Abstract: A process is described for recovering metal values from a zinc-containing complex sulphide material comprising leaching the material in a first leaching stage under non-oxidative conditions with a controlled amount of an aqueous chloride lixiviant solution containing cupric chloride in an amount which is selected so as to solubilize at least a part of the zinc in the material and to precipitate a quantity of cupric sulphide substantially equivalent on a molar basis to the zinc leached from the material, the lixiviant solution further containing sufficient of a source of chloride ions other than cupric chloride to ensure solubilization of metal chlorides present, recovering from the first leaching stage a zinc chloride-containing leach liquor, recovering metal values from said leach liquor in a metal recovery section, treating solids from the first leaching stage under oxidizing conditions in a second leaching stage with a liquor containing hydrochloric acid and metal chlorides thereby to solubilize further me

Abstract: A control device for controlling the transfer of adsorbent to and from stages of an adsorbant-in-pulp contactor comprises a vessel for receipt of an adsorbent-pulp mixture and having an inclined screen for retention of adsorbent particles and passage of pulp, means for transferring adsorbent-pulp mixture to the vessel, means for measuring the volume of adsorbent or of adsorbent-pulp mixture in the vessel, and outlet means adjacent the lower end of the screen for recovery of drained adsorbent solids.

Abstract: A process is described for recovering non-ferrous metal values from a metal-containing sulphide material containing at least one non-ferrous metal selected from zinc, copper, lead, cobalt, nickel, silver and gold, as well as iron, comprising leaching the complex sulphide material under oxidizing conditions in a leach stage with an acidic aqueous chloride lixiviant solution containing magnesium chloride, thereby to solubilize non-ferrous metal values in the material and to leave a residue comprising iron in oxide or hydrated oxide form and also sulphur, passing resulting non-ferrous metal-containing leach liquor to a metal recovery section including a solvent extraction stage in which non-ferrous metal values are recovered by liquid-liquid extraction using a hydrophobic organic extractant phase containing a cationic transport agent for non-ferrous metal transport, recovering from the solvent extraction stage an aqueous magnesium chloride-containing raffinate, subjecting a portion of the aqueous magnesium chlor

Abstract: Alkanes are catalytically oxidized in the absence of ammonia by passing a feed gas including the alkane and oxygen at an elevated temperature over a solid catalyst. The partial pressure of the alkane in the feed gas exceeds 0.70 atmospheres absolute. Examples of the catalytic oxidation are the production of acrolein and methacrolein and acrylic acid and methacrylic acid from propane and iso-butane.