Search

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The modeling of mineral deposits has been improved over the years with the incorporation of mineralogical and metallurgical information obtained from drilling samples that make up the pillars for the construction of resource models. However, sampling data is being made available in large quantities, causing current databases to grow exponentially. The use of machine learning (ML) algorithms has been applied to deal with multidimensional data problems. Principal component analysis (PCA) is a multivariate analysis (MA) technique whose aim is to reduce the dimension of multivariate data. Studies show that results obtained with the reduction of variables were satisfactory in different areas of activity. The purpose of this article is to test variable selection criteria using PCA for geometallurgical data and to check the feasibility of the technique for simplifying variable types and defining typological domains. [ABSTRACT FROM AUTHOR]

Cornstarch is one of the most used depressants in mineral flotation operations. However, corn is a costly input for the Brazilian mineral industry, since its main destination is to serve the animal and human food market and exports. In this study, sorghum and millet, two cheaper starch sources, were tested in order to reduce the mining dependence on corn. A simplex lattice design mixture {3,4} was used to evaluate the best proportion of corn, millet, and sorghum flours to be used as a pyrochlore depressant in relation to the industrially adopted cornstarch (Stargill 6172 supplied by Cargill). Flotation tests were carried out on a bench scale Denver flotation cell. All tests were performed in triplicate in a single rougher stage. The results found suggest that sorghum flour was a stronger pyrochlore depressant compared to corn and millet flours, with an average Nb2O5 content of 1.72 ± 0.05% and recovery of 80.75 ± 4.10%. These values were close to the ones found with Stargill 6172 (1.32 ± 0.02 and 80.95 ± 1.13%, Nb2O5 content and recovery, respectively), the industrially adopted depressant. The marked price and the easiness in the production of the flour in relation to the extraction of starches makes the sorghum flour a potential pyrochlore depressant, replacing the industrially used cornstarch. [ABSTRACT FROM AUTHOR]

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Reusing waste is essential for the sustainability of the planet. Among the waste, we highlight agricultural limestone classified granulometrically as filler. The present work tested pharmaceutical, food and inorganic binders, capable of producing briquettes that withstood at least 75 drops of 1.2 m and a minimum dissolution time in water at 25 °C of 8 h, presenting a lower cost (in dollars per gram) of the binder. The objective is that this briquette produced with limestone filler and binder has the possibility of being used as organomineral fertilizer. The most promising binder was xanthan gum, which produced briquettes capable of withstanding up to 300 drops of 1.2 m, 11.67 h of dissolution in water at 25 °C, at a cost of US$ 0.078/g. [ABSTRACT FROM AUTHOR]

Mining was, and continues to be, one of the main pillars of the Brazilian economy. However, companies in the sector must make sustainable decisions and always be open to technological innovations to remain competitive, optimizing their processes and seeking continuous reduction of costs and waste. In this sense, studies aimed at reducing the cost of mineral comminution are necessary, since this step is responsible for a large part of the operating costs of a mineral processing plant. Bench-scale tests were carried out in order to technologically characterize samples of chromium ore (with an average content of 38% of Cr2O3) from the Ipueira mine of Companhia de Ferro Ligas da Bahia (FERBASA), national leader in the production of chromium concentrate and its leagues. A laboratory crusher model HRC D1000 was tested and compared with the grinding currently carried out in the company's bar mills. The results obtained indicate that it is possible to comminute the chromium ore dry, adapting its granulometry to the gravimetric concentration, as well as reducing operating costs with grinding. [ABSTRACT FROM AUTHOR]

