Innovative application of mathematical methods in evaluation of ore raw materials for production of iron
Current principles of evaluation of ore raw materials are usually based on a comparison of selected isolated criteria. Today's sophisticated technological level of blast furnace process requires the introduction of raw material indicators that provide global characteristics of their quality. This can't be realized with isolated parameters only. The evaluation should incorporate the key characteristics of iron ore and convert them into a uniform evaluation parameter. This article analyzes the use of mathematical methods in the evaluation of the quality of ore raw materials.
SAATY'S METHOD AS A TOOL USED TO DETERMINE THE IMPORTANCE OF IRON ORE EVALUATION CRITERIA
The quality of ore raw materials significantly affects the technological aspects of the blast furnace process. The comparison of iron ores is complicated because of the wide range of parameters which can be used to evaluate the ores. In terms of categories, they may include physical, chemical, mechanical, and other properties. From a general point of view, current methodologies evaluating the quality of ore raw materials can be divided into two groups of methods. The first one tries to simulate the conditions which ore is exposed to when going down the stack. Another approach is based on single-purpose tests, designed to determine a selected indicator of metallurgical quality. Both of these approaches allow you to acquire a number of key information about the quality of ore raw materials and about the course of the blast furnace process. The application of these methods, however, does not provide complex information offering a global view of the total value of ore raw materials. The key factor of this process is to determine the weights of the individual criteria according to which the ore is evaluated. The determination of the weights is very inaccurate, provided that it is performed solely on the basis of an intuitive assessment of the importance of the criteria. An exact evaluation of the importance requires a utilization of some of the mathematical instruments. This article analyzes the use of Saaty's Method when determining the importance of the individual criteria used in the evaluation of the quality of iron ores.
Traceability strategy for gear-pitch-measuring instruments: development and calibration of a multiball artifact
There is a strong demand to ensure the traceability of gear-measuring instruments (GMIs). We propose a multiball artifact (MBA) for the evaluation of pitch-measuring accuracy. The aim of the MBA is to transfer the minimum uncertainty from a calibrated value at the National Metrology Institute of Japan (NMIJ) to a measured value of GMIs at a shop floor. The MBA is composed of equally spaced high-accuracy balls around an axis. The pitch-measuring accuracy of GMIs is evaluated by measuring the angular pitch deviation of the balls instead of the angular pitch deviation of a gear. We calibrated the angular pitch deviation using a coordinate measuring instrument (CMM) at the NMIJ and adapting a multiple-orientation technique. We proposed a calibration strategy of the angular pitch deviation. The calibration value of the pitch deviation for the MBA at the NMIJ was obtained with a measurement uncertainty (U95) of 0.2 µm. We evaluated the pitch-measuring accuracy of a GMI using the calibrated MBA. Each value of U95 for the cumulative and single pitch deviations for the left and right flanks was less than or equal to 0.5 µm. The small uncertainty was transferred from the NMIJ to the GMI.