Titanium minerals

Production. Titanium is the seventh most common metallic element in the earth s cmst. Titanium minerals are plentiful in nature (19). The most common mineral /raw materials used for the production of titanium dioxide pigments are shown in Table 1. 

Table 3. Analyses of Selected Titanium Mineral Concentrates, Wt...

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. 

Some deposits in addition to REO contain zircon and titanium minerals. From these ores, REO and zircon can be recovered in bulk concentrate suitable for hydrometallurgical treatment. 

Titanium is the most abundant metal in the earth crust, and is present in excess of 0.62%. It can be found as dioxy titanium and the salts of titanium acids. Titanium is capable of forming complex anions representing simple titanites. It can also be found in association with niobium, silicates, zircon and other minerals. A total of 70 titanium minerals are known, as mixtures with other minerals and also impurities. Only a few of these minerals are of any economic importance. 

This chapter discusses flotation properties of major titanium minerals and beneficiation methods used in some operating plants. In recent years, a new technology has been developed for beneficiation of hard rock titanium minerals. This is also discussed in this chapter. 

Out of the 70 known titanium minerals, only a few have any economic value. Table 25.1 shows the major titanium minerals of value. 

The most important titanium minerals are ilmenite, mtile and perovskie. Loparite is a major mineral for production of niobium and REO. 

Rutile is the most stable of all the titanium minerals. In a number of cases, rutile may contain impurities such as iron oxides, tin, chromium and vanadium. The rutile grade can range from 95% to 99% Ti02. 

Perovskite is a calcium-titanium mineral and usually contains impurities of iron, chromium and aluminium. The theoretical grade can vary from 50% to 57% Ti02. Also, sometimes contains niobium (up to 11%) and tantalum. 

Leucoxene has a composition similar to that of rutile, and is a product of alterations of a number of titanium minerals, most often ilmenite and sphene. It contains higher amounts of titanium, compared to ilmenite, and can range from 61% to 75% Ti02. 

Titanium minerals have been recovered from both hard rock and sand deposits. Until 1945, most of the ilmenite and rutile produced commercially came from sand deposits, but nowadays, the production of ilmenite from rock deposits exceeds that of sand deposits. Rutile, however, is exclusively produced from sand deposits, although a new technology exists that recovers rutile from rock deposits. 

Anorthositic deposits - nearly all of the known commercially important rock deposits of titanium minerals are associated with anorthositic or gabbroic rocks. There are three main types (a) ilmenite-magnetite (titanoferous magnetite), (b) ilmenite-haematite, and (c) ilmenite-rutile. 

Extensive research has been carried out mainly on ilmenite and, to a lesser degree, on flotation of rutile and perovskite. Flotation studies have been performed on titanium minerals from both hard rock and fine-grained sand deposits. 

A large portion of titanium minerals (ilmenite, rutile) are produced from heavy mineral sands using physical preconcentration methods including gravity, magnetic and electrostatic separation. Over the past 30 years, advances have been made using flotation, where ilmenite, mtile and perovskite can be effectively recovered from both heavy mineral sands and hard rock ores using flotation methods. 

Other substances— for example, the silicate ores, the carbonate ores, the titanium minerals— may be similarly grouped for pmposes of experi-piental study, but it is hardly necessary here to make a complete inventory of such groups. 

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