Cashew Nut Shell Liquid (CNSL)
CNSL is a dark, caustic industrial oil held in the cashew shell. Rich in phenolic compounds like anacardic acid and cardanol, it feeds resins, coatings, brake linings and specialty chemicals.
Cashew Nut Shell Liquid (CNSL) is the viscous, dark, caustic oil contained in the honeycomb structure of the cashew shell. It is a rich source of natural phenols — mainly anacardic acid, cardanol and cardol — making it a versatile industrial feedstock for friction materials (brake linings), phenolic resins, paints and coatings, surfactants and specialty chemicals. Extracted from shell as a by-product, CNSL adds a revenue stream to cashew processing beyond the kernel.
CNSL is the dark reddish-brown oil held in the honeycomb layer between the outer and inner shell of a cashew nut. It is roughly 20–25% of the nut's weight, it is a genuine industrial feedstock rather than a curiosity, and for a processor it is the difference between paying to dispose of shells and being paid for them. This page covers the material: what it is chemically, how it is extracted, what it is used for, how it is refined, and what it has sold for. For the economics of recovering it alongside kernels, see CNSL and cardanol production economics.
What CNSL is
Chemically, CNSL is a mixture of alkylphenols: long-chain phenols with a 15-carbon side chain at varying degrees of unsaturation (saturated, monoene, diene or triene). That side chain is what makes CNSL useful — it gives the phenol ring a built-in flexible tail, so resins made from it are tougher and less brittle than those from synthetic phenol. What the mixture actually contains depends on how it was extracted, and the difference is large enough to be the whole story.
| Component | Natural CNSL (cold / solvent-extracted) | Technical CNSL (roasted / hot-oil bath) |
|---|---|---|
| Anacardic acid | 60–65% | Trace — decarboxylated by heat |
| Cardanol | ~10% | 60–70% (up to ~90–95% when distilled) |
| Cardol | 15–20% | 10–20% |
| 2-methylcardol | ~2% | Minor |
| Polymeric material | Minor | ~10% |
Heat converts anacardic acid to cardanol (decarboxylation) — that is why technical CNSL from roasting or hot-oil extraction is cardanol-rich while cold-extracted natural CNSL is anacardic-acid-rich. Which one you want depends entirely on what you are selling into.
Composition figures are indicative laboratory ranges compiled from published literature; actual values vary with nut origin, extraction method and process temperature. Verify independently before commercial or regulatory use.
CAS registry number 8007-24-7. It is immiscible with water, soluble in alcohols, ethers and hydrocarbons. Raw CNSL is caustic and irritates skin, so it needs proper handling gear; refined grades are far safer. With global cashew shell output around 2–3 million tons a year, fully extracted CNSL yield would be 500,000–750,000 tons — actual extraction is well below that, which is the opportunity.
Extraction methods
Hot oil bath
shells pass through CNSL itself heated to 180–200°C. The heat ruptures the honeycomb cells and the liquid runs out. High throughput, industrial standard, gives technical CNSL.
Roasting / drum
shells are roasted directly. Simple and cheap, but a share of the liquid burns off, and fumes need extraction.
Mechanical screw pressing
ambient temperature, no thermal degradation, gives natural CNSL with anacardic acid intact. Lower yield than the hot routes, and press throughput is specified against your shelling rate rather than sold off a standard size list.
Solvent extraction
room temperature to 60°C using organic solvents. Highest quality and best preservation of anacardic acid, so the product commands more; requires solvent recovery and carries the associated safety and capital burden.
Properties that matter in use
- Density 0.95–1.05 g/cm³; viscosity that falls sharply with temperature, which is why lines are steam-traced.
- Phenolic and reactive — participates in polymerisation, condensation and addition reactions, so it substitutes directly for petroleum phenol in many formulations.
- Bioactive — antimicrobial, antioxidant and anti-inflammatory effects, largely from the anacardic acid fraction. This is what drives pharmaceutical interest.
- Caustic when raw — skin contact causes irritation and blistering. Handle with gloves and eye protection; this is not optional.
