DRY PROCESS FOR THE PREPARATION OF CERAMIC MIXES FOR FAST SINGLE FIRED VITRIFIED TILE

Ziel

Realization of an innovative system for the preparation of the powders to be dry pressed for the production of fast single-fired vitrified tile, based on the dry process rather than the wet process presently in use for the production of this type of tile.
The innovative process, which involves innovative technology for the preparation of the raw materials, represents a valid technological alternative to the traditional process (based on wet grinding followed by spray drying) and will serve as a demonstrative system for italian ceramists as well as ceramists in the other Countries of the E.C.L%
From the technological point of view, the innovative dry granulation technology makes it possible to produce fast single-fired vitrified whiteware medium-large-sized tile of quality according to the standards required by the norms in force. As far as energy consumption is concerned, the innovative dry granulation system presented the following specific energy consumption (average values) :
* heat consumption = 125 kcal/kg (0.523 GJ/t)
* electricity consumption = 45 kWh/t (0.162 GJ/t)
With the system running in process in steady conditions, the folllowing values are obtained (in comparison with a traditional wet grinding and spray drying process) :
- thermal energy savings = 1168.4 TOE/year;
- electricity = 64.6 TOE/year.
The PBP resulted in 2.6 year.
The dry granulation system realized by this project has a 11 t/h production capacity, and is the result of long term experience and technological research regarding machinery and equipment carried out in collaboration between GMV IMPIANTI, at present named GMV DINAMICA SPA and CENTRO CERAMICO. One such cooperative project was a Demonstrative Project financed by the EC (EE 561/86/IT) with positive results.
The innovative aspects of the system regard the possibility of preparing the raw materials by dry grinding in a mill with very high efficiency and successive granulation of the finely ground powders in a granulator followed by drying in a fluid bed drier.
The mill for dry grinding is a finishing mill with a drier and an integrated dynamic separator. The mill consists of two conical rollers with large diameters that roll under pressure on a horizontal track. A hot air drying system brings the raw materials entering the mill to complete dryness, thus preventing the grinding rollersfrom becoming dirty and consequently increasing the grinding efficiency. The dynamic separator selections the particle size of the material existing from the mill on the basis of the difference in pressure in the pneumatic circuit of the mill itself. The granulator is a special machine in which the powders previously dry-grounded are mixed with finely sprayed water, and reach an hydration equal 11 to 15%. Reduction of the water content of the granulated powders is carried out in a successive step in a fluid bed drier, in which the granulated powders are brought to the moisture content necessary for dry pressing (6%).
Such a system results in drastic reductions in heat consumption in this phase of the production cycle, because granulation of the dry ground powders can be achieved with modest amounts of water, which then are reduced in the fluid bed drier to moisture contents suitable for dry pressing.
In contrast, with the wet process, during spray drying it is necessary to achieve the removal of large quantities of grinding water which requires considerable consumption of energy. The project demonstrated that the dry granulation process allows to save more than 60% heat consumptions and 10% electricity in comparison with the wet process, traditionally applied to the same typology of production. In addition, the innovative dry process also resulted in other advantages economical-managerial in nature, such as lower operating and maintenance costs as well as less space required for the necessary equipment and machinery for the same productivity. Finally, the considerable reduction in hot emissions, and thus of carbon dioxide which makes the innovative process favourable from the point of view of environmental impact also should be emphasized. At present, the plant is running three shifts per day for five days a week with a 11 t/h production. At the end of the project the plant totalized 4,050 h of continuous operation.

Programm/Programme

ENG-THERMIE 1 - Programme (EEC) for the promotion of energy technology in Europe (THERMIE), 1990-1994

Thema/Themen

2.3 - INDUSTRY

Aufforderung zur Vorschlagseinreichung

Data not available

Finanzierungsplan

DEM - Demonstration contracts

Koordinator

GMV DINAMICA SPA

EU-Beitrag

Keine Daten

Adresse

VIA G. BARBOLINI 43
42014 Castellarano
Italien

Gesamtkosten