Can lithium sulfate be used as lithium carbonate?

Lithium sulphate is a chemical with the molecular formula Li2SO4 and a molecular weight of 109.94.

The appearance is colorless monoclinic crystal or white crystalline powder, soluble in water.

The water solubility at 25 degrees is 25.7%;

Lithium carbonate is an inorganic compound with the chemical formula Li2CO3 and a molecular weight of 73.89. 

It is a colorless monoclinic crystal that is slightly soluble in water and dilute acid.

Lithium carbonate and lithium sulfate have obvious differences in many aspects: solubility: 

lithium sulfate has a significantly higher solubility in water than lithium carbonate, 

so lithium sulfate is more likely to be ionized into lithium ions in aqueous solution.

The solubility of lithium carbonate is relatively low, and it needs special treatment to convert into lithium ions.

Uses: Lithium sulfate is usually used as an electrolyte in batteries, 

while lithium carbonate is commonly used in the preparation of cathode materials for lithium-ion batteries, 

such as lithium iron phosphate cathode materials.Energy density and lifetime: 

Lithium sulfur batteries have higher energy density and longer lifetime, 

while lithium carbonate batteries are slightly inferior in these two aspects.

Lithium sulfate can be used to make lithium carbonate.Generally, the following methods are adopted:

1.Evaporation and concentration: First, by evaporating and concentrating the lithium sulfate solution,

a solution containing lithium element is obtained.

Sodium carbonate is added, and then sodium carbonate is added to the above solution containing 

lithium element to promote the conversion of lithium.

Chemical conversion:

Under the reaction conditions of adding sodium carbonate,

lithium sulfate reacts chemically with sodium carbonate to produce lithium carbonate precipitate.

Li2SO4+Na2CO3=Na2SO4+Li2CO3↓

This reaction is a double ion exchange reaction in which sulfate ions (SO42-) 

are exchanged for carbonate ions (CO32-) to produce new sodium sulfate and lithium carbonate.

2. Lithium carbonate crystals are obtained after filtration, washing, and drying.

Lithium sulfate is generally extracted from spodumene, lepidolite, and salt lake brine, and cannot be naturally generated.

At present, there are two main methods for preparing high-purity anhydrous lithium sulfate at home and abroad: direct method, 

which uses industrial lithium sulfate crystals for recrystallization purification. 

This method is simple in preparation process, but during the crystallization process, phosphate, chloride, etc. 

in industrial-grade lithium sulfate crystals will also crystallize out along with the lithium sulfate crystals, 

making it difficult to prepare high-purity lithium sulfate crystals.

The indirect method uses industrial-grade lithium carbonate as the raw material, 

and utilizes the property of lithium carbonate being difficult to dissolve in water to wash away water-soluble impurities such as phosphate, 

and then reacts with sulfuric acid to produce high-purity lithium sulfate.

Lithium sulfate is expensive for several reasons: its purity is very high, with a content of over 99%, 

which can meet the needs of industrial production.Lithium sulfate is widely used in the production of ceramics, glass, 

lithium batteries and other products, with a large market demand and high production costs.

Although lithium carbonate can be produced from lithium sulfate, due to the cost of lithium sulfate, 

it is generally not used to produce lithium carbonate.