GB684572A - Improvements in or relating to preparation of boron - Google Patents

Abstract

684,572. Electro-deposition of boron. WEIL, W. M. Sept. 29, 1950 [Oct. 8, 1949]. No. 23862/50. Class 41. In a process of preparing boron electrolytically a fused bath of potassium chloride and potassium fluoborate is employed, the bath being electrolysed to deposit boron on the cathode and release chlorine at the anode. During electrolysis the mixture is maintained at a temperature within the range of 650‹ to 1000‹ C., preferably 800‹ to 850‹ C. The components of the mixture are replaced as the process continues. It is preferable that the potassium chloride be present in greater amount than the potassium fluoborate. The cathode is eventually withdrawn from the bath, and it may be quickly covered with dry sodium chloride to prevent oxidation, and allowed to cool somewhat. The cathode is then immersed in water for several hours, whereby the boron can be readily removed. The boron is treated with water, then with strong hydrochloric acid, and finally washed with water, dried and sifted. The cell for use in the process may include an externally-heated crucible of graphite or similar electrically-conductive refractory material, protected by an outer shell of high-heat-resistant metal, such as the alloy known under the Registered Trade Mark " Inconel." Heating of the contents may be carried out by electric induction or electrical resistance heating in the bath itself. The crucible forms the anode of the cell.