Methods and systems for production of lithium hydroxide and lithium carbonate are described. One or more embodiments of the method include producing lithium hydroxide from potassium chloride, lithium chloride, and water. One or more embodiments of the method include producing lithium carbonate from potassium chloride, lithium chloride, water, and a carbon dioxide source. One or more embodiments of the method include producing lithium carbonate from sodium chloride, lithium chloride, water, and a carbon dioxide source.

Methods and systems for production of lithium hydroxide and lithium carbonate are described. One or more embodiments of the method include producing lithium hydroxide from potassium chloride, lithium chloride, and water. One or more embodiments of the method include producing lithium carbonate from potassium chloride, lithium chloride, water, and a carbon dioxide source. One or more embodiments of the method include producing lithium carbonate from sodium chloride, lithium chloride, water, and a carbon dioxide source.

Disclosed are thermal energy storage systems and methods that utilize metal carbonate eutectics that can undergo high temperature reversible reactions to form mixtures of metal oxides. The metal oxides undergo an exothermic reaction with carbon dioxide to form the molten metal carbonate eutectics, and the molten metal carbonate eutectics undergo an endothermic decarbonization reaction to form the metal oxides and carbon dioxide. By carrying out the reversible reactions at a temperature above the melting point of the carbonate eutectic, the systems provide high thermal conductivity and reversible stability for thermal energy storage.

Disclosed are thermal energy storage systems and methods that utilize metal carbonate eutectics that can undergo high temperature reversible reactions to form mixtures of metal oxides. The metal oxides undergo an exothermic reaction with carbon dioxide to form the molten metal carbonate eutectics, and the molten metal carbonate eutectics undergo an endothermic decarbonization reaction to form the metal oxides and carbon dioxide. By carrying out the reversible reactions at a temperature above the melting point of the carbonate eutectic, the systems provide high thermal conductivity and reversible stability for thermal energy storage.

A method is disclosed for concentrating and purifying an eluate brine and producing a purified lithium compound. An extraction eluate, rich in lithium, is directed to a nanofiltration unit or a softening process that removes sulfate and/or calcium and magnesium. Permeate from the nanofiltration unit or the effluent from the softening process is directed through an electrodialysis unit. As the lithium-rich solution moves through the electrodialysis unit, lithium, sodium and chloride ions pass from the solution through a cation-transfer membrane and an anion-transfer membrane to concentrate compartments. A dilute stream is directed through the concentrate compartments and collects the lithium, sodium and chloride ions. The electrodialysis unit also produces a product stream which contains non-ionized impurities, such as silica and/or boron. Concentrate from the electrodialysis unit is subject to a precipitation process that produces a lithium compound that is subsequently subjected to a purification process.

A method is disclosed for concentrating and purifying an eluate brine and producing a purified lithium compound. An extraction eluate, rich in lithium, is directed to a nanofiltration unit or a softening process that removes sulfate and/or calcium and magnesium. Permeate from the nanofiltration unit or the effluent from the softening process is directed through an electrodialysis unit. As the lithium-rich solution moves through the electrodialysis unit, lithium, sodium and chloride ions pass from the solution through a cation-transfer membrane and an anion-transfer membrane to concentrate compartments. A dilute stream is directed through the concentrate compartments and collects the lithium, sodium and chloride ions. The electrodialysis unit also produces a product stream which contains non-ionized impurities, such as silica and/or boron. Concentrate from the electrodialysis unit is subject to a precipitation process that produces a lithium compound that is subsequently subjected to a purification process.

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 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.

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.