The invention relates to a method for the production of chlorine by means of photocatalytic oxidation of gaseous hydrogen chloride with oxygen as an oxidizing agent, in which the reaction is started on the surface of a photocatalyst by the action of UV radiation in a selective energy range.

A method for processing hydrogen chloride from isocyanate preparation comprises the steps: a) providing hydrogen chloride; b) purifying the hydrogen chloride provided; and furthermore step c) or step d): c) bringing the purified hydrogen chloride into contact with water and/or with hydrochloric acid which is not saturated with respect to uptake of hydrogen chloride, d) further processing the purified hydrogen chloride to chlorine by partial oxidation. The hydrogen chloride provided in step a) contains organic and/or nitrogen-containing impurities and in step b) the purification is carried out by bringing hydrogen chloride into contact with hydrochloric acid which is saturated to the extent of 90% with respect to uptake of hydrogen chloride at least in a first gas scrubber (10) and circulating this hydrochloric acid at least partially through the first gas scrubber (10).

An industrial scale smelting system that processes large quantities of ore in a production manner for recovery of a plurality of elements in useful quantities using a furnace system and a plurality of electrowinning processes with the option of raw material recovery and recirculation capabilities.

A process for preparing metal chloride Mx+Clx?, in which metal carbonate in solid form is reacted with a chlorinating agent selected from chlorine and oxalyl chloride to give metal chloride Mx+Clx?, where the metal M is selected from the group of the alkali metals, alkaline earth metals, Al and Zn, Li and Mg, or Li, and x corresponds to the valency of the metal cation, and wherein metal M is additionally added as a reactant to the metal carbonate/chlorinating agent reaction.

An industrial scale smelting system for using arc furnaces for processing large quantities of ore in a production manner for recovery of a plurality of elements in useful quantities using a plurality of electrowinning processes with the options of providing efficient energy recovery and raw material recovery and recirculation capabilities.

Systems and methods for processing slag produced by iron and steel making processes are disclosed. The slag is treated produce a series of valued industrial products, such as metal oxides, metal carbonates, rare-earth metals, and water glass. The systems and methods also integrate slag processing with CO.sub.2 sequestration and flue gas desulphurization. Processing slag minimizes the land use for stockpiling or landfilling wastes produced from iron and steel making processes and protects the ground water underneath. Overall, the solid and gaseous emissions of an energy-intensive and highly polluted industrial process have been largely reduced, recycled and valorized in order to achieve a near zero-emission goal.

An electrolytic cell, system, and method for the energy efficient electrochemical treatment of wastewater comprising organic and/or inorganic pollutants are disclosed. The system comprises an electrolytic cell comprising a solid polymer, proton exchange membrane electrolyte operating without catholyte or other supporting electrolyte. The electrolytic cell also comprises a filter layer incorporated between the anode fluid delivery layer and the anode flow field plate for removing various contaminants including particulates and/or suspended solids from the wastewater stream. The cell design and operating conditions chosen provide for significantly greater operating efficiency.

An industrial scale smelting system for using arc furnaces for processing large quantities of ore in a production manner for recovery of a plurality of elements in useful quantities using a plurality of electrowinning processes with the options of providing efficient energy recovery and raw material recovery and recirculation capabilities.

A process for preparing metal chloride Mx+Clx, in which metal carbonate in solid form is reacted with a chlorinating agent selected from chlorine and oxalyl chloride to give metal chloride Mx+Clx, where the metal M is selected from the group of the alkali metals, alkaline earth metals, Al and Zn, Li and Mg, or Li, and x corresponds to the valency of the metal cation, and wherein metal M is additionally added as a reactant to the metal carbonate/chlorinating agent reaction.