The invention relates to a process for the removal of heavy metals from solid waste materials containing heavy metals by suspending the waste material in water or in slurry of waste materials, characterized by the fact that chitosan or tannin or a mixture of these two compounds is added to the slurry, the slurry is possibly allowed to stand while being stirred, and finally the solid constituents are separated from the slurry and the solution which contains heavy metals is disposed in known ways.