Encapsulation in ceramic material of the metals Cr, Ni, and Cu contained in galvanic sludge via the solidification/stabilization method

•Cu, Ni and Cr were encapsulated in ceramic material.•The environmental impact by the heavy metals Cu, Ni, and Cr was reduced.•The percentage of retention of the metals Cr, Ni, and Cu was 95% to 99%.•The leaching of the metals Cr, Ni, and Cu in the final product was reduced.•The mechanical properties were correlated with the percentage of sludge.