VSEP Industries

Lithium Extraction Filtration

VSEP® for Lithium Extraction & Refining

Vibratory shear membrane systems that de-bottleneck clay, hard‑rock, and brine flowsheets—without flocculants, with continuous automation, and a compact footprint. Engineered for mining process engineers and hydrometallurgists who need higher recovery, lower reagent burn, and reliable uptime across highly variable feeds in their lithium extraction and refining processes.

Why this matters

Lithium projects are increasingly constrained by colloids after precipitation purification, energy‑intensive thermal steps, and large pond footprints. Conventional filters and clarifiers struggle as Mg/Ca precipitates form sub‑micron particles that don’t settle easily, pass through filter cloths and foul downstream equipment. VSEP® (Vibratory Shear Enhanced Processing) applies high‑frequency, low‑amplitude vibration directly to a membrane stack, creating intense shear at the membrane surface, disrupting the cake layer, and maintaining flux at very high TDS and high‑solids conditions. The result: near‑complete TSS capture without flocculants, continuous automated operation, and compact modular skids that fit where batch filter presses and large ponds cannot.

Lithium sources & canonical extraction routes

1) Hard‑rock (spodumene – pegmatite) (most common)

After beneficiation, the crushed ore is roasted at high temperature to convert lithium oxide to a form that can be chemically leached with sulfuric acid. Then, the slurry is neutralized to precipitate unwanted metals. This creates small colloid precipitates that need to be removed prior to crystallization.

  • Mine & concentrate: crushing, grinding, DMS/flotation to ~6% Li₂O concentrate.
  • Thermal conversion: roast 1000–1100 °C to convert α‑spodumene → β‑spodumene.
  • Leach & purify: sulfuric‑acid digestion (~250 °C) to Li₂SO₄; neutralization/precipitation (90ºC) removes Fe/Al/Mg/Ca; filtration; polish; convert to Li₂CO₃ or LiOH·H₂O; crystallize to battery grade.
  • Filtration’s role: solid–liquid separation after precipitation is critical to quality, yield, and reliability.

2) Lithium‑bearing clays (hectorite, illite‑smectite, jadarite)

During upgrading of the clay, after it has been crushed and scrubbed, it is hydrated to make a slurry so that large oversized particles and gangue can be removed by screening. This can be done with vibratory wet screens or hydrocyclones. Then it is roasted prior to acid leaching. Then it is purified by precipitation and filtration in the same way as hard rock.

  • Beneficiation: hydration, attrition scrubbing, slurry screening to remove oversize and standardize feed.
  • Conventional route: high‑temperature roasting (800–1000 °C) followed by acid leach; multi‑stage purification (precipitation with CaOH2) and crystallization.
  • Emerging routes: selective hydrothermal extraction without roasting/strong acid; mechanically assisted selective leach (high‑energy milling + cation source).

3) Brines (salars, geothermal, oilfield)

Many lithium rich brines can be found and then processed to sequentially precipitate and remove impurities due to varying solubility limits.

  • Traditional: long‑cycle solar evaporation, impurity removal (especially Mg²⁺, Ca²⁺), then conversion/crystallization.
  • Membrane‑assisted DLE: nanofiltration (NF) to strip divalents, RO for water removal, electrodialysis/electrosorption for selective ion transport, ion‑imprinted or liquid membranes for high selectivity.

Where conventional filtration struggles

  • Colloidal precipitates (Mg(OH)₂, Al/Fe hydroxides) that do not settle and pass filter cloths, forcing flocculant/polymer use and rework.
  • High‑TDS feeds (50–>200 g/L) where osmotic pressure, scaling, and viscosity collapse flux on standard membranes unless large pretreatment trains are installed.
  • Batch cycles & sludge handling with filter presses increase downtime, labor, and footprint.

