The invention provides a process for exfoliating a 3-dimensional layered material to produce a 2-dimensional material, said process comprising the steps of mixing the layered material in a solvent to provide a mixture; applying energy, for example ultrasound, to said mixture, and removing the energy applied to the mixture, such that sedimentation of the 2-dimensional material out of solution as a weakly re-aggregated, exfoliated 2-dimensional material is produced. The invention provides a fast, simple and high yielding process for separating 3-dimensional layered materials into individual 2-dimensional layers or flakes, which do not strongly re-aggregate, without utilising hazardous solvents.

The present disclosure relates to hydrometallurgical methods for the isolation and recovery of platinum from rhenium-containing materials, and more particularly, from superalloys containing rhenium, platinum, and other metals. The disclosure also relates to apparatuses capable of carrying out the hydrometallurgical methods and the product streams generated from the methods and apparatuses.

A method allowing production of high-purity perrhenic acid from rhenium sulfide by applying pyrometallurgical process is provided. A method for producing an aqueous solution of perrhenic acid, comprising: 1) a step for performing a first roasting process of rhenium sulfide under an oxygen-containing gas to generate rhenium oxide and sulfur oxide, the sulfur oxide being gasified for discharge and the rhenium oxide being obtained as a roasted residue; 2) a step for performing a second roasting process of the roasted residue under an oxygen-containing gas to collect gasified rhenium oxide; 3) a step for cooling and solidifying the gasified rhenium oxide, or a step for dissolving the gasified rhenium oxide into water while water-cooling to obtain the aqueous solution of perrhenic acid; and 4) in case where the rhenium oxide is solidified, a step for dissolving the solidified rhenium oxide into water, or heating and gasifying the solidified rhenium oxide and then dissolving the gasified rhenium oxide into water, to obtain the aqueous solution of perrhenic acid.

A method allowing production of high-purity perrhenic acid from rhenium sulfide by applying pyrometallurgical process is provided. A method for producing an aqueous solution of perrhenic acid, comprising: 1) a step for performing a first roasting process of rhenium sulfide under an oxygen-containing gas to generate rhenium oxide and sulfur oxide, the sulfur oxide being gasified for discharge and the rhenium oxide being obtained as a roasted residue; 2) a step for performing a second roasting process of the roasted residue under an oxygen-containing gas to collect gasified rhenium oxide; 3) a step for cooling and solidifying the gasified rhenium oxide, or a step for dissolving the gasified rhenium oxide into water while water-cooling to obtain the aqueous solution of perrhenic acid; and 4) in case where the rhenium oxide is solidified, a step for dissolving the solidified rhenium oxide into water, or heating and gasifying the solidified rhenium oxide and then dissolving the gasified rhenium oxide into water, to obtain the aqueous solution of perrhenic acid.

A method for allowing production of high-purity perrhenic acid from crude rhenium sulfide by applying a dry process is provided. A method for producing an aqueous solution of perrhenic acid includes 1) a step for roasting rhenium sulfide under an oxygen-containing gas to collect gasified rhenium oxide; 2) a step for cooling and solidifying the gasified rhenium oxide while keeping sulfur oxide entrained in the gasified rhenium oxide a gaseous state, and subsequently performing solid-gas separation, thereby improving purity of rhenium oxide; and 3) a step for dissolving the solidified rhenium oxide into water, or heating and gasifying the solidified rhenium oxide and then dissolving the gasified rhenium oxide into water, to obtain the aqueous solution of perrhenic acid.

A method for allowing production of high-purity perrhenic acid from crude rhenium sulfide by applying a dry process is provided. A method for producing an aqueous solution of perrhenic acid includes 1) a step for roasting rhenium sulfide under an oxygen-containing gas to collect gasified rhenium oxide; 2) a step for cooling and solidifying the gasified rhenium oxide while keeping sulfur oxide entrained in the gasified rhenium oxide a gaseous state, and subsequently performing solid-gas separation, thereby improving purity of rhenium oxide; and 3) a step for dissolving the solidified rhenium oxide into water, or heating and gasifying the solidified rhenium oxide and then dissolving the gasified rhenium oxide into water, to obtain the aqueous solution of perrhenic acid.

A method for separating an amount of osmium from a mixture containing the osmium and at least one other additional metal is provided. In particular, method for forming and trapping OsO.sub.4 to separate the osmium from a mixture containing the osmium and at least one other additional metal is provided.

A method for separating an amount of osmium from a mixture containing the osmium and at least one other additional metal is provided. In particular, method for forming and trapping OsO.sub.4 to separate the osmium from a mixture containing the osmium and at least one other additional metal is provided.

A one-step salt-assisted general synthetic methodology for the controlled phase transformation of various types of 2H-phase transition metal dichalcogenides (2H-TMDs), yielding large-scale metastable 1T-phase transition metal dichalcogenides (1T-TMDs), including WS.sub.2, WSe.sub.2, MoS.sub.2, and MoSe.sub.2 is described. By tuning the reaction conditions, alloyed 1T-TMDs such as WS.sub.2xSe.sub.2(1x) and MoS.sub.2xSe.sub.2(1x) are also obtained. Commercially-available metal salts such as K.sub.2C.sub.2O.sub.4.Math.H.sub.2O, Na.sub.2C.sub.2O.sub.4, K.sub.2CO.sub.3, Na.sub.2CO.sub.3, Cs.sub.2CO.sub.3, Rb.sub.2CO.sub.3, KHCO.sub.3, and NaHCO.sub.3, are demonstrated to be effective for the controlled phase transformation at elevated temperatures in a reducing atmosphere. The technique may be extended to the phase engineering of other materials with various polymorphs.

A one-step salt-assisted general synthetic methodology for the controlled phase transformation of various types of 2H-phase transition metal dichalcogenides (2H-TMDs), yielding large-scale metastable 1T-phase transition metal dichalcogenides (1T-TMDs), including WS.sub.2, WSe.sub.2, MoS.sub.2, and MoSe.sub.2 is described. By tuning the reaction conditions, alloyed 1T-TMDs such as WS.sub.2xSe.sub.2(1x) and MoS.sub.2xSe.sub.2(1x) are also obtained. Commercially-available metal salts such as K.sub.2C.sub.2O.sub.4.Math.H.sub.2O, Na.sub.2C.sub.2O.sub.4, K.sub.2CO.sub.3, Na.sub.2CO.sub.3, Cs.sub.2CO.sub.3, Rb.sub.2CO.sub.3, KHCO.sub.3, and NaHCO.sub.3, are demonstrated to be effective for the controlled phase transformation at elevated temperatures in a reducing atmosphere. The technique may be extended to the phase engineering of other materials with various polymorphs.