Abstract: The invention is directed to a process and apparatus for recovering metals from bottom ash from incineration plants, such as municipal waste incineration plants. The process includes directing a feed containing ash into an oxidizing unit, wherein at least part of the metals is oxidized in the presence of one or more acids and at least one oxygen donor, thus producing a stream comprising metal ions. From this stream the metals of interest are selected and converted into metallic form.

Abstract: A method of processing a copper mineral, the method comprising activating the copper mineral by milling the copper mineral to P80 of between 2 and 20 micron, and subsequently subjecting the activated copper mineral to an oxidative hydrometallurgical treatment in the presence of chloride ions in an amount of from 2 to 10 g/L.

Abstract: The present invention provides a process that employs both non-selective flotation and oxidative leaching of the resulting concentrates to recover an increased amount of copper from porphyry copper ores. The non-selective flotation step uses collectors and conditions, such as pH, that are conducive to the strong flotation of sulfide minerals generally. In the oxidative leach, the copper sulfide minerals in the concentrate fraction are oxidized to copper compounds, which are soluble in the leach solution. The oxidative leach includes the use of ammonia and sulfite under agitation leaching conditions to convert the copper sulfide minerals into ammonia soluble forms.

Abstract: There is provided a novel hydrometallurgical process for the extraction of copper from sulphidic concentrates involving an oxidizing pressure leach using dilute sulphuric acid and a carbonaceous additive. The leaching step is carried out preferably at temperatures above the melting point of sulphur but below about 200.degree. C.

Abstract: A method of making a tantalum capacitor of improved specific capacitance (and volumetric efficiency) is described. Short tantalum fibers are precipitated out of a carrier liquid to form a felt, or tumbled to form fiber containing particles, and in either case subsequently bonded so as to form a felt or particles containing the fibers in random orientation in substantially non-aligned array. These particles or felt are heated to bond the fibers together, purify and (optionally) cylindricalize them. The felt or particles can be processed in conventional fashion thereafter to form the capacitor. Cylindricalized fibers and pellets of increased surface area are also described.