Produção Nacional
Revisado por pares
Dephosphorization of chromium-rich ashes from thermally-treated leather waste for utilization in pyrometallurgical process
2012; Elsevier BV; Volume: 114-117; Linguagem: Inglês
10.1016/j.minpro.2012.10.006
ISSN1879-3525
AutoresDenizia Padilha, Bruno München Wenzel, Nilson Romeu Marcílio, Arthur D.B. Silva, Lucas P. Cavalcanti, Marcelo Godinho,
Tópico(s)Recycling and Waste Management Techniques
ResumoAcid leaching was investigated to remove phosphorus from the ashes of thermally-treated (gasification and combustion process) footwear leather waste in order to obtain a good quality raw material for the production of a ferrochromium alloy. The ash contained high amounts of chromium (55 wt.% Cr2O3) and phosphorus (1.42 wt.% P). The following key factors were selected for study: temperature, H2SO4 concentration in the leaching solution, acid solution/ash ratio and the particle size of the ash. The response was the phosphorus removal percentage and, under some experimental conditions, chromium loss. The strategy was based on a 24 full factorial design with a central point followed by the addition of star points in a face-centered central composite design. The maximum chromium loss was 1.1 wt.%. The significant effects (according to variance analysis) were used for a proposed second-order response surface model. The model was useful for finding the optimal operating conditions in the experimental region by the maximization of phosphorus leaching. 99.2 ± 2.5% phosphorus removal from the ash was achieved under the following conditions: 60 °C, 13.9 wt.% of H2SO4 in the leaching solution, 4.80 (ml of acid solution)(g of ash)− 1, 0.0370 ± 0.0370 mm particle size. Mass balance was used as a tool to indicate that the remaining phosphorus content was acceptable for producing ferrochromium alloys.
Referência(s)