Cassiterite properties

The electrostatic separation method is the exclusive choice in some specific situations, for example in the cases of rutile and ilmenite deposits. These deposits generally contain minerals of similar specific gravities and similar surface properties so that processes such as flotation are unsuitable for concentration. The major application of electrostatic separation is in the processing of beach sands and alluvial deposits containing titanium minerals. Almost all the beach sand plants in the world use electrostatic separation to separate rutile and ilmenite from zircon and monazite. In this context the flowsheet given later (see Figure 2.35 A) may be referred to. Electrostatic separation is also used with regard to a number of other minerals. Some reported commercial separations include those of cassiterite from scheelite, wolframite from quartz, cassiterite from columbite, feldspar from quartz and mica, and diamond from heavy associated minerals. Electrostatic separation is also used in industrial waste recovery. 

The most important tin mineral is cassiterite (Sn02). Theoretically, the tin content of cassiterite is 78%. However, in the majority of cases, cassiterite contains impurities and the tin content may vary from 65% to 78%. The major impurities of cassiterite include tantalum, niobium, titanium and other elements, usually in the form of solid solutions. The impurities in the cassiterite often have a pronounced effect on flotation properties of cassiterite. 

The chemical complexity of the pulp, which affects cassiterite surface properties and, in turn, affects collector adsorption. 

The phosphonic acid flotation of cassiterite is similar in many ways to that of arsonic acid. Optimum plant flotation for both collectors is generally considered to be in the pH region 4.5-5.5. The phosphonic acid, like arsonic acid, also has the inability to effectively recover cassiterite coarser than 20 pm. The reason for this is not known, because no research data is available on the flotation properties of plus 20 micron cassiterite particles. 

Research work has shown that cassiterite from various deposits and often even from parts of the same deposit differ in chemical composition, colour, flotation properties, chemical activity and electrophysical characteristics. Therefore, the mineralogical composition of tin ores and the physiological properties of the minerals, in particular cassiterite, determine to a great extent the quantity of tin lost during gravity processing and especially during flotation. 

Ta/Nb minerals often occur as impurities in ilmenite, rutile, cassiterite, wolframite and perovskite, most of which contain REE. Because tantalite and columbite have similar chemical properties, they often replace each other, and are usually found as isomorph mixtures. Tantalum and niobium can also be found as separate minerals. Tantalite and microlite are primary sources of tantalum. 

Case materials, in electronic materials packaging, 77 837-840 Case nitrided steels, properties of, 76 207 Case polymers, uses for, 25 481 82 Cash flows, 9 540-542 CASLINK software, 73 250 Caspian Sea, 5 784 CAS Registry, 73 242, 246 Cassegrain condenser, reflective, 74 233 Cassia, 23 165-166 Cassie-Baxter equation, 22 112, 113 Cassiterite, 24 783, 791 Casson-Asbeck plots, 27 709 Casson fluid flow model, 27 705 CASS test, 9 790... 

Properties M.w. 653.65 anionic Toxicology TSCA listed Uses Emulsifier, dispersant, solubilizer, surfactant for textiles, cosmetics, agric. dispersant, solubilizer for industrial, household, and metal cleaners flotation collector for cassiterite ores emulsion polymerization polishing waxes surf, tension depressant for inks demulsifier in food-pkg. adhesives emulsifier in rosin size aq. disps. and resin latex coatings for mfg. of paper/paperboard in contact with aq./fatty/dry foods... 

Cassiterite (Sn02 in rutile structure)-based materials are extensively studied due to their gas-sensing properties. The theoretical modeling of the surface processes plays an important role in this research. 

The solubility and thermodynamic properties of cassiterite, Sn02(s), have been thoroughly reviewed by Gamsjager et al. (2012). From the collection of data that was available, the following thermodynamic data were selected ... 

Vlcek L, Zhang Z, Machesky ML, Fenter P, Rosenqvist J, Wesolowski DJ, Anovitz L, Predota M, Cummings PT (2007) Electric double layer at metal oxide surfaces static properties of the cassiterite-water interface. Langmuir 23 4925 937... 

Rosenqvist J, Machesky ML, Vlcek L, Cummings PT, Wesolowski DJ (2009) Charging properties of cassiterite (a-Sn02) surfaces in NaCl and RbCl ionic media. Langmuir 25 10852-10862... 

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