**8.2. Separation and classification**

Separation and classification2 are very important elemental manufacturing processes in many industries such as the mining and chemical industries. The equipment using many different methods of separation is applied in these processes [13],[14]. Used concentrating devices depend on the fluid, the force field and the specific properties of particles, such as the density, size, shape, chemistry, surface chemistry, magnetism, conductivity, color and porosity. Various concentrating devices are applicable to particles according to their size ranges (**Fig. 3**), and for any given size range, several processes or devices might be used. The gravity concen‐ tration works the best in the range from 130 mm to 74 μm [15].

**Fig. 3.** Approximate range of applicability of various concentrating devices (M = mesh, Tyler standard) [15].

In phosphate rock beneficiation, the availability of water is of primary importance and may determine the process or processes used. Fine-grained impurities can often be removed from phosphate ores by using the combinations of comminution, scrubbing, water washing, screening and/or hydrocyclones. The disposal of tiny ore constituents (slimes) can be prob‐ lematic. The beneficiation technique of froth flotation (described in **Section 8.7**) is widely used within the world phosphate rock industry [4],[6].

<sup>2</sup> Classification is defined as the separation of a mixture of solid particles into various fractions according to their sizes or densities [14].

**8.2. Separation and classification**

tration works the best in the range from 130 mm to 74 μm [15].

388 Apatites and their Synthetic Analogues - Synthesis, Structure, Properties and Applications

are very important elemental manufacturing processes in many

industries such as the mining and chemical industries. The equipment using many different methods of separation is applied in these processes [13],[14]. Used concentrating devices depend on the fluid, the force field and the specific properties of particles, such as the density, size, shape, chemistry, surface chemistry, magnetism, conductivity, color and porosity. Various concentrating devices are applicable to particles according to their size ranges (**Fig. 3**), and for any given size range, several processes or devices might be used. The gravity concen‐

**Fig. 3.** Approximate range of applicability of various concentrating devices (M = mesh, Tyler standard) [15].

within the world phosphate rock industry [4],[6].

or densities [14].

In phosphate rock beneficiation, the availability of water is of primary importance and may determine the process or processes used. Fine-grained impurities can often be removed from phosphate ores by using the combinations of comminution, scrubbing, water washing, screening and/or hydrocyclones. The disposal of tiny ore constituents (slimes) can be prob‐ lematic. The beneficiation technique of froth flotation (described in **Section 8.7**) is widely used

<sup>2</sup> Classification is defined as the separation of a mixture of solid particles into various fractions according to their sizes

Separation and classification2

**Fig. 4.** Beneficiation of phosphate rock containing carbonates, silica and pyrite as the main gangue materials [1],[7].


**Table 1.** The comparison of phosphate ore beneficiation methods [16].

Effective beneficiation can be achieved by various processes depending on the liberation size of phosphate and gangue minerals and other ore specifications. Different processes like screening, scrubbing, heavy media separation, washing, roasting, calcinations, leaching and flotation may be used. For example, crushing and screening are used to remove coarse hard siliceous material, and attrition scrubbing and desliming are used to remove clayey fine fractions. If silica is the main gangue material, flotation is the conventional mineral process‐ ing technique used. Igneous-type ores are also amenable to flotation, which is the best approach for the processing of this type of phosphate ore [16].
