Gangue constituents

Adularia is abundant in Au-Ag deposits, where it is commonly found with Au-Ag minerals only rarely does it occur in Pb-Zn and Cu deposits. Albite is very rare and is reported only from the Nebazawa Au-Ag deposits. Barite is a common gangue constituent in Pb-Zn-Mn deposits, especially those in the southwestern part of Hokkaido and the northern part of Honshu, where it is usually a late-stage mineral coexisting with carbonate and quartz but rarely with sulfide minerals. Other rare gangue minerals include fluorite, apatite, gypsum, bementite, rutile, and sphene, but they have not been studied. 

Gangue constituents included quartz, muscovite, biotite, chlorite, and pyroxene. 

The gangue constituents and their nature are sometimes determining factors in selection of a treatment process for beneficiation of oxide copper ores. Highly weathered ores usually contain a fairly large amount of slimes, which has a negative effect on the floatability of oxide copper minerals. Also, there is an appreciable difference in floatability between oxide minerals from carbonaceous and siliceous ores. 

The problem of separating solid particles according to their physical properties is of great importance with large-scale operations in the mining industry, where it is necessary to separate the valuable constituents in a mineral from the adhering gangue, as it is called,... 

In contrast to the extensive data collected on trace-mineralized rocks between ore districts, less information is available on the arsenic contents of the ore deposits. Because iron sulfide minerals are typically gangue phases, they are commonly ignored in trace element studies of ore deposits, which tend to focus on ore minerals such as sphalerite and galena. Therefore, there have not been extensive analyses for arsenic in iron sulfides in many of the MVT ore districts or trace-mineralized areas. However, a few studies on trace element contents in iron sulfides from the Ozark region have been performed. Wu et al. (1996) analyzed 80 pyrite and marcasite samples from the Viburnum Trend of the Southeast Missouri Lead District and found arsenic in concentrations of 2 to 900 ppm. Bhati and Hagni (1980) also analyzed iron sulfide minerals from this area, but did not publish results for arsenic. Hagni (1993) described the relatively rare occurrence of nickel-arsenic-sulfide ores from the Magmont-West ore deposit of the Viburnum Trend. Leach et al. (1995) list arsenic as a trace constituent in ores from the Northern Arkansas and Southeast Missouri MVT ore districts, but without abundances specified. 

An as yet undissolved problem is that, in the case of whole flotation, a huge amount of energy is necessary to finely disintegrate the ore, of which only about 1% is valuable. If no other valuable constituents are present, the separated gangue material is worthless and cannot be used at present for any other purpose. The only possible reuse is a partial backfilling in the caverns of the underground mine. 

The processing of most ores involves a series of standardized steps. After mining, the bulk ore is processed to remove any gangue (excess waste rock and minerals). This processing typically consists of pulverizing the ore to a relatively fine state, followed by some form of gravity separation of the metals from the gangue [ 134-140]. The refined ore is processed thermally to separate the metal and non-metal constituents, and then further reduced to the free metal Since most of these metals are unsuitable for use in a pure state, they are subsequently combined with other elements and compounds to form alloys with the desired properties. 

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