Case studies

How MHP supports process decisions

Three examples of the studies and reviews MHP delivers, from a single defined problem to a phased plant design. Client details are withheld. Every figure comes from the original reports.

Process Design Study

Mixed-metals plant development

  • ClientUK mixed-metals recycler
  • MaterialZorba, meters, valves, compressors, e-waste
  • DeliverablesLayouts, flows, equipment rationale, OEM pricing

The question

The site held a wide mix of grades: Zorba, analogue meters, gas valves, fridge compressor pots, e-waste and pre-shredded fridge aluminium with copper. The existing 75 kW chain mill had no internal screen and produced output of roughly 40–200 mm, too coarse to liberate composite items.

The business wanted to recover copper and brass, separate wire, split red metals from grey, and invest in stages rather than as one capital project.

What MHP did

  • Visited the site and reviewed the material, separating confirmed facts, site observations and recommendations.
  • Designed the process around the material mix and the products required, not around a preferred manufacturer.
  • Kept the existing feed hopper, picking conveyor and dust extraction, adding airflow control to stop product being drawn into extraction.
  • Produced site layouts, process flows and equipment rationale, and sourced indicative OEM pricing.
From the study6 images · scroll or swipe →
Feed material measured during the site visit
01Feed material measured during the site visit
Analogue meters assessed for liberation
02Analogue meters assessed for liberation
Fridge compressor pots measured on site
03Fridge compressor pots measured on site
Site layout plan (client details redacted)
04Site layout plan (client details redacted)
Concept layout of the proposed line
05Concept layout of the proposed line
Concept 3D arrangement of the process packages
06Concept 3D arrangement of the process packages
Package 1 · Shredding and liberationConcept duty around 2 t/h
  1. Existing hopper
  2. Pre-shredder
  3. Vertical hammer mill
  4. Overband magnet

Targets roughly 30–50 mm for most material, with ferrous removed after liberation so joined non-ferrous is not lost.

Package 2 · Primary non-ferrous separationConcept duty around 5 t/h
  1. Belt-fed hopper
  2. Zig-zag air separation
  3. Overband magnet
  4. 15 mm trommel
  5. Two ECS circuits
Package 3 · Flexible AI refinementConcept duty around 1 t/h
  1. Selected product streams
  2. Dual-layer AI optical sorter
  3. Product-specific recipes

One flexible sorter refines several products in batches, subject to material trials.

Outcome

A manufacturer-independent basis for deciding what to build, in what order and how far to go. Each package can be funded and run separately, and the design can be used to obtain alternative supplier proposals.

Process Solution Study

Legacy fines value recovery

  • ClientUK metal recycler
  • Materialc. 500 t sub-20 mm fines
  • DeliverablesFeasibility trial, staged route, indicative pricing

The question

The client held around 500 tonnes of fines left over from historic ferrous shearing and screening. It had been offered an outlet at a gate fee below the cost of landfill, but was concerned that recoverable metal would leave site with it.

A laboratory sample would not represent such a variable stockpile, so the business needed another way to decide whether processing was worth it.

What MHP did

  • Sampled the stockpile from several locations and ran a small feasibility trial using screening, zig-zag air separation and a wet-gravity check.
  • Identified missed fine ferrous as the strongest opportunity: the historic grab-mounted magnet gave small particles poor, inconsistent exposure.
  • Found no recoverable precious-metal fraction in the tested sample and very little non-ferrous in the light fraction, so wet processing was not recommended as the main route.
  • Designed a staged route with representative equipment and indicative pricing.
From the study3 images · scroll or swipe →
Original stockpile sample
01Original stockpile sample
Air-separation trial split: heavies, lights and dust
02Air-separation trial split: heavies, lights and dust
Wet-process check on the zig-zag lights
03Wet-process check on the zig-zag lights
Phase 1 · Mobile dry recoveryRecommended starting point
  1. Feed hopper
  2. Conveyor with overband magnet
  3. Twin-deck screen
  4. Stand-alone ECS

The screen splits the feed into under 6 mm, 6–20 mm and over 20 mm. The two larger fractions run through the same ECS in separate campaigns, with settings for each size. All equipment stays mobile and reusable.

Phase 2 · Optional recovery modulesOnly where Phase 1 justifies them
  1. Zig-zag air separation and cyclone
  2. Chute-fed AI optical sorter
  3. Water table for the finest material
Outcome

The client can start with a low-complexity mobile route that recovers the known ferrous value and measures the real non-ferrous recovery before committing to fixed plant. Phase 1 records tonnes, fraction weights, sale values and disposal savings, which decide whether Phase 2 pays.

Operational Review

Drying drum line audit

  • ClientUK metal recycler
  • EquipmentRotary drying line, mixed non-ferrous
  • DeliverablesAudit findings, prioritised workstreams

The question

The drying line was expected to process 12 tonnes per hour but generally ran below 8, and typically around 5–6. Wetter feed could need more than one pass.

The business needed to know why, and where to start.

What MHP did

  • Reviewed the whole line: infeed and material presentation, conveyors and transfers, the heated drum, screening and outfeed, heating and air delivery, extraction, cyclone, filtration and dust discharge.
  • Separated causes from symptoms where problems interacted.
  • Identified priority issues: dust control around the drum, under-performing heat delivery and unreliable temperature readings, worn guide-wheel and riding-ring interfaces, screen blinding, and open transfer points.
From the study5 images · scroll or swipe →
Drum shell and riding-ring condition
01Drum shell and riding-ring condition
Guide-wheel and riding-ring interface
02Guide-wheel and riding-ring interface
Filter discharge and dust handling
03Filter discharge and dust handling
Outfeed and transfer point
04Outfeed and transfer point
Fines build-up at a discharge point
05Fines build-up at a discharge point
Six prioritised corrective workstreamsFrom one audit
  1. Heating and temperature measurement
  2. Dust containment and extraction
  3. Drum supports and drive loading
  4. Screening and fines capture
  5. Transfer-point enclosure
  6. Reliability and maintenance
Outcome

No single change would fix the line. The audit replaced trial-and-error with a clear, prioritised order of work across interacting faults.

Your next step

Facing a similar decision?

Tell us about the material, the opportunity or the challenge. No lengthy brief needed.

Discuss your project sales@mhprocessing.co.uk Call 07889 045582