Value addition processing of low grade iron ores Research Papers (original) (raw)

Supply of world chromite (chrome ore) has come under severe pressure over the past year driven by strong demand for ferrochrome used in ferroalloy production for making stainless steel. Many of the strategic minerals are inputs into... more

Supply of world chromite (chrome ore) has come under severe pressure over the past year driven by
strong demand for ferrochrome used in ferroalloy production for making stainless steel. Many of the strategic
minerals are inputs into products in fast-changing markets. This article reviews the major process
flow sheets in practice for the recovery of chromite values from various types of ores and critical issues
related to chromite ore beneficiation. The comprehensive condensation of pertinent facts is intended to
provide a single reference source rather than the reader perusing many articles. Emphasis is placed on
different processes developed in identifying and solving critical plant problems.

In India, iron ores processing industries play a vital role in the Indian economy. During the washing and processing of iron ores, slimes less than 0.15 mm are generated and discarded into the tailing pond. These slimes need processing as... more

In India, iron ores processing industries play a vital role in the Indian economy. During the washing and processing of iron ores, slimes less than 0.15 mm are generated and discarded into the tailing pond. These slimes need processing as they cannot be used directly in blast furnaces. In the present investigation, a typical iron ore slime sample containing 59.22% Fe, 4.76% SiO2, and 4.57% Al2O3 was taken. The desliming operation was carried out by using 2” Mozley hydrocyclone. The process variables used to attain the optimum condition of desliming include the spigot opening, the feed pressure, and the diameter of the vortex finder maintaining the pulp density at 10% solid. The deslimed sample was treated by different techniques including an enhanced gravity separator to achieve iron concentrate with 65% Fe so that it can be used for steel making through pelletization. The yield of the magnetic concentrate is about 46.8% with 65% Fe. To improve the yield, the overflow from 2” hydrocyclone and the rejects from magnetic separation were deslimed and processed to recover the iron values. The final concentrate is 74% yield with 64.8% Fe, 1.76% SiO2, and 1.8% Al2O3.

This investigation compares bacterial leaching to chemical leaching to solubilize copper from a copper containing ore of the new site Northern Qarashoshaq in Zhylandy (Kazakhstan) which is currently under commercial development. From... more

This investigation compares bacterial leaching to chemical leaching to solubilize copper from a copper containing ore of the new site Northern Qarashoshaq in Zhylandy (Kazakhstan) which is currently under commercial development. From ICP-OES analysis the bulk ore sample contains 1.5% of Cu and a trace level at 0.0024 % of Ag. Phase analysis shows the main copper containing minerals are covellite, сhalcocite, malachite, chrysocolla and chalcopyrite. According to X-ray diffraction analysis silver is mainly presented as jalpaite (Ag3CuS2) minerals. Copper leaching was carried out by acidophilic bioleaching for comparison with extraction by chemical methods involving the addition of sulfuric acid and Fe3+ or only sulfuric acid in flasks, as well as column leaching tests to simulate heap leaching. Ag was extracted by cyanidation methods again in flasks as well as column leaching tests. Results showed that copper extraction is up to 95% when using bioleaching in the flask, 83% in the case of Fe3+ with sulfuric acid and 76% for sulfuric acid. Furthermore, subsequent extraction of Ag reaches 97% for bioleaching and 92% for chemical leaching. Column bioleaching tests showed an 82.3% yield of copper after 70 days of the experiment and a 70% of silver, whereas for chemical leaching the yield of copper is 66.8% and silver is 51%. In conclusion this investigation demonstrated higher extraction for both copper and silver from the primary ore in the bioleaching sample compared to the chemical leaching sample. More silver was extracted in the bioleaching case as there was less copper remaining to compete for the cyanide anions.

Increasing competition in the minerais industry and fluctuating coramodity prices require new ways of saving energy, lime, and general operational costs. A good understanding of physical processing or pre-processing streams that can... more

Increasing competition in the minerais industry and fluctuating coramodity prices require new ways of saving energy, lime, and general operational costs. A good understanding of physical processing or pre-processing streams that can potentially cut these costs requires detailed analyses of chemical and physical behaviours and processing responses during rainera]. processing. It is very useful to perform a detailed mineralogical and micro-textural characterization of materials (ore, tailings, and waste) that addresses, among other parameters, particle and grain sizes, as well as particle densifies. The choice and/or corabination of the 'best' processing approaches is crucial for processing efficiencies, and can be established and verified by using automated mineralogy with the associated software. A sample of low-grade iron ore from El Volcan, Mexico, serves as an example to demonstrate in a step-by-step approach how QEMSCAN® analyses provide processing information. Elements under consideration include iron, phosphorus, and sulphur.

