钠化富硼渣中硼化物析晶动力学分析与实验研究

Theoretical analysis and experimental study on the crystallization kinetics of sodium borate in Na-modified slag

富硼渣经熔态钠化—热处理析晶—水浸工艺可制得硼砂晶体。硼的浸出率与渣中硼组分析出形态直接相关,若以NaBO2为主晶相析出,硼浸出率高;若以玻璃态存在,硼浸出率低。根据非晶固体形成动力学理论,计算富硼渣钠化过程中NaBO2成核速度(I)和晶体长大速度(IL),获得了NaBO2晶体在熔体中的最佳形成温度。采用化学分析方法研究了热处理温度对渣中硼浸出率的影响。结果表明,钠化渣的最佳热处理温度与理论计算所得最佳温度一致。

Borax could be obtained using process of modifying melting boron-rich slag with sodium carbonate-crystal precipitation-water leaching.The leaching rate of boron is directly related to the precipitation characteristics of boron component in the slag.The leaching rate is high if boron component existed in the crystal of NaBO2;otherwise the leaching rate is low in the form of amorphous phase.Calculation of nucleation rate（I） and crystal growth rate（IL） of NaBO2 according to the kinetic theory of non-crystalline solid formation.The optimal temperature of heat treatment for boron-rich slag has been obtained.The effects of heat treatment temperature on the leaching rate of boron have been investigated by chemical analysis method.The results indicate that the optimal heat treatment temperature for slag is in consistent with the calculation temperature.The leaching rate of boron can reach 76.04% while the Na-modified slag is leached by water under high pressure.