Abstract: A method for growing bulk boron arsenide (BA) crystals, the method comprising utilizing a seeded chemical vapor transport (CVT) growth mechanism to produce single BAs crystals which are used for further CVT growth, wherein a sparsity of nucleation centers is controlled during the further CVT growth. Also disclosed are bulk BAs crystals produced via the method.

Abstract: A method for purification of a sulfuric acid solution such as, for example, a copper electrolyte which entrains at least one metal ion species selected from the group consisting of antimony ions, bismuth ions, and iron ions and having a sulfuric acid concentration of at least 50 g/liter is disclosed. The method comprises exposing the sulfuric acid solution to a chelating resin possessing aminomethylenephosphonic acid group as a chelate forming group thereby effecting adsorptive separation of the aforementioned at least one metal ion species from the solution. By the method described above, the antimony ions, bismuth ions, and/or iron ions contained as impurities in the copper electrolyte can be easily and efficiently separated out of the system without entailing any ecological problem.