Cassiterite, 856 table

Tin is an essential trace element for animals. It is soft, pliable and colorless and belongs to group IV of the periodic table, and is corrosion-resistant to many media. Tin occurs in nature mostly as the oxide mineral cassiterite and is ubiquitous in the earth crust in an abundance of 2.5 x 10-4% (Clarke s number, 4 x 10 3). It is one of the earliest metals known to mankind, and evidence of its use dates back over 4000 years. The ancients... 

An unusual feature of arsonic acid flotation of cassiterite is the immobility to recover cassiterite coarser than 40 pm in size. The results obtained at the Renison Mine (Australia) indicated that cassiterite recovery in fractions above 20 pm drops sharply (Table 21.2). 

The reason for such a behaviour of arsenic acid is that arsenic is a member of the group 5A elements in the periodic table. Phosphorus and antimony are also group 5 elements and are known to be chemically similar to arsenic. On this basis [8,9], the antimonic acids were found to be poor cassiterite collectors. The alkyl phosphonic acids were not selective collectors. The ethylphenylene phosphonic acid was found to produce similar or better results compared to /7-tolyl arsonic acid. The structural formula for phosphonic acid (Figure 21.5) is similar to that of /7-tolyl arsonic acid but arsenic was replaced with phosphoms. The styrene phosphonic acid radicals are C6H5-CH-CH and p-ethylphenylene CH3-CH2-C6H4. 

A list of reagents used for beneficiation of cassiterite ores is shown in Table 21.3. 

Indium concentrations in the polymetallic veins show a wide range (3.4 to 1184ppm In, Table 1). Based on the correlation coefficients of ore geochemistry, significant Indium (up to 1184 ppm) is related to the Ps2 mineralization stage and closely associated with Fe-rich sphalerite, but also with ferrokesterite. There are important In anomalies in Psi (up to 159.4 ppm) that are related to the Sn minerals, cassiterite, ferrokesterite and stannite (Crespi 2006). 

At the third level, the most detailed partition of luminescence minerals is carried out on the basis of metals in the mineral formulae, hi rare cases we have minerals with host luminescence, such as uranyl minerals, Mn minerals, scheelite, powellite, cassiterite and chlorargyrite. Much more often luminescent elements are present as impurities substituting intrinsic cations if their radii and charges are close enough. Thus, for example, Mn + substitutes for Ca and Mg in many calcium and magnesium minerals, REE + and REE substitutes for Ca, Cr substitutes for AP+ in oxygen octahedra, Ee substitutes for Si in tetrahedra and so on. Luminescence centers presently known in solid-state spectroscopy are summarized in Table 4.2 and their potential substitutions in positions of intrinsic cations in minerals in Table 4.3. 

Germanium, tin, and lead have relatively low abundances in the earth s crust (Table 19.4, page 823), but tin and lead are concentrated in workable deposits and are readily extracted from their ores. Tin is obtained from the mineral cassiterite (Sn02) by reducing the purified oxide with carbon ... 

Table IV. Trace Element Concentrations in Cassiterite (Sn02) Smelts from Cornwall, England, Deposits and Mean Values Obtained in Residues from Tel Dan, Israel...

The molecular structures of several new collectors have been designed as shown in Table 5.37 [21]. The carbon numbers of non-polar group required for given collector-mineral systems are also calculated and given in Table 5.37. The results in Table 5.38 show that the collector synthesized according to the calculated carbon numbers of non-polar group is the best one for given collector-mineral systems. These new collectors can be used as selective collectors for flotation separation of chalcopyrite from sphalerite, cassiterite or wolframite from calcite, malachite from smithsonite and calcite. 

The flotation results of cassiterite, quartz, and tourmaline using the above polycarboxylic acids are listed in Table 2.6. 

Among the phosphonic acid collectors, the collecting capability of styryl phosphonic acid is best in the flotation of cassiterite. And the collecting capability of styryl phosphonic acid is not influenced by Ca " or Mg ". The flotation results of Edinburgh s cassiterite using various phosphonic acid collectors are shown in Table 2.10. 

Table 2.10 Flotation results of Edinburgh s cassiterite using various phosphonic acid collectors...

---