Optimized Iodine Recovery from Zinc Suboxide Derived from Steel Dust Using Alkaline Washing and Air Blowing-Out: A Sustainable Industrial Approach

The present paper proposes an advanced process to effectively recover and fully use iodine from steel dust-derived zinc suboxide, with considerations of effectiveness in the process and industrial viability. It includes, for example, alkali wash for the dissolution of iodine into an alkaline solution from steel dust and uses mechanical vapor recompression (MVR) to concentrate the dissolved iodine by preparing the solution for the air-blowing-out process. The hydrogen iodide is also oxidized under acidic conditions with the addition of hydrogen peroxide to form crude iodine, estimated at about 20 tons annually. As a matter of fact, using this process, up to 1.2 million tons of steel waste dust can be treated in a year, turning what was previously considered waste into something of value. The thermodynamic relationship between iodine recovery and pH value is further discussed in this study, pointing out that under alkaline conditions, iodine is predominantly in the form of iodide (I−) and iodate (IO3−), while at less than pH 2.8, it is in its molecular form I2. These insights would provide a theoretical backbone for maximum extraction efficiency, guiding process parameters toward optimum recovery and judicious use of the resource.