Analysis of the Possibility of Using New Types of Protective Coatings and Abrasion-Resistant Linings under the Operating Conditions of the Spiral Classifier at KGHM Polska Miedź S.A. Ore Concentration Plant

A study was carried out to select the appropriate coatings for corrosion protection of the spiral classifier working at KGHM Polska Miedź S.A. Ore Concentration Plant. The abrasion resistance of selected protective coatings and wear-resistant linings was investigated using a DT-523 rotary abrasion tester with Taber CS-10 rubber abrasive discs. The average weight loss of the coatings after a cycle of 2000 revolutions was determined. Tests of protective coatings using the electrochemical impedance spectroscopy (EIS) technique were carried out to determine the suitability of coatings in the highly saline environment of the aqueous suspension of ground copper ore. During the measurements, changes in resistance, polarising current and capacitance were determined as a function of time for the tested coatings. The linings selected on the basis of laboratory tests were also tested under industrial conditions. Their degrees of wear were characterised. The results obtained indicated the highest abrasion resistance of materials from the polyolefin group (polyethylenes), where the average weight loss did not exceed 5 g/dm2. In the case of protective coatings, the highest durability was demonstrated by coatings with additives of ceramic aggregates, phenol-epoxy, and an elastomeric coating based on polyurea, whose average weight loss during the test cycle did not exceed 19 g/dm2. EIS measurements showed that the tested coatings were resistant to the aggressive environment of the feedstock. Tests under cathodic polarisation conditions of the samples at a potential below the protection potential showed that they were resistant to a highly saline environment and were also resistant to its alkalinisation resulting from the application of cathodic protection, which will be used to protect the classifier together with protective coatings. Tests carried out under industrial conditions using wear-resistant linings made of plastics have made it possible to analyse the mechanism and degree of wear of the various materials during the operation of the classifier. Measurements of lining wear were made in relation to baseline volumes. Polyurethane, a polymer lining based on MDI and PTMG, and those made of ultra-high-molecular-weight polyethylene with anti-stick additives showed the lowest wear rates.

Elaboration and implementation technology of concentration of Magnitogorsk steel-works slime tailings

The problems of processing iron ore tailings of wet concentration plants and wastes with high content of iron, contaminated by oil products are actual from both points of view of ecology and economy. One of the reasons restraining solving the problem is absence of technologies ensuring to involve such wastes into industrial turnover. In the process` of the research, composition and opening degree of ore and non-metallic minerals of concentration slime tailing of Magnitogorsk steel-works (MMK) were studied and technology of their concentration was elaborated. Taking into consideration the contamination of initial slime tailings of MMK, it was proposed to accomplish their preliminary de-sliming to remove vegetable remains and clay slimes by disintegration in a screw-toothed crusher and washing in a spiral classifier. Results of wet magnetic separation (WMS) of the initial slime tailings of MMK, made at JSC “Uralmekhanobr” presented, the slimes having natural coarseness of –2.0+0.0 mm. It was established that WMS at the magnetic field intensity of 1500 Oe ensures effective removal of magnetite, aggregates magnetite-hematite-goetite into magnetic product. Iron content in the magnetite concentrate was varying from 61.5 to 62.6%. For processing of slime tailings of MMK, magnetic separation was proposed by high-gradient magnetic separator with permanent magnets, created specially for these purposes by “ERGA” company. To increase iron extraction degree, it was proposed to apply gravitation methods of concentration of nonmagnetic product, obtained at high-gradient WMS. It enabled to increase iron content in the final magnetite-hematite concentrate up to 59%. A technological diagram of oiled slimes processing presented. Tests with oiled slimes of bottom deposits of metallurgical production under pilot-industrial conditions of MMK exhibited a possibility to obtain additional iron concentrate with total iron content of 62.47% while oil content in it was less 0.3%.

