The present description relates to a process for extracting magnesium compounds from magnesium-bearing ores comprising leaching serpentine tailing with dilute HCl to dissolve the magnesium and other elements like iron and nickel. The residual silica is removed and the rich solution is further neutralized to eliminate impurities and recover nickel. Magnesium chloride is transformed in magnesium sulfate and hydrochloric acid by reaction with sulfuric acid. The magnesium sulfate can be further decomposed in magnesium oxyde and sulphur dioxyde by calcination. The sulphur gas can further be converted into sulfuric acid.

Provided is a method for treatment of gas mixtures and an apparatus for carrying out a method for treatment of raw gas mixtures. More particularly, there is provided a method and an apparatus for treatment of gas mixtures, such as biogas or flare gas, and in particular to a method and an apparatus for removing contaminants, in particular H.sub.2S, from a gas mixture containing CH.sub.4 and H.sub.2S.

The invention relates to the electrodialytic production of ammonia and sulfuric acid from ammonium-sulfate-rich (waste) waters. An object of said invention was to provide a process for recovering ammonia and sulfuric acid from waters containing ammonium sulfate in high concentrations. The process should be practicable on an industrial scale and have good energy efficiency. This problem is solved by a combination of electrodialysis and water electrolysis. It results in ammonium sulfate being split back into ammonia and sulfuric acid. Unlike conventional three-chamber processes, the process of the invention employs a cell having only two compartments, which can however be multiply parallelized within the stack. This type of scale-up is much more cost-effective than connecting multiple cells in parallel.

A method of producing sulfuric acid can include: obtaining a microbial culture that produces sulfuric acid; placing the microbial culture in a bioreactor in an aqueous environment; introducing an aqueous, liquid or gaseous sulfur supply into the bioreactor; and culturing the microbial culture with the sulfur supply sufficiently so that sulfuric acid is produced. The sulfur supply can be from aqueous or gaseous sulfur dioxide and/or dihydrogen sulfide, or sulfurous acid. The microbes are any microbes that processes sulfur, such as natural microbes that processes sulfur, genetically modified microbes that processes sulfur, cultivated microbes en.) that processes sulfur, purchased microbes that processes sulfur. The microbes may also include other type of microbes that facilitate culturing of the sulfuric acid producing microbes. The sulfuric acid can be produced at ambient conditions. In one aspect, the process is a batch process or a continuous process.

A process for preparing sulfuric acid may involve melting elemental sulfur in a melting stage to give molten sulfur. Sulfuric acid is subsequently produced from the molten sulfur. Further, sulfur-containing offgases formed in the melting stage may be subjected to oxidation in a supplementary oxidation stage in which sulfur-containing components of the offgases are oxidized to sulfur dioxide. The process may further involve processing the sulfur dioxide to give at least one reaction product. The melting stage may be operated without emissions by processing all of the offgases from the melting stage. An apparatus may be employed for carrying out such a process.

A process for preparing sulfuric acid may involve melting elemental sulfur in a melting stage to give molten sulfur. Sulfuric acid is subsequently produced from the molten sulfur. Further, sulfur-containing offgases formed in the melting stage may be subjected to oxidation in a supplementary oxidation stage in which sulfur-containing components of the offgases are oxidized to sulfur dioxide. The process may further involve processing the sulfur dioxide to give at least one reaction product. The melting stage may be operated without emissions by processing all of the offgases from the melting stage. An apparatus may be employed for carrying out such a process.

The present invention relates to a method for the catalytic removal of sulfur dioxide from waste gases in two reactors, wherein the first reactor is charged with an activated carbon catalyst. The method comprises: a. provision of a waste gas with a water content of less than 1 g H.sub.2O/Nm.sup.3 and an SO.sub.2 content of at least 5 ppm, b. introduction of the waste gases into a first reactor, c. catalytic conversion of the SO.sub.2 into gaseous SO.sub.3 in the first reactor by the activated carbon catalyst, wherein catalytic conversion on the activated carbon catalyst proceeds at a temperature of below 100 C., d. introduction of the prepurified waste gases from the first reactor into a second reactor, e. conversion of the SO.sub.3 with water into H.sub.2SO.sub.4 in the second reactor.

Commercial production of sulfuric acid is almost entirely accomplished nowadays using the contact process. And the trend is to increase conversion efficiency and reduce emissions of unconverted sulfur dioxide. By using a special combination of contact catalyst beds, a single contact single absorption (SCSA) system can be engineered to achieve the conversion and emission capabilities of conventional double contact double absorption systems. Thus, the complexity and cost of incorporating a second absorption tower and associated heat exchanger in the system can be omitted. In the SCSA system, the initial catalyst bed or beds comprise vanadium oxide catalyst and the last catalyst bed or beds comprise platinum catalyst operating at a much lower temperature than the initial beds.

This present invention relates to a process that can be used to create electricity, hydrogen and sulfuric acid by combining a thermodynamic cycle with electrochemical and chemical reactions

A reactor having a shell comprising: one or more reactor tubes located within the shell, said reactor tube or tubes comprising a plurality of catalyst receptacles containing catalyst; means for providing a heat transfer fluid to the reactor shell such that the heat transfer fluid contacts the tube or tubes; an inlet for providing reactants to the reactor tubes; and an outlet for recovering products from the reactor tubes; wherein the plurality of catalyst receptacles containing catalyst within a tube comprises catalyst receptacles containing catalyst of at least two configurations.