- Renewable — derived from agricultural waste, which is the core of its commercial case under tightening environmental regulation.
What it is used for
Friction materials
brake linings and clutch facings. The oldest and still one of the largest applications; the polymeric fraction is specifically valued here.
Coatings and paints
CNSL-based resins give corrosion resistance and adhesion, particularly in marine and industrial primers.
Epoxy hardeners and adhesives
cardanol-based curing agents are flexible and moisture-tolerant.
Surfactants and plasticisers
the long alkyl chain makes cardanol a natural starting point.
Bio-based flame retardants
a growing area as halogenated retardants are restricted.
Biofuel and fuel additives
lower-grade fractions burn well; shell residue after extraction is itself a boiler fuel.
Pharmaceutical intermediates
driven by the antimicrobial and antioxidant activity of anacardic acid and cardol.
Refining extracted CNSL
Decarboxylation
heating to 140–180°C converts anacardic acid to cardanol, raising cardanol content and lowering acidity. This is the step that turns natural CNSL into technical CNSL.
De-gumming
removes gums and suspended solids that would otherwise foul downstream reactions and darken the product. Degummed grades price above raw.
Solvent extraction and washing
separates the phenolic fractions, typically with methanol and ammonium hydroxide, and removes residual impurities.
Vacuum distillation
at 10–20 mmHg, concentrates cardanol well above the 60–70% of technical CNSL — published figures for distilled technical CNSL run to roughly 90–95%, and what a given plant reaches depends on its column. The heavy fraction left behind is the polymeric residue sold into friction materials.
Conversion into cardanol
Cardanol is the derivative that carries most of the value. Production starts by heating CNSL to 140–180°C to decarboxylate anacardic acid into cardanol, then vacuum distilling to separate cardanol from cardol and the polymeric residue. Published figures put distilled technical CNSL at roughly 90–95% cardanol; further solvent purification takes it above 95% for premium grades. That refining step is where the value sits, which is why the distillation column — not the press — is the expensive part of a CNSL business.
CNSL price trends, 2020–2025
CNSL is priced per metric ton and moves with cashew production volumes, because it is a byproduct — supply is set by how many nuts get shelled, not by CNSL demand. That asymmetry is the single most important thing to understand about the price series below.
| Year | Average price (USD/MT) | Price range (USD/MT) | Market value (USD m) | Key influences |
|---|---|---|---|---|
| 2020 | 700–800 | 650–850 | 350–370 | COVID-19 disruption reduced processing; coatings demand held. Back-calculated from growth trends. |
| 2021 | 750–850 | 700–900 | 371.1 | Recovery in cashew production; biofuel interest rose with the energy transition. |
| 2022 | 800–900 | 870–940 | 393.2 | Supply chains recovered; epoxy resin and friction material demand rose. Prices stabilised but varied by region. |
| 2023 | over 1,050 | 510–1,090 | 403.7–450 | Reduced Indian output pushed prices up; strong growth in bio-based applications. Wide range reflects quality spread. |
| 2024 | 700–800 | 460–970 | 461.1–481.8 | Downward trend from oversupply and economic slowdown; refined grades held steadier than raw. |
| 2025 | 650–750 | 645–745 | 511.7 | To August 2025: softened on increased Vietnamese exports. Refined 645–695, degummed 695–745. |
The 2023 figure exceeded $1,050 on average against a $510–1,090 range — an unusually wide spread that reflects how far quality varies between suppliers.
What moves the price
Cashew production volume
the dominant factor. CNSL is a byproduct, so supply tracks nut processing regardless of CNSL demand.
Extraction capacity
much of the world's shell is still burned rather than extracted, so refining investment shifts effective supply more than harvests do.
Grade
raw, degummed and refined price differently, and the spread widens in soft markets as buyers move up in quality.
Substitute prices
CNSL competes with petroleum-derived phenol, so crude oil prices set a ceiling on what it can command.
Regulation
restrictions on halogenated flame retardants and synthetic phenols push demand toward bio-based alternatives.
