Microwave Digestion of Hazardous Waste Sludge in Geothermal Hot Waters by Char/Fly Ash Granule Composts-Hazardous Sludges and Industrial Waste Water Treatment

Most of the previous were regarding characteristics of sludge from urban/municipal activities concerning environmental issues on industrial sludge discharges causing fatal disasters in the lakes and water streams. The washing treatment of mud was searched. This research study concentrated over oxidative heavy metal dissolution and sterilization washing of muddy sludge of chemical, steel and copper refinery plants. The hazardous Hg and Pd contents using washing dissolution provided recovery of metals and treated sludge as the feedstock for digestion process. The research used hazardous sludge which is the by-product of the heat treated steel manufacturing process of CN baths and sludge from pulp washing industries. However, there is a sterilization washing by microwave radiation was reported on various sludge metal contamination characteristics in wastewater treatment stage. The results of a limited number of bench-scale sludge washing experiments conducted in the tube reactor study confirmed high radiation trends for washing dissolution with H2O2 in soil samples obtained from different locations in the north lake area of discharge of at the Plant Site. In general the contaminants in waste pond soils partitioned preferentially to the fine fraction of the soil (<150 μm however, the sand fraction (−0,5 mm + 150 μm) still contained significant contamination. These tests also showed that the heavy metal contaminants were highly dissolved at 45–76% in the wash water, which will reduce washing toxicity and improve metal recovers.

Removal of Sb Impurities in Copper Electrolyte and Evaluation of as and Fe Species in an Electrorefining Plant

Antimony and arsenic concentrations and their oxidation states (Sb(III), Sb(V), As(III) and As(V)) in copper electrorefining electrolyte can affect copper cathode quality through the formation of floating slimes. A laboratory-scale pilot plant was operated to remove Sb from commercial electrolyte. The pilot plant consisted of a pre-treatment process with copper shavings followed by ion exchange. The results indicated that Sb(III) was removed from copper electrolyte completely, while Sb(V) was partially eliminated. The concentrations of As(III) and As(V) were not affected, and the poisoning of the ion exchange resin by Fe(III) was avoided by pre-reduction to Fe(II) by copper shavings. The operation configuration of the pilot plant was applied to the design of an industrial plant for Sb/Bi removal at the Atlantic Copper Refinery in Huelva, Spain. The evolution of Sb, Fe and As species in the commercial electrolyte was monitored prior to and after the installation of the Sb/Bi removal plant. The results show a ca. 45% decrease in total Sb content (from 0.29 g L−1 to 0.16 g L−1) in the electrolyte. This reduction is more noticeable for Sb(III), whose concentration decreased from 0.18 g L−1 to 0.09 g L−1, whereas Sb(V) concentration diminished from 0.11 g L−1 to 0.07 g L−1. The resin also retained ca. 75% of the Bi content (0.15–0.22 g L−1). The total As increased during the study period (from 7.7 to 9.0 g L−1) due to changes in plant inputs. Arsenic was predominantly As(V) (ca. 93–95%). The total Fe concentration experienced little variation (0.9–1.1 g L−1) with Fe(II) being the main species (ca. 94–96%).

Characterization and process development for the selective removal of Sn, Sb, and As from anode slime obtained from electrolytic copper refining

The aim of this work was to develop a process for the removal of Sn, Sb and As from anode slime out of copper refinery to disburden a subsequent pyrometallurgical processing for precious metals refinement. For this reason, a detailed literature survey was conducted, followed by a characterization to find the present compounds/alloys and their morphology. A newly developed process concept for the separate extraction of the afore mentioned three target metals was developed and verified by leaching experiments, combined with thermodynamic calculations on their behavior under varying conditions. In this context, the influence of leaching temperature, alkalinity of leaching solution, and solid-liquid ration were evaluated on the extraction yields of Sn, As, and Sb, as well as how to exploit these findings to obtain separate streams enriched in the respective metals.