Dear colleagues,

       I am happy to meet with you and to use this opportunity to tell you about semidry brick pressing technology, which has been not known earlier in the South Africa. At the same time, I would like to express my gratitude to the Clay Brick Association and to Mr. AT COETZEE, in person, who provided us not only favorable opportunity to tell you about such semidry brick pressing technology, but also found time to visit us in Russia, where we could demonstrate it vividly both to him and to the delegation of specialists of the local brick manufacturers from the South Africa.

       We also express our acknowledgement to the Head of "CERMALAB CC" R&D laboratory in the South Africa, to Mr. PETER DU TOIT, who put a lot of well-minded questions, the answers to which permitted him to have deeper insight into the essence of semidry brick pressing technology and to evaluate its benefits.

       First of all, I would like to tell you briefly about our North Caucasian Research and Development Institution (R&D) of the Building Materials and Technologies "STROMTECHNIKA".

       I am at the head of this Institution already 23 years. During this period of time we have put into operation 28 brick manufacturing plants, at which we have fulfilled all complex of necessary works, comprising laboratory testing of the local clays, design engineering, process equipment delivery, its installation, starting up and adjustment. Besides, we have performed radical retrofitting of existing plants, including replacement of the obsolete process equipment with the purpose to increase throughput capacity of said plants; erection of the brick firing kilns, replacement of available automatic systems and such other things. Our work was highly appreciated by the Government of Russia. Thus, 17 specialists of our Institution were conferred governmental awards for their high achievements in the construction of the brick manufacturing plants.

       Our Institution avails of its own production shops, dedicated to the process equipment, as well as of its own design engineering and adjustment units. We are ready to fulfill the whole amount of necessary works on the construction of the brick manufacturing plants. I would like to emphasize that all such works are carried out by specialists of our Institution without involvement of any subcontracting organizations, thus providing high fulfillment quality thereof and short terms of the very construction of the plants.

       We have large practical experience in the construction of the brick manufacturing plants, using both semidry and extrusion techniques. However, at present time, when current prices for the energy carriers are too high, we recommend application of semidry brick pressing technology, which is the most efficient and low expensive one.

       I would like to begin my report about semidry brick pressing technology from the history of the pressing machines application in the brick production. The first pressing machine has been developed about 160 years ago in Germany and it used so-called extrusion techniques. Introduction of such pressing machines permitted to eliminate hand work in the bricks manufacturing. However, application of such pressing machines only replaced hand work for the mechanized one, but the drying process still has been fulfilled as earlier.

       About 80 years ago, that is in 1938, the Russian specialists introduced a new integrated technology of the brick production.

       This technology came to replace extrusion techniques and it uses not only quite different engineering design of the pressing machines, rather it permits to eliminate the drying process at all. In other words, after it's molding, the brick is delivered immediately to the firing kiln. This results in the large economic effect and permits to reduce considerably the prime cost of the brick and, as a result, to obtain sensible profits. Obtaining of sensible profits is stipulated by the following factors:

1. Considerable reduction of the energy carriers consumption, because the fuel consumption rates for the brick firing and for the drying thereof are approximately equal. Thus, during artificial drying process, it takes place 2fold reduction of respective fuel consumption, while natural drying process requires no fuel for brick transportation over available drying section and actual area of said drying section is not too large.
2. Sensible profit is reached at account of reduction of the workers, being engaged in the transportation operations of the crude bricks, as well as of the workers, being engaged in the bricks re-piling from the drying pallets.
3. Sensible profit is also provided by the higher quality of the bricks, being made using semidry pressing technology. It is well known to everybody, that the higher is the moisture content of the crude brick, the larger will be its contraction extent and, as a result, the worse will be its quality. In addition, during molding of the bricks with low moisture content we are capable to use actually any clays, while geometrical sizes of the finished bricks will be nearly ideal.