How VSEP® works (mechanism in brief)

VSEP applies torsional resonating vibration to the membrane filter stack at high frequency (~50 hz) with a displacement amplitude of 1/2 inch. The resulting very high shear at the membrane surface continuously collapses the boundary layer, sustaining permeate flux on feeds containing fine colloids, high TSS, and very high TDS. Colloids are kept in suspension and uniformly spaced. Concentration polarization near the membrane surface is disrupted. This allows:

  • UF service to remove essentially all suspended and colloidal solids without polymers.
  • NF/RO service on challenging brines with substantially reduced scaling propensity due to the shear field at the surface and the disruption of concentration polarization.

Graphic showing how VSEP is use for lithium extraction and refining.

VSEP deployment positions for lithium projects

1) Post‑precipitation solids removal in hard‑rock and clay leach circuits

Problem: After neutralization/precipitation to remove Mg/Ca/Fe/Al, filter presses leave residual sub‑micron colloids with the Li2SO4 that carry into crystallization; polymers are often needed to aid agglomeration. Polymers represent an avoidable operating cost and can foul filter cloth.

VSEP‑UF solution:

  • Polymer‑free clarification: capture virtually 100% TSS and colloids, protecting downstream ion‑exchange/evaporation/crystallization.
  • Continuous, automated operation vs. batch filter press; minimized floor area and no press cake handling.
  • VSEP Filters and systems can be designed for up to 120ºC

Why it works: Post‑precipitation slurries have PSD centered well below 1–5 µm; vibratory shear suppresses cake buildup and keeps flux stable where static UF would blind.

2) Dewatering fine clay slurries prior to roasting

Problem: Clay circuits use screening/centrifuges to remove gangue; the centrate (fine clay slurry) can still carry high water, increasing roasting energy load. Moisture content can vary depending on the method, but slurry viscosity needs to be low enough for screening to work properly

VSEP‑UF Solution:

  • Dewater the centrate to raise solids, cutting thermal duty in the roaster/kiln (roasting commonly 800–1000 °C in conventional routes).
  • VSEP can concentrate suspended solids to near the gel-point. The dewatering efficiency will depend on the moisture content.

3) DLE pre‑concentration & divalent removal for brines

Membranes and especially VSEP membranes can be used for Direct Lithium Extraction (DLE) from salars, geothermal, oilfield, and well water brines. RO can be used for dewatering and NF can be used for multivalent ion removal.

Scenario A — Brines < ~50,000 mg/L TDS:

  • VSEP‑RO removes water upstream of evaporation ponds, shrinking pond acreage and cycle time; permeate can be re‑injected for aquifer support (project‑dependent).

Scenario B — Concentrated salar brines or VSEP RO concentrate:

  • VSEP‑NF selectively rejects Mg²⁺/Ca²⁺ even at high TDS to lower the Mg/Li ratio, reducing reagent consumption in subsequent precipitation or accelerating sequential ponding. High shear mitigates scaling at the membrane face.

(Membrane‑assisted divalent removal and Li enrichment are widely documented; VSEP’s vibratory shear addresses the fouling/scaling limit state that typically constrains NF/RO on these brines.)

4) Polishing DLE eluates (IX/adsorption systems)

Problem: Ion‑exchange or sorbent DLE does not capture 100% Li; the eluate can remain relatively dilute and contain still contain significant amounts of Li. VSEP can be used to assist DLE methods involving ion exchange or media adsorption.

VSEP‑RO Solution:

  • Concentrate Li‑bearing eluate for efficient recovery and reduce the volume of recycle streams.

5) LiOH slurry dewatering ahead of crystallization

Problem: LiOH finishing often feeds evaporators/crystallizers with dilute slurries, increasing steam consumption and limiting throughput.

VSEP‑RO Solution:

  • Thicken the LiOH slurry (while respecting osmotic/temperature constraints) to lower the thermal load on forced‑circulation or DTB crystallizers, improving OPEX and line capacity.

6) Industrial effluents containing lithium

VSEP‑RO:

  • Concentrate low‑ppm Li waste streams to a recoverable grade; reduce disposal volumes and support circular recovery programs.

