Production of green, low-cost and high-performance anorthite-based ceramics from reduced copper slag

•Novel anorthite-based ceramics are prepared from reduced copper slag.•The effect of slag addition on the sintering and microstructure is clarified.•Slag-derived ceramics vitrify earlier and show much higher MOR than the traditional ones.•Leaching toxicity of the ceramics is 2 ∼ 3 orders of magnitude lower than the initial slag.•A high degree of whiteness (∼90) is also achieved for the slag-derived ceramics.