Some Practical Aspects of Automatic Regulation and Control of Quartz Sand Preparation Process to Obtain Quality Products
M. Kostovic, P. Lazic
University of Belgrade, Faculty of Mining and Geology, Serbia, Belgrade
Keywords: Quartz sand, hydrocyclone, automatic regulation, process control, partition numbers, partititon curve, classification efficiency
Abstract
Quartz raw materials for the foundry and glass industries, which must have an appropriate satisfying chemical and particle size composition, according to the standards and special requirements of users, are produced at quartz sand separation plant in Serbia. The process of quartz sands preparation in a separation plant is simple and includes the following stages: screening, washing, classification and attrition. In practice, depending on market requirements, different types of sand from different deposits are processed. In addition, the sands in the deposits are heterogeneous and differ, most often, in the content of clay to be separated, so in many cases it is difficult to satisfy the requirements of consumers. One of the reasons is the lack of automatization, where changes in process flowsheet lead to a stop of process, which entails difficulties in operation and stoppage of this process unit. Taking in the account the above, in order to implement optimal automated control and monitoring of the process, industrial tests were carried out on a separation plant. The tests were carried out on a hydrocyclone of the first stage of classification (as the most important unit of this process), equipped with appropriate control and measuring devices (CMD) to perform this task, namely: a frequency regulator of the pump electric motor and a manometer for measuring the pressure at the feed inlet of the hydrocyclone. In order to evaluate the classification process of various quartz sands in a hydrocyclone, the classification efficiency was determined using partition numbers and a partition curve, and taking into account the parameters of the sharpness of separation. The obtained results of industrial tests have confirmed that as a result of changing the feed pressures of the hydrocyclone, while controlling other technological parameters of the process, it is possible to successfully treat raw quartz sands from various deposits and obtain a product with satisfactory characteristics, especially in regard to particle size distribution. In addition, the results are encouraging in relation to future implementation of automatic process control and appropriate monitoring.
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