Plastic Ancillary Equipment

Silicone Rubber Separator for Plastic Flake Purification

Remove silicone, rubber and other elastomers from dry rigid-plastic flakes with a friction-and-elasticity separator. Three nominal models cover 1–3 t/h. Send a representative feed sample so material suitability, achievable residue and plastic recovery can be evaluated before final specification.

  • Three nominal models from 1 to 3 t/h
  • Dry mechanical separation with no process water
  • Feedstock-based configuration and material evaluation
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Silicone Rubber Separator for plastic flake purification
  • Three nominal models from 1 to 3 t/h
  • Dry mechanical separation with no process water
  • Feedstock-based configuration and material evaluation

How Friction-and-Elasticity Separation Works

The separator exploits one simple physical difference: rubber and silicone are elastic and high-friction, while rigid plastic is hard and low-friction. These four steps are what a stable, repeatable cut depends on.

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Step 1 — Spread the feed to a monolayer

Vibration discs distribute incoming flake across the full deck width as a single-particle layer. A piled or uneven feed is the most common cause of poor separation, so feed-rate control matters as much as the deck itself.

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Step 2 — Drive the friction spindles

Four 375 mm spindles rotate at a set speed. Rigid plastic flakes have low surface friction and slide forward along the spindle axis; elastic rubber and silicone particles grip the rotating surface and are carried transversely toward the rubber outlet.

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Step 3 — Tune the cut point

Spindle speed and deck inclination set where the rigid-vs-elastic boundary falls. Adjust settings incrementally while sampling both outputs, following the operating manual, to balance contaminant removal against good-plastic recovery.

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Step 4 — Recirculate the reject

The rubber-rich fraction still carries some rigid flake. A second pass through the separator recovers that flake and tightens the rubber concentration in the final reject, improving overall yield.

Why a Dedicated Separator, Not Just Density Sorting

Silicone and rubber compounds span a wide density range and may overlap certain rigid plastics, so density alone is not a universally reliable separation basis. A friction-and-elasticity deck uses a different material-property contrast.

Separates What Density Cannot

Formulated silicone and rubber compounds can overlap the density of some plastics. Friction-and-elasticity sorting instead targets differences in elastic response and surface friction, making it useful where a sink-float cut is insufficient.

Dry, Chemical-Free Process

The separation stage uses mechanical action without process water, solvents or a dedicated heating step. This avoids separator-generated wastewater and limits additional thermal exposure of the plastic.

Improves Flake Quality for Downstream Use

Reducing elastic contaminants can improve the consistency of rigid-plastic flake before compounding, pelletizing or resale. The achievable result depends on the complete feed composition and operating conditions.

Adjustable Operating Parameters

Feed rate, spindle speed and deck inclination can be matched to the material. Final control scope and automation level are confirmed with the selected machine configuration.

Troubleshooting & Operating Reference

These are common operating factors to review when separation changes. Confirm all adjustments against the supplied operating manual and the actual machine configuration.

Problem

Rubber residue in the clean fraction is too high.

Rumtoo Solution

Check whether the feed is dry, screened and spread as a thin, even layer. Verify feed rate and spindle condition, then adjust approved operating parameters in small steps while sampling both outputs.

Problem

Too much good plastic ends up in the rubber reject.

Rumtoo Solution

Review feed uniformity and the current cut settings. Sample the reject before changing parameters; where suitable, evaluate a controlled second pass to determine whether carried-over rigid flake can be recovered.

Problem

Separation drifts over a shift with no setting change.

Rumtoo Solution

Check for changes in flake size, moisture, fines or elastomer type between batches. Re-sample the feed and inspect spindle surfaces and feeding components according to the maintenance schedule.

Problem

Fine dust is clogging the deck and outlets.

Rumtoo Solution

Inspect upstream screening and de-dusting. Fines can coat contact surfaces and reduce separation consistency, so a clean, screened feed should be treated as part of the process requirement.

Where the Separator Sits in a Plastic Recycling Line

A silicone rubber separator is a polishing stage, not a primary process. It belongs after granulation and washing, on dry flake, and before pelletizing, where remaining elastomer contamination can affect downstream processing and product acceptance.

Discharge hopper and screw conveyor for a silicone rubber separator

Clean-Flake Discharge: Hopper and Screw Conveyor

After the friction deck separates the stream, clean rigid flakes collect in the discharge hopper. The screw conveyor meters the product onward to bagging, storage or a pelletizing line, reducing uncontrolled surges and manual handling.

  • Buffer hopper stabilizes discharge between the separator and downstream equipment
  • Screw conveyor provides enclosed, controlled transfer of clean flake
  • Hopper volume, outlet height and conveyor direction are configured to the site

Controls View: Independent Electrical Cabinet

The electrical cabinet centralizes feeder, spindle, conveyor and safety controls. A touchscreen interface gives operators one place to start the line, adjust permitted process settings, monitor status and respond to alarms or interlocks.

  • PLC and HMI coordinate feeder, spindle and discharge-conveyor operation
  • Interlocks and overload protection stop unsafe or blocked operation
  • Voltage, enclosure, I/O and line-integration signals are configured to the project
Electrical control cabinet for a silicone rubber separator

Silicone Rubber Separator in Operation

See how rigid plastic flake discharges clean off the spindle deck while elastic silicone and rubber are carried to a separate outlet.

Silicone & Rubber Separation Applications

These are the streams where removing the last few percent of rubber unlocks the value of an otherwise clean plastic fraction.

  • WEEE & E-Waste Plastics

    Helps remove rubber feet, gaskets, silicone seals and elastomer keypad fragments from prepared ABS/HIPS-rich electronics-plastic streams.

