Materials and methods for increasing gold recovery from leachate solutions
The subject invention provides safe, environmentally-friendly compositions and efficient methods for extracting impurities from gold ore. More specifically, the subject invention provides compositions derived from microorganisms for pre-leaching treatments of gold ore, which can be used for reducing carbonaceous material in gold ore.
1 . A method for extracting an impurity from gold ore, the method comprising:
(i) contacting a pre-leaching composition comprising a biosurfactant with a gold ore for a period of time to yield a mixture comprising a treated gold ore and an impurity, wherein the biosurfactant includes a sophorolipid, the sophorolipid including linear sophorolipid and lactonic sophorolipid and the sophorolipid comprises at least 60% linear sophorolipid; and
(ii) separating the impurity and pre-leaching composition containing the gold from the mixture to obtain a reduced-impurity gold-containing material.
2 . The method of claim 1 , wherein the gold ore comprises carbonaceous material.
3 . The method of claim 2 , wherein the carbonaceous material comprises elemental carbon, a hydrocarbon, an organic acid, or any combination thereof.
4 . The method of claim 1 , further comprising crushing, grinding, or pulverizing the gold ore into particles 10 mm or less in diameter prior to step (i).
5 . The method of claim 1 , wherein the pre-leaching composition is in liquid form, and wherein step (ii) comprises stirring, shaking, and/or bubbling the mixture for a time period of about 1 minute to about 48 hours.
6 . The method of claim 1 , wherein the impurity and preleaching composition of step (ii) is present in the liquid phase and the gold ore is removed from the liquid.
7 . The method of claim 6 , wherein the gold ore is in a foam that is formed on the surface of the liquid.
8 . The method of claim 1 , wherein step (ii) comprises a beneficiation process.
9 . The method of claim 8 , wherein the beneficiation process is comminution, scrubbing, washing, screening, flotation, hydrocycloning, or any combination thereof.
10 . The method of claim 9 , wherein a flotation composition comprises a biosurfactant.
11 . The method of claim 1 , further comprising:
(iii) leaching gold from the reduced-impurity gold-containing material.
12 . The method of claim 11 , wherein step (iii) comprises applying a leaching solution to the reduced-impurity gold-containing material, optionally, under agitation for a period of time or about 1 hour to 48 hours, wherein the gold ore is contained within a coordination complex that is removed from the impurity.
13 . The method of claim 12 , wherein the leaching solution comprises a cyanide or a thiosulfate.
14 . The method of claim 1 , wherein the biosurfactant is a yeast culture comprising the sophorolipid.
15 . The method of claim 14 , wherein the yeast culture is a Starmerella sp. and/or a Candida sp. yeast.
16 . The method of claim 1 , wherein the biosurfactant further includes mannosylerythritol lipid, trehalose lipid, rhamnolipid, or any combination thereof.
17 . A method for extracting an impurity from gold ore, the method comprising:
(i) contacting a pre-leaching composition comprising a biosurfactant with a gold ore for a period of time to yield a mixture comprising a treated gold ore and an impurity, wherein the biosurfactant includes a sophorolipid, the sophorolipid including linear sophorolipid and lactonic sophorolipid and the sophorolipid comprises at least 70% linear sophorolipid; and
(ii) separating the impurity and pre-leaching composition containing the gold from the mixture to obtain a reduced-impurity gold-containing material.