基于LIBS技术在线监测熔融铝水中的元素成分

In-situ Analysis of Molten Aluminum by Laser-induced Breakdown Spectroscopy System

在辽宁忠旺集团有限公司的熔铸厂,利用自主研制的LIBS液态金属成分在线分析仪对熔融铝水的成分进行了在线监测.研究了通入探杆中氩气的最佳流量以及探测深度与氩气波动的规律,发现氩气流量为1~1.4L/min时,光谱强度最强,探测深度位于氩气压力波动范围在±300Pa,并且压力波动有规律时的位置,各元素浓度稳定性好;利用实验室分析得到的固样数据对设备进行了标定,长时间测试得到的在线监测结果为:Si、Fe、Cu、Mn、Cr的重复精度都小于2%;浓度在0.1%~1%之间的Si、Fe、Mg的测量偏差都小于0.01%,浓度低于0.1%的Cu、Mn、Cr的测量偏差都小于0.001%;探杆多次升降浓度测量的稳定性小于3%.LIBS液态金属成分分析仪的测量重复精度、测量偏差以及多次升降测量的稳定性都能满足工业现场要求,完全可以实现实时、在线监测熔融铝水的成分.

LIBS on-line analyzer for liquid metal composition, which is designed by the LIBS project group of Shenyang Institute of automation, Chinese Academy of Sciences, is a analytical system for on-line monitoring of molten metal components in the metallurgical industry. We used this system to monitor the composition of molten aluminum in melting and casting plant of Liaoning Zhongwang Group Co., Ltd. After several months testing, we obtained that the optimum flow rate of argon in the probe tube is 1~1.4 L/rain, and when the detection depth is located at the position where the pressure fluctuation range of argon is ±300 Pa and the pressure fluctuation is regular, the concentration of each element is stable. Finally, we calibrated our equipment by solid sampling data from laboratory analysis. The obtained results of on-line monitoring are as follows：the repeatability accuracy of Si. Fe. Cu. Mn and Cr is less than 2% the measurement deviationis less than 0.01% for Si, Fe, Mg （concentration is between 0.1%~1%）, and is less than 0.001% for Cu, Mn and Cr （concentration is less than 0.1%） ;the stability of the multiple rise and fall of the probe is less than 3 %. On-line monitoring data meet the requirements of factory, so we can realize real time and on line monitoring the compositions of molten aluminum.