两段中和法制备高品质羟基磷酸钙

开发出将磷酸与方解石、石灰依次中和制备高品质羟基磷酸钙的两段中和法。介绍了反应原理，并通过实验确定了工艺参数（搅拌转速、投料比例、反应温度、反应时间、反应物浓度等），比较了3种干燥方式的优缺点，并以选用“卧螺离心沉降 + 强力粉碎干燥”的干燥方式为例详细叙述了工艺流程。将两段中和法所得产品和磷酸与方解石中和法所得产品进行了比较，结果显示两段中和法产品具有纯度高、有害杂质少、灼烧减量低等优点，产品质量完全符合中国现行产品标准GB 25558-2010的要求。

Preparation of high quality hydroxyapatite by two-stage neutralization method

Two-stage neutralization method for the preparation of high quality hydroxyapatite by neutralizing phosphoric acid with calcite firstly and lime secondly was developed.Reaction principle was introduced and technical parameters(agitation speed,feed ratio,reaction temperature,reaction time,and concentration of reactants etc.) were fixed by experiments.Advantages and disadvantages of three kinds of drying mode were compared and the process flow was described in detail while taking ’spiral centrifuge settlement+strong crushed drying’ drying mode as an example.Products produced by two-stage neutralization method and the phosphoric acid-calcite neutralization method were compared and results showed the former method′s product had many advantages,such as high purity,few harmful impurities,and a low loss on ignition,and its quality completely met the requirements of China′s existing product standard(GB 25558—2010).