Title of Invention	AN IMPROVED PROCESS FOR PREPARING FRIIT COMPOSITION.
Abstract	An improved process for preparing frit composition characterised in that mixing drum filter cake, borax, alkali and alkaline earth metal carbonates in a ratio of 1:1:0.1 to 1:2: 0.2 , heating the above said mixture at 850-950°C for a period of 2 to 3 hours, cooling and recovering the frit composition by conventional method.

Full Text

This invention relates to an improved process for preparing frit composition. The process of present invention is particularly useful for making frit materials/compositions containing silica, oxides of iron, aluminium, lead zinc and alkali and alkaline earth metals, useful for glazing of ceramics utilizing drum filter cake- a lead containing hazardous waste generated in secondary zinc manufacturing industries. Usage of the frit materials obtained by the process of the present invention is in preparation of frit/glazes useful for glazing of ceramic materials such as ceramic tiles, sanitary wares etc. The glazes are glassy materials, which are coated on the surface of the, ceramic bodies for their protection and beautification. In addition to aesthetic appeal, glazes impart important technical characteristics such as improvement in impact strength, acid and alkali resistance and making the surface impervious to the absorption of water/moisture. Conventionally the frit compositions used for making glazes either contain compounds or are lead free. The lead bearing frit compositions are made from feldspar, quartz, alkali and alkaline earth metal carbonates, borates etc. (M.Djuric and F.Tot; Am. Ceram.Soc.Bull.vol. 73 No.8 1994), in addition to lead as one of the constituent added. (Prinya Sainamthip and James S. Reed ; Ceram. bull, vol.68 No.l, 103-106) in the form of red lead/litharge/white lead etc. (T.A. Caton; Br.Ceram Trans. 1994 vol.93 No.l 33-37). The conventional process of making frit materials involves (1) Powdering of different raw materials by grinding in ball mill, rod mill, pot mill etc. (2) Heating of the powdered raw material mix. in required proportions in the temperature rang of 1000-1250° C for 2-4 hours duration (A Janah; Trans, of Indian Ceram. Soc. Vol. 46 No.l 1987). (3) The molten frit material so obtained is cooled by pouring into water to obtain globules of frit material. The above conventional process of making frit material suffers from the following drawbacks. (i) Utilizes non replenishable natural resources as quartz, feldspar, lime stone etc., (ii) Requires considerable grinding energy as hard materials such as quartz and feldspar having hardness values of 7 and 6 respectively on the Moh's scale have to be powdered , and (iii) Requires heating at higher temperatures in the rang of 1000-1250 °C for a duration of 2-4 hours leading to significantly high energy consumption. Accordingly the present invention provides an improved process for preparation of frit material/compositions which comprises mixing drum filter cake, borax, alkali and alkaline earth metal carbonates in a ratio of 1:1:0.1 to 1:2:0.2 heating the above said mixture at 850-950°C for a period of 2 to 3 hours, cooling and recovering the frit composition by conventional method. The main objective of the present invention is an improved process for making frit materials/compositions useful for glazing of ceramics, by utilizing a lead containing hazardous waste material generated in the secondary zinc manufacturing industries. Thus the developed process has two fold benefits, (i) firstly it helps in solving the problem of hazardous solid waste disposal (ii) Secondly it helps in converting a toxic solid waste into a non-toxic value added material. To this end, the present invention broadly consists of making frit materials/compositions utilizing a lead containing hazardous waste obtained from secondary zinc manufacturing process/industries, which is in powder form and contains many necessary constituents required for making frit materials/compositions. The drum filter cake waste material contains about 25-30% silica, 10-18% iron oxide, 6-10% alumina, 4-6% manganese dioxide, 2-4% lead oxide, 1-4% zinc oxide, 1-2% potassium oxide, 1-3% calcium oxide, 1-2% sodium oxide, 0-1% magnesium oxide etc. Drum