Making a Magnetorheological Fluid from Mining Tailings
- PDF / 1,445,239 Bytes
- 6 Pages / 593.972 x 792 pts Page_size
- 13 Downloads / 208 Views
N
MAGNETORHEOLOGICAL fluids (MRFs) are materials in which properties vary considerably in the presence of an external magnetic field; for this reason, they belong to the group of smart materials. Various types of materials with these properties have been identified, the most important of which are magnetic suspensions (MRFs and ferrofluids, electrorheological (ER) fluids, piezoelectric materials, and alloys with shape memory),[1] where the rheological properties of magnetic suspensions change according to the applied magnetic field. MRFs are divided into two groups: the ferrofluids, which are a stable colloidal mixture of ferrimagnetic and/or ferromagnetic nanoparticles, and MRFs that are suspensions of micro-dispersed magnetizable particles in a fluid carrier.[1] The first development of MRF was credited to Jacob Rabinow (1949) at the US National Bureau of Standards.[2,3] The particles in the MRF possess magnetic multidomains; thus, the application of an external magnetic field induces a magnetic dipole in each particle resulting in strong interactions between the particles. This phenomenon could lead to the formation
G. QUITIAN and N. ROJAS are with the Instituto de Minerales CIMEX, Universidad Nacional de Colombia sede Medellı´ n, Medellı´ n, Colombia. Contact e-mail: [email protected] W. SALDARRIAGA is with the Laboratorio de Materiales Cera´micos y Vı´ treos, Universidad Nacional de Colombia sede Medellı´ n, A.A. 568, Medellı´ n, Colombia. Manuscript submitted November 3, 2016.
METALLURGICAL AND MATERIALS TRANSACTIONS B
of a network of particles or an agglomerate along the suspension. As a result, the MRFs change from a liquid to a semi-solid state, with this being a reversible process in the presence of magnetism.[1] In the absence of a magnetic field, the viscosity of the MRF is a function of the properties of the oil carrier, the agents of the suspension, and fraction and particle size distribution.[1,4] The objective of this work is to show the feasibility of making a MRF from mining tailings. From this last material, magnetite was obtained, which was characterized mineralogically by X-ray diffraction (XRD) and energy dispersive spectrometry (EDS) and physically (size and geometry). Finally, the fabricated MRF was rheologically characterized in a device attached to a rheometer. II.
MATERIALS AND METHODS
The discrete medium of MRF was obtained from black sand, which came from gold alluvial tailings material. This material was magnetically separated in order to refine the material of interest (magnetite). Then the material was washed and dried in an oven for 24 hours at a temperature of 313.15 K (40 °C). Further drying of the sample was completed through a process of size reduction by pulverizing and milling it (ceramic mill with alumina balls) for 8 hours. Subsequent separation of the sample was performed again by magnetic means. A wet screening process with a 635 mesh screen was performed to obtain the sample under study. This sample is referred to as MP-635 and it features a 90 pct of its particle size un
Data Loading...
