Development of chemical sensor to measure Al concentration in molten Zn bath using composite mixed salt electrolyte.

研制了一种复合混合盐电解质化学传感器，用于锌合金熔体中铝含量的测量。该传感器是由NaCl和AlCl_3的混合卤化物熔融后饱和固体NaCl组成的复合型电解质。可变的固体与液体体积比使人们能够获得作为传感器组件的宽范围的机械性能，从几乎纯液体特性到固体电解质的固体特性。两种类型的传感器，具有和不具有β-氧化铝膜电解质以分离与纯Al参比电极和熔融Zn电极接触的电解质，在实验室规模（小于10 kg）和实际锌浴器（大于4, 000 kg）上进行了性能测试。前者传感器可表示为;Zn-Al* NaC 1 <@D2sat.@> D2+ AlCl <@D23@>D2（+ZnCl <@D22@>D2）：<@D7（Na<@D1+@>D1）（l）β-氧化铝@> D 7：Nac <@D2sat.@> D_2 +AlCl<@D_23 @> D_2 * Al通过本课题获得的结果如下：（1）两种类型的传感器， ...更多信息 为了防止ZnCl_2在电解液中的反向扩散，在不使用β-Al_2O_3膜电解质的情况下，在100 mass ppm Al以上，显示出良好的可逆性、重现性。(2)两种传感器表现出良好的一致性，但前者表现出更好的性能，在启动时间和寿命。(3)为了用电动势法测定锌铝合金和锌铁铝合金的活度系数，测定了稀锌铝合金和锌铁铝合金的热化学性质。(4)本传感器与β-氧化铝在CGL线测试的适用性得到了证明，并进行了30 ppm的相对误差约1500 ppm铝和寿命为10天的平均。(5)寿命主要取决于ZnO颗粒在电解液中的附着力和AlCl_3的挥发。(6)传感器寿命或有效性可以通过在线监测传感器的交流阻抗来估计。(7)通过理论和实验研究，证明了本发明的复合混合盐电解质作为化学传感器是有效的，可用于测量熔融金属和合金中多种组分的浓度或化学势，例如熔融Cd中的Zn，熔融Al合金中的Na等。Less

Chemical sensors using composite mixed salt electrolyte have been developed to measure aluminum content in molten Zn alloys. The present sensors are composed of composite type electrolyte of molten mixed halides of NaCl and AlCl_3 saturated with solid NaCl. A variable solid to liquid volume ratio enables one to obtain a wide range of mechanical properties as a sensor component from almost pure liquid characteristics to solid ones as those of solid electrolytes.Two types of sensors, with and without beta-alumina membrane electrolyte to separate electrolytes contacting with pure Al reference and molten Zn electrodes, were tested for its performance in both laboratory scale (less than 10kg) and practical Zn bather (greater than 4,000kg). The former sensor can be expressed as ;Zn-Al*NaC1<@D2sat.@>D2+AlC1<@D23@>D2(+ZnC1<@D22@>D2):<@D7(Na<@D1+@>D1)(/)beta-alumina@>D7:Nac1<@D2sat.@>D2+AlCl<@D23@>D2*AlThe results obtained through this project are as follows :(1) Two types of sensors with and w … More ithout beta-alumina membrane electrolyte in order to prevent from counter diffusion of ZnCl_2 through the electrolyte showed excellent reversibility, reproducibility above 100 mass ppm Al.(2) Both sensors showed good agreement with each other, but the former showed better performance in start-up duration and its life time.(3) Thermochemical properties of dilute Zn-Al and Zn-Fe-Al alloys were determined in order to evaluate activity coefficient of Al in molten Zn by EMF method using the composite electrolyte.(4) The applicability of the present sensor with beta-alumina in CGL line test was proved, and relative error of 30 ppm around 1500 ppm Al and life time of 10 days as an average was performed.(5) The life time was governed by adhesion of ZnO particles to electrolyte and the evaporation of AlCl_3.(6) The sensor life time or the validity can be estimated by on-line monitoring of an ac impedance of the sensor.(7) Through theoretical and experimental examinations, the present composite mixed salt electrolyte is proved to be valid for chemical sensors to measure concentration or chemical potential of a wide variety of component in molten metals and alloys, for example, Zn in molten Cd, Na in Al alloys, and so on. Less