# Viscose fibre: Production route

From wood pulp to fibre: xanthate or solvent

Source page: https://www.materialinsights.org/chemicals/viscose/routes/

What this tab covers How it is made: the main production routes or, for product families, the main product types and technologies, compared on share of supply, inputs per tonne, plant scale, yield, co-products and unit cost.

All man-made cellulosic fibres start with dissolving pulp. They differ in how the cellulose is dissolved. The viscose (xanthate) route uses caustic soda and carbon disulphide, and its quality depends on how well the plant recovers CS2 and treats zinc and sulphur. Modal is a modified viscose. Lyocell dissolves pulp directly in N-methylmorpholine N-oxide (NMMO) and recovers the solvent in a closed loop. Acetate is a different chemistry, mostly for cigarette filters. Recycled pulp from cotton waste can feed all of them.

#### Routes compared

| Route | Share of supply | Inputs per tonne | Typical scale | Yield | Co-products | Unit cost |
|---|---|---|---|---|---|---|
| **Viscose staple fibre (xanthate process)** | about 80% of MMCF (Textile Exchange, 2024) | about 1.0-1.05 t dissolving pulp, 0.5-0.7 t caustic soda, 0.6-1.0 t sulphuric acid, 0.08-0.10 t CS2 net, about 0.01 t zinc sulphate (indicative) | 100-400 kt/yr sites; Grasim sold 636 kt of staple fibre in April-December 2024 | about 0.95 t fibre per t pulp cellulose (indicative) | sodium sulphate (about 0.6-1 t per t), H2S, CS2 vapour, zinc in effluent (indicative) | cash cost about $1.4-1.7/kg in Asia (indicative); international CSF $1.51-1.65/kg in 2023-2024 (Grasim) |
| **Modal (high wet modulus viscose)** | a few per cent of MMCF (indicative) | similar to viscose; more zinc and modifiers (indicative) | Lenzing, Birla Cellulose, Chinese producers | similar | as viscose | premium to viscose (indicative) |
| **Lyocell (NMMO direct solvent, closed loop)** | a growing share of MMCF; generic Chinese lyocell capacity more than doubled in three years (Lenzing, 2025) | about 1.0-1.1 t pulp; NMMO make-up only; water about 263 m3/t (Taylor 2010 via Felgueiras et al. 2021) | 50-100 kt/yr lines; Grasim adding 2 x 55 kt/yr | high (indicative) | very few; NMMO degradation products | premium; Lenzing's average fibre price was $2.27/kg in 2025 against generic CSF near $1.64/kg (Grasim, Dec 2024) |
| **Recycled cellulosic fibre (textile waste to pulp)** | 1.1% of MMCF (about 90 kt) in 2024, up from 0.7% | textile waste plus virgin pulp blend | pilot to about 100 kt/yr; Renewcell's Swedish plant went bankrupt in 2024 and restarted as Circulose (indicative) | not published | dyes, polyester fraction | premium, not published |
| **Cellulose acetate** | a minority of MMCF (indicative) | pulp, acetic anhydride, acetone (recovered) | Eastman, Celanese, Daicel (indicative) | high | acetic acid recycled | not published |

#### How each route works
**Viscose staple fibre (xanthate process)**

Pulp is steeped in caustic, shredded, aged and xanthated with CS2, dissolved in dilute caustic, ripened, filtered and spun into an acid bath. Modern plants recover CS2 by condensation and adsorption and convert H2S to sulphuric acid.

Cheap and flexible; pollution and worker health risks where CS2 recovery is poor.
 Textile Exchange 2025; Grasim Q3 FY2025; indicative **Modal (high wet modulus viscose)**

A modified viscose route with slower regeneration and stretching, usually from beech pulp, giving a stronger, softer fibre for underwear and premium knits.

Higher value; same chemical issues as viscose.
 indicative **Lyocell (NMMO direct solvent, closed loop)**

Pulp is dissolved directly in hot aqueous NMMO and dry-jet wet spun into water. The solvent is washed out and over 99% is recovered and reused, so there is no CS2 or zinc.

Cleanest route (GWP about 0.05 t CO2e per t for an integrated Austrian plant, Shen and Patel 2010); higher capex and NMMO thermal-runaway risk.
 Lenzing FY2025 presentation; Grasim; Felgueiras et al. 2021 **Recycled cellulosic fibre (textile waste to pulp)**

Cotton-rich waste is sorted, de-coloured and pulped into dissolving-grade cellulose (for example Circulose, Lenzing Refibra, Birla Cellulose Liva Reviva) and blended into viscose or lyocell dope.

Cuts forest demand; costly and dependent on sorted waste supply.
 Textile Exchange 2025; indicative **Cellulose acetate**

Pulp is acetylated with acetic anhydride, dissolved in acetone and dry-spun; most goes to cigarette filter tow, some to textiles.

Different market; textile use is small.
 indicative Unit economics are indicative ranges from the sources named; costs move with feedstock and energy prices, plant size and region.

## Other sections

- [Summary](https://www.materialinsights.org/chemicals/viscose/index.md)
- [Overview](https://www.materialinsights.org/chemicals/viscose/overview/index.md)
- [Correlation](https://www.materialinsights.org/chemicals/viscose/correlation/index.md)
- [Production](https://www.materialinsights.org/chemicals/viscose/production/index.md)
- [Feedstocks](https://www.materialinsights.org/chemicals/viscose/feedstocks/index.md)
- [Cycles](https://www.materialinsights.org/chemicals/viscose/cycles/index.md)
- [Trading](https://www.materialinsights.org/chemicals/viscose/trading/index.md)
- [Movement](https://www.materialinsights.org/chemicals/viscose/movement/index.md)
- [Regulation](https://www.materialinsights.org/chemicals/viscose/regulation/index.md)
- [Characteristics](https://www.materialinsights.org/chemicals/viscose/characteristics/index.md)
- [Emissions](https://www.materialinsights.org/chemicals/viscose/emissions/index.md)
- [Relationships](https://www.materialinsights.org/chemicals/viscose/links/index.md)