Title of Invention

"METHOD FOR A DIRECT STEEL ALLOYING"

Abstract

The invention pertains to ferrous metallurgy and can be used for steel production. The method of direct steel alloying by set of elements, including-metal-making in a steel-making vessel, charging of the oxide material, comprised of manganese oxides, reduction of alloys by charging of slay-forming materials. Oxide and/or. fluoride, and/or carbonate materials of other alloys are charged additionally on the surface of the liquid metal with uniform distribution of thereof and the oxide material, containing manganese oxides on the surface of the liquid metal. Reduction of alloys is made through charging of the reducing agent during charging of the oxide material, comprised of oxide and/or. fluoride, and/or carbonate materials of other alloys. Charging of the reducing agent is begun upon the reach of the layer height of charged alloys equal to 0,1 0.15 of total layer height on the separation boundary of metallic and slag phases. Reduction of alloys is carried out at melting temperature of the mixture, comprised of: the oxide material, containing manganese oxides and oxide and/or. fluoride, and/or carbonate materials of other alloys, ensuring constant contact of the molten reducing agent and homogeneous compound of molten alloys within total reduction process. while the reducing agent is charged in the quantity sufficient to provide the thermity mixture of charged alloys. Charging of the oxide material, comprised of manganese oxide or oxide and/or. fluoride, and/or carbonate materials of other alloys is carried out dispersedly or by portion with the consumption of each portion at least 0,1 of total consumption. Aluminum or silicon, or carbon materials or rare-earth group of metals or combination thereof can be used as the reducing agent. The claimed method ensures high degree of assimilation by metal of alloys and reduces contamination of steel by non-metallic inclusions. 2 dependent claims of the claims

