Methods and systems are provided for treating the tail gas stream of a sulfur recovery plant. The methods including generating a tail gas stream from a sulfur recovery plant, treating the tail gas stream with a hydrogen sulfide removal unit and a hydrogen selective membrane unit, generating a stream low in hydrogen sulfide and a stream rich in hydrogen. The hydrogen sulfide rich stream is recycled to the sulfur recovery unit. The hydrogen selective membrane unit includes a glassy polymer membrane selective for hydrogen over hydrogen sulfide and carbon dioxide.

A system and method for recovering sulfur in a copper smelting process, in which fine dust is removed from high-concentration SO.sub.2 flue gas from a matte smelting furnace, the flue gas is introduced into a fluidized bed carbothermic reduction tower and reduced by a carbon-based reducing agent to obtain reducing gas, which is introduced into a high temperature separator. The separated reducing gas contains unsaturated powder coke, and the reducing gas is condensed to obtain sulfur. The saturated powder coke entrained enters a desorption tower to desorb SO.sub.2 gas, and the desorbed powder coke enters a fluidized bed sulfur reduction tower. Part of the SO.sub.2 gas discharged from the desorption tower is discharged to the fluidized bed carbothermic reduction tower to produce sulfur, and the other part is introduced into a desulfurization tower.

The present invention discloses a process for preparing sulfur from reduction of sulfate/nitrate by iron-carbon and recovering desulfurization/denitration agents. High-concentration SO.sub.2 flue gas produced by calcination of a sulfate and NOx produced by heating decomposition of a nitrate can be directly reduced to elemental sulfur vapor and N.sub.2 through reaction with an iron-carbon material at a high temperature. Then, after dust removal, cooling and fine dust removal, sulfur is recovered by a sulfur recovery device, and metal oxides can replace alkaline mineral resources such as limestone as raw materials of desulfurization (denitration) agents. This process can recycle the desulfurization and denitration agents.

The invention relates to a process for removal of metal carbonyl from a gas mixture. The gas mixture is subjected to a gas scrubbing in an absorber with methanol as the physical scrubbing liquid to obtain the laden methanol. The metals of the metal carbonyls are at least partially precipitated from the laden methanol as metal sulfides to obtain a first suspension comprising metal sulfides and at least a proportion of the laden methanol. The first suspension is sent to a treatment vessel and therein brought into direct contact with water vapor in countercurrent to obtain a second suspension comprising at least water, methanol and metal sulfides and a gaseous product. The second suspension and the gaseous product are withdrawn from the treatment vessel as separate streams.

A method for preparing a sol comprising TiO.sub.2 and ZrO.sub.2 and/or hydrated forms of TiO.sub.2 and ZrO.sub.2. The method includes mixing a material which includes metatitanic acid in an aqueous phase with a zirconyl compound or with a mixture of several zirconyl compounds. The material is provided either as a suspension or as a filter cake from the sulfate method. The material includes a H.sub.2SO.sub.4 content of 3 to 15 wt.-% relative to a quantity of TiO.sub.2 in the material. The zirconyl compound or the mixture of several zirconyl compounds is mixed in a quantity that is sufficient to provide the sol depending on the H.sub.2SO.sub.4 content.

An absorbent composition that is useful in the selective removal of hydrogen sulfide relative to carbon dioxide from gaseous mixtures that comprise both hydrogen sulfide and carbon dioxide and the use thereof. The absorbent composition includes an amine mixture of an amination reaction product of tert-butylamine with a polydispersed polyethylene glycol (PEG) mixture having an average molecular weight within a certain specified range of molecular weights. The amination reaction product may also comprise a first sterically hindered amine and a second sterically hindered amine. The absorbent composition, preferably, includes an organic co-solvent, such as a sulfone compound. A method is also provided for improving the operation of certain gas absorption processes by utilizing the absorbent composition.

Provided are a method for treating sulfur hexafluoride and an apparatus for collecting and treating by-products. The method for treating sulfur hexafluoride, and the apparatus for collecting and treating by-products according to the present invention are a significantly effective method and apparatus capable of safely treating sulfur hexafluoride at low cost.

Provided are a method for treating sulfur hexafluoride and an apparatus for collecting and treating by-products. The method for treating sulfur hexafluoride, and the apparatus for collecting and treating by-products according to the present invention are a significantly effective method and apparatus capable of safely treating sulfur hexafluoride at low cost.

A device includes a desulfurization system which forms a hydrogen sulfide-containing acid gas; a system for extracting elemental sulfur and a hydrogen sulfide-containing tail gas as exhaust gas; a device for generating electricity and gypsum from the tail gas; and a gas line system for supplying acid gas from the desulfurization system to the system for extracting elemental sulfur and to the device for generating electricity and gypsum, and for supplying tail gas from the system for extracting elemental sulfur to the device for generating electricity and gypsum. The gas line system has a gas distributing apparatus which supplies acid gas solely to the system in a first position, supplies acid gas solely to the device in a second position, and supplies a first part of the acid gas to the system and a second part of the acid gas to the device in a distributing position.

Systems and methods use bimetallic alloy particles for converting hydrogen sulfide (H.sub.2S) to hydrogen (H.sub.2) and sulfur (S), typically during multiple operations. In a first operation, metal alloy composite particles can be converted to a composite metal sulfide. In a second operation, composite metal sulfide from the first operation can be regenerated back to the metal alloy composite particle using an inert gas stream. Pure, or substantially pure, sulfur can also be generated during the second operation.