       The company STEELS, which is also represented here, offers technologies, which imply reduction of the drying time and which are more beneficial, than traditional extrusion techniques, being used. However, only Russian semidry brick pressing technology permits to exclude completely the drying process and to obtain sensible profits.

       Considering, that moisture content of the raw materials for clay conditioning in South Africa is low, here bricks production will imply the following three (3) stages:

1. Crushing of the raw materials;
2. Semidry pressing of the crude bricks;
3. Firing of the crude bricks.

       The whole set of the process equipment will consist of the hopper feeder, crusher, pressing machine and firing kiln. Depending on the raw material hardness, the crusher may have different structure. As you can judge, only little quantity of the process equipment is used in case of semidry pressing technology application.

       Moreover, semidry pressing technology requires little quantity of the process equipment; its power consumption is insignificant, while total area of the whole brick manufacturing plant is minimum one. All these factors reduce plant construction and plant operation expenses in several times.

       As an example of the promising application of the semidry brick pressing technology, I would like to bring Rostov region of Russia. As our Institution is situated in this region, exactly here we introduce widely such semidry brick pressing technology.

       More visually, you can see it graphically on this diagram.

       I would like you to get acquainted also with respective technical and economic indices of the brick manufacturing plant, having throughput capacity of 20mln brick pieces per year: - Total power capacity of all electric motors-190kW, including power capacity of the electric motor of the pressing machine: 30kW;
- Overall dimensions of the brick manufacturing plant: 24õ84õ7,7ì;
- Number of the workers per one shift: 10-12
- Payback period of the brick manufacturing plant: 2-3 years.

       Analysis of the kilns, intended for the bricks firing, shows that if we do not take into consideration firing kilns of the XIX century models and experimental aggregates, like cover (bell-type), blast (shaft-type) kilns and others, then there are two principal types of the kilns. Thus, tunnel kilns are the most widely used. One may refer to the salient features of the kiln of this type the opportunity to automate crude bricks decking process on the firing bogy. Such type of the kiln was considered the best one in 70-80s, when the price of electric power was rather low. However, at present, high gas and energy consumption rates are principal drawbacks of said kilns.

       Moreover, considerable capital expenditures are required for construction of the tunnel kilns, which to a larger extent, comprise the cost of the firing bogies fleet and the cost of the gas recirculation systems. These elements make up about 50% of the total firing kiln cost and, while being under the fire impact, they permanently burn out, thus requiring complete or partial replacement thereof each 2-4 years, speaking nothing about their current repairs. Resulting fuel consumption rate is 160-180kg for 1000 pieces of conventional bricks.

       Other type of the firing kiln, which emerged nearly 20 years ago in Rostov region, but acquired wide spreading and it is now develops most dynamically, are so-called ring firing kilns, fitted with detachable domes (roofs).

       They combine certain advantages of the ring and tunnel kilns. That is, on the one hand, they are fully mechanized, while on the other hand, they require no firing bogies fleet. Crude bricks are loaded into such kilns and are unloaded there from through available domes (roofs) in the packages, each containing 300-600 pieces thereof. After loading, the kiln domes (roofs) are covered with the plates, made of refractory material and crude bricks firing process is performed, like in the ordinary ring kiln.

       To the advantages of said ring kilns, one may refer dispersed withdrawal of resulting exhaust gases and lower (inferior) allocation of the firing burners, which permit to produce bricks of the higher grade and quality, than in ordinary tunnel kiln. Taking into account that there are no firing bogies and recirculation systems and that the ring kiln is 3fold shorter than the tunnel one, provided their equal throughput capacity, the capital expenditures for construction of the ring firing kiln are 2.5-3fold less.

       Fuel expenditure for making 1000 pieces of the bricks makes up 80-100kg of conventional fuel.

       Why ring kilns, fitted with detachable domes (roofs) have such low fuel consumption rate? Let us investigate the fuel consumption rate during operation of the tunnel kiln, as follows:

1. For the heat efflux together with exhaust gases;
2. For the heat efflux by the fired bricks;
3. For the heat efflux by the firing bogies.

