The disclosure relates to a method for producing hydrogen gas and/or magnetite comprising the steps of reacting a wüstite-containing material, such as steel slags, with H.sub.2O at a temperature ranging from 150° C. to 500° C., cooling down the gaseous reaction product to separate hydrogen gas from water steam and collecting hydrogen gas, and recovering magnetite from the solid reaction product.

A system and method for the simultaneous sequestration of CO2, production of hydrogen, and production of electricity at any iron and steel industries is described. In one illustrative example, the raw materials particularly used in a blast furnace can also be used for locking CO2 gas in the form of siderite. Siderite, thus formed, can be decomposed to generate pure CO2 gas. Eventually, the generated pure CO2 gas can be sequestered underground, sold or used for oil gas recovery or for other applications.

A system and method for the simultaneous sequestration of CO2, production of hydrogen, and production of electricity at any iron and steel industries is described. In one illustrative example, the raw materials particularly used in a blast furnace can also be used for locking CO2 gas in the form of siderite. Siderite, thus formed, can be decomposed to generate pure CO2 gas. Eventually, the generated pure CO2 gas can be sequestered underground, sold or used for oil gas recovery or for other applications.

Embodiments herein relate to the production of biocompatible magnetic nanoparticles with a high SAR-value which produce a large amount of heat when exposed to an alternating magnetic field. The produced heat can be used among others for therapeutic purposes, in particular for combating cancer.

Embodiments herein relate to the production of biocompatible magnetic nanoparticles with a high SAR-value which produce a large amount of heat when exposed to an alternating magnetic field. The produced heat can be used among others for therapeutic purposes, in particular for combating cancer.

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 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 method of recovering magnetite from bauxite residue, comprising reducing the pH of the bauxite residue to form a treated bauxite residue, drying the treated bauxite residue, adding to and mixing into the treated bauxite residue a solid source of carbon, to create a mixture, heating the mixture to a reduction temperature of at least 800° C. in a reducing reactor to produce a reduced bauxite residue in which a major portion of Fe.sub.2O.sub.3 present in the treated bauxite residue has been converted to Fe.sub.3O.sub.4, exposing the reduced bauxite residue to a particle separation step, and then separating the reduced bauxite residue into an iron-enriched portion and an iron-depleted portion.

A method of recovering magnetite from bauxite residue, comprising reducing the pH of the bauxite residue to form a treated bauxite residue, drying the treated bauxite residue, adding to and mixing into the treated bauxite residue a solid source of carbon, to create a mixture, heating the mixture to a reduction temperature of at least 800° C. in a reducing reactor to produce a reduced bauxite residue in which a major portion of Fe.sub.2O.sub.3 present in the treated bauxite residue has been converted to Fe.sub.3O.sub.4, exposing the reduced bauxite residue to a particle separation step, and then separating the reduced bauxite residue into an iron-enriched portion and an iron-depleted portion.

The present invention disclosed use of lactam as a solvent in the preparation of nanomaterials by precipitation method, sol-gel method or high temperature pyrolysis. These methods are able to recycle lactam solvent, which meet requirements of environmental protection.