THE IMPORTANCE OF MINERALOGY ON REGRIND ENGERY CONSUMPTION
ABSTRACT
The general trend in the minerals industry is towards the processing of fine grained, disseminated mineral
deposits. This has led to an increase in the number of fine/ultra-fine grinding installations using stirred
media mills.
One of the challenges in selecting regrind equipment is that there is no industry standard for determining
the specific energy required to achieve a given product size. The challenge is that both the equipment type
and the mineralogy of the deposit have an effect on specific energy consumption. This necessitates material
testing in a validated laboratory or pilot test environment to improve the confidence in equipment selection.
Fresnillo PLC recognized this issue and addressed it by providing samples for testing in a laboratory
regrind system. The objective of the test program was to determine the specific energy required to achieve
a product size of 10 um (P80). A specific energy plot was generated for both a lead and zinc flotation
concentrate. It indicated that 33 kWh/t and 50 kWh/t were required for the two samples (Pb and Zn
respectively). This difference highlights the effect of mineralogy on the energy required for fine grinding.
The regrind feed and products were submitted to a range of basic mineralogy tests to quantify the mineral
differences that could have changed the specific energy requirements. These tests provided general
mineralogy, documented optical textures, and provided particle size microscopy. The lead concentrate was
found to contain significant amounts of silicates in addition to the dominant sulphide, pyrite. Galena and
angelesite were both found in low concentrations. The zinc concentrate was determined to be mostly
sphalerite with minor amounts of quartz, chalcopyrite, pyrite and galena.
The material testing results indicate the importance of basic mineralogy studies in conjunction with
comminution testing to determine specific energy consumption.
Authors:
D Rahal
FLSmidth USA, INC
7158 S FLSmidth Drive, Midvale, UT 84047-5559, USA
Tel +1 801 871 7000
M Escobedo,
FLSmidth S.A. de C.V.
San Alberto 406 2P, Residencial Santa Bárbara, San Pedro Garza García, N.L., México C.P.66266
Mobile. +52 (81) 17901876
S Ortiz
Fresnillo PLC
Calz Saltillo 400 939, Residencial Campestre la Rosita, Torreón, Coahiila, Mexico
Mobile. +52 1 (87) 13474254
KEYWORDS
Testing, regrind, mineralogy, grain size, stirred mill, energy consumption, fine grind