A new limit theorem involving the Smarandache LCM sequence

The main purpose of this paper is using the elementary method to study the LCM Sequence, and give an asymptotic formula about this sequence

Automated mine optimization system for diamond mines

A diamond mine generally consists of mining and mineral beneficiation operations. Mining operation includes planning, drilling, explosion, loading; hauling and mineral processing normally has the following operations: crushing; screening; washing; transporting; separation; sorting; storing; water treatment, etc. The operation could be described as a complex and expensive balancing act where material flow rates, size, density and other factors must all be in required balance if any degree of plant optimization and efficiency is to be achieved. One of the main objectives to optimally operate a mine is to maintain balanced production among all product streams. To achieve a balanced and optimal production at a mine, two tasks at least must be considered. The first is to have an optimal production plan, including a set of optimal production targets for all process units. And the second task is to make sure that all those optimal targets in the mentioned optimal production plan must be achieved at all process units by using all resources available. To achieve the mentioned two tasks, all measurements, equipment and systems at the mine must be available in real time, particularly those critical measurements such as weightometers, densitometers, ore types; stockpile levels. With the advancement and applications of technologies in mineral processing industry, an automated mine optimization system is developed to include the following three functions: (1) mine production optimizer; (2) various dynamic controllers; and (3) a set of soft sensors. Over the past ten years, a large amount of work has been done to develop the system, started from forming the concept to testing and implementation at various mines. The system can potentially help improve the production throughput up to 30% at the mineral processing operation of a mine

Effect of South Africa chrome ores on ferrochrome production

About 80% of world chrome ore reserves are found in South Africa, mainly in the Bushveld Igneous Complex. Chrome ores from six locations across the Bushveld Complex are used to investigate the effects of ore types on the smelting processes, such as the consumption of fluxes, reductant; and most importantly, the consumption of electricity..

Chrome ores on ferrochrome smelting

Chrome ores from six locations across the Bushveld Igneous Complex in South Africa are used to investigate the effects of ore types on the smelting processes, such as the consumption of fluxes, reductant; and most importantly, the consumption of electricity. The electric energy consumption is highly related to the SiO2 content of chrome ores. The lowest electric consumption of 3.31 MWh/t is required when the SiO2% of chrome ores is 6%. Considering the fact that the other contents do not change much in the selected 6 lumpy ores, an increase of SiO2 will decrease the contents of Cr and Fe oxides in the ores. As a result, it requires more ore and less quartzite to feed in the furnace. With the combined effect of more ores and less quartzite, the smelting process produces more slag and requires more electric energy to heat and melt the slag

Online smart sensor to measure stockpiles used in mineral processing

With the advancement and the wide usage of measurement instruments associated with stockpiles, such as weightometers, a smart sensor can be developed to online monitor the level of a stockpile. Furthermore, the stockpile smart sensor can be used to determine the mixing behaviour of different ores discharged out of the stockpile, by combining the smart sensor technique and element modelling. The mixing behaviour of different materials includes when and how the mixing takes place, and more important, when the mixed materials with a certain portion is discharged out of the stockpile. In this article, only the level function of the stockpile smart sensor will be discussed in detail. The stockpile smart sensor can help estimate accurate residual time for different group of ores charged to the stockpile. The smart sensor makes it possible to monitor the behaviour of different ore types in real time in a stockpile, including when and how the different ores are mixed in the stockpile and when the mixed ores are discharged with certain mixing portion. Using the smart sensor system, the information on ore types can be provided for ores that are discharged from the stockpile. The ore type information includes ore grade, density, hardness, strength, etc. The stockpile smart sensor, developed originally for a diamond mine, can be used for stockpiles of other mines, including iron ore mines, coal mines, copper mines, chromium ore mine, and cement plants

