Shear Viscosity of a Copper Ore Pulp in a Grinding-classification Circuit

Concha, F.; Castro, O.; Muñoz, Luis G.

doi:10.1080/08827509908962469

Cited by 2 publications

(1 citation statement)

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“…They separated the functional form of this equation into three terms, one for the effect of temperature, a second for the effect of concentration and a third for the interaction between these variables. Concha et al (1999) performed 70 experiments with underflow material from the feed, overflow and underflow of a copper ore grinding-classification circuit and with ground underflow for several time ranges, temperatures from 5 to 25°C and concentrations from 15 to 40 % solid by weight. After obtaining nine parameters of the four dimensional groups by non-linear curve fitting, they concluded by simulation that particle size has a significant effect on rheograms solely for shear rate values below _ c % 200 s À1 .…”

Section: Krieger-daughertymentioning

confidence: 99%

Suspension Rheology

2013

Solid-Liquid Separation in the Mining Industry

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The importance of rheology in the mining industry derives from the fact that all materials being processed are suspensions, that is, mixtures of solid particles and fluids, usually in water. In mineral processing plants, water is mixed with ground ore to form a pulp that constitutes the mill feed. The mill overflow is mixed again with water to adjust the solid content for classification in hydrocyclones. Pulp characteristics are essential in the transport of products to their final destination. A suspension, like all types of materials, must obey the laws of mechanics under the application of forces. The flow patterns of suspensions in tubes depend on their concentrations and transport velocities. In diluted suspensions at low velocities particles will settle. The suspension is termed a settling suspension and the flow regime is considered heterogeneous. At a velocity beyond a value at which all particles are suspended gives a non-settling suspension and the flow regime is homogeneous with Newtonian behavior. Concentrated suspensions are usually homogenous with non-Newtonian behavior. The variables and field equations for all types of fluids are presented and constitutive equations differentiate between Newtonian and non-Newtonian behavior. Empirical models of non-Newtonian behavior are presented, including pseudo-plastic and dilatant behavior with Cross and Carreau and Power-law models, and yield-stress models with Bingham and Hershel-Bulkley models. The study of the operational effect on viscosity includes variable such as solid particle size and concentration, temperature, pressure, time and pH. Rheometry provides experimental methods to determine rheological parameters such as viscosity and yield stress. E. C. Bingham introduced the word rheology in 1929 to describe the study of deformation and flow of all types of materials. The axioms of mechanics and the mass and momentum balances are valid for all macroscopic bodies and the distinction among different materials is established by constitutive equations, that is, the response of materials to applied stresses. Strictly speaking, rheology covers the mechanical study of all matter considered as continua, but it is usually reserved for those with non-linear constitutive equations, therefore leaving out Hooken solids and Newtonian fluids. Rheology can be considered a description, with constitutive equations also called rheological equations of state, of material behavior and not of

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Section: Krieger-daughertymentioning

confidence: 99%