Processes for producing lithium compounds using forward osmosis

Abstract

Systems, methods and apparatuses to concentrate lithium containing solutions using forward osmosis units are provided, which, for example, can include providing at least one forward osmosis unit having at least one lithium containing solution chamber having at least one first inlet and at least one first outlet, at least one brine chamber having at least one second inlet and at least one second outlet, and at least one selectively permeable membrane positioned between the at least one lithium containing solution chamber and the at least one brine chamber, and conveying a lithium containing solution through the at least one lithium containing solution chamber and a concentrated brine solution through the at least one brine chamber, said conveying causing water from the lithium containing solution to be drawn through the at least one selectively permeable membrane and into the concentrated brine solution, such that a concentrated lithium containing solution exits through the first outlet and a less concentrated brine solution exits through the second outlet.

1 - 6 . (canceled) 
     
     
         7 . A method of increasing lithium concentration in a lithium containing solution, the method comprising:
 providing a lithium containing solution comprising lithium, silica, and divalent ions;   providing a brine solution;   processing the lithium containing solution in a silica management process to remove silica;   providing at least one forward osmosis unit having:
 at least one lithium containing solution chamber having at least one first inlet and at least one first outlet; 
 at least one brine chamber having at least one second inlet and at least one second outlet; and 
 at least one selectively permeable membrane positioned between the at least one lithium containing solution chamber and the at least one brine chamber; 
   conveying the lithium containing solution through the at least one lithium containing solution chamber to concentrate the lithium containing solution;   conveying the brine solution is through the at least one brine chamber,   wherein water from the lithium containing solution is drawn through the at least one selectively permeable membrane and into the brine solution, such that a concentrated lithium containing solution exits through the first outlet and a less concentrated brine solution exits through the second outlet; and   extracting lithium from the concentrated lithium containing solution in a lithium capture step to obtain a lithium rich stream.   
     
     
         8 . The method of  claim 7 , wherein an amount of silica in the lithium containing solution after the silica management process is less than about 150 ppm. 
     
     
         9 . The method of  claim 7 , wherein the lithium capture step comprises contacting the concentrated lithium containing solution with a sorbent. 
     
     
         10 . The method of  claim 9 , wherein a portion of eluate obtained from the sorbent is recycled to the sorbent to increase a ratio of lithium to sodium in the lithium rich stream. 
     
     
         11 . The method of  claim 7 , wherein the concentrated lithium containing solution exiting the at least one first outlet has a concentration of lithium chloride of at least about 15 weight % based on the total weight of the concentrated lithium containing solution. 
     
     
         12 . The method of  claim 7 , further comprising the step of supplying the less concentrated brine solution exiting the at least one second outlet to a recycling unit. 
     
     
         13 . The method of  claim 7 , further comprising recovering lithium from the lithium capture step to produce the lithium rich stream. 
     
     
         14 . The method of  claim 7 , further comprising purifying the lithium rich stream to remove divalent ions and borate ions. 
     
     
         15 . The method of  claim 7 , further comprising concentrating the lithium rich stream to produce a twice concentrated lithium rich stream. 
     
     
         16 . The method of  claim 15 , further comprising purifying the twice concentrated lithium rich stream by removing sodium and potassium ions to produce a concentrated lithium rich solution having reduced sodium and potassium ion concentrations.