REFRASUD INTERNATIONAL S.R.L.

Transcription

1 REFRASUD INTERNATIONAL S.R.L.

2 Page 2 of 8 INNOVATION TECHNOLOGY: CARBONXIDE The company Refrasud International S.r.l. (hereafter referred to as Refrasud), works in refractory field and offers different qualities of products. For their production it is used a special chemical conditioner called CARBONXIDE, which gives the finished product specific chemical and physical characteristics. During the sintering phase CARBONXIDE facilitates the formation of a better distributed and widespread microstructure and microporosity (see Photo n pag.2), compared to standard refractory products (see Photo n pag.2). Advantages to be underlined: 1) Energy costs reduction 2) Longer life of refractory products 3) Minor maintenance costs Thanks to the introduction on the market of this conditioner that can be used in almost all the refractory products (except of refractory cements and castables containing aluminum phosphate or chemically bonded alumina bricks), Refrasud is able to improve and increase performances of these products in terms of thermal capacity and duration. A major part of the merit of this innovation lies in a special attention that Refrasud has always paid to Research, placing continued testing programs as a center of its activities.

3 Page 3 of 8 Quality microanalysis or a refractory structure with CARBONXIDE Pic. 1 Quality microanalysis of a STANDARD refractory structure Pic. 2 Detail of a refractory material structure where the detected porosity holes are smaller viewed at the same scale. Pic. 3 Detail of a refractory material structure where the detected porosity holes are bigger viewed at the same scale. Pic. 4 The microcomponents detected have small dimensions viewed at the same scale Pic. 5 The microcomponents detected have much bigger dimensions viewed at the same scale Pic. 6 The grain dimensions detected are small viewed at the same scale. The grain dimensions detected are bigger viewed at the same scale.

4 Page 4 of 8 The additive goes into action during the sintering phase and/or ceramization phase preventing from rising of grain sizes and favoring a notable increase in quantity of pores with a smaller diameter. Products treated with additives based on CARBONXIDE have a particular structure characterized by a total porosity equal to a standard products porosity but with a much bigger number of pores per cm 3 (of 30 40%) with smaller diameter (of 30 50%) [see Table 1 and Photos 1 and 2] The data reported below show results of a research performed by Mechanical Engineering of the University of Lecce on two samples of alumina bricks of quality ZH 85 A containing 82% of alumina: the first with additive and second one without additive. The table given below evidences the differences between the two samples: Table 1 Properties Brick ZH 85 without additive Brick ZH 85 A with CARBONXIDE Average pore radius (Micron) : 0.83± ±0.02 Total porosity (%) : 20.0± ±0.6 Bulk density (g/cm3): 2.70± ±0.05 Values of porosity, pores diameter and bulk density of the samples measured using mercury porosimetry (CERTIFICATE N.1)

5 Page 5 of 8 It could be deducted that the microporous formation obtained through the use of CARBONXIDE is more favorable to a "discharge" of a tension and more appropriate for improving of a compactness and a thermo-mechanical resistance of produced materials. The following characteristics are noted: Greater Specific Heat (20% 30%) Lower Thermal conductivity (10% 20%) Lower Thermal Diffusivity (30% 50%) Better Thermal Shock resistance Better Hot Crushing Strenght ( C) (20% 30%) Lower thermal expansion (10% 20%) The above-mentioned characteristics have been confirmed by a numerous laboratory tests performed by Societè Francaise de Ceramique (France), University of Lecce (Italy), Salentec Laboratory(Italy) and some other Italian and overseas laboratories situated within refractory manufacturers plants. The laboratory tests have been carried out on insulating bricks and refractory bricks and castables, some of the results are reported below. A refractory lining produced with additive by the mean of this technology permits to obtain a much lower Thermal Diffusivity value compared to standard refractory linings.

