Modern reject equipment for deinking and industrial recycled paper grades
From trash to treasure - rejects are valuable and can generate income
Recycled fiber lines generate a wide range of rejects at various points of origin and with very different properties. Rejects are remarkably inhomogeneous, with a wide variety of particle sizes, densities, dry contents, etc. – this makes effective processing a challenging task. The careful design of each piece of reject equipment and the configuration of the reject system are decisive in converting the rejects into valuable sources of energy or new raw materials.
The following major unit operations are used for treating the various rejects and processing them in order to obtain clean fractions:
- Coarse and fine metal separation
- Ballistic separation of heavy particles, such as stones and bricks
- Screening by particle size
- Mechanical dewatering and compacting
- Cutting and shredding to set the desired particle size
- Sorting of unwanted materials and impurities
- "Ancillary processes" and unit operations such as sand separation or channel screening
- Conveying, bunkering (including baling and wrapping), and dosing the rejects
The respective reject equipment must be combined and arranged properly to achieve maximum benefit.
ANDRITZ Ballistic Separator ReBal
A solid, inclined screen plate that oscillates sets the material on it in motion. Heavy and spherical or cubic parts roll down into the heavy fraction, which includes unwanted debris – such as stones, bricks, and other heavy items – that have to be removed in order to protect the downstream equipment in a reject line. Furthermore, this fraction includes very valuable compounds, such as plastic bottles or cans. All flat and light particles – such as plastics, sheets of paper – move upwards towards the light fraction. The screen plate (sieve) creates a fine fraction.
The ReBal can process wet material (with consistencies down to 20%) and has a high throughput of up to 60 m³/h. The machine is manufactured in-house and has already been applied in several reject lines supplied by ANDRITZ.
- Closed system for clean machine environment
- Various adjustment possibilities (e.g. angle of inclination, machine speed) and screen plates
- High throughput up to 60 m³/h
- Low energy consumption
- Gas-spring-supported maintenance openings ensure easy accessibility
ANDRITZ Reject Compactor ReCo
Rejects from recycled fiber lines are quite wet when they leave the process, with a lot of free water and water stored in the fibrous material. While free water is relatively easy to remove, the water in the fibers is more critical. Considerable force is needed to achieve an acceptable dry content in the material. However, the higher reject consistencies also help save on drying and disposal costs.
The Reject Compactor ReCo is a robust screw press for dewatering rejects from recycled fiber lines. It is designed to obtain highest dryness levels. The final dryness depends on the reject material (especially the fiber content) and the press settings selected.
The Reject Compactor ReCo is available in three different models:
- ReCo-C: for coarse pulping rejects with higher consistencies, typically 10-45%
- ReCo-F: for fine rejects with higher fiber content and consistencies down to 1.5%
Both types, ReCo-C and ReCo-F, can reach final drynesses of up to 70%
- ReCo-L: light design with smaller capacities for fibrous rejects and/or consistencies as low as 0.8%; discharge consistency up to 35%
ANDRITZ Granulator UG
Shredding is a core unit operation in any reject treatment system and sets the correct particle size for the subsequent process steps, such as fine metal separation or optical sorting.
The ANDRITZ fine shredder UG is designed for treating pulp and paper rejects that typically contain a large amount of heavy particles. Due to its rigid design, such contaminants pose no risk for operation of the machine. The UG has a high-speed, single-shaft rotor with special hardened knives. Screen plates with various hole diameters determine the final particle size.
- Uniform output particle size due to accurate cutting geometry
- Insensitive to coarse and heavy contaminants
- High throughput due to uniform feeding by a hydraulic pusher
- Energy-efficient drive, including machine protection
- Easy maintenance, fast knife adjustment
- Decades of practical experience from hundreds of installations in various recycling applications
ANDRITZ Sediment Separator ReSed
A sediment separator – often also called sand separator – removes sand or other heavy solids from liquids. In a paper mill, those liquids can be filtrates from cleaners and screens or process water. The principle is quite simple: the feed flow is fed to a sedimentation tank where the heavy particles settle at the bottom; the settled particles are conveyed upwards by an inclined, shaftless screw while being dewatered further; and the dewatered solids drop off at the top of the screw where they are typically collected in a container.
The ANDRITZ ReSed features a smart design of the sedimentation tank and its internals that reduce turbulences in the flow. The machine is designed such that the sedimentation tank is completely filled with water to avoid any floating fibers that could plug the machine. The ANDRITZ ReSed provides excellent clear water quality, while its simple and robust design results in low energy consumption and maintenance costs.
- Efficient separation of heavy particles
- Trouble-free operation, also for larger debris
- Smart design of sedimentation tank
- Excellent clear water quality
- Low energy consumption and maintenance costs thanks to simple and robust design