Abstract

The purpose of this work was to explore the incorporation of black manganese oxide powder extracted from alkaline batteries into sintered-clay bricks. The black manganese oxide powder was added into the clay mixture in two different states: pristine and pre-vitrified. Three levels of addition were evaluated according to the final wt% of manganese in the bricks: 0.0, 0.1, and 2.5. The resulting test-bricks were then assessed to determine the following physical and mechanical properties: color change, water absorption, water saturation coefficient, compressive strength, and leaching/efflorescence tendency. The results were statistically tested for significance and compared to a standard industrial formulation for non-structural sintered-clay bricks used locally in Girón, Santander (Colombia). In general, the properties of the test-bricks deviated slightly from the standard formulation only when the final content of manganese in the test-bricks reached 2.5 wt%. In particular, the test-bricks with 2.5 wt% of manganese added in the pre-vitrified state, showed a darker brown color, 1.7 % less water absorption, and a 68 % increase on compressive strength, when compared to the industrial reference red-clay bricks. It is worth to point out that none of the test-bricks studied showed efflorescence tendency. In conclusion, the work proves that the Mn-oxides contained in spent alkaline batteries can be successfully incorporated into nonstructural red clay bricks. These findings would help to ease the adoption of novel circular economy strategies in developing countries with no access to metallurgical facilities for battery recycling.

Graphic Abstract