Abstract: A hydrometallurgical method for simultaneously extracting zinc, lead, silver, iron and calcium from electric arc furnace dust (hazardous waste) produced by the steelmaking industry (steelworks), in the form of industrial products: zinc as zinc sulphate or zinc cathodes; lead and silver as a concentrate of lead and silver; iron as reduced elemental iron for return to the electric arc furnace; and, lastly, calcium as gypsum, without solid waste or liquid effluents being generated relates to the chemical nature of the electric arc furnace dust (complex oxides) changes to a sulfide complex, and eliminating the hazards associated with the generation of fugitive heavy-metal salts. In addition, the hydrometallurgical problem of low recovery of zinc and iron is solved. Consequently, hydrometallurgy is made easier and more environmentally friendly, as condensed water is used as a leachate, the condensed water being continuously regenerated by vacuum evaporation systems without generating effluents.

Abstract: In various example embodiments, a system and method for presentation of bidding activity are presented. A series of bids is received from users participating in an auction of an item that is available for sale from an online marketplace. One or more values from the series of bids are determined. Times of receipt for the series of bids are also determined. A graph that depicts the series of bids as a set of points is generated. Display of the graph on a web page corresponding to the auction of the item is caused.