Integrated management of ash from industrial and domestic combustion: a new sustainable approach for reducing greenhouse gas emissions from energy conversion

Environmental Science and Pollution Research - This work supports, for the first time, the integrated management of waste materials arising from industrial processes (fly ash from municipal solid...     

Pyrolysis of WEEE plastics using catalysts produced from fly ash of coal gasification

Catalytic pyrolysis of thermoplastics extracted from waste electrical and electronic equipment (WEEE) was investigated using various fly ash-derived catalysts. The catalysts were prepared from fly ash by a simple method that basically includes a mechanical treatment followed by an acid or a basic activation. The synthesized catalysts were characterized using various analytical techniques. The results showed that not treated fly ash (FA) is characterized by good crystallinity, which in turn is lowered by mechanical and chemical treatment (fly ash after mechanical and acid activation, FAMA) and suppressed almost entirely down to let fly ash become completely amorphous (fly ash after mechanical and basic activation FAMB). Simultaneously, the surface area resulted increased. Subsequently, FA, FAMB and FAMA were used in the pyrolysis of a WEEE plastic sample at 400°C and their performance were compared with thermal pyrolysis at the same temperature. The catalysts principally improve the light oil yield: from 59 wt.% with thermal pyrolysis to 83 wt.% using FAMB. The formation of styrene in the oil is also increased: from 243 mg/g with thermal pyrolysis to 453 mg/g using FAMB. As a result, FAMB proved to be the best catalyst, thus producing also the lowest and the highest amount of char and gas, respectively.

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Nickel and cobalt recycling from lithium-ion batteries by electrochemical processes

The presence of LiCoO(2) and LiCo(x)Ni((1-x))O(2) in the cathodic material of Li-ion and Li-polymer batteries has stimulated the recovery of Co and Ni by hydrometallurgical processes. In particular, the two metals were separated by SX method and then recovered by electrochemical (galvanostatic and potentiostatic) processes. The metallic Ni has been electrowon at 250 A/m(2), pH 3-3.2 and 50 degrees C, with 87% current efficiency and 2.96 kWh/kg specific energy consumption. Potentiostatic electrolysis produces a very poor Ni powder in about 1 h with current efficiency changing from 70% to 45% depending on Ni concentration in the electrolyte. Current efficiency of 96% and specific energy consumption of 2.8 kWh/kg were obtained for Co at 250 A/m(2), pH 4-4.2 and 50 degrees C, by using a solution containing manganese and (NH(4))(2)SO(4). The Co powder, produced in potentiostatic conditions (-0.9 V vs. SCE, pH 4, room temperature) appears particularly suitable for Co recycling as cobaltite in new batteries.