filter cake 10-48gms, borax 40-60gms,sodium carbonate 4-7 gms, potassium carbonate 4-5 gms, alumina 2.28 - 4.2 gms, calcium carbonate 1.5 -2.0 gms, magnesium carbonate 0-2 gms, zinc oxide 0-5.0 gms were mixed to homogenize and then heated in the temperature range of 900 - 950 °C for a duration of 2-3 hours, in order to complete the chemical reactions among the various ingredients of frit compositions, necessary to form borosilicate glasses based frit material compositions, wherein the toxic lead ions have been complexed in the glassy matrix and thus renders the toxic lead ions non-leachable in the frit material /compositions prepared. The liquid mass of frit composition thus obtained was cooled by pouring it into ambient water. The dried frit material was tested for lead leachability tests. For using the frit material for making glazes the dried glassy frit material was mixed with 8-10% china clay, 1-2 carboxy methyl cellulose using wet grinding. The slurry so obtained was spread on both, backed green ceramic tiles and biscuit fired tiles. The tiles were then heated in the temperature range of 800 - 950°C for a duration of 30 - 60 minutes. The glazed tiles so prepared were furnace cooled. The glazed tiles were then tested for flexural strength, impact strength, % water absorption and the thickness of glaze layer. Accordingly the present invention provides, an improved process for preparing frit composition characterised in that mixing drum filter cake, borax, alkali and alkaline earth metal carbonates in a ratio of 1:1:0.1 to 1:2: 0.2 , heating the above said mixture at 850-950°C for a period of 2 to 3 hours, cooling and recovering the frit composition by conventional method. In an embodiment of the present invention alkali & alkaline earth metals carbonate used may be sodium, potassium, calcium, magnesium. In an another embodiment of the invention wherein the process utilizes drum filter cake and thus convert drum filter cake - a lead containing hazardous waste into value added non-toxic frit material useful for glazing of ceramics. The following examples illustrates the process for making frit materials useful for glazing of ceramics, utilizing lead containing hazardous waste materials obtained from secondary zinc manufacturing industries. Example - 1 The drum filter cake (DFC) waste material containing 26.2% silica, 16.30% iron oxide, 8.2% alumina, 4.65% manganese dioxide, 2.32% lead oxide, 1.74% zinc oxide, 1.45% potassium oxide, 1.1% calcium oxide 0.9% sodium oxide, 0.2% magnesium oxide was used in the present example. For making frit/glaze material 28 gms of DFC, 50 gms. Of borax. 7.235 gms of potassium carbonate, 9.0 gms. of sodium carbonate, 4.2 gms of alumina, 1.46 gms of calcium carbonate, 9.0 gms of sodium carbonate and 0.21 gms of magnesium carbonate were mixed thoroughly to obtain a homogeneous powder mix. The homogeneous mix so obtain was then heated in a graphite crucible using electric muffle furnace at 950°C for a duration of two hour. At the end of heating duration the molten mass of frit material was cooled by pouring carefully into ambient water. The frit material so obtain was wet ground with 5 gms. of china clay and 0.1 gms of methyl cellulose. The slurry so obtained was sprayed on biscuit fired wall tiles.. The tiles after drying in air oven at 110°C for two hours were sintered in an electric muffle furnace at 900°C for a period of one hour and furnace cooled. The glazed tiles so obtained were tested for impact strength and water absorption properties. The impact strength was found to be in the range 0.025-0.029 kgf.cm"1 and water absorption in the range of 6-8 %. Example - II 30 gms of DFC, 50 gms of borax, 7.15 gms of potassium carbonate, 7.15 gms of sodium carbonate, 4.2 gms of alumina,, 1.46 gms of calcium carbonate, 0.21 gms of magnesium carbonate were mixed thoroughly to obtain a homogeneous powder mix. The homogeneous mix so obtain was then heated in a graphite crucible using electric muffle furnace at 850 ° C for a duration of two hours. At the end of heating duration the molten mass of frit material was of cooled pouring carefully into ambient water. The frit material so obtain was wet ground with 5 gms. of china clay and 0.1 gms. of methyl cellulose. The