The aim of this work is the evaluation of both adsorption-desorption mechanisms of hexavalent chromium in two metallurgical wastes. These processes were investigated using batch tests. Theses wastes correspond to the metallurgical processes of Ni-Co recovery in Cuban industries. The first one (called SAL-waste) is originated by sulphuric acid leaching and the second one (ACL-waste) is the by-product of ammonia-carbonate metallurgical leaching. The wastes are mainly constituted by iron minerals. Grain size distribution is poorly graded with a average value of diameter is about 0.02 mm. The adsorption isotherms of Cr in ACL and SAL are strongly non-linear and well described by the Freundlich equations (S = Kf Cn w). Desorption isotherms of Cr in both wastes are near-linear and illustrate very well the presence of a hysteretic process. The time of Cr adsorption short and desorption is very ...

The aim of this work is the evaluation of both adsorption-desorption mechanisms of hexavalent chromium in two metallurgical wastes. These processes were investigated using batch tests. Theses wastes correspond to the metallurgical processes of Ni-Co recovery in Cuban industries. The first one (called SAL-waste) is originated by sulphuric acid leaching and the second one (ACL-waste) is the by-product of ammonia-carbonate metallurgical leaching. The wastes are mainly constituted by iron minerals. Grain size distribution is poorly graded with a average value of diameter is about 0.02 mm. The adsorption isotherms of Cr in ACL and SAL are strongly non-linear and well described by the Freundlich equations (S = Kf Cn w). Desorption isotherms of Cr in both wastes are near-linear and illustrate very well the presence of a hysteretic process. The time of Cr adsorption short and desorption is very ...

This study aims to analyze the main causes of major environmental disasters caused by mining-metallurgical activities worldwide. 363 cases were analyzed, including significant incidents and disasters, as reflected in various databases, reports and publications. The main causes of these disasters should be noted: 1) insufficient or improper environmental impact study (EIA), 2) the failure of waste storage structures ( Tailing dams, tailings piles leaching, etc.). 3) No using best available techniques (BAT) in mines and metallurgical activities, 4) errors in the design of facilities, 5) failure to use appropriate security measures according to the risks involved. The magnitude of these disasters has been increasing for several reasons: the negligent behaviour of firms and administrations, the existence of nearby villages, the unique and fragile ecology of the area of location of mining ope...

This study aims to analyze the main causes of major environmental disasters caused by mining-metallurgical activities worldwide. 363 cases were analyzed, including significant incidents and disasters, as reflected in various databases, reports and publications. The main causes of these disasters should be noted: 1) insufficient or improper environmental impact study (EIA), 2) the failure of waste storage structures ( Tailing dams, tailings piles leaching, etc.). 3) No using best available techniques (BAT) in mines and metallurgical activities, 4) errors in the design of facilities, 5) failure to use appropriate security measures according to the risks involved. The magnitude of these disasters has been increasing for several reasons: the negligent behaviour of firms and administrations, the existence of nearby villages, the unique and fragile ecology of the area of location of mining ope...