Methods for extracting lithium from brines

A method comprising:

• determining a number of one or more solar evaporation ponds;
• an amount of a first precipitation additive comprising soda ash, slaked lime, or a combination thereof;
• and an amount of a second precipitation additive comprising soda ash, by using a geochemical prediction model given an initial composition of a brine;
• evaporating at least a portion of the brine using the number of one or more solar evaporation ponds to form a first slurry;
• wherein a concentration of magnesium in the brine is about 100 ppm to about 50,000 ppm and a concentration of lithium in the brine is about 0.01 ppm to about 5,000 ppm;
• separating a first liquid from the first slurry;
• combining the first liquid with the amount of the first precipitation additive to form a second slurry comprising magnesium hydroxide, magnesium carbonate, or a combination thereof;
• separating a second liquid from the second slurry;
• evaporating at least a portion of the second liquid in a solar evaporation pond to form a third slurry;
• separating a third liquid from the third slurry;
• combining the third liquid with the amount of the second precipitation additive to form a fourth slurry comprising lithium carbonate;
• separating a first solid from the fourth slurry;
• rehydrating the first solid to form a fifth slurry;
• and
• separating a solid product from the fifth slurry, wherein about 90 wt % or more of a salt in the solid product is lithium carbonate.

A method comprising:

• determining a number of one or more solar evaporation ponds;
• an amount of a first precipitation additive comprising soda ash, slaked lime, or a combination thereof;
• and an amount of a second precipitation additive comprising soda ash, by using a geochemical prediction model given an initial composition of a brine;
• evaporating at least a portion of the brine using the number of one or more solar evaporation ponds to form a first slurry;
• wherein a concentration of magnesium in the brine is about 100 ppm to about 50,000 ppm and a concentration of lithium in the brine is about 0.01 ppm to about 5,000 ppm;
• separating a first liquid from the first slurry;
• combining the first liquid with the amount of the first precipitation additive to form a second slurry comprising magnesium hydroxide, magnesium carbonate, or a combination thereof;
• separating a second liquid from the second slurry;
• combining the second liquid with the amount of the second precipitation additive comprising soda ash to form a third slurry comprising lithium carbonate;
• separating a first solid from the third slurry;
• rehydrating the first solid to form a fourth slurry;
• and
• separating a solid product from the fourth slurry, wherein about 90 wt % or more of a salt in the solid product is lithium carbonate.