Project Parameters
| Parameter | Value |
|---|---|
| Process route | MVR evaporation: lithium precipitation mother liquor concentration + sodium sulfate by-product crystallization |
| Industry | Battery materials — lithium chemicals (Central China, Jiangxi) |
| Feed type & key components | Lithium precipitation mother liquor; lithium-bearing sulfate solution with sodium sulfate co-salt |
| Plant capacity | 30,000 tpa lithium carbonate (comparable published plant: 20,000 tpa in Hunan) |
| Construction materials | SS316L wetted parts (indicative for sulfate service) |
Representative process configuration compiled from published industry project data. Indicative values, not a process guarantee.
Project Description
Lithium carbonate plants concentrate, purify and precipitate: the lithium arrives from spodumene or brine or recycle streams as a sulfate or chloride liquor, is purified to battery grade, and is precipitated as Li2CO3 with soda ash. Every one of those steps moves water, and the plant’s water balance closes in the evaporation section — which is why a 30,000 tonne-per-year lithium carbonate project in Central China (Jiangxi, the center of spodumene conversion capacity) is built around an MVR evaporation package, with a comparable 20,000 tpa plant published in the same regional cluster.
The evaporation duties come in two natures. The lithium-bearing streams — particularly the mother liquor from lithium precipitation, which still carries soluble lithium that the plant wants back — demand concentration with lithium recovery: every kilogram of lithium lost to a waste stream is product-grade revenue. The sodium sulfate streams, the reaction’s by-product salt, demand crystallization to a marketable by-product. The flowsheet integrates both under one thermal architecture.
Process Technology
Mother liquor from the lithium precipitation section is returned to the front of the evaporation loop. MVR evaporators concentrate the liquor: mechanical vapor recompression supplies the thermal drive electrically, and the concentration returns both water and dissolved lithium to the head of the lithium circuit — the recycle that lifts overall lithium yield to the levels battery-chemical economics require.
Purification chemistry runs through the loop: the concentrate passes ion-exchange or deep impurity removal steps that strip the calcium, magnesium, sodium and boron that would otherwise ride into the precipitator, because battery-grade lithium carbonate is specified at ppm impurity levels and the evaporator is where the impurity loop would otherwise close into itself. The purified, concentrated lithium liquor advances to lithium carbonate precipitation with soda ash.
The other side of the flowsheet handles the sulfate. Sodium sulfate solution — by-product of the lithium conversion chemistry and the purification steps — is crystallized in its own MVR-driven crystallization train, recovering Na2SO4 as a dewatered, saleable industrial by-product rather than a waste load. The two trains share the plant’s electrical thermal architecture: compressors on both the lithium liquor concentration and the sulfate crystallization duties, running on the site’s power.
Condensate from both trains returns to the process — washing, dissolution and regeneration water in a plant whose water permit, like its lithium yield, is a designed outcome. The integrated package — lithium liquor concentration, impurity control, lithium recycle and by-product sulfate recovery — is what a modern lithium carbonate plant’s evaporation scope means.
Equipment Configuration
One set of the following equipment is typical for this duty:
- MVR evaporators for lithium precipitation mother liquor concentration and lithium recycle
- Deep purification interface (ion exchange / impurity removal) on the concentrated liquor
- MVR-driven sodium sulfate crystallization train for by-product salt recovery
- Centrifuges and drying for the sodium sulfate by-product
- Condensate recovery across both trains for process water reuse
- DCS control of concentration loops, lithium inventory and sulfate crystallization
Performance & Outcome
Compiled from published industry project data, indicative: plants of this class run 20,000–30,000 tpa lithium carbonate on integrated MVR evaporation, returning lithium via mother liquor recycle, recovering sodium sulfate as by-product, and closing the water balance with condensate reuse. Lithium yield and specific energy are quoted per project flowsheet.
