Beneficial use of aluminium and iron components of sludge incineration residues in ceramic materials

摘要

A huge amount of sludge is generated from sewage treatment and waterworks. With the development of sludge incineration technology, most of the produced residues are buried in landfills, resulting in the loss of major constituents such as aluminium and iron that are present in the sludge residue. Moreover, toxic metals can leach out, causing further pollution. The need for "waste-to-resource" technology provides an incentive to develop economically viable reuse options. This study investigated the feasibility of beneficially incorporating aluminium and iron into marketable ceramic products. With CuO in the system, the CuAl_2O_4 spinel predominantly incorporated aluminium from waterworks sludge residues, while the CuFe_2O_4 spinel was a major iron-containing phase in the sewage sludge residue series. The maximum fraction of aluminium in the CuAl_2O_4 reached 98% and 83% for the α-Al_2O_3 + CuO and kaolinite + CuO systems, respectively. Using Fe_2O_3, iron was transformed into both tetragonal and cubic CuFe_2O_4, reaching complete incorporation. With various colours and microstructures formed the products can be used as pigments, in construction, and as ceramic membranes. The findings of this study suggest a promising process for the beneficial use of waste aluminium and iron as ceramic raw materials, and may provide an economical means of reducing environmental concern over solid wastes.