How these VSEP deployments intersect with standard unit ops

Unit Operation Conventional Pain Point VSEP Role Upstream/Downstream Impact
Precipitation → filtration Colloids pass presses; polymer use UF without flocculants; continuous Cleaner leach liquor → fewer crystallizer upsets; better Li yield
Clay roast prep Wet centrate raises energy load UF dewater Smaller kilns or more throughput at same fuel rate
Brine DLE pretreatment High Mg/Li, foulants NF/RO with vibratory shear Lower Mg/Ca; reduced reagents; smaller ponds
DLE eluate handling Dilute Li, high volume RO concentration Smaller crystallization trains; higher Li recovery
Final LiOH finishing High evaporator duty RO pre‑concentration Lower steam use; higher capacity
Effluent management Disposal cost, lost Li RO concentration Resource recovery; lower discharge volume

Benefits specific to VSEP in lithium applications

  • Polymer‑free clarification after precipitation; capture of virtually all suspended solids including sub‑micron colloids.
  • Continuous automation vs. batch presses (reduced labor, no cake handling).
  • Compact footprint vs. clarifiers/presses/pond expansions.
  • Membrane stability at high TDS/high solids—the shear field suppresses cake formation and scaling, enabling NF/RO where static modules stall.
  • Reduced reagent burn from lower Mg/Li and Ca/Li ratios ahead of precipitation.
  • Lower thermal duty in roasting and crystallization by front‑end dewatering.

Technical notes for design & integration

  • Feed variability: Design for turndown and variable PSD; VSEP maintains flux under changing PSD/colloid loads where fixed‑shear modules foul. (General membrane/DLE challenge)
  • Scaling control: For NF/RO on brines, vibratory shear reduces surface concentration polarization; staged recovery targeting Mg/Ca breakpoints.
  • Energy model: Compare kWh/m³ permeate vs. kg steam/kg water removed in the evaporator/roaster; RO‑preconcentration typically wins on OPEX where osmotic pressure permits.
  • Crystallizer interface: Cleaner mother liquor improves crystal habit and reduces inclusions; stable nucleation/growth regimes depend on removing colloids upstream.

FAQs

Q1: Will membranes remove all colloids after precipitation without flocculants?
A: High‑shear UF in VSEP service is designed to capture essentially all suspended solids and colloids produced by Mg/Ca/Fe/Al precipitation, eliminating polymer dosage and reducing downstream fouling. (Need for this step corroborated by filtration literature.)

Q2: Can membranes really handle high‑TDS brines?
A: Yes, when applied as NF/RO in staged recovery and protected by VSEP’s shear at the membrane face; membrane reviews document NF/ED selectivity and energy ranges at very high salinity.

Q3: Where does VSEP sit in a brine DLE train?
A: Frequently before IX/adsorption to reduce divalents and foulants, after IX to concentrate eluate, or ahead of ponds to reduce pond acreage and cycle time.

References (selected)

Lithium Clay from Hydrocyclone

VSEP was demonstrated as a way to concentrate the overflow from a hydrocyclone concentrating lithium clay. During the hydrocyclone process, the majority of the lithium clay is removed at the bottom of the cyclone, however, some of the lighter clay fines still exit via the overflow leading to a loss of lithium. VSEP was used to concentrate and recover the lithium fines from the overflow. At this stage the α‑form of lithium in the clay is retained in the solid particles. The goals are twofold – (1) concentrate the lithium clay fines in the overflow as much as possible, and (2) create a clean, lithium free water for reuse in the production process.

15.7 gfd, 80% recovery

0.75% Feed Solids, 4.2% Concentrate solids

UP 005 UF membrane

9/1/21

Samples from VSEP system.

 

Lithium Hydroxide Brine

During production of lithium hydroxide, the lithium hydroxide is purified and crystallized using an evaporator and crystallizer. VSEP demonstrated use to pre-concentrate the lithium hydroxide brine prior to feeding the evaporator to reduce the large energy consumption of the two pieces of equipment. VSEP can do two things – 1) concentrate the lithium hydroxide stream as much as possible, and 2) provide a clean water stream with low levels of lithium using RO membranes.