Learning and teaching using process modelling and simulation

Abstract: Depending on the way of teaching, teachers can make enormous difference in the quality of learning and teaching at university. This paper covers how to use process modelling and process simulation to help students to understand some of the complex industrious processes easier and better. Many industrious processes, such as the production of ferrochrome, are extremely complicated and often those processes are interacted and involve many physicochemical reactions that happen simultaneously. When there is any change in one of the inputs, it usually requires to understand the potential effects on the production processes and then decide what actions should be taken to accommodate the change of the mentioned input, in order to manage the production processes to achieve the desired target. Due to the complexity of the production, it takes many hours to complete a charge calculation, which involves with the calculation of mass and energy for the entire furnace. Using process simulation built with process models, it is possible to carry out many what-if scenario exercises in classroom, resulting in easier and better understanding of the cause-effect relationship existing in the production of ferroalloy

Using programming to optimize mineral processing

Ore beneficiation at a mine could be described as complex and expensive, involving many balancing processes where material flow rates, size, density and other factors must all be in balance, if any degree of plant optimization is to be achieved. To determine the optimum setup for maximizing throughput at the final step in the beneficiation process, such as the dense media separation units, a mine optimizer is developed to maximize the production throughput as objective function, using constraint-based global optimization. The mine optimizer uses a search engine to find a set of operational conditions, that will help achieve the maximum production within all constraints, such as the availability of plant, the capacity of all press units; the change in material size and property (between crushers) and other operational conditions at the mineral process plant. The result is that improving cheaper upstream processes, such as blasting, can significantly increase the throughput of expensive downstream processes, like crushing, through improved fragmentation of the ROM ore. For instance, if the ROM ore is not in the required range, the plant production is unbalanced and consequently the mine could loss production by 10-20%, even up to 50% of production loss in the worst case. On one hand, a finer ROM ore may result in lower production of both crushing and coarse separation by 50%, while other process units are running at 100% capacity, such as slimes and tailing dumping. In addition, a finer ROM ore! may destroy the mineral value as well, such as in the cases of mining coal, iron ore, and diamond ore, where a higher price is paid for the products of larger size

System integration of automated mine optimization system

Abstract: With the advancement and applications of technologies in mineral processing industry, an automated mine optimization system is developed to include the following functions: mine production optimizer; various dynamic crusher controllers; and a set of soft sensors. The system consists of a real-time engine to run optimizer, dynamic controllers and soft sensors. The real-time engine is integrated with process control systems at a mine, including mining dispatch system and geological data base through ODBC protocol, processing plant SCADA system and production reporting systems via OPC protocol. The system can potentially help increase production output up to 30% of a mine with mining and mineral processing operations, such as diamond mine, iron ore mine, chromite ore mine, manganese ore mine, coal mine, etc

Improvement of wear property of carbon steel by vanadium carbide surface layer

Carbon steels are widely used in manufacturing of simple constructions and machine elements. The main limitations of these materials are their low hardness, poor friction and poor wear properties. For that reason, many attempts have been made to improve their hardness and other mechanical properties. One of the challenges is to find ways to improve the surface property of cheap steels in order to enhance its usage properties and ultimately extend the service life in an economic way. Due to its high hardness, vanadium carbides are often applied to the surface of carbon steels through coating processed and thermal diffusion processes. Samples of high carbon steels are treated using the molten slag process to form vanadium-based alloy layer on the surface of steel. After treatment using the mentioned molten slag process, the anti-wearing property of high carbon steel is improved by 15.6 times. The surface-alloy layers on high carbon steel are found in the form of vanadium carbide with a composition of VC0.8. The hardness of the alloy layer is 2200Hv, 3.4 times higher than that of high carbon steel

Effect of South Africa Reductants on Ferrochrome Production

With a limited supply of electricity, and sharp increase of electricity tariffs, South Africa’s share of world ferrochrome production has declined to 38% in 2011. The situation is set to continue and could go from bad to worse in the near future.Consequently, all ferrochrome producers in South Africa are looking for any alternatives that can use less electricity. An investigation of the effect of various reductants on the electric energy consumption is under consideration. A group of reductants, consisting of 6 types of coke and 2 types of anthracite, is selected to investigate the effect on energy consumption of ferrochrome production in submerged arc furnace. An excel-based simulation is used to calculate all charges and energy usage with similar production conditions used by most ferrochrome producers in South Africa