The ball shaper for the recycling industry

Rotor impact mill


Efficiently processing shredder fractions


Efficiently processing shredder fractions

The BHS rotor impact mill is a high-performance crusher with a vertical shaft that addresses the needs of the recycling industry. The mill’s unique impeller rotor works together with a toothed anvil ring to subject the inserted material to severe mechanical stress. Material compounds are crushed and separated selectively, entangled materials are isolated, and brittle-hard materials are crushed very finely. At the same time, metals are shaped into balls and cleaned. Watch the video to find out how to optimally prepare shredder fractions for separation by disaggregating composite material and pelletizing metals with the RPMX rotor impact mill.

Unique crushing principle

  • Impeller rotor is one of its kind worldwide
  • High energy load to the feed material thanks to centrifugal forces
  • Impact and shearing forces produce intensive shredding results
  • Rotation results in a nearly constant gap 

Future-proof investment

  • Flexible use for variety of tasks thanks to variable peripheral speed of the rotor and adjustable gap between horseshoe hammers and anvil ring
  • Effective processing of fine off-spec particle sizes

Selective crushing

  • Brittle materials such as glass and minerals are finely shredded and/or pulverized via impact and shearing forces

Shaping of metals into balls

  • Possible to pelletize even ductile materials due to high levels of stress being applied between the horseshoe-shaped hammers and the fixed anvil ring 

Separation of composite materials

  • Multi-stage application of stress cleans metals and separates out various materials
  • Example of cable recycling: Efficient removal of the plastic sheathing from the conductor

Machine operation

  • Optimum settings achieved thanks to adjustable rotor speed and annular gap
  • Easy to retool

Easy maintenance and high availability

  •  Parts subjected to stress are protected by easily replaceable wear parts
  • Materials used in wear parts are optimized for the relevant application 

Unit ready for operation

  • Ready-to-install unit consisting of machine and drive train mounted on a base frame
  • Unimpeded access thanks to large cover that can be raised hydraulically and pivoted by 360°

Reliable greasing

  • Low-maintenance, reliable operation thanks to a recirculating oil lubrication system with cooling and integrated monitoring 

Vibration absorption

  • Rubber spring elements absorb vibrations generated during operation
  • An electronic vibration monitor causes the machine to shut down if excessive vibrations are registered

Innovative fine processing of your material


Innovative fine processing of your material

BHS offers an established and optimized process for metal recovery from fine fractions. This consists of pre-sorting and the key process step of shredding, which is performed by a rotor impact mill, easily accomplishing multiple challenging processing tasks at once. The process then moves on to the steps of sorting via screens, standard separation, as well as magnetic and eddy current separation. Each plant is individually adapted to the customer’s requirements due to the large variance of the input material.


Rotor impact mill RPMV: Variety of applications

Operating principle of the RMPV (side view)

Rotor impact mill RPMV: Variety of applications

The feed material is loaded into the top center of the machine. When it impacts the rotor, the material is accelerated towards the outside by means of centrifugal forces; there, the horseshoe-shaped hammers engage it and throw it against the anvil ring, In the milling gap, it is crushed as a result of the impact and shearing forces. The material leaves the rotor through the gap and falls down through two outlet chutes.

Rotor impact mill RPMX: Perfect fine processing

Operating principle of the RPMV (top view)

Rotor impact mill RPMX: Perfect fine processing

The material is selectively transported into the gap between the anvil ring and hammer from above by means of the rotor cover plate. In this way, the full height of the grinding gap is utilized, resulting in a longer retention time and a higher stress frequency. An intense ball shaping effect is achieved in combination with a high circumferential speed, a narrow grinding gap of 4 to 6 mm and a specially toothed anvil ring.


Rotor impact mill available in two models

The RPMV is a rotor impact mill used in the recycling industry. The ball shaper, which has proven itself for many years in a wide range of applications in the recycling industry, sets a new standard with the RPMX. The RPMX rotor impact mill is a turbo-ball shaper. It is used in the reclamation of materials from fine fractions containing metal (such as stainless steel and cable strands) that had previously been considered difficult to process.

Rotor impact mill of type RPMV – the ball shaper

Rotor impact mill of type RPMV

Rotor impact mill of type RPMV – the ball shaper

The RPMV has proven itself in separating composites, crushing brittle components and shaping metals into balls with particle sizes from 5 to 30 mm.

Rotor impact mill of type RPMX – the turbo-ball shaper

Rotor impact mill of type RPMX with rotor cover plate

Rotor impact mill of type RPMX – the turbo-ball shaper

A higher circumferential speed and the considerably smaller grinding gap characterize the RPMX. This feature set makes it ideal for ball shaping and separating composite parts with particle sizes from 0 to 15 mm.