Regional export policy
Vietnamese export volumes visibly softened 2025 prices; African export patterns move it too.
Projections, 2026–2030
Prices are expected to rise moderately, driven by green chemistry and biofuel applications, tempered by improving extraction efficiency adding supply. Volume growth is the more confident part of the forecast: roughly 1,110 thousand MT in 2026 rising to about 1,340 thousand MT by 2030.
| Year | Projected avg. price (USD/MT) | Projected range (USD/MT) | Projected market value (USD m) | Projected volume (000 MT) |
|---|---|---|---|---|
| 2026 | 750–850 | 700–950 | 570 | 1,110 |
| 2027 | 800–900 | 750–1,000 | 635 | 1,170 |
| 2028 | 850–950 | 800–1,050 | 710 | 1,220 |
| 2029 | 900–1,000 | 850–1,100 | 790 | 1,280 |
| 2030 | 950–1,050 | 900–1,150 | 876.5 | 1,340 |
Projections, not commitments. The volume column is the firmer of the two — price depends on how fast extraction capacity is built.
Raw CNSL is caustic and causes skin burns; anyone specifying a shell press should budget for gloves, eye protection and splash containment from the outset. All prices here are dated market observations reproduced from published reporting, not quotations — TTQ builds shell presses and shell-fired boilers but does not trade CNSL. If your interest is whether recovery pays on your own kernel line, the worked economics are on the cardanol production page.
What CNSL is used for
- Friction materials — brake linings and clutch facings
- Phenolic resins and laminates
- Paints, varnishes and coatings
- Surfactants and specialty chemicals
Its most valuable derivative is cardanol. CNSL is extracted during shell oil extraction.
CNSL is caustic and can irritate skin — it is an industrial material handled with appropriate protection, not a food product.
The process, drawn
Two extraction routes, two different liquids
Heat decides the chemistry. The route you choose determines what you can sell the CNSL into.
- Anacardic acid 60–65%
- Cardanol ~10%
- Cardol 15–20%
- Buyers Pharmaceutical, bioactive, speciality
- Anacardic acid Trace Decarboxylated by heat
- Cardanol 60–70% Up to ~90–95% distilled
- Cardol 10–20%
- Buyers Resins, coatings, friction materials
Heat converts anacardic acid to cardanol. Composition figures are indicative laboratory ranges compiled from published literature; actual values vary with nut origin, extraction method and process temperature. Verify independently before commercial or regulatory use.
Where the raw nut actually goes
One tonne of RCN leaves the plant as three streams, not one. The kernel pays the wages; the shell pays the fuel bill.
The testa is the thin brown skin taken off at peeling. CNSL comes from the SHELL, not from the testa or the husk — a distinction worth holding onto when reading supplier literature.
The geometry behind it
Where CNSL actually sits
A cashew is not a nut with a shell around it — it is a drupe, and the layer that matters commercially is the honeycomb mesocarp between the outer and inner shell walls. That honeycomb holds the CNSL. It is separated from the kernel at shelling, which is why the testa peeled off later contains none of it.
Cross-section, schematic. The commercial consequence is the one people get wrong: “husk” is used for both the shell and the testa, and only the shell yields CNSL.
Frequently asked questions
What is CNSL?
What is CNSL used for?
Related reading & machines
Cardanol from Cashew Nut Shell Liquid
Cardanol is the main phenolic compound distilled from CNSL — a renewable, bio-based building block for resins, plasticisers, coatings and green chemistry.
Open →Cashew Shell: Waste, Fuel and Feedstock
The cashew shell is not just waste — it is a fuel that powers the plant, a source of the industrial oil CNSL, and a feedstock for biomass energy and carbon credits.
Open →Cashew Nut (Shell) Oil Extraction Process
Cashew "oil" usually means Cashew Nut Shell Liquid (CNSL) — a valuable industrial oil extracted from the shell by roasting/expelling or solvent methods, not the edible kernel.
Open →Talk to a cashew engineer
Tell us your target capacity, grades and location — we’ll come back with a costed proposal.