Obtaining iron-manganese concentrate from metallurgical wastewater
The separation of valuable components from industrial wastewater has always been a topical task. In this article a cost-effective technology of producing iron-manganese concentrate from wastewater of vanadium pentoxide production was explored. This concentrate is a demanded raw material in metallurgical industry. Initial concentrations of iron and manganese in certain wastewater were 815 mg/L and 4020 mg/L respectively, and pH of the waste water was 1,2. As precipitants NaОH 20% solution, NaHCO3 crystallized, a saturated solution of NaHCO3 and Na2CO3 saturated solution were studied. For economic reasons it was decided to use a saturated solution of Na2CO3 to precipitate metals together as carbonates when pH was 9,21. At the dose of Na2CO3 (saturated solution) 12,3 g/L 99,86% of iron and 99,98% of manganese were precipitated. Then, after the sludge calcination in a muffle furnace at 600℃, a mixture of oxides Fe2O3 and Мn2О3 was obtained; which is the product of the technology. As a result of precipitation from the industrial wastewater, the iron-manganese concentrate with the ratio Mn/Fe=5,6 was obtained. The wastewater capacity is 40 m3/h, thus, one can get 7,7 tons of product a day with the consumption of Na2CO3 11,8 t/h.