Application of control units VAZM-2U in ore grinding

This paper considers the results of research work aimed at developing control systems to control ore grinding processes that would be compatible with the control unit VAZM-2U developed by Soyuztsvetmetavtomatika. The underlying principle concerning the unit is that grinding of ores with different mineralogical compositions is governed by the same common regularities in correlation between the physical processes that develop in grinding circuits and the defining process parameters. A grinding mill is fed with ore that has varying physical and mechanical properties, and this can lead to accumulation of material in the mill. Indicators of the probable overload condition include mill vibration level and active power draw of the mill drive motor. The point at which the overload condition has arrived is determined by analyzing active power draw and reverse vibration trends. It is demonstrated that a mill overload condition may take place in those time intervals when both the vibration level and the active power draw of the mill motor fall. In this case the VAZM-2U unit calculates a correction command for the ore flow rate regulator, and this way the overload condition is overcome while the ore feed rate returns to the initial value. The VAZM-2U unit can also help reach the maximum output of the overflow product from a spiral classifier avoiding overgrinding, with the finest material being monitored. The unit can also determine the underflow flow rate in the spiral classifier while adjusting this parameter within a given range of allowable values. The underflow flow rate is estimated with the help of an adaptive mathematical model, which can be utilized in closed-loop grinding circuits that include classifiers. The ore grinding control algorithms implemented in the VAZM-2U unit can be modified to be applicable for milling and flotation control.

Comparative Cleaning Stages in Recovery of Copper and Cobalt from Tailings using Potassium Amylxanthate as Collector

Copper and cobalt demand is projected to be increased from here to 2050 and the challenge is to find treat economically minerals which contains those metals. Several tailings from oxide ores throughout the word contain good grades of copper and cobalt that should be recovered by froth flotation. This paper investigates the recovery of copper and cobalt through reprocessing of spiral classifier tailings by determination of specific reagents dosage. The flotation behaviours of malachite and heterogenite were studied through many roughing and cleaning flotation tests in order to recovery most of copper and cobalt. The effect of specific reagents was be varied and others parameters were kept constant. The highest recoveries of both copper and cobalt in rougher concentrate were respectively 82.51% and 72.51% with grades of 12.52% and 0.99% respectively. However, the cleaner concentrate was 24.54 Cu% and 1.38% Co with recoveries of 69.26 % and 40.7% respectively. It was concluded that the reprocessing of spiral classifier tailings through froth flotation is benefit because it recovers most of desired metal and reduces the risk of their presence on environment through.

Energy efficiency optimization of ore grinding by ball mills in a closed cycle with a single-spiral classifier

Factors are identified whose role in increasing the productivity of ball mills is not fully disclosed. The criterion of optimality in the task of increasing the energy efficiency of ore grinding by ball mills and the influence of these factors on its value. Ways to improve the energy efficiency of ore grinding are proposed.

Optimisation of Operational Parameters of a Spiral Classifier Using Design of Experiment (DOE)

Classifying Mn Ore to improve upon the grade and the properties has become a crucial activity for the Mn industry since it increases the market value of the ore. Ghana Manganese Company (GMC) has renovated their oxide washing plant by integrating it with a spiral classifier to make a batch system operating process. Particle size of <3.35mm (Mn grade of 43-47%) obtained from the primary section of the plant served as feed to the classifier and with the plant condition (i.e. at 60 min washing time, 30 rev/min speed of spirals and feed tonnage of 6 t), Mn grade of 49% was achieved. This paper focused on the optimisation of some selected operational parameters of the classifier to obtain a Mn grade >50% using Design of Experiment (DOE). Series of test works were designed using the DOE for the classifier using the constraints of washing time (30-90 min), speed of spirals (20-40 rev/min) and feed tonnage (6-9 t). The outcome of the test work after simulation showed that all the selected parameters had a great influence on Mn grade. The spiral speed and feed tonnage correlated negatively to the Mn grade with washing time correlating positively. Operating the spiral classifier at a feed rate, spiral speed and washing time of 6 t, 25 rev/min, and 30 min, respectively, yielded Mn grade of 53%. A Confirmatory test using the established conditions gave a Mn grade of 53%, which is a 4% increment in the previous Mn grade which was 47%. The outcome of the studies is the new established operational conditions which is adhered to by the plant, producing a manganese concentrate grade ranging between 52-54%. Keywords: Design of Experiment (DOE), Spiral Classifier, Grade, Manganese

Production of process automation technology in the first stage of preparation ore of wet grinding

The creation of a new technology of automation of ore preparation processes in cycles of wet ore grinding is considered on the basis of analysis and modeling, modeling of the technological and physical features of apparatus and processes. An example of creation automation technology for controlling the performance of a spiral classifier in sand, modeling, testing technology and practical use in the conditions of the ore processing plant.