The Nigeria nation is blessed with abundant mineral resources; fossil fuels and solid minerals. The most popular being the fossil fuels since these constitute the nation’s greatest foreign exchange earner. They have, therefore, tended to overshadow the solid mineral sector of mining industry.
It is reassuring to note that the government has progressively in recent past years shown great interest in the exploitation of Nigeria’s solid minerals as a means of diversifying our economic base, putting in place the NATIONAL POLICY ON MINERALS METAL IN NIGERIA and other such policy documents in order to drive investment in the sector.
Solid minerals are many types occurring in many diverse environments in response to many diverse geology and geologic events. The resources can nonetheless be discussed under five (5) groups thus:
1. Iron and Iron-alloy metals
2. Non-ferrous Industrial metals
3. Precious metals
4. Metal fuel
5. Industrial minerals
Exploitation of the Non-metallic Minerals has not attained the desired level, mainly because of the various constraints associated with their exploitation, development and processing for utilization. Many of the non-metallic minerals, which are vital to the industrial take off of the country, have been found in commercial quantities within the country.
They include limestone, dolomite, marble, kaolin, barite, diatomite, feldspar, quartz and silica sands, gypsum, talc, silimanite, kyanite, phosphate, salt and bentonite.
Bentonite belongs to the group of clays whose technical properties are controlled by the proportion of montmorillonite, a sub-group within the smectitic clays. It is clay derived from deposits of weathered volcanic ash.
Bentonites are hydrated aluminosilicates, which composed predominantly of the clay mineral montmorillonite. They are composed of a 3-tier structure with alumina sheets’ sandwiched between tetrahedral silica units. A simplified formula for montmorillonite is A12O3.4SiO2.H2O. The other minerals that could be found in bentonite in small content are chrystobalite, biotite, chalcedony, calcite, pyrite, dolomite and plagioclase.
There are three principal types of bentonite namely:
(i) Natural sodium bentonite or sodium montmorillonite;
(ii) Natural calcium bentonite or calcium montmorillonite; and
(iii) Sodium activated bentonites or sodium activated montmorillonites
Natural sodium bentonite as the name suggests, occurs with sodium as the predominant exchange cation. They are characterized by high swelling, high liquid limit and high thermal durability. It is usually used for oil and gas drilling mud.
The vast majority of the montmorillonites occurring in abundance worldwide is of the calcium type and is referred to as calcium bentonite. Much lower swelling and liquid limit values compared to natural sodium bentonite, characterize them. Calcium bentonite is used as a bleaching agent in cooking oil industries, bleaching agent in lubricant oil recycling, as a catalyst, absorber, filler, etc.
This report seeks to examine the financial viability or otherwise of establishing bentonite mine in Nigeria.