Process for preparing a ceramic article containing sludge

A process for preparing a ceramic article containing sludge comprising:

• drying sludge to a moisture content of at most 10% by weight and until the content of organic matter is reduced to less than 20% by weight;
• heating the dried sludge in a spouting bed reactor operating at a temperature in a range of between 900-1250° C., a residence time of from 1 to 10 seconds and with gas velocity of at least 10 m/s until the content of organic matter is less than 5% by weight;
• mixing clay, one or more additives, and the heated sludge to form a mixture;
• wherein the one or more additives are selected from the group consisting of sand, glass, glass dust, colorant, rice husk ash, fly ash, kaolin, paper ash and combinations thereof;
• wherein the amount of the one or more additives comprises up to 10% by weight of the mixture;
• and
• wherein the amount of sludge comprises at least 40% by weight of the mixture;
• shaping the mixture;
• drying the shaped mixture;
• and
• firing the shaped mixture at a temperature of between 900-1200° C., resulting in a ceramic article;
• wherein the sludge is selected from the group consisting of domestic sludge, natural sludge, and industrial sludge;
• and
• wherein if domestic sludge, it excludes digestate that is obtained from a Municipal Solid Waste process comprising liquefaction of the organic fraction of MSW by addition of one or more enzymes.