Cyclic preparation method for producing titanium boride from intermediate feedstock potassium-based titanium-boron-fluorine salt mixture and producing potassium cryolite as byproduct

A cyclic preparation method for producing titanium boride from intermediate feedstock potassium-based titanium-boron-fluorine salt mixture and producing potassium cryolite as byproduct, wherein the method comprises the following steps:

• A) boric acid or boric anhydride is added with hydrofluoric acid to generate fluoroboric acid by reaction at 100-200° C., the fluoroboric acid is then added with potassium sulfate aqueous solution to generate potassium fluoborate precipitates by reaction, and the potassium fluoborate precipitates are centrifuged and bleached to obtain potassium fluoborate;
• titanium-iron concentrate is added with hydrofluoric acid to generate fluotitanic acid by reaction at 100-200° C.;
• the fluotitanic acid is then added with potassium sulfate solution to generate potassium fluotitanate precipitates, and the potassium fluotitanate precipitates are centrifuged and bleached to obtain potassium fluotitanate;
• B) the potassium fluoborate and the potassium fluotitanate are put in a reactor based on a molar ratio of 2:1, inert gas is fed into the reactor after evacuation, the reactor is heated up to 700-800° C. and then added with aluminum, and titanium boride and potassium cryolite are generated by rapid stirring and then reaction for 4-6 hours;
• or aluminum is put in the reactor, inert gas is fed into the reactor after evacuation, the reactor is heated up to 700-800° C. and then added with the potassium-based titanium-boron-fluorine salt mixture of potassium fluoborate and potassium fluotitanate based on a molar ratio of 2:1, and titanium boride and potassium cryolite are generated by rapid stirring and then reaction for 4-6 hours;
• C) the potassium cryolite is sucked out and then fed into a rotary reaction kettle together with concentrated sulfuric acid, hydrogen fluoride gas as well as potassium sulfate and potassium aluminum sulfate are generated by reaction in the rotary reaction kettle, and the hydrogen fluoride gas is collected and then dissolved in water to obtain hydrofluoric acid;
• the solid mixture of potassium sulfate and potassium aluminum sulfate is crushed and then dissolved in water, potassium hydroxide is added for the purpose of reaction, and potassium sulfate aqueous solution is obtained after solid aluminum hydroxide is separated;
• and
• D) the obtained hydrofluoric acid aqueous solution and potassium sulfate aqueous solution are recycled either for leaching titanium-iron concentrate to prepare potassium fluotitanate, or for leaching boric acid or boric anhydride to prepare potassium fluoborate.