THE SPECIAL CHARACTERISTICS OF A FELDSPAR ORE IN PERU: A PROMISING INDUSTRIAL MINERAL PROJECT

摘要

Mining in Peru is mainly concentrated on metallic and polymetallic ores of gold, copper, lead, zinc, silver, tin, iron, etc. However, little has been done to develop extensive and rich non-metallic or Industrial Minerals deposits with the exception of some silica and phosphate deposits. This paper presents the characterization and metallurgical studies for the development of a feldspar deposit. These studies showed that the special characteristics of the ore, such as high porosity, high Al_2O_3 content, low clays content, and sized material allowed us to obtain commercial products applying relatively simple and low cost concentrating unit operations. The characterization studies showed that the feldspar products contained no quartz and about 90% of albite (NaAlSi_3O_8). The 14×40-mesh size fraction product analyzed 5.91% Na_2O, 22.56% Al_2O_3, 65.73% SiO_2, 0.65% K_2O, 6.50% CaO, and 0.40% Fe_2O_3; whereas, the 40×150-mesh size fraction product analyzed 6.22% Na_2O, 24.30% Al_2O_3, 60.80% SiO_2, 0.91% K_2O, 7.06% CaO, and 0.54% Fe_2O_3. These products could be used for manufacturing glass, ceramics, refractory, and filters in different applications. In addition, Middlings, could be used as insulation material due to its porosity (bulk density of 0.828 Kg/dm~3), analyzing 4.46% Na_2O, 15.7% Al_2O_3, 67.2% SiO_2, 2.57% K_2O, 3.94% CaO, and 4.24% Fe_2O_3. The material showed a sphericity of 0.77, a roundness of 0.68, and acid solubility of 13.3025% on only washed and 2.72% effective for clean material suitable for use in these applications. No selective accumulation of the valuable mineral was observed at any specific size fraction. However, iron and titanium bearing impurities trended to concentrate in fine fractions (minus 70 mesh -212 μm-). Metallurgical studies demonstrated that this feldspar ore required sizing at 14×40 mesh and 40×150 mesh to render commercial products. In the case of the 14×40-mesh size fraction, the process involved magnetic separation, gravity separation, and flotation for feldspar (direct flotation) using a blend of primary and condensate amines. However, the reverse flotation for mica-biotite and iron bearing minerals was also possible using petroleum sulfonate. The metallurgical process for the 40×150-mesh size fraction required magnetic separation and reverse flotation of iron and titanium bearing minerals, the feldspar being reported in the sink material. Commercial products from this feldspar deposit for glass, ceramics, refractory, and filtration; and for the manufacturing of insulation material were obtained.