Veerendra Singh

Application of image processing in mineral industry: a case study of ferruginous manganese ores

Abstract The twenty-first century is bringing radical changes in mineral industry. High speed and low cost computational and sensing devices make it possible to reach at remote location and instantaneous control on the processes. Image processing which was very useful for some selected applications is getting popularity in mineral industry in changed scenario. In the present article image processing technique is explained briefly and its application in mineral industry has been summarised. A case study of ferruginous Indian manganese ore is presented. These ores show variation in their colour owing to variation in chemical composition. These ores were studied in red, green and blue colour space, histogram analysis; textural analysis and edge detection technique were used for separation of alumina lumps and to distinguish different ores. It shows acceptable results to carry out further studies for developing new cost effective ore blending and ore sorting methodologies for mineral industry. MATLAB 7·0 was used for image processing studies.

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.

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.

Ore pretreatment methods for grinding: journey and prospects

ABSTRACT Pretreatment of ores to improve energy efficacy of grinding has been explored for decades. However, many of these techniques are still at developmental stages and a review has been presented in this paper to discuss the research journey and problems associated with commercialization of these techniques. This review reveals that a variety of stress-generating techniques have been used to treat the composition and morphology of particles to improve the grinding process. Grinding additives are used commercially successful technology while microwave pretreatment also has been successfully piloted. Newly developed techniques such as ultrasonics and electric disintegration have shown potential for success but the cost economics of these processes is still not as attractive as desired. Incipient techniques based on bio-milling, shock waves, and nuclear hold promise for the future. It is also expected that the technological advances around information technology, instrumentation, and energy science will help to solve techno-economic challenges associated with commercialization of the known technologies. Demand for energy-efficient grinding pretreatment methods will grow in the future considering the depletion of high-grade resources and stringent environmental constraints related to reject disposal.

Study of the kinetics of the magnesium leaching from serpentine bearing chromite overburden rocks for mineral carbonation

ABSTRACT Characterisation and leaching studies have been carried out on serpentinite rock samples collected from Sukinda mines, India. Dissolution characteristics of samples have been studied using HCl, H2SO4 and HNO3 acid. Effect of particle sizes, solvent concentrations, reaction temperatures and reaction time have been investigated. It was found that Mg recoveries vary between 54.95% and 98.12%. Leaching of fine particles of <53 µm sizes using H2SO2 solution of 1 M at 70°C for 2 h can recover maximum 93% Mg with lowest Si content (6.6%). Kinetic studies indicated that dissolution of Mg follows product layer diffusion mechanism and activation energy calculated was 37.88 kJ mol−1. CO2 treatment of leach liquor resulted in precipitation of magnesium carbonates and hydroxides at a solution pH adjustment between 7 and 10. The study revealed that these rocks can be used for CO2 fixation and H2SO4 can be the best solvent.

Assessment and Mechanism Investigation of Selective Flocculation Process for Ultrafine Chromite Particle

During beneficiation of low-grade chromite ore, huge amounts of ultrafine tailings are generated and contain substantial metal values which need to be recovered. Selective flocculation technique is one of the processes for beneficiation of ultrafine particles. Here an attempt was made to establish selective flocculation process by using two types of synthetic mixtures. In addition to this, selective flocculation was also attempted on natural tailings. It was found that it is possible to enrich the chromite value using the selective flocculation process. The selectivity of the wheat starch to the chromite mineral was also investigated using image analysis, FTIR analysis, and zeta potential analysis.

Selective Classification of Mineral Sand Slimes in an Air Fluidized Bed

Studies were carried out for selective classification of mineral sands to remove unwanted slimes (particles of <0.63 µm in size). Vertical and arched fluidized bed setups were tested to retain the coarser heavy mineral particles from fluidized mineral sand beds. Theoretically calculated process parameters were used to develop the experimental setups. The mathematical model given by Nguyentranlam and Galvin (“Particle classification in the reflux classifier.” Minerals Engineering, 14(9), 2001, pp. 1081–1091) was used to develop an arched fluidized bed setup. Experiments were carried out at six different superficial air velocities (0.21, 0.25, 0.34, 0.41, 0.64, and 0.82 m/s) in the vertical and arched fluidized bed setups. An acceptable agreement was found in the experimental and theoretical results. The overall process capability of the vertical fluidized bed to selectively remove the slimes was 44.8% with the loss of 3.93% of heavy minerals. The overall process capability was improved up to 52% with the loss of 4.08% of heavy minerals by the proposed arched fluidized bed setup. The developed arched fluidized bed setup showed improved performance for selective elutriation of mineral sand slime particles with compromising heavy mineral losses.