11.7 gfd, 44% recovery

6.1% Feed Solids, 10.5% Concentrate Solids

RO membrane

11/7/23

 

Lithium Bearing Wastewater

A VSEP customer had an industrial effluent that contained 1,300 mg/L of lithium. The SDI and other parameters would make it difficult for conventional membranes to perform well. For this reason, VSEP vibratory filtration was demonstrated. The VSEP filtrate was sent to an existing RO system for polishing. The VSEP reject was sent to a holding tank and treated to precipitate unwanted metals the that were removed via an existing filter press. Process temperature is 66ºC, and so, cooling was required to approximately 55ºC to be within the limits of RO membranes.

70 gfd, 90% recovery

1.4% Feed Solids

RO membrane

11/22/03

 

Lithium Brine with Suspended Solids

An Australian-based mining company with lithium operations in the U.S. and Canada used VSEP to look at alternative options to traditional methods of filtration after the precipitation/purification step. The VSEP UF membrane removed virtually all of the suspended solid colloids producing a clean lithium rich filtrate.

85 gfd, 95% recovery

0.92% Feed Solids, 1.49% Concentrate Solid

10 kDa UF membrane

1/31/24

Why VSEP® Works Where Spiral RO Cannot

The Fundamental Difference: Vibratory Shear at the Membrane Surface

Spiral RO systems rely on laminar crossflow, which:

  • Is insufficient to prevent concentration polarization
  • Allows solids concentrations of 10–20× at the membrane surface
  • Does not provide enough agitation at the membrane to prevent scaling
  • Cannot tolerate supersaturated gypsum solutions

VSEP® Technology Advantage

VSEP® uses torsional membrane oscillation:

  • 50 Hz vibratory shear
  • Prevents concentration polarization
  • Disrupts crystallization at the membrane surface due to high agitation
  • Allows precipitation in the bulk flow as the shear decays away from the membrane

Precipitation occurs away from the membrane, RO membrane remains clean, system behaves like a controlled membrane crystallizer

This makes VSEP® uniquely suited for supersaturated slurries and high‑hardness wastewater with no pretreatment. VSEP® is often used instead of or in front of crystallizers or evaporators due to its low energy costs.

Image depicting the difference between VSEP membrane shear vs conventional spiral RO crossflow shear.

VSEP Limitations and Design Considerations

  • Recovery limited by osmotic pressure (TDS) and viscosity
  • Performance will vary based on effluent composition
  • Temperature affects throughput
  • Prescreening is required to remove solids >100 µm
  • VSEP cannot accept aromatic solvents and oxidizers

Design note: Actual performance is site‑specific. We pilot test to select membrane type, flux, recovery, and pretreatment options. Chemistry varies by plant configuration. Final system sizing, membrane selection, and performance projections are only provided after pilot validation.

Pilot Testing and Performance Projections

New Logic offers pilot testing—including full‑scale demonstrations to evaluate water treatment performance. Performance projections are based on measured pilot data, not nameplate assumptions. Every project is unique, so pilot testing is needed.

Pilot testing allows:

  • Verification of filtrate quality
  • Measurement of flux, recovery, and fouling behavior
  • Accurate operating cost projections
  • VSEP System sizing

Learn How VSEP Can Complement Your Process

VSEP systems are operating worldwide in the mining and minerals industry to treat the toughest slurries — including alkaline, fine‑particle residues.

👉 Contact us at info@vsep.com to discuss your dewatering or DLE project.

Learn More

VSEP® has been used globally since 1987 for many difficult industrial filtration applications, including acid purification, landfill leachate, mining effluents, oil and gas wastewater, and PFAS‑impacted streams. The VSEP engineering team that reviewed this information has 30+ years of experience in the mining and industrial industries.