Lithium brine is treated with a multiple pass nanofiltration (NF) membrane system. Sulfate is added to permeate from an upstream pass before it flows through a downstream pass. Optionally the sulfate may be added to the permeate by dosing it with sulfuric acid or a slat such as sodium sulfate. The softened brine may then be processed further, for example by a combination of solvent extraction, electrolysis, crystallization and drying, to produce a lithium hydroxide product that can be used to make batteries.

A process and system are disclosed for producing lithium oxide from lithium nitrate. In the process and system, the lithium nitrate is thermally decomposed in a manner such that a fraction of the lithium nitrate forms lithium oxide, and such that a remaining fraction of the lithium nitrate does not decompose to lithium oxide. The thermal decomposition may be terminated after a determined time period to ensure that there is a remaining fraction of lithium nitrate and to thereby produce a lithium oxide in lithium nitrate product. The lithium oxide in lithium nitrate product may have one or more transition-metal oxides, hydroxides, carbonates or nitrates added thereto to form a battery electrode. The lithium oxide in lithium nitrate product may alternatively be subjected to carbothermal reduction to produce lithium metal.

Disclosed herein is a method for recovering water from a salt solution. The method can include mixing the salt solution with a salting out solution that includes at least one enolizable ketone and at least one alcohol. The salting out solution can absorb the water from the salt solution and the water can be released using a regenerant solution. A base solution can also be added to fully regenerate the salting out solution so that it can be reused.

Disclosed herein is a method for recovering water from a salt solution. The method can include mixing the salt solution with a salting out solution that includes at least one enolizable ketone and at least one alcohol. The salting out solution can absorb the water from the salt solution and the water can be released using a regenerant solution. A base solution can also be added to fully regenerate the salting out solution so that it can be reused.

Disclosed herein is a method for recovering water from a salt solution. The method can include mixing the salt solution with a salting out solution that includes at least one enolizable ketone and at least one alcohol. The salting out solution can absorb the water from the salt solution and the water can be released using a regenerant solution. A base solution can also be added to fully regenerate the salting out solution so that it can be reused.

Disclosed herein is a method for recovering water from a salt solution. The method can include mixing the salt solution with a salting out solution that includes at least one enolizable ketone and at least one alcohol. The salting out solution can absorb the water from the salt solution and the water can be released using a regenerant solution. A base solution can also be added to fully regenerate the salting out solution so that it can be reused.

The present invention relates to a salt recovery solution and to a process for separating a salt from an aqueous solution. The present disclosure also relates to a salt recovery solution and to its use to concentrate a salt or brine solution by recovering water therefrom. The salt recovery solution suitable for recovering a salt from an aqueous solution comprises at least one tertiary amine containing compound; and at least one enolisable carbonyl.

The secondary amide contained in the extraction system consists of a single compound or a mixture of two or more compounds, wherein R.sub.1 is selected from a C2˜C12 alkyl, or a C3˜C12 cycloalkyl containing a single-ring structure, R.sub.2 is selected from a C1˜C11 alkyl, or a C3˜C11 cycloalkyl containing a single-ring structure; the total number of carbon atoms in the molecule is 12˜18. With a volume ratio of an organic phase and a brine phase being 1˜10:1, at a brine density of 1.25˜1.38 g/cm.sup.3 and at a temperature of 0˜50° C., a single-stage or multi-stage countercurrent extraction and a stripping are conducted to obtain a water phase with a low magnesium-lithium ratio, which is subjected to concentration, impurity removal and preparation to get lithium chloride, lithium carbonate and lithium hydroxide respectively. Water is used for stripping, greatly reducing the consumption of acid and base, and the separation process is shortened.

The extraction system contains secondary amides and alkyl alcohols which are separately used as the extractants for extracting lithium and boron and consist of a single compound or a mixture of two or more compounds, and the total number of carbon atoms in their molecules are 12˜18 and 8˜20 respectively; the extraction system has a freezing point less than 0° C. With a volume ratio of an organic phase and a brine phase being 1˜10:1, at a brine density of 1.25˜1.38 g/cm.sup.3, at a brine pH value of 0˜7 and at a temperature of 0˜50° C., a single-stage or multi-stage countercurrent extraction and a stripping are conducted to obtain a water phase with a low magnesium-lithium ratio, which is subjected to concentration, impurity removal and preparation to get lithium chloride, lithium carbonate, lithium hydroxide and boric acid respectively. Water is used for stripping, greatly reducing the consumption of acid and base.

Methods, apparatus, and systems for removing salt from brine are provided. A surfactant is mixed with the brines and the brines are atomized to form airborne brine droplets from which the liquid component can be rapidly evaporated. The remaining airborne salt particles are than filtered from the air stream and the water vapor condensed for collection and downstream use or processing.