Disclosed herein is a method for recovering an acid or a base during a metal extraction process. The method comprises contacting a feed stream comprising the acid or base and the metal with an ultrafiltration membrane to produce an ultrafiltration retentate and an ultrafiltration permeate, and contacting the ultrafiltration permeate with a nanofiltration membrane. The nanofiltration retentate produced comprises a majority of the metal from the feed stream, and the nanofiltration permeate produced comprises a majority of the acid or base from the feed stream. Also disclosed herein is a recovery apparatus for recovering an acid or a base during a metal extraction process.

Disclosed herein is apparatus for recovering an acid or a base during a uranium extraction process. The apparatus contacts contacting a feed stream comprising the acid or base and the uranium with an ultrafiltration membrane to produce an ultrafiltration retentate and an ultrafiltration permeate, and contacting the ultrafiltration permeate with a nanofiltration membrane. The nanofiltration retentate produced comprises a majority of the uranium from the feed stream, and the nanofiltration permeate produced comprises a majority of the acid or base from the feed stream.

Disclosed herein is a method for recovering an acid or a base during a metal extraction process. The method comprises contacting a feed stream comprising the acid or base and the metal with an ultrafiltration membrane to produce an ultrafiltration retentate and an ultrafiltration permeate, and contacting the ultrafiltration permeate with a nanofiltration membrane. The nanofiltration retentate produced comprises a majority of the metal from the feed stream, and the nanofiltration permeate produced comprises a majority of the acid or base from the feed stream. Also disclosed herein is a recovery apparatus for recovering an acid or a base during a metal extraction process.

Provided is a process for recovering uranium comprising (a) bringing a solution (I) into contact with a resin (I) to produce a mixture of a solution (II) and a resin (II), wherein the solution (I) is an aqueous solution that comprises 30 to 200 g/L sulfuric acid and that comprises 1 g/L to 50 g/L uranium, and wherein the resin (I) is a strong acid cation exchange resin, and (b) separating the solution (II) from the resin (II).

A method includes contacting a coal feedstock with an acidic solution to form residual coal and a leachate. The method further includes separating the residual coal from the leachate where the leachate contains rare earth elements and where the residual coal has preserved organic content and reduced inorganic content. Another method includes contacting a coal feedstock with a basic solution to form residual coal and a leachate. The method further includes separating the residual coal from the leachate where the leachate contains rare earth elements.

A volume reduction treatment method able to reduce the volume of the final disposal waste of a spent uranium catalyst. As a result, the disposal cost of the spent uranium catalyst is able to be reduced and the utilization of waste repositories are able to be improved.

The present invention relates to a volume reduction treatment method of a spent uranium catalyst. According to the volume reduction treatment method of a spent uranium catalyst of the present invention, the disposal cost of the spent uranium catalyst can be reduced and the utilization of the repository can be improved since the method can significantly reduce the volume of the final disposal waste of the spent uranium catalyst.

Nanofiltration can be used to improve a hydrometallurgical process in which valuable metal is extracted from ore or tailings by leaching with a suitable lixiviant. The process requires at least two nanofiltration subsystems in which raffinate from a solvent extraction process is treated in a nanofiltration subsystem, after which permeate therefrom is combined with a pregnant solution stream and is treated in a second nanofiltration subsystem. This arrangement can lead to advantages in the amount of lixiviant recovered, in the raw materials required, in the effluent produced, in the size of plant, and in overall cost.

A method includes contacting a coal feedstock with an acidic solution to form residual coal and a leachate. The method further includes separating the residual coal from the leachate where the leachate contains rare earth elements and where the residual coal has preserved organic content and reduced inorganic content. Another method includes contacting a coal feedstock with a basic solution to form residual coal and a leachate. The method further includes separating the residual coal from the leachate where the leachate contains rare earth elements and where the residual coal has reduced inorganic content, but preserved organic content.

The invention relates to the use of an organic-inorganic hybrid material, comprising an inorganic solid support on which are grafted organic molecules having the general formula (I) below: ##STR00001##
in which: x, y and z=0 or 1, with at least one of x, y and z different from 0; m=1 to 6; v and w=0 or 1, with v=1 when w=0, and v=0 when w=1; if x=0, R.sup.1H or a saturated or unsaturated, linear or branched, C.sub.1 to C.sub.12 hydrocarbon group, whereas, if x=1, R.sup.1=a group bound to the inorganic solid support by at least one covalent bond; if y=0, R.sup.2H or a saturated or unsaturated, linear or branched, C.sub.1 to C.sub.12 hydrocarbon group, whereas, if y=1, R.sup.2=a group bound to the inorganic solid support by at least one covalent bond; if z=0, R.sup.3H or a saturated or unsaturated, linear or branched, C.sub.1 to C.sub.12 hydrocarbon group, whereas, if z=1, R.sup.3=a group bound to the inorganic solid support by at least one covalent bond; R.sup.4 and R.sup.5H, a saturated or unsaturated, linear or branched, C.sub.2 to C.sub.8 hydrocarbon group, or a monocyclic aromatic group;
for extracting uranium(VI) from a sulfuric acid aqueous solution. The invention also relates to a method that makes it possible to recover the uranium(VI) present in a sulfuric acid aqueous solution, selectively with respect to the other metal cations that may also be present in said solution.