Purified potassium hexafluoromanganate and methods for purifying potassium hexafluoromanganate
A potassium hexafluoromanganate (K2MnF6) composition includes no more than six parts per million of each of one or more Group 13 elements, no more than 520 parts per million of one or more alkaline earth metals, no more than fourteen parts per million of one or more transition metals, and/or no more than forty parts per million of calcium. A method for providing this composition, as well as lighting apparatuses, backlight units, and electronic devices including phosphors formed from the composition also are provided.
1. A method comprising:
obtaining a first solution comprising potassium hexafluoromanganate (K 2 MnF 6 ) and one or more impurities, wherein the first solution is prepared at an elevated temperature in a range of between sixty-five and seventy-five degrees Celsius;
filtering the first solution of the potassium hexafluoromanganate and the one or more impurities to form a filtrate; and
separating the potassium hexafluoromanganate from the one or more impurities by crystallizing the filtrate, wherein separating the potassium hexafluoromanganate from the one or more impurities comprises crystallizing the filtrate by:
adding a potassium containing solution to the filtrate to form a second solution; and
cooling the second solution by exposing the second solution to a temperature less than the elevated temperature;
and
wherein the crystallized filtrate of potassium hexafluoromanganate has no more than forty parts per million of calcium.
2. The method of claim 1 , wherein filtering the first solution of the potassium hexafluoromanganate and the one or more impurities includes vacuum filtering the first solution through one or more filter bodies to form the filtrate.
3. The method of claim 1 , wherein obtaining the first solution includes dissolving the potassium hexafluoromanganate and the one or more impurities into hydrofluoric acid.