蓄热用Ba(OH)_(2)·8H_(2)O制备

Preparation of Ba(OH)_(2)·8H_(2)O for Thermal Storage

Ba(OH)_(2)·8H_(2)O是潜热储热密度最高的结晶水合盐,是非常重要的一种相变储热材料。目前生产Ba(OH)_(2)·8H_(2)O产品主要以BaCl_(2)为原料生产,产品中含有一定量的Cl^(-),长时间蓄热运行势必造成设备腐蚀,需要减少Ba(OH)_(2)·8H_(2)O中Cl^(-)的含量。本实验选用硝酸钡、液碱为原料,通过复分解反应制备无氯的蓄热用Ba(OH)_(2)·8H_(2)O产品的工艺方案。实验确定的最佳工艺条件为:0.1 mol硝酸钡,加水80 mL,30%液碱过量25%,反应温度95℃,冷却结晶温度-3℃,在真空度0.07 MPa下,60℃烘干120 min。在上述条件下制备的Ba(OH)_(2)·8H_(2)O产品质量达到了行业标准HG/T2566—2014优等品的指标要求,且产品不含氯,产品产率90%以上。

Ba(OH)_(2)·8H_(2)O is a crystalline hydrated salt with the highest latent heat storage density,and it is a very important phase change heat storage material.At present,the production of Ba(OH)_(2)·8H_(2)O is mainly based on BaCl_(2) raw material,which contains a certain amount of Cl^(-).It will inevitably cause equipment corrosion for Long term thermal storage operation,and it is necessary to reduce the Cl^(-)content in Ba(OH)_(2)·8H_(2)O.This experiment uses barium nitrate and liquid alkali as raw materials to prepare a chlorine free Ba(OH)_(2)·8H_(2)O product for thermal storage through double decomposition reaction.The optimal process conditions determined by the experiment are 0.1 mol of barium nitrate,80 mL of water added,30%liquid alkali excess 25%,reaction temperature 95℃,cooling crystallization temperature-3℃,and drying at 60℃for 120 minutes under a vacuum of 0.07 MPa.The quality of Ba(OH)_(2)·8H_(2)O prepared under the above conditions meets the requirements of the industry standard HG/T2566—2014 for superior products,and the product does not contain chlorine,with a yield of over 90%.