Roberto Galery - Academia.edu (original) (raw)

Papers by Roberto Galery

REM - International Engineering Journal, 2024

Process simulations can be used to improve grinding circuit performance, which efficiently reduce... more Process simulations can be used to improve grinding circuit performance, which efficiently reduces operating costs. The population balance model (PBM) is widely accepted for grinding modeling because it can reproduce breakage events in tumbling mills, as described by Austin et al. (1984). In this study, a pseudodynamic model is introduced, integrating the PBM with the Monte Carlo Method to stochastically simulate variables in an industrial grinding circuit. This integrated approach enabled circuit simulations over a period of 2 hours, representing the operational variables as seen in historical data. Model validation showed a correlation of 0.74 in the product size distribution when comparing simulated outcomes with the original population.

Canadian Journal of Chemical Engineering, Jun 8, 2022

Among several methods employed for sizing thickeners available in the literature, the Kynch, Bisc... more Among several methods employed for sizing thickeners available in the literature, the Kynch, Biscaia Jr., Talmadge and Fitch, Roberts, Coe and Clevenger, and Oltmann methods use experimental data from sedimentation curves and graphical approaches. By using the Weibull distribution, it is possible to represent sedimentation curves with algebraic equations, which does not require the use of graphical approaches and provides more accuracy and speed for sizing calculations. In the present work, the main objective is the development of a set of equations for sizing continuous thickeners, for six conventional methods found in the literature, using the Weibull model. A comparative analysis of calculated and literature diameters for each graphical method presented variations between 0.73% and 8.93%. The use of the Weibull model presented the best accuracy for the Biscaia Jr. method, with a 0.73% average absolute error.

Comminution is the most energy intensive process in mining industry, due to its low efficiency. C... more Comminution is the most energy intensive process in mining industry, due to its low efficiency. Comminution efficiency decreases with particle size, providing a great incentive for the optimisation of fine grinding applications. Related to this issue, the Size Specific Energy (SSE) approach is a technique that provides a better evaluation of comminution efficiency, once it takes in account the generation of fines and it is less dependent on particle shape. Based on this, the SSE can be used as a benchmarking for fine grinding evaluation. The aim of this paper is to apply the SSE approach to the evaluation of grinding efficiency of gravity induced stirred mills. Batch grinding experiments were conducted in a laboratory gravity induced stirred mill using an iron ore sample with a top size of 0,180mm

The vertical mill was developed in Japan in the 1950s, for fine and ultrafine grinding applicatio... more The vertical mill was developed in Japan in the 1950s, for fine and ultrafine grinding applications. In the last decades this type of mill has been utilized, preferably in regrind circuits. Recently, the vertical of mill has also been considered for primary grinding applications. This paper aims to present the historical of the successful applications and the most modern tools for design and simulation.

Comparative Biochemistry and Physiology Part B: Comparative Biochemistry, 1973

REM - International Engineering Journal

The sizing of vibrating screen machines can be done by various methods, most of them based on the... more The sizing of vibrating screen machines can be done by various methods, most of them based on the classic method of Allis Chalmers (ACM). Due to the wide diffusion and applicability, the Peter King (PKM) and Karra (KM) methods present great technical relevance as well. The objective of this study was to evaluate and compare the results of the screen surface areas, calculated by these three methods, and the real areas of the industrial machines. The study was based on data generated in 11 real industrial screening operations, being possible to evaluate the deviations of the areas calculated by the mathematical methods in relation to the real areas of the industrial machines. Results have shown that although all methods have restrictions on their use, PKM has the smallest deviations compared to the real dimensions of the industrial machines for four screening conditions. All these conditions showed screen apertures from 4.76mm to 19mm, moisture from 2.12% to 3.3%, Gneiss as feed material and deviations smaller than 13%.

Journal of Materials Research and Technology

REM - International Engineering Journal, 2022

In the search for alternatives to obtain more information from rock tests and to make them more a... more In the search for alternatives to obtain more information from rock tests and to make them more accessible, this study applies the Digital Image Correlation technique (DIC 2D) in a diametral compression test called Brazilian Test, comparing the result measured by an extensometer with the result obtained by DIC. Rock tests provide information about rock characteristics applicable to several engineering areas, such as mining and construction. In tests using strain gauges to measure strain, the equipment is expensive and there is a risk of breaking the instrument due to the contact with the specimen. However, tests measuring strain through the DIC technique may be more accessible, using open source software and lower cost equipment when compared to the cost of the extensometers. The results of this study demonstrate that the DIC technique enables: 1) complementing the information of diametrical tests obtained using strain gauges, for example, supporting the visualization of crack propagation; and 2) in some cases, replacing the use of extensometers, as far as a variation is tolerated.

