Carlos Alberto Pereira

Flotation concentration of a xenotime pre-concentrate.

Abstract The world market for rare-earths elements is increasing due to the development of new products and applications, resulting in the need for technology to treat deposits having highly complex mineralogy, such as that of Pitinga, AM, Brazil, with estimated reserves of 146,960 t of rare-earths oxides (REO), including Y2O3. Mineralogically the mine of Pitinga is very rich. The initial and major target of the company Paranapanema was the production of tin concentrates from placer deposits and later from primary ore. However, geological studies identified several other minerals of potential economical importance, such as: columbite-tantalite, zircon, cryolite and xenotime, the objective of the present investigation. The response of a pre-concentrate sample of the non-conducting fraction from Pitingas electrostatic separator to laboratory scale physical concentration methods was very poor. Another possibility for the selective separation of xenotime and zircon (the major associated mineral) is flotation. Microflotation experiments were performed in a modified Hallimond tube with pure samples of xenotime and zircon, in the presence of hydroxamate as collector and five different reagents as depressants. The zeta potential of xenotime and zircon was determined in the presence of supporting electrolyte and hydroxamate.

Caracterização tecnológica de rejeito de minério de ferro

Nesse trabalho, e apresentada a caracterizacao dos finos, estocados na barragem I como rejeito proveniente do tratamento de minerio ferro. Na caracterizacao das amostras, estao apresentadas analises granulometricas por peneiramento a umido, analises quimicas por espectrometria de plasma e analise mineralogica por difracao de raios X. De posse das analises de caracterizacao, foram executados ensaios tecnologicos, visando a obtencao de concentrado para aplicacao na industria metalurgica. Foram avaliadas duas rotas de concentracao em escala de bancada: uma (rota I) constando de classificacao (0,15mm), separacao magnetica (-1,0+0,15mm), deslamagem e flotacao (-0,15mm) e outra (rota II) constando de separacao magnetica (-1,0mm total). De acordo com a distribuicao granulometrica dos finos do minerio de ferro, 8,21% das particulas encontram-se retidas em 0,150mm e 58,81% abaixo de 0,045mm. A amostra, conforme Tabela 1, apresenta teores medios (calculado) de 48,08% de Fe, 20,58% de SiO2, 3,16% de Al2O3. Os minerais portadores de ferro identificados foram hematita, martita, magnetita e goethita e os minerais de ganga foram quartzo, gibbisita e caolinita. A melhor opcao de concentracao estudada consistiu na utilizacao de circuito de concentracao somente por separacao magnetica, rota II. A recuperacao em massa e metalurgica foram, respectivamente, 68,00% e 90,81%, apresentando um concentrado com 67,54% de Fe, 1,50% de SiO2 e 0,49% de Al2O3, atendendo a especificacao do produto comercializado pela empresa.

Lead recovery by flotation with sodium lauryl sulfate

Lead recoverable slag is of economic and environmental importance. The aim of this study was to assess the possibilities of its recovery by flotation with sodium lauryl sulfate (SLS). The similar nature of the lead and iron particles formed by solidification of the melted slag impairs selectivity during the flotation process. In order to verify the most favorable conditions for selectivity, SLS adsorption mechanisms for lead and iron particles were studied. The adsorption was monitored by means of zeta potential and surface tension determinations. Flotation tests were conducted under the most promising conditions identified for selectivity. The results suggest that SLS adsorption in lead particles is of a chemical nature. It was observed that the formation of lead lauryl sulfate is easier in alkaline medium. A 79% lead recovery was obtained at pH 10 using only 10-3 M collector concentration. Nevertheless, the best selectivity conditions were obtained in an acid medium.

Efeito da dispersão em polpas de minérios itabiríticos

The reverse flotation of iron ores is preceded by a desliming stage whose ef ficiency increases with the use of reagents that promote the dispersion of the pulp. The present study addressed the influence of the type and of the concentration of the dispersant on the dispersion efficiency and on the flotation results. The results were

USE OF CANGA AS DIMENSION STONE

A canga e um produto residual resistente a meteorizacao mecânica e praticamente inerte ao intemperismo quimico. A grande ocorrencia desse material na regiao de Ouro Preto e a viabilizacao do seu uso em prol da comunidade incentivam o seu estudo e desperta o interesse em conhecer suas propriedades fisicas e quimicas. Nesse contexto, surge essa pesquisa pioneira fundamentando a utilizacao da Canga no setor de rochas ornamentais com enfoque na arte da Cantaria. As amostras coletadas no sitio geologico da regiao em estudo foram caracterizadas utilizando difratometria de raios-X, ensaios de massa especifica e porosidade, determinacao de dureza Rockwell e ensaios nao destrutivos com o esclerometro Schmidt. Os testes com o esclerometro mostraram-se muito eficientes para detectar imperfeicoes internas na peca, o que foi comprovado pelo teste de porosidade. Alem disso, o fato desse teste ser nao destrutivo e de facil realizacao torna a sua utilizacao viavel, nao ocorrendo perda de material. O desempenho do material no decorrer do estudo encoraja o seu prosseguimento, visto que, mediante correlacao realizada com quartzito, usualmente utilizado como rocha ornamental, foi comprovada a configuracao da canga para esta finalidade. Suas propriedades ainda sugerem a aplicacao em outros setores como de cerâmica e construcao civil.

