Research On Preparing Nano-sized Black Iron Oxide Using Pyrite Cinder

There are approximately 12,000,000 tons of discharged pyrite cinders every year in China. However only 10 percent of these pyrite cinders is reused in cement industry and so on as assistant reagent. The reusing proportion is very low;moreover the added product value is also low, limiting the large-scale reusing of pyrite cinders. Thus massive cinders can only be disposed by piling up, which not only occupying substantive lands but also polluting the environment. Many domestic scientists have researched a lot in general utilization of pyrite cinder, so that pyrite cinders could be reused in more fields. However majority of these researches are still at laboratory research stage without realizing the industrialization production due to process or cost and so on. So it is significant to research a process with more brief flow, lower cost and higher added value.Black iron oxide belongs to iron series pigments. It is applied widely in fields of cement building materials, dope, printing ink, rubber, ceramics and plastic because of its stability to light and atmosphere, alkali-resistance, high tinting strength and hiding power. Nano-sized black iron oxide has some special nature, like diaphaneity, the intense absorption ultraviolet ray ability besides chemical stability of ordinary black iron oxide because its particle size is smaller than 100nm. Thus Nano-sized black iron oxide can be applied to protect ultraviolet ray sensitive matter such as upscale automobile upper lacquer, wooden product and transparent plastic. The price of Nano-sized black iron oxide is far expensive than ordinary black iron oxide, but it is still cheaper and more attractive in automatic upper lacquer and wood tinting compared with organic pigment allowing for its innocuity and ability of absorption ultraviolet ray.This thesis prepared Nano-sized black iron oxide by precipitation oxidization process with FeSO₄ solution. The FeSO₄ solution was obtained from pyrite cinders by deoxidized baking, the sulfuric acid pickling and purifying process. The effect of materials ratio, reaction temperature, aeration time, aeration velocity, concentration of FeSO₄ solution and stir velocity on the purity and particle size of black iron oxide was discussed. Nano-sized black iron oxide with purity between 97.35 percent and97.90 percent and particle size about 21 nanometer was synthesized by optimization of process.Compared with other processes, this process has the advantages of more briefflow, shorter reaction time, more manageable parameters, lower cost and higheryield.