Study of the distribution of minor elements between copper matte and
fayalite slag is important in determining appropriate methods to
maximise the recovery of valuable metals and the rejection of harmful
elements. Boliden Mineral AB operate a large copper smelter in northern Sweden, where they had noted that the loss of silver to the slag in the settling furnace appeared to be a direct function of the tin content of the slag. This work was aimed at determining whether or not this was a cause-and-effect relationship. Copper matte containing approximately 50 wt per cent copper and small amounts of silver and tin was equilibrated with silica-saturated fayalite slag at 1250C, then quenched. The matte and slag were then analysed for their silver and tin contents. It was found that there was no relationship between the silver distribution and the tin distribution. The silver matte/slag distribution ratio had a value of 120 40 while that for tin was 2.8 0.3. It is suggested that the most likely cause of the relationship observed at the Boliden smelter was matte entrainment in the slag.