Clay heap for brick making
Roofing fired tiles
Ceramics encompass such a vast array of materials that a concise definition is almost impossible. However, one workable definition of ceramics is a refractory, inorganic and non-metallic material. Ceramics can be divided into two classes: traditional and advanced. Traditional ceramics include clay products, silicate glass and cement; while advanced ceramics consist of carbides (SiC), pure oxides (Al203), nitrides (Si3N4), non-silicate glasses and many others. In OGMR vision, a special attention should be driven to the traditional ceramics, specifically to clay products. Ceramics offer a lot of advantages compared to other materials. They are harder and stiffer than steel; more heat and corrosion resistant than many other materials or polymers; less dense than most of metals and their alloys; and their raw materials are both plentiful and inexpensive. Ceramic materials display a wide range of properties which facilitate their use in many different product areas. In case of valorisation of natural resources of the country, the project wishes to focus on creation of ceramic production units, therefore, the sponsors‟ attention should focus on a number of certain clay, feldspar and kaolin deposits.
1. The origin of the clay
Clay is a natural material found in the earth all over the world. The clay is formed from the remnants of igneous rocks which have been naturally crushed, milled and mixed with other minerals by the forces of wind, ice and water erosion under lithostatic pressure from other rocks in the earth crust. According to general lithology of Rwanda, three types of clay deposits are found: clay that results from alteration of granite rocks, clays from volcanic rocks, and those from shale. Clay from granite rocks: There are some clay deposits in Kigali, Gitarama, Butare, Rwamagana, etc... In general they are sand clays with dusts or particles of sand or pure clay. The valleys are relatively large and the relief is gently sloping and they are easily accessible. Clay from the volcanic rocks: Lava flow from cut valleys: This clay is of a good quality but can contain pieces of non decomposed lava.
Clay from the shale: The regions of shale are generally mountainous. This is the case of Kibuye, Gisenyi, Cyangugu, Gikongoro and some parts of Kibungo region. In general the valleys are relatively large except where the large rivers pass (Mukungwa and Nyabarongo rivers). The area is not easily accessible. Noble clay: The “noble clays” are composed mainly of kaolin which is mainly the result of superficial weathering (under hot and humid climate) or hydrothermal weathering of magmatic acidic rocks (like leucogranites) rich in potassic feldspar and poor in ferromagnesian minerals. When the clay deposits exist, they are usually of good quality, but loam or clayish-loam deposits. also you can find
2. General use of the clay
Humans have found applications for ceramics for the past 30,000 years, every day new and different applications are being discovered. The application of the ceramic material is found in a very wide range of domains, such as: Aerospace: space shuttle tiles, thermal barriers, high temperature glass windows, fuel cells... Consumer uses: glassware, windows, pottery, tableware, ceramic tiles, home electronics, paints, refractory, bathtubs, washbowls... Automobile: catalytic convertors, ceramic filters, ceramic rotors, pressure sensors, safety glass windshields, piston rings... Medical (bio-ceramics): orthopaedic joint replacement, prosthesis, dental restoration, bone implants... Military: air and naval vehicles, missiles... Computer: insulators, resistors, superconductors, capacitors, microelectronic packaging... Other industries: bricks, cement, laboratory equipment...
3. Possible use of the clay in Rwanda
Bricks and tiles for...