Method for comprehensive utilization of ulexite ore resources

A method for comprehensive utilization of ulexite ore resources, comprising:

• (S1) pretreating a ulexite ore sample by water washing to obtain a pretreated ore, and performing a first acidolysis on the pretreated ore to obtain a first slurry, wherein the first acidolysis is performed through steps of:
• mixing the pretreated ore with water at a weight ratio of 1:3-7;
• and adding 75-85 wt. % of a total required amount of a nitric acid solution followed by reaction at 70-85° C. for 30-60 min to obtain the first slurry, wherein the nitric acid solution has a weight concentration of 50%;
• (S2) filtering the first slurry via a vacuum filter to obtain a first filtrate and a first filter residue;
• and washing the first filter residue followed by discharge;
• (S3) adding the rest of the total required amount of the nitric acid solution to the first filtrate followed by a second acidolysis to obtain a second slurry;
• and cooling the second slurry to 10-30° C. to perform crystallization of boric acid;
• (S4) filtering a cooled slurry obtained in step (S3) to obtain a boric acid crystal and a second filtrate;
• and washing and drying the boric acid crystal to obtain a boric acid product;
• (S5) reacting the second filtrate with a decalcifying agent followed by filtration to obtain a third filtrate and a second filter residue, wherein under a first reaction condition, the second filter residue is a calcium sulfate dihydrate whisker, and under a second reaction condition, the second filter residue is a calcium sulfate hemihydrate whisker;
• (S6) determining a Mg2+ concentration and a Na+ concentration in the third filtrate;
• when the Mg2+ concentration reaches 35 g/L or the Na+ concentration reaches 40 g/L, concentrating the third filtrate, followed by cooling crystallization and filtration to obtain a third filter residue and a fourth filtrate, wherein the third filter residue is a mixture product predominated by sodium nitrate;
• (S7) discharging the mixture product obtained in step (S6) to prepare a sodium nitrate product;
• (S8) when the Na+ concentration and the Mg2+ concentration in the third filtrate in step (S5) are respectively less than 40 g/L and 35 g/L, proceeding step (S9);
• and
• (S9) repeating steps (S1-S8) to complete treatment of a next ulexite ore sample, wherein in step (S1), before addition of nitric acid, the third filtrate serves as a circulating mother liquor to replace water to be mixed with a pretreated product of the next ulexite ore sample ore in a weight ratio of 1:3-8.