One-step method to prepare Na2CrO4 using chromium slag exposed to the high-temperature atmosphere

Chromium (Cr) slag, a byproduct of steelmaking, is an important recyclable secondary resource. The preparation of Na 2 CrO 4 from Cr slag has the potential to enhance the economic value of the slags and address environmental challenges linked to Cr(VI). This study investigated the heating processes of Cr slag without and with 30   wt.% Na 2 CO 3 under different atmospheres (air and argon) from 30 ℃ to 1400 ℃. The results showed that 30   wt.% Na 2 CO 3 reacted with Cr 2 O 3 and FeCrO 4 , starting to form Na 2 CrO 4 at 915 ℃ in air. When the heating temperature exceeded 1200 °C, Na 2 CrO 4 started to volatilize, which can be collected. Conversely, heating Cr slag with Na 2 CO 3 in argon generated NaCrO 2 without Cr volatilization. This research proposed a green one-step and cost-effective method for Na 2 CrO 4 preparation: Cr slag heated with 30   wt.% Na 2 CO 3 in air to 1400 ℃. It can use the residual heat from steelmaking, contributing to the recovery and utilization of secondary resources.