For decades significant amounts of inert purge water has been used in mineral refining industries throughout the world to flush tapping points. In most processes the addition of inert purge is deemed parasitic and dilutes the process and must be removed later during the process manufacturing cycle.
By mechanically keeping tapping points clear the use of inert purge is substantially reduced.
An average alumina refinery consumes 25 litres per hour of purge water per tapping point. With the introduction of the Autorodder this purge consumption is reduced to approximately 5 litres per hour. On average an alumina refinery will have some 1000 tapping points. The Autorodder therefore saves 20 litres per hour per tapping point with approximate water savings per average alumina refinery of 20,000 litres per hour.
Whilst this saving in water is substantial, the additional saving of greenhouse gases from the generation of energy provides an additional contribution to our economy.
Each litre of purge added to the process has to reach the process temperature. Purge enters a tapping point at ambient temperature and extracts heat from the process to reach the same temperature as the process stream.
For example the alumina refinery process operates at greater than 100oC. Purge water is introduced into the process at 20oC. By saving 20 litres per hour per tapping point we are also saving the requirement to heat this additional unnecessary volume of water. Depending on the fuel source used to generate the heat for the process the estimated savings using the above figures equates to approximately 5 tons per annum of greenhouse gas emissions per tapping point.