  • ELV / Automotive Plastics

    Helps reduce rubber trim, weatherstrip and silicone-hose fragments in prepared PP- and ABS-rich end-of-life-vehicle plastic streams.

  • Cable & Wire Regrind

    Can be evaluated for prepared cable-regrind streams containing compatible rigid-plastic fractions together with rubber or silicone insulation fragments.

  • Injection-Molding Regrind

    Helps reduce rubber over-mold and silicone-gasket contamination in prepared ABS, PC and PP regrind before downstream reuse.

  • Clean Post-Industrial Packaging Scrap

    Can be evaluated for clean, non-hazardous PP/PE packaging regrind containing rubber closures or silicone components.

  • Mixed Crushed Sponge, Rubber & Plastic

    Suitable for evaluation when a prepared post-crush stream contains sponge, rubber and compatible rigid-plastic particles with distinguishable elastic behavior.

Silicone Rubber Separator Specifications

Three nominal models cover 1 to 3 t/h. Actual capacity and separation performance depend on flake size, moisture, elastomer type, contamination level and feed stability.

ModelThroughput (t/h)Power (kW)Dimensions L×W×H (mm)ConstructionConfiguration
RTM1500S1–1.56.722150 × 2200 × 4300SS 201 + A3 steel4 × 375 mm spindles · 2 × 3 kW main motors · 4 × 90 W vibration discs · 4 × 90 W integrated units
RTM3000S1.5–27.082450 × 2200 × 4300SS 201 + A3 steel4 × 375 mm spindles · 2 × 3 kW main motors · 8 × 90 W vibration discs · 4 × 90 W integrated units
RTM4000S2–37.402950 × 2200 × 4950SS 201 + A3 steel4 × 375 mm spindles · 2 × 3 kW main motors · 8 × 90 W vibration discs · 4 × 90 W integrated units

Material-contact parts are stainless steel 201; the frame is A3 carbon steel. Listed throughput is nominal and assumes dry, pre-screened, relatively uniform flake. Final capacity, configuration and separation expectations must be confirmed against the customer’s actual feed.

RFQ Checklist — What We Need to Size Your Separator

These inputs help us assess material suitability, recommend a nominal model and define the feed, discharge and evaluation requirements for a proposal.

  1. Base Plastic & Rubber Type

    Tell us the rigid resin (ABS, PS, PP, PC, PVC, PE) and the contaminant — silicone, EPDM, NBR, natural rubber or sponge. Elasticity and friction differ by rubber type and change the cut.

  2. Current & Target Rubber Content

    Approximate elastomer percentage in the feed and the maximum residue your buyer or downstream process will accept.

  3. Flake Size & Dryness

    Granulated flake size range and whether the material is washed and dried. Friction separation needs dry, screened flake to perform.

  4. Throughput & Operating Hours

    Average and peak t/h plus hours per day, so we size between the RTM1500S, RTM3000S and RTM4000S with margin.

  5. Upstream & Downstream Stages

    What feeds the separator (granulator, washing line, de-duster) and what follows (pelletizer, bagging, further sorting) — so feed and discharge heights match your line.

  6. A Representative Sample

    The most useful input for evaluation. A representative sample helps determine whether the material is suitable and what testing is required before any performance target is agreed.

Silicone Rubber Separator vs Other Sorting Methods

Where a friction-and-elasticity deck can fit when evaluating rubber-in-plastic contamination alongside other sorting methods.

MethodWhat It Sorts OnLimitation for Rubber-in-Plastic
Sink-float / density tankDensity difference in waterSilicone and many rubbers overlap common plastics in density, so they will not reliably float or sink apart
Electrostatic separatorSurface charge / conductivityWorks for some polymer pairs but is inconsistent on rubber-vs-plastic and needs very dry, fine, single-size feed
Manual / optical pickingColor and visual cuesRubber and plastic often share color; slow and labor-intensive at flake scale
Friction-and-elasticity separatorElasticity and surface frictionTargets the exact property that distinguishes rubber from rigid plastic — dry, chemical-free, and tunable to a residue target

Frequently Asked Questions

What does a silicone rubber separator actually remove?

It is designed to remove soft, elastic contaminants — such as silicone, vulcanized rubber, EPDM, NBR, natural rubber and sponge — from compatible rigid-plastic regrind. Suitability depends on the actual material combination and particle condition.

How is it different from a sink-float tank?

A sink-float tank sorts by density in water. Silicone and many rubbers have densities close to common plastics, so they do not separate cleanly by flotation. The friction-and-elasticity separator sorts on elasticity and surface friction instead, which is a reliable property difference between rubber and rigid plastic.

What rubber residue level can it reach?

There is no universal residue figure for every feed. Results depend on flake size, moisture, elastomer type, inlet contamination, feed rate and the number of passes. A representative sample must be evaluated before a performance target is agreed.

Does the material need to be washed and dried first?

Yes. Friction separation relies on the surface-friction difference between rubber and plastic, and surface moisture or dust masks it. The separator belongs after washing and drying, on clean dry flake, for stable results.

Which models are available and what is the throughput?

Three standard models: RTM1500S (1–1.5 t/h), RTM3000S (1.5–2 t/h) and RTM4000S (2–3 t/h). All use four 375 mm spindles and two 3 kW main motors, differing in vibration-disc count and frame size. We size the model to your throughput with margin for surge.

Can I send a sample to confirm it works on my material?

Yes. Share representative feed details first so we can confirm the sample quantity, preparation and evaluation plan needed for your material.

Get a Silicone Rubber Separator Proposal

Share your base plastic, elastomer type, feed condition, target quality and throughput. Rumtoo will assess the application and recommend the next evaluation and equipment-selection steps.

Expert response within 24 hours. No obligation quote.