Copyright of Tecnologia em Metalurgia, Materiais e Mineração is the property of Associacao Brasileira de Metalurgia e Materiais and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tecnologia em Metalurgia, Materiais e Mineração is the property of Associacao Brasileira de Metalurgia e Materiais and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Most copper flotation tailings contain a significant amount of sulfide minerals that can generate effluent resulting from the oxidation of sulfides when they are exposed to oxygen and water. This study aimed to characterize and evaluate the acid drainage potential of five different copper flotation tailings, named samples I, II, III, IV, and V. Sample I was taken from an industrial operation, while Samples II, III, IV, and V were produced in pilot plant tests. All samples were characterized and submitted to static acid drainage tests, such as paste pH, Net Acid Generation (NAG) pH, and Modified Acid-Base Accounting (MABA). The sulfur as sulfide/total sulfur mass ratios varies from 0.40 up to 0.89 showing the presence of a high amount of minerals rich in pyrite and alunite, being higher than 13 wt% of pyrite in samples IV and V and around 19 wt% of alunite in sample III. Samples I and II presented a high number of alkaline elements, totalizing more than 8 wt% of K2O+CaO+MgO, while samples III, IV, and V show the lowest amount of these elements (<4 wt%). Only samples III, IV, and V show Paste pH results lower than 5.0, indicating superficial oxidation on their surfaces and/or the presence of water-soluble acidity minerals. Due to the high pyrite content in samples III and IV, it was not possible to measure their NAG pH due to the high heat released with the addition of hydrogen peroxide. The low NAG pH obtained with sample III (5.30) was due to its high pyrite content (0.30 wt%) in comparison with the results obtained with sample I (NAG pH of 8.15 and 0.10 wt% of pyrite), and sample II (NAG pH of 8.18 and 0.10 wt% of pyrite). The MABA results show that samples III, IV and V presented acid drainage potential due to the neutralization potential (NP)/acidity potential (AP) ratio being lower than 1. On the other hand, samples I and II presented NP/AP ratio higher than 4, not showing potential to generate acid drainage. Due to these results, it is recommended to carry out acid drainage kinetic tests with samples III, IV, and V to determine the long-term weathering rates, evaluate lag time to acid generation and provide reaction rates for geochemical modeling. [ABSTRACT FROM AUTHOR]

Starches are depressant reagents used in mineral flotation in order to confer selectivity to the process. For this, they need to be previously gelatinized, with the alkaline method being the most used technique in the mineral industry. In Brazil, NaOH is used as alkali and the flour/NaOH ratio is a parameter analyzed in this process. Although they are important, studies on this topic are scarce in the literature. That said, the work consisted in determining the ideal flour/ NaOH ratio for the gelatinization of depressants based on corn, sorghum and millet and in proving the effectiveness of the process under optical microscopy with polarized light. Subsequently, flotation tests with niobium ore using corn, millet and sorghum flours and their respective mixtures as depressants were carried out and the results were compared with industrial corn starch. The results showed that the new proposed depressants used smaller amounts of NaOH to be gelatinized in relation to corn starch. The optical microscopy stage confirmed the disruption of Maltese crosses for all flours, indicating complete gelatinization. The best pyrochlore depressant was sorghum flour and the results showed statistical similarity with corn starch. [ABSTRACT FROM AUTHOR]

Brazil is among the world's largest iron ore producers. The standard concentration method is reverse cationic flotation using amines, and their derivatives, such as quartz collector and corn (as either grits, flour, or starch) as the hematite depressant. Corn is considered cheap, abundant, and available all around the country. However, its demand has been abruptly increasing over the last few years, mainly due to the emerging of new attractive markets, such as ethanol production. In order to propose a feasible replacement for corn, hematite and quartz samples from the Brazilian Iron Quadrangle were tested in a modified Hallimond tube using millet starch as depressant for the first time (corn and sorghum starch were used as benchmark). Tests were carried out with four different depressant dosages and four different pHs, all in triplicate. It was possible to reach quartz floatability above 98% and hematite depressability above 93% for millet and sorghum starches. This fundamental study shows that replacing corn with millet poses a real opportunity to reduce operational costs. [ABSTRACT FROM AUTHOR]

Mudflow is often associated with seismic activities. The present study applied a seismic based detection of the surface waves generated by the mudflow of Brumadinho dam collapse using records of Brazilian Seismographic Network. The signal envelope and time-frequency spectrograms of the mudflow signals were used in the analysis. As a result, the mudflow signals were successfully detected from the data recorded at a nearby seismic station. The findings of this study provide a good basis for future research to develop a flood early warning system based on cost-effective, remote and contentious seismic monitoring approaches. [ABSTRACT FROM AUTHOR]