Advantages of the Rotor

  • Replaceable crushing tools
    The anvil ring elements are suspended on the mill housing (RPMV) or bolted on (RPMX). The horseshoe-shaped impact hammers are mounted to the rotor and are held on the rotor pegs by centrifugal force. Both the anvil ring and the impact hammers are easily replaced.
  • Adjustable gap
    A set of replaceable spacers is used to configure the ring gap. The ongoing wear and tear of the impact hammers causes the gap width to change; this can be easily corrected by replacing spacers in different sizes (shown in red in the illustration).
  • Optimized service life
    The rotor direction can be reversed, allowing both sides of the impact hammers to be fully utilized.

Spacers & impact hammers

Spacers for increasing degrees of wear

Impact hammers of the rotor impact mill

Simplified replacement of the crushing tools

Both the anvil ring and the impact hammers can be easily
replaced. On the RPMV, the anvil ring elements are sus-
pended in the milling housing, and on the RPMX they are
firmly bolted in place. The optional mandrel and load hook
tools can be used for easy hammer replacement. This sig-
nificantly simplifies maintenance and reduces the physical
strain on operating personnel.

Optimized and improved impact hammers

For consistent output quality, a higher throughput rate and
significantly reduced wear, the impact hammers have been
continuously improved. To ensure this over the entire service
life, the size of the ring gap to the anvil ring and thus the
gap width can be effectively readjusted over the long term
by simply replacing spacers of different sizes as the impact
hammers wear

Options & accessories
 Rotorprallmühle RPMX
Rotor impact mill of type RPMX

Electro-hydraulic cover opening

An electrohydraulic lid opener can be installed as an option to ensure quick opening of the machine lid for maintenance and inspection purposes.

Installation in electrical terminal box

If required, all electrical wiring can be bundled in a terminal box for easy installation.

Intensive cooling

In the event of high ambient temperatures or if the material to be processed is hot, a supplementary lubrication unit featuring a larger storage volume and stronger cooling power can be provided.

Air cannon

In order to reduce material deposits in the outlet area, the mill can be optionally equipped with air cannons.


The use of a crane is recommended when replacing wear parts.

Control unit

To provide an alternative means of operation, the machine can be shipped with a PLC controller (including touch panel) and a frequency converter if required. This allows for autonomous operation and monitoring of the machine’s functions. The PLC controller can also be used to operate additional system components, such as in-/outlets, a dust removal system, a sorting unit, etc.

Steel structure

To complement the machine, we offer standardized or customized steel add-on solutions such as supports, platforms, railings, and stairs.

Plant technology

We are also able to provide you with complete system solutions that include, for example: Steel construction, bunker and dosing technology, feeding and draining/discharging technology, classifying and separation technology, as well as dust removal systems. We plan the system design in accordance with your requirements and comprehensively coordinate the project with you.

Technical specifications

Performance data
TYPERotor diameter x heightNumber of hammersCircumferential speed
Drive power
RPMV 11131.150 x 135 mm8 pieces70 m/s132 kW
RPMV 15131.500 x 135 mm12 pieces70 m/s200 kW
RPMX 11161.150 x 160 mm8 pieces90 m/s250 kW
RPMX 15161.500 x 160 mm12 pieces90 m/s315 kW
Dimensions and weights
RPMV 11134.600 mm2.000 mm2.700 mm406 mm7.700 kg
RPMV 15134.900 mm2.120 mm2.740 mm610 mm12.000 kg
RPMX 11164.600 mm2.000 mm2.790 mm406 mm8.500 kg
RPMX 15164.900 mm2.120 mm2.850 mm610 mm12.800 kg

1) Weight for standard design without motor and accessories.
2) Depending on the drive power.

All specifications apply to the standard design. Technical data for customized designs may differ from the specified data. All technical data may change due to development. Subject to modification without notice. 


“Rotor Impact Mill (RPMV & RPMX)” product flyer
Brochure of the "Recycling Technology" business unit
Display all

Tests give certainty

Which technical solution is the right one for your recycling process? Don’t leave anything to chance. Our team of specialists will test your material at our test center and develop a solution tailored to your specific needs.

E-Waste World | Metal Recycling | Battery Recycling - Conference & Expo 2024

06/26/2024 - 06/27/2024 | Frankfurt am Main (Germany)

ICBR 2024 - International Congress for Battery Recycling

09/10/2024 - 09/12/2024 | Basel (Switzerland)

IFAT India 2024

10/17/2024 - 10/19/2024 | Delhi (India)

Success stories

Long-Life service contract for high machine availability at recycling company in Austria

April 2022
Wear parts that aren’t made the manufacturer of a machine often promise to be a more cost-effective alternative to the original spare parts. However, they also pose risks to a continuous production process in the long run. Frequently, these spare parts are inferior to the original – not only in terms of quality, but also in terms of service, maintenance and availability. METRAN Rohstoff-Aufbereitungs GmbH therefore opted for a BHS LONG-LIFE service contract for its two rotor impact mills of type RPMV 1113 in 2022.

