On-line Real-time Measuring Of Sodium Aluminum Solution On Three-temperature Three-conductivity Method

Measuring the densities of the composition of sodium aluminum solution plays a significant part in producing AI2O3 by bell. The main chemical compositions of sodium aluminum solution are NaOH, AI2O3 and Na2CO3, and at present analysis of the composition of sodium aluminum solution mainly depends on manual timed sampling and chemical laboratory agent titration. Though the densities analyzed by this method are greatly precise, interval of sampling time is longer. So this method doesn't contribute to guiding production on time. At the time, analysis working capacity of the method is large, and certain chemical agent is to be consumed. For the occasion, on-line real-time measuring the chemical composition of sodium aluminum solution by automatic process analyzer is very necessary. In this regard, many methods are tried, and two-temperature two-conductivity method used in Gui Zhou Aluminum Plant is most typical and more successful. Although two-temperature two-conductivity method is better than other method, the accuracy of the NaOH and AI2O3 density calculated by this method has certain limitation. On the other hand, because Na2CO3 density can't be calculated by this method, the method has certain limitation in guiding production. To solve these problems, three-temperature three-conductivity method is proponed in the text. The key to three-temperature three-conductivity method differing from two-temperature two-conductivity method lies in that sodium aluminum solution conductivity mathematics model established by three-temperature three-conductivity method has four factors, namely NaOH density, AI2O3 density , Na2CO3 density and temperature. By this method, the NaOH density, AI2O3 density, and Na2CO3 density of sodium aluminum solution can be calculated though getting different three temperatures and corresponding conductivities. Comparing with two-temperature two-conductivity method, NaOH density, and AI2O3 density can be calculated by three-temperature three-conductivity method, meanwhile Na2CO3 density can also be calculated by three-temperature three-conductivity method. Therefore three-temperature three-conductivity method can better guidingproduction.The on-line real-time system for measuring the densities of the composition of sodium aluminum solution researched in the text is based on three-temperature three-conductivity method.The system has three main functions as following.(1) Detecting the temperature and conductivity of sodium aluminum solution,and through mathematics model calculating the NaOH density, AI2O3 density and Na2CO3 density of sodium aluminum solution. And in this case calculating acridity rate.(2) Displaying data and trend curve, recording data and printing report tables.(3) Solving the problem of solution cicatrisation by automatic sampling and cleaning.The main content of the text has several aspects as following.(1) Introducing the significance of the on-line real-time system for measuring the densities of the composition of sodium aluminum solution.(2) Introducing the principle of measuring sodium aluminum solution compo-sition density by three-temperature three-conductivity method. .(3) Introducing the establishment process of the three temperature and three conductivity mathematics model of sodium aluminum solution.(4) Introducing the hardware equipment selection and designing process of the system.(5) Introducing the design of the system software.(6) Introducing field installation, idea of testing.