Anais do XVII Encontro Nacional de Estudantes de Engenharia Ambiental e V Fórum Latino-Americano de Engenharia e Sustentabilidade, 2019

Siltitos verdes, conhecidos tradicionalmente como verdetes, ocorrem na regiao de Sao Gotardo, cen... more Siltitos verdes, conhecidos tradicionalmente como verdetes, ocorrem na regiao de Sao Gotardo, centro-oeste de Minas Gerais, inseridos na Formacao Serra da Saudade, Grupo Bambui. Estudos petrograficos baseados em lâminas delgadas, difratometria de raios X, microssonda eletronica e microscopio eletronico de varredura foram realizados para identificar a mineralogia destes siltitos. Sao rochas sedimentares silto-argilosas compostas por glauconita (40-80%), feldspato potassico (10-15%), quartzo (10-60%), muscovita (5%), e tracos de biotita (2%), goethita (<1%), oxidos de titânio e manganes (<1%), e fosfatos de bario e terras-raras (<1%). Niveis enriquecidos em potassio, com teores de K2O entre 8 e 12%, estao associados as porcoes mais ricas em glauconita, de cor verde escuro. A glauconita e autigenica e possui alto grau de maturidade. As grandes concentracoes deste mineral indicam que os siltitos verdes podem estar associados com uma superficie de inundacao maxima que se desenvo...

Powder Technology, 2021

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

The Canadian Journal of Chemical Engineering, 2020

Mining, Metallurgy & Exploration, 2010

To increase zinc recovery in the concentrate, this investigation performed mineralogical characte... more To increase zinc recovery in the concentrate, this investigation performed mineralogical characterization, dispersion studies, bench and pilot-scale flotation experiments and an industrial flotation trial. The objective was to verify the flotation behavior of the silicate zinc ore (calamine type) in the presence of slimes, with the aid of dispersing agents. Characterization studies identified the major minerals in the flotation feed as hemimorphite (calamine), quartz and dolomite. Dispersion tests showed that enhanced dispersion of the particles in the pulp in the absence of reagents occured at a pH range between 8.5 and 12.0. Bench-scale flotation experiments were planned using the statistical tool of complete factorial design at two levels, replicated once. These experiments showed, and were confirmed at the pilot-plant scale, that higher doses of sodium sulfide and polymeric dispersant combined with sodium silicate favored a higher metallurgical recovery. At 6,800 g/t (218 oz/st) sodium sulfide and 6,992 g/t (224 oz/st) polymeric dispersing agent combined with sodium silicate, a zinc grade of 38.4% in the final concentrate was achieved, at an average metallurgical recovery of 72.4%. The industrial trial confirmed the pilot scale results, leading to zinc recovery of 76.1% and a 37.3% zinc grade in the concentrate.

Tecnologia em Metalurgia Materiais e Mineração, 2019

Resumo O presente trabalho teve por objetivo o estudo da pelotização do pó de aciaria elétrica (P... more Resumo O presente trabalho teve por objetivo o estudo da pelotização do pó de aciaria elétrica (PAE), resíduo obtido na produção de aço através do forno elétrico a arco, como carga para forno Waelz, para obtenção de concentrado de zinco. Para caracterização do PAE foram realizadas análises granulométricas, análise química e análise mineralógica. Os resultados das análises granulométricas mostram grande heterogeneidade granulométrica, devido ao alto grau higroscópico do material que, na presença de umidade, tende a aglomerar. As análises química e mineralógica mostraram predominância de minerais de ferro e zinco. O PAE foi submetido a aglomeração a frio em disco pelotizador. Para determinação da resistência mecânica das pelotas, foram realizados ensaios de compressão uniaxial e drop number. Os resultados de resistência foram promissores e acima dos padrões inicialmente estabelecidos. Testes em forno piloto Waelz foram realizados para medir o impacto do uso das pelotas no processo. Os resultados dos testes em forno piloto também foram animadores, apontando para uma diminuição de acreção sem impactar no rendimento médio do zinco. Palavras-chave: Pó de aciaria elétrica (PAE); Pelotização; Forno Waelz.

Mine Planning and Equipment Selection, 2014

The Financial Compensation for the use of Mineral Resources - CFEM, is a compensation for the min... more The Financial Compensation for the use of Mineral Resources - CFEM, is a compensation for the mining activity in the municipalities where it is allocated. This study shows the importance of CFEM in the State of Minas Gerais - Brazil, where the mining activity is very important. The importance of CFEM is on its application on the counties, as it must be used in projects that bring improvements on the life conditions of the population. Usually, the HDI – Human Development Index of the municipalities where mining projects are developed is higher than the HDI of the State in which such projects are located. However, the correct management of this compensation must be reconsidered focusing on the development of local communities. It is important to highlight that, besides CFEM, the mining companies develop many other projects related to culture, education, sports, among others in the communities where they are located, bringing benefits for the population. With the new mining code, some changes in CFEM are expected, mainly in its calculation and in the percentages of some mineral resources taxes. Besides, a better distribution of the values is being considered, mainly associated to surrounding counties which are also affected by the mining activities. Thus, CFEM is understood as an important compensation for the mining activity that can bring many benefits if well applied and managed.

Journal of Materials Research and Technology, 2015

ABSTRACT