Environmentally friendly large-scale preparation method of fluoride nanomaterial

An environmentally friendly large-scale preparation method of fluoride nanomaterial, wherein the fluoride is MF2, REF3 or compound fluoride;

• the compound fluoride is one or more than one of AMF3, AREF4, A2REF5, A3REF6, ARE2F7, A2RE2F8, ARE3F10, ARE7F22, A5RE9F32, MREF5, M2REF7, MRE2F8, MRE4F14 or REOF;
• M is one or more than one of Be, Mg, Ca, Sr, Ba, Zn, Cd or Mn;
• RE is one or more than one of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, Sc, Al, Ga or Bi;
• A is one or more than one of Li, Na, K, Rb or Cs, wherein the method comprises the following specific preparation steps:
• step 1:
• taking oxide, carbonate, basic carbonate or hydroxide containing M and/or RE as raw material;
• adding volatile acid a to the raw material;
• or directly taking volatile acid salt containing M and/or RE as raw material;
• heating to reflux to dissolve the raw material;
• and converting the raw material into water-soluble salt to obtain a water-soluble salt solution b;
• filtering precipitates which may exist in the solution;
• step 2:
• conducting an evaporation process on the water-soluble salt solution b in step 1 to evaporate excess volatile acid a and water which do not participate in the reaction, wherein evaporation temperature is 50-130° C. and relative vacuum is −(0.01-0.09) MPa;
• then, adding oily organic matter c with high boiling point to continue evaporation under reduced pressure;
• replacing the volatile acid bound with M and/or RE, wherein evaporation temperature is 80-160° C. and vacuum is 1-3000 Pa;
• converting all the water-soluble salt b into oil-soluble precursor salt to obtain an oil-soluble salt solution d;
• step 3:
• adding oil-infiltrating fluorine source e to the oil-soluble salt solution d obtained in step 2;
• when the product is compound fluoride, adding an oil-infiltrating compound of A;
• conducting a heating reaction at a temperature not higher than 80° C. to generate nanofluoride;
• then heating and crystallizing the nanofluoride under the protection of inert gas at heating temperature of 180-330° C. and reaction time of 0.5-5 h;
• after cooling, centrifuging and washing the product;
• and separating the product of fluoride nanoparticles from the oily organic matter c with high boiling point;
• step 4:
• collecting the evaporated volatile acid a in step 2 for use in the acid dissolution process of step 1;
• step 5:
• collecting the oily organic matter c with high boiling point in step 3 for use in the reduced pressure evaporation process of step 2.