Full Text

This invention pertains to ferrous metallurgy and can be used for steel production. Known is a method of steel alloying by manganese, including melting, tapping of metal into ladle, charging of alloys and inert gas blowing of metal. Further to metal tapping into ladle low phosphorus manganese slag of ferroalloy production, reducing agent and lime is supplied on the surface of melt in a quantity ensuring slag basicity of 2.0 3.5 and oxygen is supplied on the surface within 3 30 seconds (inventor's certificate of the USSR No.1044641, cl. C 21 (' 7/00. l983). The drawback of this method is that further to charging of lime into the ladle in the quantity ensuring the basieity of 2,0 - 3,5. oxygen is supplied on the surface of the metal that results in additional oxidation of the metal by the supplied oxygen, an increase of non-metallic oxide inclusions contained in it. and deterioration of steel quality. Manganese of low phosphorus manganese slag of ferroalloy production is present in a form ol chemically solid compound MnSiO.; the rodonite. At specified consumption of the lime in a mixture of low phosphorus manganese slag before reduction of the manganese along with formation of calcium silicates strong solid mixtures (Ca. MnO) are formed with high melting temperature more than 140()"C, and free lime as well. Addition of the lime helps to destroy chemical connections of silicate manganese, its reduction by silicon and formation of'CaiSiC^ and (7a,;Si(.)s in the slag defining the high melting temperature results in low extraction of manganese, high contents of non-metallic inclusions and deterioration of steel quality. The closest analogue to the claimed invention is a method of steel production, including metal-making in a steel vessel, oxidation, alloying, production of liquid metal, comprising silicon and aluminum reducing agents, charge of oxide mixture into liquid metal that contains manganese and calcium oxides with a ratio of Ca()/Mnx()v - 0.6 1,2, processing of liquid metal in the ladle by the slag arising out of the reduction of manganese by silicon and aluminum dissolved in metal, which is made by holding of liquid metal under the slag with the basicity of CaO/SiO, - 0,7 1.8, while together with the oxide mixture the reducing agent containing silicon is additionally charged into the liquid metal (RU2096491, cl. C 21 C 7/00. 1997). Features of the closest analogue match the following significant features of the claimed invention: metal-making in a steel vessel, charge of oxide material containing manganese oxides, reduction of alloys by charge of the reducing agent and charge of slag-forming materials. Preliminary oxidation and alloying of the metal in the known method is made in a steel-making vessel with oxidation slag put into place and high oxidation of the metal. This results not only in overconsumption of oxidizers and alloys interacting with iron oxides in the slag but also to an increase of metal contamination by hard-to-remove non-metallic inclusions silicon oxide (silicates), aluminum oxides (aluminates). manganese sulfides and iron. further processing of the metal in ladle based on the known method is made by reduction ol manganese from its oxides through charge of ferrosilicon into the ladle the reducing agent that contains silicon. The reduction process of manganese is conducted in diffusion mode, which inevitably requires additional time for its progress. Besides, quantity of silicates, aluminates and sulfides generated earlier in the steel-making vessel is enlarged by newly generated silicates arising out of the reduction of manganese. With the lack of means for globularization of these inclusions and with availability ol" high-silicate slag built on the surface of the metal, the known method can not ensure removal of non-metallic inclusions from the metal to the slag. Nor it can favour the desulphuri/.ation process, which results in an increase of the metal contamination by oxide and sulfide inclusions and deterioration of"its quality. The known method initiates unfavourable conditions for reduction of manganese because charge ol oxide mixture into the liquid metal, in which the ballast additive (CaO) totals from 1/2 to 2/3 of overall mixture quantity results in the following: deterioration of mixture melting conditions, longer time, and. consumption of additional melting time, which determines use of silicon, a low active material as reducing agent to be charged together with oxide mixture. b'se of silicon reducing agent is reasoned by possible local overheating of the mixture with the reducing agent, and consequently its arising on the surface of the slag melt and intensive irrational interaction with atmosphere oxygen. Loss to gaseous phase of the reducing agent, which contains silicon is nothing, however, sour silicon oxides (SiO:) generated as a result of manganese reduction process worsen thermodynamical conditions of manganese reduction. The above causes higher consumption of calcium-contained oxides (lime) and higher consumption of electricity required for oxide mixture reheating. The thermity of the oxide mixture even coupled with aluminum and silicon pre-charged into the liquid metal does not ensure spontaneous progress of the reduction process, and additional consumption of the reducing agent containing silicon as compensation in a form of chemical heat results in deterioration of manganese reduction rates as a result of an increase ol'SiO; in the slag. As a basis of the invention is a task to improve a method oi'direct steel alloying by a set of elements through optimization of technological process. Kxpecled technical result is establishment of favourable physical and chemical and temperature conditions of the method of direct steel alloying by a set of elements that result in enhanced aggregate assimilation of alloys by the metal, reduction in contamination of steel by non-metallic inclusions and improvement of its quality. The technical result is achieved by the following. I'he direct steel alloying method by a set of elements including: metal-making in a steel-making vessel. charging of oxide material containing manganese oxides. reduction of alloys by charging of reducing agent and charging of slag-forming materials According to the invention oxide and/or. fluoride, and/or carbonate materials of other alloys are charged additionally on the surface of the liquid metal, while the following should be observed: even distribution of the above materials and the oxide material, containing manganese oxides upon the surface of the liquid metal. reducing agent is charged during charging of the oxide material, containing manganese oxides and oxide and/or. fluoride, and/or carbonate materials of other alloys, beginning charging of the reducing agent once the layer height of charged alloys is reached, equal to 0.1 - 0,15 of total layer height on the boundary of metallic and slag phase, while the