A Bond Work index mill ball charge and closing screen product size distributions for grinding crystalline grains

Q1 Earth and Planetary Sciences

International Journal of Mineral Processing Pub Date : 2017-08-10 DOI:10.1016/j.minpro.2017.05.011

Mario Menéndez, Malcolm Gent, Susana Torno, Nerea Crespo

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引用次数: 2

Abstract

Ball mill charge size distributions originally specified for Bond grindability tests to determine the Bond Work index (BWi) are not commercially available. Those proposed to date do not match all of Bond's (1961) original specifications of total ball mass, number and surface area. An alternative mill ball charge is proposed that closely approximates Bond's original total ball mass, number of balls and ball surface area.

Results of 30 Bond Work index tests of six pure materials (calcite, magnesite, labradorite (feldspar), quartz, andalusite and glass) using closing screen apertures (P₁) values of 500, 250, 125, 90 and 63 μm are analysed. The samples were selected on the basis of having distinct hardness's (Mohs hardness 3 to 7.5), being relatively free of crystallographic defects and having distinct cleavage properties The 80 percentile size of the fines produced (P₈₀) concur with those of published values.

The trend based of P₈₀ values for P₁ values of 150 to 44 μm recommended by Bond poorly fit with published P₁ values > 250 μm. It is demonstrated that the BWi test P₁ values of mono-mineralogical or mono-material samples determines the P₈₀ value obtained. Based on test results of this investigation a polynomial exponential equation relating P₈₀ to P₁ values with an R² correlation factor of 0.9977 is presented. This relation is independent of the tested material hardness and crystallographic defects and planes of weakness.

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用于研磨晶粒的键合功指数磨球装料和闭合筛网产品尺寸分布

为确定粘结工作指数(BWi)而进行的粘结可磨性试验最初规定的球磨机装料粒度分布并不是市售的。迄今为止提出的那些不符合邦德(1961)的所有原始规格的总球质量，数量和表面积。提出了一种与邦德原始总球质量、球数和球表面积非常接近的替代磨球装药。分析了6种纯材料(方解石、菱镁矿、labradorite(长石)、石英、红柱石和玻璃)在闭合孔径(P1)值为500、250、125、90和63 μm时的30个键合功指数测试结果。样品的选择是基于不同的硬度(莫氏硬度3到7.5)，相对没有晶体缺陷和具有明显的解理性能。所产生的细粒的80百分位尺寸(P80)与已发表的值一致。Bond推荐的P1值在150 ~ 44 μm范围内的P80值趋势与已发表的P1值>拟合较差;250μm。结果表明，单矿物学或单材料样品的BWi测试P1值决定了得到的P80值。根据本研究的检验结果，提出了P80与P1值的多项式指数方程，R2相关因子为0.9977。这种关系与被测材料的硬度、晶体缺陷和弱点面无关。

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来源期刊

International Journal of Mineral Processing 工程技术-工程：化工

CiteScore

3.02

自引率

0.00%

发文量

审稿时长

11.1 months

期刊介绍： International Journal of Mineral Processing has been discontinued as of the end of 2017, due to the merger with Minerals Engineering. The International Journal of Mineral Processing covers aspects of the processing of mineral resources such as: Metallic and non-metallic ores, coals, and secondary resources. Topics dealt with include: Geometallurgy, comminution, sizing, classification (in air and water), gravity concentration, flotation, electric and magnetic separation, thickening, filtering, drying, and (bio)hydrometallurgy (when applied to low-grade raw materials), control and automation, waste treatment and disposal. In addition to research papers, the journal publishes review articles, technical notes, and letters to the editor..