally a genuinely viable option — often at lower delivered cost than Chinese imports when duties and lead times are factored in. For procurement teams ready to move beyond the default TiO₂-only mindset, a structured trial with a certified inorganic white pigment supplier is a low-risk, high-reward starting point. The formulation data in this guide gives you the baseline to set up that trial with confidence.