Check with Nyumba ya Chuma (Lusaka rd) or Timwood (Dar es Salaam rd). They should be able to get you Fondu or Trimor. If it's a serious project, Trimor would be the best but then you would need Meltex fibre to mix with. I doubt Meltex is locally available though. Both castables cost kindu 50 bob a kg and comes packed in 25 kg bags.
@popat,
....you are smoking some banned substance,no?
Nothing great was ever achieved without enthusiasm.