Systems and Methods for Recovering Lithium from Brines Field

Abstract

Systems and methods using solar evaporation to preconcentrate lithium containing brines to at or near lithium saturation, followed by a separation processes to separate lithium from impurities. A separated impurity stream is recycled to a point in the evaporation sequence where conditions are favorable for their precipitation and removal or disposed in a separate evaporation pond or reinjected underground, while a lower impurity stream is transferred to one or more of the removal location, to a subsequent pond in the sequence, or to a lithium plant or concentration facility. Further concentration of lithium by evaporation can then take place because impurities are removed thus eliminating lithium losses due to co-precipitation and achieving significantly higher concentrations of lithium.

1 . A system for efficiently extracting lithium from brines allowing significantly higher lithium recovery, concentration, and production capacity from the same ponds, the method comprising:
 one or more solar evaporation ponds configured to allow evaporation of brine to occur in each pond and for brine to flow from a first pond to one or more other ponds, or to a process plant for lithium separation;   a conduit configured to remove at least a portion of the brine at a brine removal location at one or more of the ponds and transmit the removed brine to a separator whereby one or more impurities are separated from lithium to form a high impurity stream and a low impurity stream;   wherein the high impurity stream is optionally recycled to the one or more of the evaporation ponds at a location the same as, upstream from the brine removal location, or disposed in a separate pond or reinjected underground, and the low impurity stream is fed to one or more of the ponds, or to a lithium separation plant, or to a concentration facility.   
     
     
         2 . The system according to  claim 1 , wherein the high impurity stream is recycled to a pond precipitating a salt selected from the group consisting of bischofite, calcium borate, anhydrite, gypsum, carnallite, epsomite, anhydrite, kainite, Glauber's salt, halite, sylvite, sylvinite, schoenite, polyhalite, calcium borate, hexahydrite, kieserite, or others. 
     
     
         3 . The system according to  claim 1 , wherein the low impurity stream is fed to a pond that is substantially free of co-precipitated Li in the form of lithium carnallite, lithium metaborate, lithium sulfate, lithium sulfate monohydrate, lithium potassium double salt, lithium schoenite, or others. 
     
     
         4 . The system according to  claim 1 , wherein the portion of brine removed at the brine removal location comprises preferably 1% to 100%, 5% to 100%, 25% to 100%, or 50% to 100% of the total brine flow in the ponds. 
     
     
         5 . The system according to  claim 1 , wherein the increase in lithium recovery is from about 10 to about 80% (absolute units). 
     
     
         6 . The system according to  claim 1 , wherein the separator is configured to at least partially separate lithium from impurity cations and anions which have a propensity to form lithium salts that can precipitate under further brine concentration, and which impurity cations and anions are suitable for earlier precipitation with each other in a preceding evaporation pond. 
     
     
         7 . The system according to  claim 1 , wherein the separator is a separation selected from the group consisting of a selective ion separation membrane, nanofiltration, ion sorption, ion exchange, solvent extraction, solvent absorption, dialysis, and electrodialysis, or other. 
     
     
         8 . The system according to  claim 1 , comprising recycle of the high impurity stream to a point in one or more preceding evaporation ponds where conditions are favorable for precipitation and thus removal of one or more impurity ions without lithium co-precipitation. 
     
     
         9 . The system according to  claim 1 , configured to advance the low impurity stream to a downstream pond, mechanical evaporator, or precipitation plant for further concentration or processing to lithium products. 
     
     
         10 . The system according to  claim 9 , wherein the further concentration in the downstream pond, mechanical evaporator or precipitation plant occurs substantially without lithium co-precipitation and associated lithium loss. 
     
     
         11 . The system according to  claim 1 , wherein the system is configured to achieve a lithium concentration increase from about 10% to about 1,000%. 
     
     
         12 . The system according to  claim 1 , where the high impurity stream is fully or partially evaporated in a separate pond or re-injected underground. 
     
     
         13 . The system according to  claim 1 , where the low impurity stream is fully or partially evaporated in a separate pond. 
     
     
         14 . The system according to  claim 1 , wherein the precipitated salts are harvested and processed separately or with the clean concentrated lithium brine in a processing plant. 
     
     
         15 . The system according to  claim 1 , further comprising:
 a chloride (Cl − )-sulfate (SO 4   2− ) separator configured to separate chloride from sulfate.   
     