following should be observed: - reduction of alloys is made at melting temperature of the mixture, comprised of the oxide material, containing manganese oxides and oxide and/or, fluoride, and/or carbonate materials of other alloys. - ensure constant contact between the molten part of the reducing agent and homogeneous compound of molten alloys within total reduction process, while the reducing agent is charged in the quantity appropriate for the thermity of the mixture of charged alloys. It is appropriate to charge the oxide material, containing manganese oxides and oxide and/or. fluoride, and/or carbonate materials of other alloys separately or by portion with portion consumption of at least 0.1 of total consumption of the above. It is appropriate to use aluminum or silicon, or carbon materials as reducing agent or rare-earth metals or combination thereof. The claimed method is based on the following realization principle: - reduction in temperature in the reaction zone favours to an increase of the balance reaction constant. - consequently it improves completeness of its progress, while the above method provides the following conditions. 1. Minimum temperature in the reaction zone with minimum slag viscosity with high sorption ability with regard to reduction reaction product, i.e. easily absorbed Al2O3 or other oxide active element, or combination thereof used as reducing agent. 2. Constant presence in the reaction /one within total reduction process of initial component reaction of the oxide material containing manganese oxide or material containing oxide and/or, fluoride, and/or carbonate materials of other alloys and reducing agent. 3. Efficient removal from the reaction zone products thereof: the reduced alloy in the metal volume, and oxides of active elements, reducing agents in the slag phase. Since manganese is unlimitedly dissolved in the liquid iron, therefore absorption of reduced manganese micro particles by the liquid metal is made promptly. Convective flows, being always present in the liquid metal carry away layers enriched by reduced element to the liquid metal, and manganese-average chemical composiiiori. Other reduced alloys with reduced manganese micro particles present are also dissolved in the metal intensively, since reduction of thereof is made in the liquid phase mode, and consequently there's no obstacle for dissolution in the liquid metal. The reducing agent is charged and maintained in the following way in order to perform melting strictly on the boundary of separating metallic and slag phases. The reducing agent is charged in the quantity enough to provide the thermity of charged materials: oxide material containing manganese oxide or oxide and/or, fluoride, and/or carbonate materials of other alloys. for spontaneous progress of the reduction reaction of elements out of oxides, fluorides or carbonates thereof it is required to provide some reserve of potential heat of the specific mixture of alloys and reducing agent able to maintain melting of not only initial materials, reduction of alloys but also efficient separation of formed metallic and slag phases. During the direct steel alloying process using alloys containing oxides, fluorides, carbonates and reducing agent heating conditions of the reduction process are favourable, since the liquid metal, inner surfaces of steel vessels and etc. are regarded ad source of heat. In this case alongside with supply of some quantity of the energ_\ to the reaction /one such heating conditions are maintained excluding ignition of highly active elements - reducing agents and removal thereof to gaseous phase, fherefore the thermity of each specific mixture is selected by trial considering that spontaneous reaction progress should be maintained with minimum loss of the reducing agent. Since the density of highly active elements is considerably lower than the density of the liquid metal, therefore when the reducing agent is charged into the liquid metal, the reducing agent arises at the separation boundary of metallic and slag phases. It is not dissolved based on traditional melting pattern in the liquid metal of any solid body (melting temperature is less than liquid metal temperature), i.e. first comes freezing-out of metal layer on reducing agent lump (granule or other) Then together with arising of the reducing agent melting of the fro/.en-out metal occurs (impacted by two factors: high temperature of the liquid metal and mechanical movement, i.e. renewal of the molten metal on the frozen-out surface of the reducing agent by increasing melting speed). All the above results in the following: melting of the reducing agent occurs simultaneously with melting of alloys during direct contact between the molten reducing agent and the homogeneous compound of molten alloys. The direct steel alloying process by set of elements is made in the following way. Liquid slag, slag-forming mixtures (lime, dolomite, fluorspar and/or others) are charged into steel-making vessel, e.g. oxygen converter, shaft arc furnace and others, then the melt is oxygen-blown, further to removal of oxidation slag from the surface of the liquid metal the oxide material containing manganese oxides is charged: as such manganese ore, concentrate, agglomerate, ferroalloy production slags and others are used, and oxide or oxide and/or. fluoride, and/or carbonate materials of other alloys with even distribution thereof upon the surface of the liquid metal. As oxide material containing other alloys can be used materials containing oxides of alloys, e.g. niobium, titanium, molybdenum, chrome and others. As the material containing fluorides of" alloys can be used fluorides of rear-earth metals, calcium and others. As the material containing carbonates of alloys can be used titanium oxyearbonitride. niobium carbonates, rear-earth metal groups and others. Alloys are charged separately or by portion, with the portion of at least 0,1 of total consumption, and the above are charged either separately or as a combination thereof, depending on given chemical composition of steel. Consumption of each portion of charged alloys out of total consumption is determined by required even distribution of the material on the surface of the liquid metal, and consequently by required maintain of even material melting speed and reduction of alloys out of the above. Reduction in alloy portion consumption by at least 0,1 of total consumption end up in deterioration of material melting process, since deslagging occurs that leads to prolongation of melting time, irrational use of the reducing agent and worse extraction rales of alloys. Upon reaching of the layer height of charged alloys equal to 0.1 0.15 of total layer height, the reducing agent is started to be charged at the separation boundary of metallic and slag phases, and continue its charging during charging of alloys. Charging of the oxide material containing manganese oxides