Since mid-2014, the Brazilian construction sector has been facing a severe economic recession. However, the demand for raw materials for concrete production remains high, especially for aggregates. This is because approximately 70-80% of the concrete volume is made up of gravel and sand. It is estimated that 740 million tons of gravel and sand were consumed in Brazil by civil construction in 2014. However, in 2015 this same consumption was reduced to 519 million tons. The adoption of innovative raw materials with high quality, low price, and lower environmental impacts in its production chain is of paramount importance for increasing the sustainability in the construction sector. The aim of this work was to characterize physically and chemically waste rocks from mines located on the southeastern part of the Goiás state in order to use them as coarse aggregates for concrete. The technical standard NBR 7211/2009, published by the Brazilian Association of Technical Standards (ABNT) was used. Four samples of 100 kg were collected from different lithologies and classified by dry screening to obtain four different gravel types (0, 1, 2, and 3). Specific mass, compacted unit mass, water absorption, clay and friable material content, mechanical strength, fine material content, particle size distribution, and shape index were determined. All samples passed the tests and, therefore, the waste rocks has features that allow them to be used as coarse aggregates in civil construction. [ABSTRACT FROM AUTHOR]

Brazil is the largest producer of Niobium alloys, with a production of 58,000 tons of Nb2O5 concentrate in 2016, corresponding to a 92.81% of the world production. The Brazilian Niobium ores grades vary from 0.51 to 2.71%. Ferroniobium (Fe-Nb) is an iron niobium alloy with niobium content of 60-70%. It is the main source for niobium alloying of HSLA steel and covers more than 80% of the worldwide niobium production. In 2014, Brazil produced 51,737 tons of Fe-Nb, being around 90% of it for exportation. In the final stage of the Fe-Nb production, the alloy needs to be crushed in a jaw crusher, which generate fine particles (around 26% of the feed below 10 mm at Niobras/CMOC). The selling price of the fine particles have a significant loss in the market, since the fine particles cannot be used directly in steelmaking. A process to agglomerate the Fe-Nb fine particles into briquettes with size and chemical composition similar to original products was developed. Organic binders were used as well as a lubricant agent. The briquettes were characterized both physically and chemically. For the physical characterization, the briquettes were tested for mechanical and water resistance, thermal shock and Brinell hardness. Briquettes containing addition of 3% of zinc stearate, 2% of iron powder, and 1% of water reached a Niobium content above 62% and contaminants levels of below the standard Fe-Nb specifications. The results indicate that Fe-Nb alloy fines can be technically and economically agglomerate by briquetting. [ABSTRACT FROM AUTHOR]

The main source of phosphate in Brazil are igneous rocks, which need to be concentrated through froth flotation to separate phosphate ore from the other minerals. Searching for new sources of reactants to be used in mineral processing, spent yeast cells (SYC), from a local brewery was tested. Saccharomyces cerevisiae was choose because its relative easy industrial grow, has no biological risk and can be found worldwide. Microflotation experiments were conducted in a modified Hallimond's tube with high purity apatite mineral samples at pH 10 in order to investigate the influence of the collector dosage in the mineral recovery. The results showed that despite SYC has had lower recovery than collectors industrially adopted, it has a potential future use in mineral flotation as a cheap, biodegradable, eco-friendly, and sustainable reagent with no acquisition cost since the brewery complex is located less than 30 km from Catalao and Ouvidor mine sites in Brazil. [ABSTRACT FROM AUTHOR]

The flotation of Phosphate ore with silicate-carbonate gangue, such as those present in Catalão I Alkaline Ultramafic and Carbonatitic Complex has low selectivity between apatite mineral family and carbonate. Hallimond tube microflotation tests with saponified Jatropha Curcas L oil were carried out to measure the recovery of apatite, calcite and quartz. Five concentrations of the collector under two saponification conditions (room temperature and 90 °C) were tested. Three different pH values were analysed (8, 9 and 10), totalling 90 assays for each mineral. The mineral samples were analysed by SEM, EDS, fluorescence and X-rays diffraction, and had their zeta potential measured. The Jatropha Curcas oil presented significant recovery of apatite and calcite and selectivity in the flotation of the tested minerals. [ABSTRACT FROM AUTHOR]

