Techno-Economic Analysis of Zinc Borate Production from Zinc Oxide and Boric Acid

The synthesis of zinc borate, 2ZnO.3B2O3.3.5H2O, was investigated via reaction of solid zinc oxide with boric acid aqueous phase in the existence on seed crystals. Commercially important type of zinc borate was synthesized using the 4.7 M boric acid concentration and B2O3 to ZnO molar ratio of 2 at 90°C, at 900 rpm and for 4 hours reaction time in a stainless-steel reactor. The amount of seed crystals was 1.5% of the boric acid initially used. At the end of each experiment, X-ray diffraction (XRD) instrument as well as Fourier-Transform infrared spectroscopy (FTIR) instrument were carried out for identifying final products. A continuous process was developed with SuperPro Designer software. The design was derived from experimental and literature data. A techno-economic analysis of the zinc borate synthesis process was carried out for different annual plant capacities (6,000-12,000t). Unit prices of raw materials and final product were obtained from the literature and the market as USD600/ton boric acid, USD2,200/ton zinc oxide and USD4,500/ton zinc borate. The fixed investment cost of the zinc borate production plant with capacity of 10,000 ton/year was found to be USD22,780,000 and the operating cost was found to be USD26,273,000/yr. The payback time was determined as 1.93 years from the economic analysis of the process.