The ores of chromite, nickel, copper, and zinc show a wide distribution over geologic time, but those of iron, titanium, lead, uranium, gold, silver, molybdenum, tungsten, and tin are more restricted. Many of the limitations to specific time intervals are probably imposed by the evolving tectonic history of Earth interacting with the effects of the biomass on the evolution of the earth's s surf...

We give necessary and sufficient conditions for a skew polynomial ring K[t; σ, δ] over a division ring K to be a left V -domain. In particular, when this ring admits a unique simple left module, the conditions obtained include: 1) all polynomials are Wedderburn, 2) all n× n matrices over K are (σ, δ)-similar. We also provide necessary and sufficient conditions for this ring to be both left and ...

This study describes the application of an empirical method to estimate the energy consumption in laboratory of the primary grinding of nickel ore with a specific mineralogical texture. This method developed by Donda was previously used in iron ore from the Iron Quadrangle (Minas Gerais, Brasil) with the same purpose. Through the grinding test, performed under standard conditions and based on t...

introduction iron ore is one of the most important natural raw materials that is widely used for manufacturing iron and steel. this type of ore contains various amounts of radionuclides; thus, exposing workers handling their extraction, transportation, and processing to radiation. materials and methods in this study, 12 ore samples (each mass weighing about 2 kg) were collected from the iron or...

Aluminum metal was found to liberate cesium almost quantitatively from pollucite ore when reacted under conditions of operation determined by experiments described in the paper. In the treatment, ore ground to pass a 150 mesh sieve is mixed with atomized aluminum and the mixture heated under an inert atmosphere in a retort. Pollucite ore from one source yielded its cesium when treated at 950°C ...

Mining tailings as a raw material for preparing autoclaved bricks have attracted much attention. The tailings subjected to milling always have the characteristic of fine granularity. However, the proportion of the fine aggregates in autoclaved bricks was very low using the current gradation formula, which impeded the utilization of the tailings. In this work, a novel model of aggregate gradatio...

Milling is a vital unit operation in various material processing operations and consumes around 2% of the energy produced in the world [1,2]. It dictates the cost economics of mineral, cement, power, pharmaceutical and ceramic industries. Grinding is an important unit operation for chrome ore pelletisation process. Chromite ore along with 5% coke is milled in the wet ball mill and filtered ore ...