slurry so obtained was sprayed on biscuit fired wall tiles. The tiles after drying in air oven at 110 °C for two hours, were sintered in an electric muffle furnace at 920 °C for a period of one hour and furnace cooled .The glazed tiles so obtained were tested for impact strength and water absorption properties. The impact strength was found to be in the range of 0.026- 0.027 kgf.cm"1 and water absorption in the range of 7-9 %. Example -III 47.75 gms of DFC, 50 gms of borax, 5.235 gms of potassium carbonate, 5.85 gms of sodium carbonate, 2.28 gms of alumina, 1.96 gms of calcium carbonate, 0.21 gms of magnesium carbonate were mixed thoroughly to obtain homogeneous powder mix. The homogeneous mix so obtain was then heated in a graphite crucible using electric muffle furnace at 900°C for a duration of two hours. At the end of heating duration the molten mass of frit material was cooled by pouring carefully in to ambient water. The frit material so obtain was wet ground with 5 gms. of china clay and 0.1 gms of methyl cellulose. The slurry so obtained was sprayed on biscuit fired wall tiles. The tiles after drying in air oven at 110° C for two hours, were sintered in an electric muffle furnace at 950 °C for a period of one hour and furnace cooled. The glazed tiles so obtained were tested for impact strength and water absorption properties. The impact strength was found to be in the range of 0.0028- 0.0030 kgf.cm-1 and water absorption in the range of 8 -10%. The following are the main advantages of the present invention 1. The process of present invention utilizes a lead containing hazardous waste generated in secondary zinc manufacturing process/industries for making frit materials useful for glazing of ceramics. The various constituent present in the drum filter cake are very much essential and are suitable for making frit material at relatively lower temperature itself. 2. The process of present invention is carried out at low temperature in the range of 850-950 °C for a period of 2-3 hours. 3. The process of present invention is useful for converting a lead containing hazardous waste into value added non-toxic frit materials wherein the toxic lead ions have been complexed in the glassy matrix of frit materials and thus rendering toxic lead ions unleachable and the frit material prepared is useful for glazing of ceramics. 4. The process of present invention offers two fold benefit, firstly it helps in utilization of lead containing toxic waste and secondly it converts toxic in to value added material useful for glazing of ceramics. 5. The process of present invention has opened up an additional source of raw material which has direct bearing on saving of non replenishable natural raw materials. 6. The process of making frit material utilizing drum filter cake helps in saving considerable grinding energy, as the waste is as such generated in powder form itself. The conventional process of making frit materials involves use of feldspar and quartz which requires considerable high grinding energy as both the minerals have high hardness value of 7 and 6 on Mohs Scale ,respectively. We Claim: 1. An improved process for preparing frit composition characterised in that mixing drum filter cake, borax, alkali and alkaline earth metal carbonates in a ratio of 1:1:0.1 to 1:2: 0.2 , heating the above said mixture at 850-950°C for a period of 2 to 3 hours, cooling and recovering the frit composition by conventional method. 2. An improved process as claimed in which claim 1 wherein the drum filter cake used is a lead containing hazardous waste. 3. An improved process as claimed in claim 1 to 2 wherein the alkali and alkaline earth metal carbonates used is selected from sodium, potassium, calcium, and magnesium. 4. An improved process as claimed in claim 1 to 3 wherein the period of heating is effected for 2 hours. 5. An improved process for preparing frit composition substantially as herein described with reference to examples.

Documents:

428-del-2001-abstract.pdf

428-del-2001-claims.pdf

428-del-2001-correspondence-others.pdf

428-del-2001-correspondence-po.pdf

428-del-2001-description (complete).pdf

428-del-2001-form-1.pdf

428-del-2001-form-18.pdf

428-del-2001-form-2.pdf

428-del-2001-form-3.pdf