Study On Analysis Methods For Rapid Determination Of Trace Elements In Chlor-alkali Industry

Inductively coupled plasma (ICP) atomic emission spectrometry, since was established in the 1960s, has been developed rapidly because of its wonderful characteristics of rapidness, accuracy, high-selectivity and easy-operation, and has a wide range of applications to many fields. In recent years due to its progress, ICP-MS analysis has showed potential applications to replace ICP-AES. However, in chlor-alkali industry, because of high salt composition in samples and low price, ICP-AES analysis is still used commonly.This thesis is focused on the rapid analysis of trace elements in the chlor-alkali industry ionic membrane caustic soda brine, the determination of trace sulfur in the oil and chemical products, the establishment of a determination method for palladium carbon catalyst and the rapid detection of epoxy leadcadmium. Sample preparation techniques and ICP-AES measurements are studied. The main contents are as follows:1. The standard curve method is used to developed methods for rapid determinations of Ca, Mg, Fe, Sr, Ba, Ni, Al elements in salt water samples of ionic membrane caustic soda. The instrument parameters are optimized and the results obtained are compared with those using standard addition method. National standard materials are used to validate accuracy and precision of the developed methods. The relative standard deviation (RSD) is less than 2.00%, the standard recovery is 95.0%-107.5%. The standard curve method has been proven to be fast, accurate and reliable.2. Chlorobenzene is an important raw organic material in petroleum chemical industry. Sulfur content in the material will affect on the catalyst. With a method of adding matrix, sulfur content in chlorobenzene sample is determined by directly sampling, resolving a problem of inaccurate determination due to uncomplete oxidation of the sample when using the traditional method. The applications to real sample analysis show satisfactory results.3. In traditional method to detect palladium catalyst, a sample is pretreated by extracting with aqua regia repeatedly after burning. Its drawbacks are time-consuming and uncomplete digestion, that is easy to impact the analysis results. To resolve this problem, a modified pretreatment method is developed, in which wet digestion is applied. A mixture of aqua regia and perchloric acid are used to digest and extract palladium in the catalyst. The solution pretreated is clear and no residue. By selecting suitable acid mediums and the recovery test, accuracy of the method is assessed. The relative standard deviation (RSD) is less than 1.00%, and the recoveries 97.3-103.2%.4. Microwave digestion method is more and more popular in the pretreatment of samples in laboratory. This method is used to digestion of the epoxy resin samples. With standard curve method contents of lead, cadmium, mercury are determined for RoHS. Its accuracy and precision are satisfactory.