The present work covers two different waste streams:

(i) salt slag from scrap remelting;

(ii) wastewater generated sludge from surface treatment and anodizing processes.

As incorporation matrixes several silicate-based common materials were used, namely:

(a) Portland cement-based mortars,

(b) bauxite-based refractories,

(c) clay-based bricks.

The thesis is presented in several independent chapters, being the III, IV and V composed by state-of-the-art overview and discussion of current experiences and results:

I Introduction

II General overview of environmental management and inertization industrial wastes

III Al-based slat slag

IV Al-based anodizing sludge

V Incorporation in ceramic matrixes

VI General conclusion and future work

VII Description of experimental methods and techniques

Before starting the incorporation studies, a full characterization of the residues were conducted involving:

(i) chemical and mineralogical composition;

(ii) toxicological behaviour;

(iii) grain size distribution;

(iv) thermal behaviour.

Final waste-containing and non-doped products were comparatively evaluated by using some previous mentioned techniques and relevant functional parameters (e.g., mechanical resistance) were also estimated.

Less common electrical properties and microstructural details were also determined.

As a general conclusion, results confirm the potential of tested incorporation method in fixing waste-containing species. Definition of incorporation limits and processing conditions were also defined in each situation. Critical aspects deserving particular attention include:

(i) grain size control of slag particles by milling and screening (at 0,18 mm);

(ii) washing/leaching treatment of the salt slag;

(iii) need of drying or calcining steps for the sludge.

In addition to the incorporation process, new (alternative) sludge-based products started to be designed and the full definition of processing conditions and final capabilities still deserves further studies.