       Considering absence of the firing bogies in the ring kilns, fitted with detachable domes (roofs), resulting heat is not lost. Other important factor of the low fuel consumption rate of the ring kiln, fitted detachable dome (roof), is lower (inferior) allocation of the firing burners.

       Everybody understands that lower (inferior) allocation of the firing burners is the most successful idiosyncrasy. This permits to reduce considerably the fuel consumption rate, which is required for heating. Just take as an example, usual tea pot. Its heating takes place when the flame is below. That is why, nobody and never tries to heat it from above or from the side.

       Similar lower (inferior) allocation of the firing burners in the tunnel kiln is designedly unfeasible, because the firing bogies move therein and that is why the firing burners are installed in the side-wise or in the top-wise manner, thus resulting in excessive fuel consumption rate.

       Firing kiln, fitted with detachable dome (roof) was developed in our STROMTECHNIKA Institution and it is copyrighted with respective patent. We have built already 30 such kilns and all of them operate successfully and demonstrate good economic efficiency

       Also, I would like to draw your attention to the lever tongs, specially developed by us for such kilns and intended for gripping of the brick piles and ceiling panels. Application of such lever tongs permits to lift and to move respective brick piles without any pallets. This is very important benefit, as it simplifies and facilitates transportation of the brick piles. That is, the brick pile is positioned once near available pressing machine. Further, no any re-piling of the bricks within the package is required. That is, one and the same brick pile is positioned in the kiln, one and the same brick pile is transported to the warehouse of the finished produce and one and the same brick pile is loaded into the trucks. And again, all said operations are performed without any pallets and without any brick package re-piling. We consider this as our large success, which brings sensible profit to the brick manufacturing plant owner.

       As well, I would like to draw your attention to kiln ceiling panels. Refractory material of the kiln is made on the base of the fibrous alumina and it sustains higher temperature, than other refractory materials, i.e. more than 1400°C. It means that it is possible to fire not only ceramics, but also certain items, made of refractory materials. For example, it is possible fire refractory bricks, which result in larger profit. Apart from excellent refractory properties material of the ceiling panels possesses high heat-insulation characteristics. So, when the lower side of respective ceiling panel is under 1100°C, you can put your hand on the upper side of the kiln and you will not feel any heat. These properties of the ceiling panels permit also to reduce fuel consumption rate of the kiln. I would like to draw your attention once again to the advantages of the brick manufacturing plants, using semi-dry pressing techniques, as opposed to those, using extrusion techniques. There are, as follows:

1. Electric power consumption is reduced more than 2fold;
2. Fuel consumption rate of the kiln is reduced more than 2fold;
3. Harmful emissions into the atmosphere, containing CO2, are reduced also 2fold, because, as less we burn fuel, the less will be harmful emissions into the atmosphere.
4. Expenditures for construction of brick manufacturing plant, using semi-dry pressing techniques, are several times lower.
5. Total area of the very brick manufacturing plant and its production building is several times less.
6. Number of working personnel is much less.
7. Construction of the brick manufacturing, using semi-dry pressing techniques, takes shorter time.
8. Overall dimensions of the bricks, being made using semi-dry pressing technology, are ideal and equal.
9. Assortment of the items, being made using semi-dry pressing technology, is as follows: ceramic bricks; refractory bricks; architectural bricks; profile bricks; bricks, having box-like shape; roof tiles; pavestones; floor tiles and wall boards.
10. The most significant and the only one correct index of the economic efficiency of any brick manufacturing plant, is the payback period of respective funds, being invested into construction of the plant. In this respect, brick manufacturing plants, using semi-dry pressing technology, are off any competence. Our plants are paid back within 3-4 years.

       I would like to thank Association directorate and colleagues for their attention.