To obtain electrical periclase with a high degree of uniformity (GOST 13236-83) at Bogdanovich Production Union for the Production of Refractory Materials powders of different fractions in a specified ratio are mixed in a DVKh-1000 mixer of the Notamix company (the Netherlands) after preliminary separation of them in a classifier.According to the technical instructions the basic criterion for evaluation of the degree of uniformity of the finished product is its grain size distribution. However, the nonuniformity of distribution of the natural impurities in periclase makes necessary a composite approach to evaluation of the effectiveness of operation of a mixer, that is, of providing uniformity of both the grain size distribution and the chemical composition of the finished product.The distribution in their natural mixture of CaO was taken as the control parameter of the chemical analysis of the periclase powders.This article presents the results of investigation of the influence of loading of the material on the equalizing capabilities of the DVKh-1000 mixer and of determination of the optimum mixing time of the material to obtain the maximum possible uniformity of the powder.The DVKh-1000 mixer operates in batch action with charging of the mixer, mixing, and discharging of the material. The basic distinguishing design element of the mixer is the conical bunker (operating position vertical) with a planetary worm mixer [I] (Fig. i). The capacity of the mixer is 2 tons, the mixer is top-charged, and it is discharged through a metering device located in the lower portion of the bunker.The effectiveness of mixing of the periclase powders was evaluated by comparison of the content of the impurity CaO determined by the gamma absorption method before and after mixing. In charging of the mixer samples are taken at equal intervals of time with maintenance of the weight ratios between the portions being charged, and in discharging of the material from the mixer during packaging of the finished production powders in standard packages. The weight of a single sample is 300 g and it represents about 40 kg of powder and is determined by the condition of the degree of contrast of the gamma absorption method.Under the production conditions of Bogdanovich Production Union three series of experiments were made with the following operating conditions of the mixer:in the first series two 2-ton lots were produced with mixing times t of 27 and 22 min; in the second series two 1-ton lots were prepared with t equal to 9 and I0 min; in the third series three 0.75-ton lots were prepared with t equal to 20, 30, and 40 min. Such a set-up of the experiment provided for simultaneous development of the interaction of the elements of the quality control system and its production effectiveness.For certain lots of powders curves characterizing the uniformity of the material before and after mixing are given (Fig. 2). The Institute of Mining. Eastern Refractory Institute.
The Satka group of magnesite deposits is the raw material base of Magnesite Corporation. The complex structure of the deposits and the high degree of variability of the substance composition of the magnesite is the result of its origin. The ore bodies are a complex polymineral formation (geochemical field) within which both geometric and statistical rules are revealed.Special investigations and many years of experience in mining have shown that the internal structure of the ore bodies is characterized by high alternation of the types of magnesite, which is determined by the conditionality of the boundaries between them. As the result the grade of magnesite raw material in the depths may be evaluated only from the data of tests of drilled holes. Such an evaluation has only a statistical character, which is reflected in the insufficient effectiveness of intraface selection. If an area of the ore field is graded on the basis of results of sampling with use of drilled holes (7 x 7 m grid) a quite variegated picture is obtained. The tying in of commercial grades of magnesite to one hole is 25 % of the cases, to two 19%, to three 14%, to four 11%, to five 7%, and to six and more 24%. Therefore sufficiently large commercial formations are no greater than a fourth of the reserves and, taking into consideration the low correlation in the space of adjacent results of sampling (the correlation coefficient r for CaO is in the space of a deposit 0.43 and transverse to the course 0.23 and for SiO 2 0.18 and 0.32, respectively), the fact of nonconfirmation of the planned evaluation of the grade of magnesite within the limits of conduct of a weekly-daily program of mining work is understandable.The structural organization of Magnesite Corporation is quite complex consisting of two mines (Karagai and Volch'egorsk-Stepnoe), two crushing and concentration plants (DOF-1 and DOF-2), and shops for the production of magnesia powders and parts. In accordance with the classification the mined and processed magnesite is divided into five types (Table 1).Magnesite raw material is mined selectively in open pit mines. From the mine faces the ore is delivered to the reloading areas and then the magnesite is transported by narrow-gauge railroad to the crushing and concentration plant. The ore delivered to the plant is crushed to the 40-0 mm fraction and delivered for use in production of magnesia powders.The main operation control of mining work are the weekly-daily charts. Analysis of them makes it possible to reveal the reasons for significant deviations of the actual results of mining work from the planned and to develop measures for elimination of negative factors. Summarized data of analysis of the weakly-daily charts at Karagai Open Pit Mine is shown in Table 2. In it the relationships between the planned volumes of mining of magnesite in the mine by types and those obtained in operational (permit) and actual calculation of these volumes in the plant are given. The analysis conducted makes it possible to state that variations in the vol...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.