with oxide and/or. fluoride, and/or carbonate materials of other alloys is determined by required maintain of melting temperature of the mixture of the above materials below the liquid metal temperature. It allows to organize intensive beginning of the reduction process upon formation of the homogeneous compound of molten alloys and timely charging of the reducing agent and maintain high reduction speed that results in enhanced aggregate assimilation of alloys by the metal, reduced contamination of steel by non-metallic inclusions and improved quality of steel. Hfficient use of the reducing agent is ensured by simultaneous melting of alloys and the reducing agent that assists to intensive progress of liquid phase reduction reaction of alloys. liven distribution of alloys ensures simultaneity and completeness of their melting, implementation of the alloying process across total area of the liquid metal, and maintain of heterogeneous layer of alloys preventing arising of the reducing agent on the surface of the slag melt at the beginning of the reduction process and irrational interaction thereof with atmosphere oxygen. Charging of the reducing agent during charging of alloys ensures early beginning of the reduction process and constant contact of the molten reducing agent with the formed homogeneous compound of molten alloys. It prevents transformation of the reduction process into diffusion mode accompanied by low speeds and completeness of the reduction process, increased consumption of the reducing agent, contamination of the metal by non-metallic inclusions and deterioration ol steel quality. Charging of the reducing agent is appropriate to commence upon reaching of the layer height of charged alloys equal to 0.1 0,15 of total height because such layer height forming heterogeneous volume on the surface of the liquid metal prevents the reducing agent from arising on the surface and interaction with atmosphere oxygen reducing portion of useful utili/alion of the reducing agent and increased contamination of the metal by non-metallic inclusions. When the reducing agent is charged earlier then the alloying layer reached at least 0.1 of total layer height, the material is partially not prc-melt with formation of homogeneous phase and consequently, the reducing agent is unable to participate in the reduction reaction that leads to its irrational use. Charging of the reducing agent upon reach of the layer height of alloys over 0.15 of total layer height is also inappropriate, since intensive formation of the homogeneous phase of alloys destroys the balance ot' simultaneity of alloys and reducing agent melting, which can lead to worsening of alloy reduction rate, contamination of the metal by non-metallic inclusions and deterioration of steel quality. According to the claimed method the reducing agent is charged onto the separation boundary ol metal and slag. Upon charging of the reducing agent into the metal, first metallization of the reducing agent occurs, then metal film and reducing agent are molten, and the above results in deterioration of melting process of the reducing agent and destroy of balance of simultaneous melting of alloys and the reducing agent. To perform charging of the reducing agent into the slag, if the first is already present or to perform it on the surface is inappropriate as well, since in the lirsi case the reducing agent is deslagged that leads to deterioration of the melting process, and secondly, interaction with atmosphere oxygen occurs. The reduction of alloys is conducted at melting temperature of the mixture, comprised of: the oxide material, containing manganese oxide, or oxide and/or. fluoride, and/or carbonate materials of other alloys. It is determined by the fact that in case of presence of homogeneous compound of molten alloys, and molten reducing agent, the reduction completeness is improved by minimization of the temperature. It assists to increase aggregate assimilation of alloys by the metal, reduction in contamination of non-metallic inclusions and improvement of steel quality. Increase of the temperature to the level higher that the alloy melting temperature according to the claimed method is not made since the reduction process is actually over upon the completeness of melting of charged materials. Maintain of constant contact of the molten reducing agent and homogeneous compound of molten alloys according to the claimed method is required in order to ensure high reduction speed and completeness of the reduction process. The claimed option of the claimed method does not exclude other options with the claimed inventive step and it can be realized in any vessel with liquid metal, e.g. Siemens-Martin oven, steel-making vessel, ladle furnace and etc. HXHIBIT fhe direct steel alloying method by manganese and chrome was implemented in 250-t converter vessel. fhe liquid slag was charged into the converter vessel with the following chemical composition, mas % C - 4,42; SiO2 0.82; S 0,020; F 0.095, iron is the rest, and slag-forming materials, as such lime with the following chemical composition . mas % was used: CaO 92.0; MgO 6.5: other secondary mixtures the rest. As the oxide material, containing manganese oxide the following material with below chemical composition, mas %: (MnO + Mn2O3 ~ MnA) 61,81 (out of which Mn - 44.6); SiO2 12.3: Fe2O, - 2,3; A12O3 - 3,2; CaO 11,7; MgO -3,7; C 2.1; P - 0.2; S - 0.010; others - the rest. As the material containing chrome oxide the following material with below chemical composition mas % was used,: Cr2O3 - 70.81; f'eO 12,2; A1:03 9,3 1; Si02 5,9; MgO 1.78, others the rest. As the reducing agent aluminum and carbon materials were used. As aluminum material aluminum production sieved slag with the following chemical composition, mas % was used: Al,m.tai 44.8: others - the rest, as carbon material coal with the following chemical composition, mas %: (.' 85.9; S 0.47; others - rest. Further to charging of the liquid slag and into slag-forming materials into the converter vessel the liquid metal was blown by oxygen with the consumption 940 Nm'/min within 8 minutes and oxidation slag was removed. Further to it the oxide material containnm manganese oxides with the consumption 14.0 kg/t (3500 kg) and the material containing chrome oxides with the consumption !2 kg/t (3000 kg) fractions 10 20 mm each with even distribution along the surface of the liquid metal were charged dispersed!