FABRICATION OF SAWDUST BRIQUETTES USING LOCAL BANANA PULP AS A BINDER

Abstract

Sawdust is generated in large quantities in sawmills in Manicaland province in Zim-babwe, posing an environmental threat if incinerated or left to accumulate. This pres-ents an opportunity for valorising the waste into briquettes. To make the briquettes cost effective, a cheap and locally available binder is needed. Hence, the use of banana waste pulp (green banana, ripe banana, pseudo-stem pith and fruit-bunch-stem) as a sawdust briquettes binder was investigated in this study. The quality of fabricated briquettes was evaluated based on relative density, shatter index, ignition time, burning rate, and time taken to boil a constant amount of water. The briquettes showed improved qualities with the increase in binder ratios. The sawdust-binder ratio of 1:4 showed the best briquettes qualities. Factor rating method was done in order to obtain the best scored (scale 0-100) briquettes reflecting weightier factors (scale 0-1). The weightiest factors were time taken to boil water (0.25) and shatter index (0.25), with three other factors weighing 0.5. The best five binder formulations in their order were; banana-pseudo stem-pith (pith) and ripe banana (RB) in the ratio of 3:1 respectively (score weight of 68.75), fruit-bunch-stem, banana-pseudo-stem-pith (pith), green banana (GB) and ripe banana (RB) in the ratio of 2:2:1:1 respectively (score weight of 68.3), banana-pseudo-stem-pith (pith), ripe banana (RB) and green banana (GB) 2:1:1 respectively (score weight of 66.95), banana-pseudo-stem-pith, ripe banana and green banana in the ratios of 2,5:1,5:1 respectively (score weight of 66.05) and banana-pseudo-stem-pith and ripe banana in the ratios of 1:1 (score weight 65.55).