     
         16 . The system according to  claim 1 , wherein the lithium concentration is increased to the maximum determined by LiCl solubility limit, which is around 60,000-67,000 ppm Li in solution. 
     
     
         17 . The system according to  claim 1 , wherein the lithium concentration is increased 10 to 1,000 fold, or 10 to 500 fold, or 10 to 100 fold. 
     
     
         18 . The system according to  claim 1 , wherein operation of a LiTAS™ separator in a moderate recovery mode results in reduction of size of the separation equipment, thereby reducing the capital cost of separation equipment per ton of lithium processed by 30-70%, or by 40-60%. 
     
     
         19 . The system according to  claim 1 , wherein operation of the LiTAS™ separator in a moderate recovery mode reduces flow through the separation equipment, thereby reducing the operating cost of separation equipment per ton of lithium processed by 20-60%, or by 30-50%. 
     
     
         20 . The system according to  claim 1 , wherein the system results in high concentration brines, reducing flows through the processing plant thereby also reducing processing plant capital costs by 30-70%, or 40-60%. 
     
     
         21 . The system according to  claim 1 , wherein the system results in low impurity brines, reducing reagent requirements for impurity removal through the processing plant thereby also reducing processing plant capital costs by 30-70%, or by 40-60%. 
     
     
         22 . The system according to  claim 1 , wherein the system results in high concentration brines, which increase processing plant per pass recovery by 30-60% as the mother liquor concentration is fixed, or by 10-30% as the mother liquor concentration is fixed. 
     
     
         23 . The system according to  claim 1 , wherein for brownfield operation with existing ponds, production capacity from the same ponds can be increased by 2-fold to 50-fold by treating low concentration feed brines, or by 3-fold to 20-fold with by treating medium concentration feed brines. 
     
     
         24 . The system according to  claim 1 , wherein for brownfield operation with existing ponds, production capacity from the same ponds can be increased by 4-fold to 10-fold by treating high concentration feed brines. 
     
     
         25 . The system according to  claim 1 , wherein for greenfield operation, same production can be maintained by treating low concentration feed brines with 2-50% of the pond area otherwise required to reach LiCl saturation concentration, or by treating medium concentration feed brines with 5-35% of the pond area otherwise required to reach LiCl saturation concentration. 
     
     
         26 . The system according to  claim 1 , wherein for greenfield operation, same production can be maintained by treating high concentration feed brines with 10-25% of the pond area otherwise required to reach LiCl saturation concentration. 
     
     
         27 . A method for improving efficiency in extracting lithium from brines using one or more solar evaporation ponds, the method comprising:
 separating at least a portion of the brine at a brine removal location to obtain a removed brine;   transmitting the removed brine through a separator such that one or more impurities are separated from lithium to form a high impurity stream (i.e., the impure stream) and a low impurity stream (i.e., the pure stream);   recycling at least a portion of the high impurity stream to the one or more evaporation ponds at a location the same as or upstream from the brine removal location; or   evaporating the high impurity stream, fully or partially, in a separate pond; or   re-injecting the high impurity stream underground; and   transferring the low impurity stream to one or more of the removal locations, to another pond, or to a lithium separation plant, or to a concentration facility.   
     
     
         28 . The method according to  claim 27 , comprising further concentrating the low impurity stream by natural solar pond evaporation or forced mechanical-thermal evaporation, membrane distillation or other methods. 
     
     
         29 . The method according to  claim 27 , wherein the separator comprises a selective monovalent-multivalent or monovalent-monovalent ion separation. 
     
     
         30 . The method according to  claim 27 , wherein a lithium concentration is attained in an amount of an increase from about 10% to about 1,000%. 
     
     
         31 . The method according to  claim 27 , further comprising:
 providing a chloride (Cl − )-sulfate (SO 4   2− ) separator for separating chloride from sulfate.   
     
     
         32 . The method according to  claim 27 , wherein the precipitated salts are harvested and processed separately or with the clean concentrated lithium brine in a processing plant. 
     
     
         33 . The method according to  claim 27 , wherein the method is applicable to any salt lake, surface water, continental underground brines, geothermal brines, or other brine sources. 
     
     
         34 . The method according to  claim 27 , wherein the method is applicable to brine concentrations of 10 ppm or higher, preferably 50 ppm or higher, and more preferably 100 ppm or higher.