THE HIGH throughput rates and low residence times that are achievable with the
new generation clarifier have focussed attention on the need to improve the
handling and transport properties in the mud thickening zone. This places more
emphasis on the ability of the mud scraper designs to transport the mud towards
the centre mud cone. The investigations into the effects of the clarifier design on
mud transport have been conducted using pilot tests and factory trials. The mud
transport efficiency of current flat inclined blades is low at 0.18. It was estimated
that the throughput of new generation clarifiers would be limited by the ability
of the mud scraper system to maintain the required delivery rate of mud to the
mud cone for withdrawal. A number of options for improved transport capacity
have been assessed. A hybrid blade design has been developed that combines the
existing flat inclined blade with a new lead section with a greater angle to
provide a more incisive separation as the blade progresses through the mud
layer.