Recycling Plastics from Lead Acid Batteries
Rotajet Systems Limited manufacture fully integrated systems plastic washing and separation systems for processing plastics generated from recycling lead acid batteries. In lead acid battery recycling after the battery breaker, the lead, lead paste is separated using density, the acid is neutralised, and the PP, ABS and PE filled plastic separators then go into further separation. The resulting PP is generally contaminated with ABS, filled PE, sulphuric acid, etc….This material needs to be further process to achieve best possible value.
Due to the action of the battery breaker the mixed material is typically <60mm, The plastic washing and separation system that Rotajet manufacture can either be run in line with the battery breaker or offline in which the material is bunkered and processed as a standalone process line.
Rotajet Feed Hopper:
The Rotajet PP washing and separation system requires the material is feed in at a uniform rate, this dictates that a feed hopper is installed at the start of the line (the size of the feed hopper, can be adjusted according to throughput requirements.). Due the free acid that still contaminates the plastic material we recommend that the feed hopper is manufactured from 316 stainless steel. The Rotajet feed hopper is fitted speed controlled screw auger conveyors, this ensure a consistent feed to the Rotajet plastic pre washer.
Rotajet Pre Washer:
The Rotajet plastic pre washer is used for the remove any remaining lead paste, surface dirt and neutralise any free sulphuric still present. The Pre Washer is fitted with a incline high speed screw auger fitted with a screens that allow the washing liquor to drain and then filtered prior to reuse. A spray bar is fitted along the full length of the Rotajet plastic prewahers, this spray bar is used to wash the plastic at high pressure and volume. When washing plastics from lead acid recycling the wash liquor is dosed with sodium hydroxide, this is used to neutralised any excess sulphuric acid. The level of sodium hydroxide in solution is maintained using pH which is measured at discharge valve on the washer. The used wash liquor is filtered and is discharge into bulk storage tanks for ready for reuse.
Rotajet Float Sink Tank:
The washed material is fed into a Rotajet HKS Float sink tanks. The use of the Rotajet float sink tank is to remove any material with a density that is greater than >1, this results in the ABS, lead, other metals, filled PE separators, rubber, grit etc….sinking. The sinking fraction is removed from the Rotajet float sink tank using a series of bottom screw augers. The floating fractions are transferred along the surface of the tanks using rotating paddles, which drive the float material forwards towards the outlet screw of the tank, each paddle submerges the material under the surface of the liquid that frees any intermingled sinking fraction and allows it sink.
The floating fractions weirs over into the incline take off screw of the Rotajet float sink tank, this is fitted with a screen that allows the water to drain prior to pumping back to a storage tank for reuse.
The water in the storage tank is pumped back into the Rotajet float sink tank via. A series of spray bars, this ensures the floating fraction is cleaned with filtered water prior to discharge into the incline screw.
Wet Granulator :
The floating fraction is fed from the Rotajet Float sink tank into a wet granulator for final size reduction and rinsing. The wet granulator is fitted with a spray bar that rinses the PP floating fraction as it is being granulated. The granulated PP and water flows into a incline screw and transferred into the Rotajet MD horizontal friction dryer.
Rotajet MD Horizontal Mechanical Dryer:
The Rotajet MD series dryer is fitted with a high speed rotor, the rotor is fitted with d2 manufactured wear paddles. The plastic material is forced through the Rotajet friction dryer using both air and the striking force of the high speed paddles. The Rotajet MD mechanical dryer is fitted with a full length removable hexagon screen, the screen can be fitted with various size holes depending on the application, generally for plastic granulate a 1mm screen is fitted to allow the water to drain. After the dryer the material is blown into a Rotajet “Zig Zag” separator for final product clean up and bagging off.
Rotajet “Zig Zag” Separator:
The dried material is blown into the Rotajet “Zig Zag” separator; this is used to remove any wood, film, expanded PS and dust particles. The separator works by removing contamination via. Air flow. The Rotajet Zig Zag separator is fitted with Rotatory valve which allows the dried material to enter the Zig Zag column without allowing air flow. The “Zig Zag” column is fitted with light fraction removal fan drawing air up through the column, as the material descends through the Rotajet Zig zag separator, the light fractions are removed and heavier fractions drop to the bottom. At the bottom of the “zig zag” column is a removal fan that transfer the final finished product into a Rotajet double big bagging system.