Among the phosphorus bearing minerals, the apatite group is the main source of the phosphate used as input in the industrial fertilizers manufacture. Macaúba (Acrocomia Aculeata) is a tree, which naturally occurs in Brazilian's savanna and contains high concentrations of fatty acids in its nuts (36.2%). The most abundant fatty acids in the nuts are lauric acid (39.7%) and oleic acid (25.8%). The present study sought to demonstrate, through microflotation experiments conducted in Hallimond tube, the potential use of macaúba oil in the flotation of apatite. The tests were performed with 1 g of high purity apatite, in the particle size range of -100+150 # (-150+106 µm) at pH levels of 8, 9, and 10 g and concentrations of the collector of 2.5; 5.0; 7.5 and 10.0 mg/L. The collectors used were the macaúba's nut oil hot saponified at 90 °C and at room temperature and Clariant's Flotigam 5806. The oil saponification at 90 °C yielded higher recoveries than that at room temperature and in some tests, the performance was superior to that achieved Flotigam 5806. [ABSTRACT FROM AUTHOR]

Macaúba (Acrocomia Aculeata) is a palm tree typical of the Brazilian savanna with great socioeconomic interest due to its high capacity of vegetable oil production with high levels of fatty acids. This paper evaluated the technical viability of saponified macaúba's nut oil (SMNO) as a collector in apatite's micro flotation in Hallimond tube, being the oil chemically characterized and saponified before its utilization. Tests were performed varying the solution pH (8, 9 and 10) and collector concentration (2.5, 5.0, 7.5 e 10 mg/L). To compare the obtained results with SMNO the industrial collector Clariant's Flotigan 5806 was used in the same tests conditions. Results shows that SMNO reached the highest recoveries rates of apatite in pH 8 and 9, particularly at the concentrations 7.5 and 10 mg/L. When compared to Flotigam 5806, the MNO showed lower recoveries at all pHs and concentrations tested. [ABSTRACT FROM AUTHOR]

A problem for solving mass balances in mineral processing plants is the calculation of circulating load in closed circuits. A family of possible methods for the resolution of these calculations is the iterative method, consisting of a finite loop where in each iteration the initial solution is refined in order to approach the exact solution. The present work presents a low-complexity iterative algorithm for circulating load calculation in mineral processing closed circuits, thus enabling the construction of reliable mass, metallurgical and water balances. The proposed equations on the algorithm were obtained through the analysis of many industrial systems, taking into account the process operational parameters. A validation was performed with real industrial data, in order to ensure a greater reliability of the obtained results. Two different types of closed circuits are presented, each one with different levels of complexity, to clarify the proposed algorithm. With the results, it is possible to affirm that the proposed iterative algorithm can be successfully applied to any kind of closed circuit in mineral processing. The results were satisfactory with respect to processing speed, convergence of the solution and the number of iterations required for the circulating load calculation. [ABSTRACT FROM AUTHOR]

Hydrocyclones are devices worldwide used in mineral processing for desliming, classification, selective classification, thickening and pre-concentration. A hydrocyclone is composed by one cylindrical and one conical section joint together, without any moving parts and it is capable of perform granular material separation in pulp. The mineral particles separation mechanism acting in a hydrocyclone is complex and its mathematical modelling is usually empirical. The most used model for hydrocyclone corrected cut size is proposed by Plitt. Over the years many revisions and corrections to Plitt's model were proposed. The present paper shows a modification in the Plitt's model constant, obtained by exponential regression of simulated data for three different hydrocyclones geometry: Rietema, Bradley and Krebs. To validate the proposed model literature data obtained from phosphate ore using fifteen different hydrocyclones geometry are used. The proposed model shows a correlation equals to 88.2% between experimental and calculated corrected cut size, while the correlation obtained using Plitt's model is 11.5%. [ABSTRACT FROM AUTHOR]