Produção de blocos de concreto a partir do reaproveitamento do lodo de uma indústria de curtume

Abstract

Technological development allied to the growth of production processes has provided improvements in the population's quality of life, however, this advance has been bringing more and more waste. The tannery industries produce one of the residues considered more aggressive to the environment, as chromium salts are used in their tanning process, which is generally found in the trivalent state, and can be oxidized to hexavalent chromium, which is easily soluble and toxic. Aiming at the reuse of this waste, providing a reduction of a liability and transforming it into an environmental asset, the present work aims to verify a possibility of producing concrete blocks with an incorporation of chromium sludge from the tanning process of a leather industry. The chromium sludge was provided by a tannery located in the north of the state of Paraná, which was modified in terms of its physicochemical composition. Subsequently, the sludge was dried for the preparation of specimens with the addition of different specifications of chromium sludge T1 (0%), T2 (5%), T3 (10%) and T4 (15%), with a trace of the materials 1: 3. With the characterization of the waste, it was possible to classify it as Class I (Hazardous), as special metals were found. The analyzes carried out on the collected blocks were compressive strength, visual vision and water absorption. As a result, it was possible to verify that there was a loss of compaction with the addition of the sludge, but these are still known to fall under the classification C of blocks with or without structural function. In relation to water absorption, it was observed that the more sludge, the lower the absorption, obtaining an average result of 4%. Visual analysis analysis showed that the blocks not known in accordance with the regulations, having cracks and holes, probably referring to poor compaction of the aggregates, causing loss of strength. Despite this, it can be overcome that the method of encapsulating the residue in the cement matrix is viable, as it met the parameters of resistance and water absorption, in addition to promoting the use of a residue with a high toxic potential, producing a new product with value aggregate.