} into the converter vessel on the surface of the liquid metal. Upon the reach of layer height of the charged alloys equal to 0.1 0.1? of total layer height, not suspending the charging of oxide materials the reducing agent was charged on the separation boundary of metallic and slag phases: sieved slag of aluminum production, fraction 20 30 mm with the consumption 178? kg and coal, fraction 10 20 mm with the consumption 465 kg, ensuring the thermit) of the mixture of charged oxide materials. I he reduction of alloys was conducted at the melting temperature of the mixture, comprised of: the oxide material, containing manganese oxides and materials, containing chrome oxitles, ensuring constant contact oi the molten reducing agent with homogeneous compound of molten materials within overall reduction process. In order to obtain steel of required chemical composition it is needed to charge into the converter vessel alloying additives (copper, nickel) and ferrosilicon as oxidizer to be charged into the ladle. finished steel was cast in ingots with weight 12,5 t, which were rolled in sheets with thickness 10 20 mm and performed metallographie examinations. fhe steel with the following chemical composition, mas % was produced: C 0,1 1: Si 0.24; Ivln 0.57; S 0.010; P 0,007; Al - 0,025; Cr 0.60; Ni 0,70; Cu 0.46: Fe - the rest. Manganese extraction rate totaled 92,7%. while chrome extraction rate totaled 89,3%. Contamination of steel by non-metallic inclusions (point) totaled: oxides - 1,4; sulfides 1.2: silicates 1,3. The heat according to the closest analogue was also made in 250-t converter vessel with oxidation and alloying of the metal in the converter vessel. The metal without slag tapped from the converter vessel at the temperature of 1690'C, which contained aluminum and silicon. During the tapping the manganese ore mixture was charged into the ladle simultaneously (Mn - 48,0%. Si(> - 3.5%. Fe -3,4%, C'aO - 1,5%, AW), - 2,5%, P -- 0.05%) and lime (CaO 90%) with ratio C'aO : MnvOv 1:1, carbon ferrochrome grade FX 650 and ferrosilicon grade FX - 65. Nickel and copper were charged into the converter as for the case with the above claimed invention was charged into the converter vessel in order to obtain steel of required chemical composition. Further to holding within 10 minutes with the basicity of the slag after the holding C'aO/SiO: = 1.3. the steel of the following chemical composition, mas % was produced: C 0.15; Mn - 0.51; Si 0,27; Al 0,003; Cr 0.54; Ni 0.72: Cu 0,55; S 0.017; P 0.015: Fe the rest. Manganese extraction rate totaled 71.2%. chrome extraction rate totaled 67.8%, contamination of steel by non-metallic inclusions (point) totaled: oxides 3,5; sulfides 2.8; silicates 2.0. Use of the above method ensures high degree of assimilation of alloys and reduces steel contamination by non-metallic inclusions. WE CLAIM 1. A method of direct alloying of steel, comprising melting a steel of the kind as herein described in a steel-making vessel; alloying the steel with manganese reduced from oxides during addition of a material containing manganese oxides and a reducing agent and reaction between manganese oxide and reducing agent, said method characterized in that the manganese reduction is carried out in association with reduction of other alloying elements from a material containing non-metallic compounds of the kind as herein described of the alloying elements and charged on the molten metal surface, and/or with reduction of manganese from a charged material containing other non-metallic manganese compounds; the addition of a reducing agent starts when the layer height of the charged material is from 0.1 to 0.15 of the total layer height; the reduction temperature is maintained at the level of the melting temperature of the charged material and the reducing agent; constant contact is provided between the molten part of the reducing agent and the molten part of the charged material containing non-metallic compounds of alloying elements, the reducing agent being delivered in the amount ensuring required thermal characteristics of the mixture of the charged material and the reducing agent to obtain finished steel of the kind as herein described. 2. The method as claimed in claim 1, wherein the material containing non-metallic compounds of alloying elements comprises oxides or carbonates of alloying elements, or combination thereof of the kind as herein described. 3. The method as claimed in claim 1, wherein the reducing agent is an aluminum-containing, or silicon-containing, or carbon-containing material, or a material comprising a group of alkaline-earth metals, or combinations thereof. 4. The method as claimed in claim 1, wherein the charging of a material containing non-metallic compounds of alloying elements is performed continuously or in batches, each batch being no less than 0.1 of the total consumption. 5. The method as claimed in claims 1 to 4, wherein the direct steel alloying process is carried out in a steel-making vessel, a slag-forming material and a carbon-containing material used as a reducing agent are further charged into the vessel in the amount selected from the ratio of 1 : (0.18-0.20) : (0.10-0.12) of the material containing non-metallic compounds of alloying elements, the slag-forming material and the carbon-containing material, respectively, when the molten metal reaches a temperature that exceeds the usual for a given steel quality tapping temperature by a value determined from the expression: At=33[Mn], where At is the value in excess of the tapping temperature, °C; [Mn] is the amount of reduced manganese, percent by weight; 33 is the empirical coefficient; and the oxidizing slag is withdrawn from the steel-making vessel. 6. The method as claimed in claim 5, wherein the material containing non-metallic compounds of alloying elements, the slag-forming material and the carbon-containing material are charged in batches, each batch comprised of all the charged materials having the weight of 0.01-0.02 of the molten metal weight. 7. The method as claimed in claims 1 to 3, wherein in a direct steel alloying process carried out in a casting ladle, a carbon-containing material is preferably added into the ladle; the charged reducing agent is aluminum; and lime is additionally added as a slag-forming agent in the alloying process; the components being taken in following ratio, in percent by weight: the material containing non-metallic compounds of alloying elements 56-65; aluminum 12-16; carbon-containing material 5-7; lime -the balance. 8. The method as claimed in claims 1 and 3, wherein when alloying steel with chrome in a casting ladle, the non-metallic compounds of other elements are preferably chrome oxides that are added to the ladle during tapping the molten metal, to increase manganese and chrome content in the finished steel for each 0.1 percent the chrome oxides are charged in the amount selected from a manganese-chrome ratio of from 1.1 to 1.2 in the material containing non-metallic compounds of these elements, and aluminum added as a reducing agent is charged together with calcium carbide in the ratio of 1: (2.9 - 3.2). 9. The method as claimed in claim 8, wherein the material containing chrome oxides is preferably a converter slag of medium-carbon ferrochrome production. 10. A method of direct alloying of steel substantially as herein described with reference to the foregoing examples.

