Sunil Kumar Tripathy

Effect of desliming on the magnetic separation of low-grade ferruginous manganese ore

In the present investigation, magnetic separation studies using an induced roll magnetic separator were conducted to beneficiate low-grade ferruginous manganese ore. The feed ore was assayed to contain 22.4% Mn and 35.9% SiO2, with a manganese-to-iron mass ratio (Mn:Fe ratio) of 1.6. This ore was characterized in detail using different techniques, including quantitative evaluation of minerals by scanning electron microscopy, which revealed that the ore is extremely siliceous in nature and that the associated gangue minerals are more or less evenly distributed in almost all of the size fractions in major proportion. Magnetic separation studies were conducted on both the as-received ore fines and the classified fines to enrich their manganese content and Mn:Fe ratio. The results indicated that the efficiency of separation for deslimed fines was better than that for the treated unclassified bulk sample. On the basis of these results, we proposed a process flow sheet for the beneficiation of low-grade manganese ore fines using a Floatex density separator as a pre-concentrator followed by two-stage magnetic separation. The overall recovery of manganese in the final product from the proposed flow sheet is 44.7% with an assay value of 45.8% and the Mn:Fe ratio of 3.1.

Processing of Ferruginous Chromite Ore by Dry High-Intensity Magnetic Separation

ABSTRACT Mineral and morphological characteristics of chromite ore strongly affect the separation efficiency while upgrading the low-grade deposits. Usually, chromite ore enrichment is carried out by using gravity separation due to high-concentration criterion between chromite and other minerals. However, chromite ore from Sukinda region, India, is a typical ore body with high iron content in the chromite spinel as well as gangue content in the form of oxide and hydroxides of iron-bearing minerals. So, the separation efficiency reduces by gravity method due to the lower value of concentration criterion. To address this, dry magnetic separation is an alternative approach to separate these iron-bearing gangue minerals from the chromite. This work investigated on the application of different dry high-intensity magnetic separators to separate the chromite grains from ferruginous chromite ore deposits of India. Prior to the separation, two different ore deposits of Sukinda region are subjected to detailed mineral, chemical, morphological, as well as magnetic properties characterization to visualize the separation. Tests confirm the effect of magnetic field strength along with other process parameters that influence the process of the separation of iron-bearing gangue minerals. The results on these separators are related to the influence of mineralogy, process parameters, and magnetic property of minerals, based on the experimental and statistical analysis of the process. Also, effect of desliming of the low-grade deposit prior to the dry magnetic separation is highlighted.

Magnetic separation studies on ferruginous chromite fine to enhance Cr:Fe ratio

The Cr:Fe ratio (chromium-to-iron mass ratio) of chromite affects the production of chrome-based ferroalloys. Although the literature contains numerous reports related to the magnetic separation of different minerals, limited work concerning the application of magnetic separation to fine chromite from the Sukinda region of India to enhance its Cr:Fe ratio has been reported. In the present investigation, magnetic separation and mineralogical characterization studies of chromite fines were conducted to enhance the Cr:Fe ratio. Characterization studies included particle size and chemical analyses, X-ray diffraction analysis, automated mineral analysis, sink-and-float studies, and magnetic susceptibility measurements, whereas magnetic separation was investigated using a rare earth drum magnetic separator, a rare earth roll magnetic separator, an induced roll magnetic separator, and a wet high-intensity magnetic separator. The fine chromite was observed to be upgraded to a Cr:Fe ratio of 2.2 with a yield of 55.7% through the use of an induced roll magnetic separator and a feed material with a Cr:Fe ratio of 1.6.

Artificial Neural Network Modeling of Ball Mill Grinding Process

Grinding consumes around 2% of the energy produced in the world but existing methods of milling are very inefficient and use only 5% of the input energy for real size reduction rest is consumed by machine itself. Chrome ores are comminute, filtered, pelletized and sintered to use into submerged arc furnace for ferrochrome production. Variation in ore properties affects the particle size distribution during milling. Artificial neural network based model is developed to predict the particle size distribution of ball mill product using grinding data available for difference in grindability of Sukinda chromite ores. Input variables for model were ball size, ball load, ball-ore ratio, grinding time. Output was particle size distribution (+75 μm, -75 μm, +38 μm; -38 μm). Three different kinds of mathematical models have been compared to predict the particle size distribution. Finally a neural network based model was found most accurate. Dynamic artificial neural network model does not require any material constant and optimizes the mathematical correlation with better accuracy in a dynamic process. This methodology can be used to develop an online system to predict the ball mill performance to improve the performance of grinding circuit in mineral, metal and cement industry.

Dry High-Intensity Magnetic Separation in Mineral Industry – A Review of Present Status and Future Prospects

ABSTRACT High intensity dry magnetic separators are in use for various applications in the mineral as well as coal processing industries. Evaluation of the performance of these separators treating different minerals has become an active research topic. Several attempts have been made by different researchers and technologists to understand the separation behavior of particles in each of these separators treating different types of para-magnetic minerals. Despite all these efforts, these separators are yet to find widespread applications to treat different para-magnetic minerals. Therefore, the present status of these separators with a brief description of their operating principles, applications, and modeling are reviewed in this article. Also, the research work needs to focus on each separator has been highlighted.

Multiobjective optimisation of spiral concentrator for separation of ultrafine chromite

Chromite beneficiation plants generate large amount of tailings with significant amounts of ultrafine chromite minerals. In the present investigation, Box−Behnken experimental design was used to model the effects of feed rate, feed pulp density and splitter position on the performance of a spiral concentrator for separating the ultrafine chromite values from the plant tailings. Splitter position has a major influence on both grade and recovery of the concentrate fraction of spiral concentrator. Second-order quadratic models were used for describing the performance of spiral concentrator. Multiobjective optimisation of process parameters was carried out for achieving both in grade and recovery which were higher than 40% and 30% Cr2O3, respectively.

Recycling of ferromanganese gas cleaning plant (GCP) sludge by novel agglomeration

Ferroalloy industries rely on minerals which are not available in pure form. The total value chain is very cost intensive and market driven. From mineral and environment conservation point of view every possible aspect must be explored for the economic utilisation of waste and low-grade ores. Unlike other metallurgical processes, Ferro alloys production generates a wide variety of waste rich in manganese/chrome which has a potential for recycling back. Fine size, high moisture content and presence of alkalis categorise this material into hazardous waste and economically non-viable. The challenge is to convert such anthropogenic material into a suitable feedstock for the furnace. In this article, the results of smelting trials carried out in electric arc furnace (EAF) using novel extruded briquettes (BREX) produced from the wastes of ferroalloy plant is discussed. The briquette produced by this technique exhibit high physical and metallurgical property and can replace the natural ore as a charge to some extent. Extruded briquettes (BREX) can be efficiently used as one of the essential charge component (up to 30% of the ore part of the charge) for the Silicomanganese smelting thus improving technical and economical parameters of the furnace and decreasing the self-cost of the Silicomanganese production.

Comparative separation analysis of direct and reverse flotation of dolomite fines

ABSTRACT In the present investigation, beneficiation of a low-grade dolomite fines was carried out with the aim to remove the siliceous gangue content. Extensive experimental studies on direct and reverse flotation were carried out on low-grade ore by varying the critical process variables, and the performance was compared. The experimental results show that it is possible to reduce the silica content following both direct and reverse flotation processes. Further, direct flotation results show better control over the quality of the product while reverse flotation has an edge on the product yield.