Numerous iron ore deposits are hosted within the Meso to Neo-Archean banded iron formations (BIFs) extending across the Singhbhum-Orissa Craton, eastern India. Despite the widespread distribution of BIFs, which forms part of the iron ore... more

Numerous iron ore deposits are hosted within the Meso to Neo-Archean banded iron formations (BIFs) extending across the Singhbhum-Orissa Craton, eastern India. Despite the widespread distribution of BIFs, which forms part of the iron ore group (IOG), heterogeneity in their grade and mineral composition is occasionally observed even within a single ore deposit. Kiriburu-Meghahatuburu iron ore deposit (KMIOD), west Singhbhum district, Jharkhand, eastern India is characterized by a dominant hematite (often martitized) occurrence with a total resource of >150 million tonnes (MT) at 62.85 wt % Fe. Very high-grade blue dust ore (friable and powdery hematitewith~67% Fe), high-grade massive, hard laminated hematitic ores (~66% Fe) and medium to low grade goethitic/lateritic ores (50%–60% Fe) are the common iron-ore lithologies in KMIOD. These ores can be distinguished in the field from their physical appearance, meso-scale texture and spatial occurrences with the host rocks along with the variation in chemical composition. The high-grade ores are characterized by high Fe (>62 wt %), low Al 2 O 3 (1.5–2.5 wt %), low SiO 2 (2.0–4.5 wt %) and low P (<0.06 wt %). Detailed field studies and laboratory investigations on the ore mineral assemblages suggest that the mineralization of high-grade iron ores at KMIOD is controlled by three major parameters, i.e., lithological, paleoclimatic and structural controls. High-grade iron ores such as blue dust seem to be formed during leaching processes through inter-bedded ferruginous shale and banded hematite jasper (BHJ) occurring within BIFs. Structural elements such as folds, joint network, fracture arrays, local faults and steeply dipping bedding planes are surmised as strong controls for the evolution of different iron ore types from the BHJ. Most of the high-grade ores are concentrated at the hinge portions of second generation folds (F 2) owing to the easy access for circulation of meteoric solution along the fractures developed due to release of stresses at the hinge portions aided by supergene ore enrichment processes. The BHJ and interbedded ferruginous shale seem to have been given a significant contribution for the formation of different grades of iron ores over the area. Lithologically, the BIFs are governed by rheological features providing channel ways in the ore enrichment process. The variation in the iron ore mineralogy is caused by the variation in depositional and paleoclimatic environment, structural setting and lithological attributes. Hence, these parameters could be used for future exploration and grade recovery of iron ore resources in the region and in the adjoining areas.

Although dicalcium silicates can constitute up to 10 vol% of many modern hematite/goethite iron ore sin- ters, traditional mineralogical investigations of such sinters have largely overlooked this phase and focused on the more abundant... more

Although dicalcium silicates can constitute up to 10 vol% of many modern hematite/goethite iron ore sin- ters, traditional mineralogical investigations of such sinters have largely overlooked this phase and focused on the more abundant iron oxides and ferrites. However, dicalcium silicates have a range of properties that make them unique in sinter parageneses. These properties may contribute significantly to bulk sinter prop- erties and also make dicalcium silicates potentially exploitable in novel upgrading processes. Analyses on a pot grate test sinter have shown that phosphorous (and possibly other elements including potassium and chromium) was heavily concentrated in the dicalcium silicates. A series of etch tests have demonstrated that dicalcium silicates can be selectively removed from the surface of polished sinter samples using weak acids. In addition, bulk leaching trials showed that the phase can also be removed from powdered and coarser ( 5 mm) sinter in mild acids. These leaches resulted in a 90 % reduction in phosphorous with a 7 % improvement in iron grade for the powdered material and a 70 % reduction in phosphorous with a 5 % improvement in iron grade for the coarser material. Two novel processes are proposed to exploit the leacha- bility of contaminated dicalcium silicates from sinter: one being a potential route to a high-grade iron prod- uct, the other being a return fines washing circuit.

The central theme of this article is that the usual Shannon’s entropy [1] is not sufficient to address the unknown Gaussian population average. A remedy is necessary. By peeling away entropy junkies, a refined version is introduced and it... more

The central theme of this article is that the usual Shannon’s entropy [1] is not sufficient to address the unknown Gaussian population average. A remedy is necessary. By peeling away entropy junkies, a refined version is introduced and it is named nucleus entropy in this article. Statistical properties and advantages of the Gaussian nucleus entropy are derived and utilized to interpret 2005 and 2007 waste disposals (in 1,000 tons) by fifty-one states (including the District of Columbia) in USA. Each state generates its own, imports from a state for a revenue, and exports to another state with a payment waste disposal [2]. Nucleus entropy is large when the population average is large and/or when the population variance is lesser. Nucleus entropy advocates the significance of the waste policies under four scenarios: (1) keep only generated, (2) keep generated with receiving in and shipping out, (3) without receiving in, and (4) without shipping out. In the end, a few recommendations are suggested for the waste management policy makers

Thomas Edison's experiences in iron mining and refining and cement manufacture in New Jersey between 1880 and 1920 offer some useful comparisons with contemporary oil and gas industrialists and entrepreneurs in the Bakken shale formation... more

Thomas Edison's experiences in iron mining and refining and cement manufacture in New Jersey between 1880 and 1920 offer some useful comparisons with contemporary oil and gas industrialists and entrepreneurs in the Bakken shale formation and Alberta tar sands.