Sampling systems for on-stream x-rayanalysers in ore-dressing plants

Sampling systems for on-stream analysers in ore-dressing plants must be designed to take into account the requirements of the analyser and the conditions prevailing in the process. The accuracy of the analysis provided by the analyser is determined by process factors such as ore type and grinding. For process control and development, the required sample accuracy is a relative sampling error less than 1%. Static primary samplers give acceptable accuracy for normal sulphide ores up to a particle size of 85% - 150μm. This covers the needs of most small-to-medium size concentrators. The size of the sample error in static samplers is discussed. Other methods available are immersion of the analyser probe and the use of automatic samplers. Experience of both is reported.