https://hal.archives-ouvertes.fr/hal-01697286/document

A semi-mobile flash dryer/calciner unit to manufacture pozzolana from raw clay soils - application to soil stabilisation

Sarooj is a local term used for pozzolana. It has been used extensively as a hydraulic binder in buildings, hydraulic installations, forts and castles, and in the renovation of historical monuments. It is produced by burning specific clay soil that possesses adequate quantities of silica, alumina and iron oxides. In the past, the material was produced using a large amount of energy most of which is wasted by blowing winds. The burning system was usually thermally inefficient, and the output is rarely checked for quality. Test on products produced by using the traditional method may yield poor quality Sarooj due to inadequate burning or over burning or even insufficient grinding in the end. In this research, extensive experimentation has been performed on the method of production of Sarooj to determine the factors influencing Sarooj quality. Based on these factors, a new method of production is proposed. In this method, a fully mobile kiln was designed to produce Sarooj on the site. The kiln can produce 200 kg/h of Sarooj, and can be installed within one hour of arriving on the site. It can be towed by a tractor or a normal vehicle to the desired location, connected to the natural gas supply and the electric power. The construction is light, compact, and easy to start and shut down. In this paper, the plant is described in detail, together with some preliminary results of testing done on Sarooj produced by the kiln. Full details of tests on the product of the kiln will be given in a subsequent paper.

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Design of a Rotary Kiln for Production of Sarooj

Applying the principles of fluidization, a counter current fluidized bed calciner was designed for heat activation of clays and a pilot plant of capacity of 2 tonnes per day was set up at the Sri Ram Institute for Industrial Research. The pilot plant studies revealed that the fluidized bed technique could be effectively used for production of clay pozzolana. It has advantages such as high thermal efficiency, lower floor space, and it is economical compared to the conventional methods. Based on these studies, a demonstration-cum-production plant of capacity of 20 tonnes per day has been set up by National Buildings Organisation at Sultanpur, Delhi, where uniform quality of pozzolana conforming to IS specifications is being produced.

A. V. R. Rao

Papers

Production of Clay Pozzolana by Fluidized Bed Technique