硫化钙的氧化行为研究

Study on oxidation behaviors of CaS

硫化钙(Ca S)是磷石膏分解时的中间产物,稳定性极差,不易于保存。采用可控程序高温管式炉在N2/O2气氛下,研究了Ca S在不同温度、O2浓度和不同时间下的氧化特性,并通过X射线粉末衍射仪(XRD)来表征氧化产物物相。结果表明,在300℃左右Ca S开始氧化,最终稳定产物为硫酸钙(Ca SO4),且随温度升高,氧化产物中Ca SO4的含量增加;温度为700℃时Ca S基本氧化完全,即达到最佳理想状态;O2浓度越高,Ca S越容易被氧化,φ(O2)=21%时氧化产物中Ca SO4的质量分数高达91.13%。Ca S的氧化速度较快,80%都在10 min左右被氧化。

Calcium sulfide （CaS） is the intermediate product of the phosphogypsum decomposition.It is not stable and hard to preserve.High-temperature programmed tubular oven was used to study the oxidation characters of CaS under different temperatures,O2 concentrations, and times in N2/O2 atmosphere.X-ray powder diffraction （XRD） was used to determine phases of oxidation products.Results showed that the oxidation reaction of CaS began at about 300℃ ,the final stable product for oxidation was calcium sulphate （CaSO4）, and with the increase of temperature, CaS04 content in the oxidation products also increased;when the temperature was 700℃ ,CaS was basically oxidized eompletely,i.e.the ideal state.High oxygen concentration tended to lead easier oxidation of CaS.21% （volume fraction） oxygen concentration could get 91.13% high CaSO4 mass fraction in the final oxidation products.CaS had a fast oxidation speed, 80% of it was oxided at about 10 min.