Recycling of washed olive pomace ash for fired clay brick manufacturing

Milled or micronized washed olive pomace ash was used to replace different amounts (5 and 10 wt%) of clay in brick manufacture. The properties of these bricks were compared to conventional products following standard procedures. Bricks formed with ash showed a decrease of 0.13–0.16 W/m K in thermal conductivity. With a minimum bulk density and bending strength of 1790–1810 kg m−3, and 10–12 N mm−2, respectively, fired bricks fulfil standard requirements for clay masonry units. Milled ash performs better than micronized ash. The ash leachate is a valuable source of potassium for the manufacture of fertilizers.