6 Page 6 of 8 Example of differences between Thermal Diffusivity values of two alumina bricks containing 70% Al2O3 STANDARD BRICK (70% Al2O3) α = BRICK WITH ADDITIVE (70% Al2O3) λ 2,3 = = 0,7149 CpxPs 1,214 x 2,65 α = λ 1,886 = = CpxPs 1,55 x 2,65 0,4591 where α = thermal diffusivity [m2/s] = 0,7149 Cp = specific heat [J/KgK] = 1,214 Ps = density [Kg/m3] = 2,65 λ = thermal conductivity [W/mK] = 2,3 α = thermal diffusivity [m2/s] = 0,4591 Cp = specific heat [J/KgK] = 1,55 Ps = density [Kg/m3] = 2,65 λ = thermal conductivity [W/mK] = 1,886 TABLE OF MATERIALS AND THEIR PROPERTIES. Nature of materials Steel Bauxite Bauxite + additive Chamotte (fire clay) Chamotte + additive Dolomite Magnesite Insulation brick t< Insulation brick t Baux + additive λ (W/mK) 50 2 C kj/kg K 0,795 1,214 ρ Kg/m , α m2/hx3,6 x , , A (λ. ρ. C)1/2 527,5 82,5 1,7 1,578 2, , ,7 1,2 1,214 2, , ,02 2,9 4 1, ,32 2, , , , ,60 58,8 90,1 125,8 0,465 1, , ,5 0,581 1, ,2 3 2 x 0,85 1,214 x 1,3 2,8 10 1, ,7 1,70 1,578 Cham.+ additive 1,02 1,578 2, , ,8 α. = is the quickness by which the material adapts its temperature in accordance with the thermal gradient. it could be noticed that a lower value of λ in the numerator and a simultaneous increase of the value of Cp in the denominator causes a decrease of the thermal diffusivity value that presents a quickness of the thermal loss and its measure is [m2/s].

7 Page 7 of 8 CERTIFICAZIONS THERMAL CONDUCTIVITY Hereafter the table with laboratory tests results performed by Société Francaise de Céramique on two insulation bricks of quality JM26: the first a standard one and the second one with CARBONXIDE, both with the same specific weight and total porosity. STANDARD BRICK W / Mk BRICK WITH CARBONXIDE W / Mk Certificati SFR (Sociètè Francaise de Cèramique) n e n (ex Ifintur) (CERTIFICATE N.2 and CERTIFICATE N.3) THERMAL CONDUCTIVITY Hereafter the table with laboratory tests results performed by Société Francaise de Céramique on two samples of refractory castable Carbovibro 50 LI produced by Refrasud, both with the same specific weight and total porosity. CARBOVIBRO 50 LI (N) WITHOUT ADDITIVE W / Mk CARBOVIBRO 50 LI (A) WITH CARBONXIDE W / Mk Certificates SFR (Sociètè Francaise de Cèramique) n e n (ex Ifintur) (CERTIFICATE N.4 and CERTIFICATE N.5) SPECIFIC HEA T Hereafter the table with laboratory tests results performed on two samples (one with additive and another without additive) both with the same specific weight and total porosity. CARBOVIBRO 50 LI (N) WITHOUT ADDITIVE J / kgk A CARBOVIBRO 50 LI (A) WITH CARBONXIDE J / kgk Certificates SFR (Sociètè Francaise de Cèramique) n e n (ex Ifintur) (CERTIFICATE N.6 and CERTIFICATE N.7)

8 Page 8 of 8 COMPARATIVE TESTING OF HEAT DISSIPATION In order to demonstrate the difference during a time period between two alumina based refractory castables (one with CARBONXIDE and the other without additive), we can evidence the laboratory results carried out by the Refrasud laboratory on two castable samples with the same values of specific weight and total porosity. The both samples have been fired in a furnace at 600 C and 900 C for 20 hours and measured till the total cooling off. CASTABLE WITHOUT ADDITIVE CASTABLE WITH CARBONXIDE Furnace temperature: 600 C - Environment temperature: 29 C Time point Temperature Time point Temperature 303 C 313 C after 10 minutes 218 C after 10 minutes 227 C after 20 minutes 145 C after 20 minutes 147 C Certificate Refrasud International n. 2378/11 (CERTIFICATE N.8) CASTABLE WITHOUT ADDITIVE CASTABLE WITH CARBONXIDE Furnace temperature: 900 C - Environment temperature: 34 C Temperature Temperature 435 C 468 C after 10 minutes 280 C after 10 minutes 318 C after 20 minutes 184 C after 20 minutes 215 C Certificate Refrasud International n. 2380/11 (CERTIFICATE N.9) HMOR (HOT MODULUS OF RUPTURE) (1500 C) Laboratory tests results performed on two samples (one with additive and another without additive) both with the same specific weight and total porosity. CARBOVIBRO 50 LI (N) WITHOUT ADDITIVE TEST MPA AVERAGE 0.80 CARBOVIBRO 50 LI (A) WITH CARBONXIDE TEST MPA AVERAGE 1.06 CertificatiesSFR (Sociètè Francaise de Cèramique) n e n (ex Ifintur) (CERTIFICATE N.10 and CERTIFICATE N.11)