Documents:

4360-DELNP-2005-Abstract-(14-11-2008).pdf

4360-DELNP-2005-Abstract-(26-11-2008).pdf

4360-delnp-2005-abstract.pdf

4360-DELNP-2005-Claims-(14-11-2008).pdf

4360-DELNP-2005-Claims-(25-11-2008).pdf

4360-DELNP-2005-Claims-(26-11-2008).pdf

4360-DELNP-2005-Claims-(28-11-2008).pdf

4360-delnp-2005-claims.pdf

4360-DELNP-2005-Correspondence-Others-(14-11-2008).pdf

4360-DELNP-2005-Correspondence-Others-(25-11-2008).pdf

4360-DELNP-2005-Correspondence-Others-(26-11-2008).pdf

4360-DELNP-2005-Correspondence-Others-(28-11-2008).pdf

4360-delnp-2005-correspondence-others.pdf

4360-DELNP-2005-Description (Complete)-(26-11-2008).pdf

4360-delnp-2005-description (complete).pdf

4360-delnp-2005-form-1.pdf

4360-delnp-2005-form-18.pdf

4360-DELNP-2005-Form-2-(14-11-2008).pdf

4360-delnp-2005-form-2.pdf

4360-delnp-2005-form-26.pdf

4360-DELNP-2005-Form-3-(25-11-2008).pdf

4360-delnp-2005-form-3.pdf

4360-delnp-2005-form-5.pdf

4360-DELNP-2005-Others-Document-(26-11-2008).pdf

4360-delnp-2005-pct-237.pdf

4360-delnp-2005-pct-301.pdf

4360-delnp-2005-pct-306.pdf

4360-delnp-2005-pct-373.pdf

4360-DELNP-2005-Petition-137-(14-11-2008).pdf

4360-DELNP-2005-Petition-137-(26-11-2008).pdf