A process and apparatus for managing hydrogen sulfide in a refinery is provided. In the process, a hydrogen sulfide stream from said refinery is fed to a sulfur recovery unit to produce sulfur and a sulfur compound stream or to a thermal oxidizer. The sulfur compound stream and the hydrogen sulfide stream are then thermally oxidized to produce a sulfur oxide stream. The sulfur oxide stream is then reacted with an ammonia stream. In aspect, the product of the reaction can be a fertilizer. The ammonia stream can be obtained from stripping the hydrogen sulfide stream.

A method for the processing of potassium containing materials comprises: (i) Separation of a potassium containing mineral from gangue minerals; (ii) Acid leaching whereby substantially all potassium, iron, aluminium and magnesium is solubilised and mixed potassium/iron double salt formed; (iii) Selectively crystallising the mixed potassium/iron double salt formed in the leach step (ii); (iv) Second separation to separate the mixed potassium/iron double salt formed in step (iii); (v) Thermal decomposition to produce an iron oxide, a potassium salt and one or more phosphates; (vi) Leaching the product of the thermal decomposition; (vii) Third separation to separate the iron oxide and phosphate from the potassium salt; (viii) Recovering the potassium salt by crystallisation; (ix) Separating the iron oxide and phosphate of step (vii) by leaching and subsequent solid liquid separation; and (x) Precipitating phosphate from liquor produced in step (ix) through the addition of a base.

A process and apparatus for managing hydrogen sulfide in a refinery is provided. In the process, a hydrogen sulfide stream from said refinery is fed to a sulfur recovery unit to produce sulfur and a sulfur compound stream or to a thermal oxidizer. The sulfur compound stream and the hydrogen sulfide stream are then thermally oxidized to produce a sulfur oxide stream. The sulfur oxide stream is then reacted with an ammonia stream. In aspect, the product of the reaction can be a fertilizer. The ammonia stream can be obtained from stripping the hydrogen sulfide stream.

The present invention relates to a process for decomposing calcium sulfide (CaS) into calcium oxide (CaO) and sulfur dioxide (SO.sub.2), comprising:—providing a reactor containing calcium sulfide and a source of carbon,—oxidizing the source of carbon so as to generate carbon dioxide (CO.sub.2),—reacting the calcium sulfide with said carbon dioxide so as to produce carbon oxide (CaO), sulfur dioxide (SO.sub.2) and carbon monoxide (CO) according to the following reaction: CaS+3CO.sub.2˜CaO+SO.sub.2+3CO wherein the oxygen and carbon contents in the oxidation step are chosen such that: (i) the mass ratio C/CaS is comprised between 0.15 and 0.35 and (ii) the mass ratio O.sub.2/C is comprised between 5 and 25.

The present invention relates to a process for decomposing calcium sulfide (CaS) into calcium oxide (CaO) and sulfur dioxide (SO.sub.2), comprising: —providing a reactor containing calcium sulfide and a source of carbon, —oxidizing the source of carbon so as to generate carbon dioxide (CO.sub.2), —reacting the calcium sulfide with said carbon dioxide so as to produce carbon oxide (CaO), sulfur dioxide (SO.sub.2) and carbon monoxide (CO) according to the following reaction: CaS+3CO.sub.2˜CaO+SO.sub.2+3CO wherein the oxygen and carbon contents in the oxidation step are chosen such that: (i) the mass ratio C/CaS is comprised between 0.15 and 0.35 and (ii) the mass ratio O.sub.2/C is comprised between 5 and 25.

Embodiments of a self-sustainable solid oxide fuel cell (SOFC) system for powering a gas well comprise a first SOFC comprising a first cathode, a first anode, and a first solid electrolyte; a second SOFC comprising a second cathode, a second anode, and a second solid electrolyte; SO.sub.2 removal equipment; a combustion circuit comprising a combustor and a circulating heat carrier in thermal connection with the combustor, the first SOFC, and the second SOFC; and one or more external electric circuits. The first anode comprises a first oxidation region configured to produce SO.sub.2 and electrons. The second anode comprises a second oxidation region configured to electrochemically oxidize CH.sub.4 to produce syngas and electrons and electrochemically oxidize H.sub.2 to produce H.sub.2O and electrons. The external electric circuits are configured to generate power from the electrons produced in both the first SOFC and the second SOFC.

Magnesium oxide produced by a process is used as a neutralizing agent for preliminary neutralization treatment of a leached slurry obtained by leaching a nickel oxide ore at a high temperature and pressure with sulfuric acid added. A neutralizing agent is added to a leachate, obtained by leaching a nickel oxide ore, to separate impurities, and a sulfurizing agent is added to the resulting neutralized solution to obtain nickel and cobalt sulfides, followed by separating the sulfurized solution; discharge waste water, obtained by adding a neutralizing agent to the sulfurized solution to separate aluminum and manganese, is concentrated to precipitate and separate calcium contained in the discharge waste water as calcium sulfate; the resulting solution is concentrated to precipitate magnesium in the solution as magnesium sulfate; the magnesium sulfate is roasted with a reducing agent to obtain magnesium oxide and a sulfurous gas; and the magnesium oxide is washed.

A method for the processing of potassium containing materials comprises: (i) Separation of a potassium containing mineral from gangue minerals; (ii) Acid leaching whereby substantially all potassium, iron, aluminum and magnesium is solubilized and mixed potassium/iron double salt formed; (iii) Selectively crystallizing the mixed potassium/iron double salt formed in the leach step (ii); (iv) Second separation to separate the mixed potassium/iron double salt formed in step (iii); (v) Thermal decomposition to produce an iron oxide, a potassium salt and one or more phosphates; (vi) Leaching the product of the thermal decomposition; (vii) Third separation to separate the iron oxide and phosphate from the potassium salt; (viii) Recovering the potassium salt by crystallization; (ix) Separating the iron oxide and phosphate of step (vii) by leaching and subsequent solid liquid separation; and (x) Precipitating phosphate from liquor produced in step (ix) through the addition of a base.