Rotorshredder makes recycling meatballs even more efficient

June 2019
BHS-Sonthofen has developed a new procedure for processing meatballs in order to increase the amount of copper recovered. Electric motors and motor armatures represent a small fraction of waste from incineration or large shredders, and it is difficult to cleanly separate them by type. Yet they contain a good deal of valuable copper, whose share is up to 22 percent. This impressive new procedure features a Rotorshredder optimized for this process, subsequent materials separation and copper processing using a rotor impact mill.

Less wear for economically efficient processing of ASR

March 2019
Since March 2019, a BHS-Sonthofen rotor impact mill (type RPMX) has been in operation at Jansen Shredder Recycling BV in Moerdijk, the Netherlands, for the fine processing of automotive shredder residues (ASR). Thanks to years of experience in the processing of metal-bearing waste materials, the experts from Sonthofen found the optimal solution for processing abrasive materials. Wear costs at Jansen have significantly decreased since.

Plant for recycling automotive shredder residues (ASR) in Finland.

July 2017
Kajaanin Romu Oy operates one of Finland’s most cutting-edge plants for recycling scrap in the town of Kajaani, located approximately 500 km northeast of Helsinki. The company commissioned a BHS-Sonthofen plant for processing automotive shredder residue (ASR) fine fractions of particle sizes between 0 and 30 mm. It separates the feed material abundant with valuable metals into ‘light’ and ‘heavy’ fractions in a single pass. This allows the plant operators to economically produce fractions that can be sold profitably. Moreover, the plant significantly reduces the cost of material disposal at landfills.

DHZ AG – Extracting concentrated metals from incinerator bottom ash

July 2016
DHZ AG operates a modern recycling center in Lufingen in the Swiss canton of Zurich. The facility focuses on processing incinerator bottom ash (IBA). BHS-Sonthofen supplemented two existing IBA processing plants with an additional plant that extracts high-quality, heavy and light non-ferrous metal fractions from the coarse concentrate generated upstream. These are of such high quality that they can be sold directly to smelters or to industrial customers.

Don’t let valuables end up at the dump!

January 2016
A metric ton can contain up to 20 grams of gold and up to 200 to 300 grams of silver, as well as platinum and other precious and non-ferrous metals. Heavy non-ferrous fractions of material left over after shredding and processing large automotive, electrical or electronic scrap components still hold a lot of value. Previously, the recyclable materials were deposited in landfills. Based on our unique process, BHS-Sonthofen processing plants can recover these metals.

Technical articles in the media

Customized recovery | Recovery of metallic fines from ASR

February 2023

The recovery of metallic fines from ASR requires a customized approach. Auto shredder residue (ASR), fines from shredded electrical and electronic equipment and waste incinerator bottom ash all have one thing in common: They contain valuable metals that are worth recovering. Therefore, processing these fine materials is of high importance.

recycling today scrap recycling | Winter 2023 | Supplement to recycling today

Recuperación de metales valiosos: alto rendimiento para un procesamiento fino mejorado

August 2022

BHS optimiza la calidad de su molino de impacto de rotor con un nuevo diseno de martillo. AMBISORT Circular ofrece siempre procesos novedosos y de alto valor añadido para el sector del reciclaje. Un destacado ejemplo es la recuperación de valiosos concentrados de metales a partir de varios composites y desechos industriales, que sin duda es todo un desafío técnico.

RETEMA 07/08-2022

BHS fine treatment process recovers valuable metals from residual materials

July 2022

There is currently no way around the issue of resource saving but how can valuable materials can be recycled in the best possible way? Metals in particular are considered important scarce raw materials whose recovery is essential for the sustainable use of resources. BHS-Sonthofen offers an effective solution for metalliferous residues with a size of up to 25 mm.

recovery 04-2022

Economically efficient processing of automotive shredder residues

July 2020
For almost a year, a BHS-Sonthofen rotor impact mill has been in operation at Jansen Shredder Recycling BV in Moerdijk, the Netherlands, for the fine processing of automotive shredder residues (ASR). Thanks to years of experience in the processing of metal-bearing waste materials, the experts from Sonthofen found the optimal machine for processing abrasive materials. Wear costs at Jansen have significantly decreased since.
ALUMINIUM Journal 7-8 / 2020

June 2020
recycling today June 22, 2020

Satisfied customers worldwide

Find a sales representative

Find your personal contact person on site. We are there for you worldwide.

Find a sales representative

Find your personal contact person on site. We are there for you worldwide.