Influence of attrition variables on iron ore flotation

The presence of slimes is harmful to the flotation process: the performance and consumption of reagents are negatively affected. Traditionally, the desliming stage has been responsible for removing slimes. However, depending on the porosity of the mineral particles, desliming may not be sufficient to maximize the concentration results. An attrition process before the desliming operation can improve the removal of slime, especially when slimes cover the surface and/or are confined to the cavities/pores of the mineral particles. Attrition is present in the flowcharts of the beneficiation process of phosphate and industrial sand (silica sand). Research has been undertaken for its application to produce pre-concentrates of zircon and iron ore. However, there is still little knowledge of the influence of the attrition variables on the beneficiation process of iron ore. This study presents a factorial design and analysis of the effects of these variables on the reverse flotation of iron ore. The standard of the experimental procedures for all tests included the attrition of pulp, under the conditions of dispersion, desliming and flotation. The parameter analysed (variable response) was the metallurgical recovery in reverse flotation tests. The planning and analysis of the full factorial experiment indicated that with 95% reliability, the rotation speed of the attrition cell impeller was the main variable in the attrition process of the iron ore. The percentage of solid variables in the pulp and the time of the attrition, as well as their interactions, were not indicated to be significant.

Simultaneous use of direct and reverse flotation in the production of iron ore concentrate plant

The exploitation of low-grade iron ore deposits represents the current scenario for this business. Thus arise several types of research that aim at improvements and innovations as solutions to such situation. Therefore, herein, suggested is an alternative route for iron ore flotation that targets a higher mass recovery with concentrate within the market specification. First, the sample was deslimed at 38 μm and with the underflow a cut was performed in the 74 μm cyclone in order to separate the coarse particles from the fine. With the coarse particles, i.e. with the underflow, there a reverse flotation was carried on obtaining a concentrate with 67.7% of Fe and 0.9% of SiO2. In the fine particle overflow, direct flotation was done, generating a low-quality concentrate with 40.9% of Fe and 39.7% of SiO2. The mass recovery in direct flotation was 88% and in the reverse flotation was 61.1%. The concentrate generated from two flotations had a mass recovery of 67.4% with a content of Fe of 53.4% and 21.6% SiO2.

Recuperação de ferro a partir do rejeito de espirais da mina de água limpa por meio de separação magnética.

Mineral raw materials are submitted to mineral processing in order to adapt them as the physical aspect to a subsequent process, aiming at the extraction or refining of one or more metals, organic or inorganic compounds useful to human activity. However, and with some contemporary demand, the industry uses several processing procedures to reuse or redirect volumes before considered the processing waste. Specifically, and involved with studies of reuse, the present work used a magnetic separation mechanisms to deal with iron ore tailings from the spirals concentrators of Agua Limpa Operational Unit/Vale S.A - Rio Piracicaba-MG. The work proved to be possible the treatment of this tailing with feasible iron recovery. Was used a field strength of 6000 Gauss and water flow equal to 500 mL/s which made possible to achieve 93% of metallic recovery with containing about 60% of Fe. Other considerable earnings were the reduction of iron levels in the tailings, which dropped from 20% to 3% on average, allowing the optimization of a nonrenewable resource and increase of tailings dam useful life.

Nickel ore grinding energy determination

This study describes the application of an empirical method to estimate the energy consumption in laboratory of the primary grinding of nickel ore with a specific mineralogical texture. This method developed by Donda was previously used in iron ore from the Iron Quadrangle (Minas Gerais, Brasil) with the same purpose. Through the grinding test, performed under standard conditions and based on the degree of liberation and percentage retained on 0.074 mm, it is possible to obtain the energy consumption for grinding. The results mean a validation of the method with a good approximation between industrial and laboratory values. In practice the energy consumption is 26.6 kWh/t and through Donda’s method, when using the liberation degree as a parameter, the energy found was 26.8 kWh/t.

Methodology for selection of samples from borehole probe for technological characterization of iron ore.

The risks in the evaluation of mining projects are directly related to the probability of errors in the estimates, and, as the estimates are based on sampling results, this activity must be performed in a careful and planned way, to prevent surprises at the beginning of operation. To validate the representativeness of the borehole samples selected for the mineral processing studies, the geological resources evaluation team proposed a methodology based on the utilization of statistical analyses that, beyond considering the spatial distribution of the samples in the deposit, also assessed if they are representative of the populations under investigation. With this data, the geologist is able to make a fast analysis of the sampling’s representativeness.