The preparation of pellets by the compaction of an aluminosilicate-based adsorbent from electronic waste

• Preparing pellets from a novel aluminosilicate-based adsorbent was investigated.
• Binder type and content, water content, and compaction pressure were optimized.
• Calcium carbonate was selected as the binder of choice.
• The compaction process was successful at producing high quality pellets.

Pelletization is an important part of the commercialization of adsorbents. Two factors must be considered in determining the pelletization conditions, namely mechanical strength of the pellets and their water resistance in aqueous environments. The primary objective of this study was the preparation of pellets from an aluminosilicate-based adsorbent for industrial fixed-bed adsorption columns. The pellet formation conditions, including binder type and content, water content, and compaction pressure, were optimized. Calcium carbonate was demonstrated to be the most promising binder for the aluminosilicate material. The experiments showed that with a water content of 30% and final applied compaction pressure of 80 MPa, the amount of binder required for pelletization can be as low as 2.5 wt%. Although higher compaction pressures produced pellets with higher mechanical strength, there exists a trade-off between the mechanical strength and the cost of the compaction process. Overall, the compaction process was successful at producing pellets with ample mechanical strength (as high as 800 kN/m2) and satisfactory water resistance (pellet integrity not affected by immersion).