Method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material

A method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material, wherein the method comprises the following steps:

• a:
• Mix and leach a lithium extraction acid clinker of spodumene with water to obtain a leached pulp;
• b:
• Filter the leached pulp from step a to obtain a filtrate and a filter residue, wash the filter residue with water to obtain a washing liquid and a filter residue 1, and combine the washing liquid with the filtrate to obtain ta filtrate 1;
• c:
• Neutralize the filtrate 1 from step b to obtain a neutralized pulp;
• d:
• Filter the neutralized pulp from step c to obtain a second filtrate and a second filter residue, wash the second filter residue with water to obtain a second washing liquid and a high purity gypsum, combine the second washing liquid with the second filtrate to obtain a filtrate 2, and extract lithium from the filtrate 2 to obtain lithium salt;
• e:
• Neutralize and mix the filter residue 1 from step b to obtain coarse and fine particles by classification;
• f:
• Grind the coarse particles from step e until at least 70 wt % of the ground particles passes 325 mesh;
• g:
• Perform a weak magnetic separation at a magnetic field intensity of 0.05-0.5 Tesla on of the fine particles from step e to obtain a lithium rich iron material 1 and a non-magnetic material;
• h:
• Perform a strong magnetic separation at a magnetic field intensity of 1.0-1.7 Tesla on the non-magnetic material from step g to obtain low iron and low sulfur silicon aluminum micro-powder and a weak magnetic material;
• i:
• Perform gravity separation on the weak magnetic material from step h to obtain a lithium rich iron material 2 and a tantalum niobium crude concentrate;
• and
• j:
• Pickle the tantalum niobium crude concentrate from step i with an acid to obtain a tantalum niobium concentrate.