AU2011221428A1 - Refractory material for cement industry kilns and use thereof - Google Patents

Abstract

Abstract The present invention relates to a refractory material for cement industry kilns and the use thereof. The inventive material can be used inside cement industry kilns in order to counteract the thermal and physico-chemical deformation that occurs inside the kilns. 5 The invention composition is based on a combination of a percentage by weight equal to or greater than about 10 of andalusite (AInSiO4 ), a percentage by weight equal to or greater than about 10 of silicon carbide (SiC) and a percentage by weight equal to or greater than about 5 of clay. Moreover, kaolinite (A14 [(OH)8 (SiO4)4]) can be used instead of andalusite in equal proportions. 10 The refractory material can be used to line the inside of the cement kilns in the calcination areas (2), in the kiln outlet (6) and in the coolers (7). rAm- AM A11R 0'2 v 7.0591' 714 U0) Figure 1

Description

P/00/01I Regulation 3.2 AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention title: Refractory material for cement industry kilns and use thereof The following statement is a full description of this invention, including the best method of performing it known to us: duwm A0118692684v1 305966734 1 REFRACTORY MATERIAL FOR CEMENT INDUSTRY KILNS AND USE THEREOF Cross reference to related applications This is a divisional application divided out of Australian Application No 2008200266, 5 the entire contents of which are incorporated herein by reference. Technical field of the invention The present invention relates to a refractory material for cement industry kilns and the use thereof. In one aspect, the material of the present invention can be used to line the inside of cement industry kilns, or be placed in particular areas of the kiln so as it may 10 augment refractory capacity. Description In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date: 15 (i) part of common general knowledge; or (ii) known to be relevant to an attempt to solve any problem with which this specification is concerned. The cement industry is familiar with the use of refractory materials to line the interior of the kilns used to manufacture the said product in order to withstand the high working 20 temperatures, which can reach around 1500 degrees Celsius in some areas, and the resulting physical and chemical reactions. However, the differing compositions of the refractory materials also lead to their having differing degrees of hardness and resistance to the deformation that is caused by the differences in kiln temperature in different parts of the same kiln, among other factors. In some embodiments, the present invention achieves a 25 refractory material of improved hardness and resistance than the materials hitherto employed. Various refractory materials are currently known and used but they all present drawbacks, both operative and functional, particularly as regards progressive deformation by high kiln temperatures, spalling and cracking. Consequently, the use of the materials 30 developed to date always presents certain limitations compared to the invention described herein, as a result of the technical and cost advantages which some embodiments of the present invention may provide. Already known refractory materials are the addition of glass manufacture crucibles, lime, silica, chromium, magnetite, aluminium oxide and aluminous silica glass (F:H: Norton, Refractarios, first Spanish edition published by Blume in 1972), as 35 well as Japanese patent no. JP 11230679 concerning variations in porosity of refractory duwm AO1 18692684v1 305966734 2 bricks, no.JP 11130485 as prefabricated panels or no.JP 11201649 as glass textures. In relation to the arrangement of shapes of the materials the outstanding examples are European patent no. EP 0911594 and German patent DE 19729582 concerning prefabricated bricks. All of these are prior to the invention described herein but are generic and imprecise 5 compared to the same, and are often designed for the steel industry. In all these inventions the resulting chemical composition or form are either not applied to the peculiarities of the cement industry or are not detailed and not sufficiently established compared to that described herein. According to a first aspect of the present invention, there is provided a refractory 10 material for use with cement industry kilns and its use for resistance to thermal, physical and chemical deformation, the material comprising a chemical composition that combines a percentage by weight equal to or greater than about 10 of andalusite (At, SiO 4 ), a percentage by weight equal to or greater than about 10 of silicon carbide (SiC) and a percentage by weight equal to or greater than about 5 of clay. 15 According to a second aspect of the present invention, there is provided a method of use of the refractory material according to the first aspect, for lining a portion of the inside of a kiln in one of the following areas: in a calcination area, in a safety area, in an outlet area, or in an area having coolers. According to a third aspect of the present invention, there is provided a refractory 20 material for use with cement industry kilns and its use for resistance to thermal, physical and chemical deformation, the material comprising a chemical composition that combines a percentage by weight equal to or greater than about 10 of kaolinite (A1 4

[(OH)

8 (SiO4)4 1 ]), a percentage by weight equal to or greater than about 10 of silicon carbide (SiC) and a percentage by weight equal to or greater than about 5 of clay. 25 The deficiencies of the prior art materials may be advantageously overcome by various embodiments of the present invention by providing a chemical composition comprising: a neo-silicate such as andalucite (AlSiO 4 ), a crystalline solid such as silicon carbide (SiC) and a hydroaluminosilicate pelitic rock such as clay. This composition surpasses the above-mentioned limitations and increases the operational capacity and 30 performance of the material, while its application presents certain features that significantly favour its use in cement industry kilns. All the foregoing helps to achieve results as regards refractory quality, location within the kilns and resistance to alterations in shape wherever the invention is used (whether in geometrical configurations such as bricks or in formless configurations such as mortar) that 35 already-known media do not provide. According to another aspect, the present invention described herein combines certain chemical compounds for their physical properties: andalucite (Al 1 SiO 4 ) for its low porosity, rinwn An I1R6Q26R4v1 O59667A4 3 low thermal conductivity and refractory capacity, silicon carbide (SiC) for its resistance to oxidation and abrasion, while also being highly refractory, and clay for its plasticity. This three-part combination of solid crystalline compounds formed from silicon can be made up of different proportions by weight of each of its constituents in order to achieve 5 a greater or lesser degree of thermal conductivity, according to the location and function of the refractory material in the different parts of the kiln. In short, the result obtained by combining these compounds makes it possible to obtain a technical advantage with a product of greater hardness and greater resistance to the deformation caused by the heat inside cement production kilns and the physical and 10 chemical reactions that occur within such kilns. This leads to considerable cost advantages as the new invention reduces the number of kiln stoppage cycles for maintenance and replacing worn material in each work period. As well as these technical and cost improvements, it also results in a production process advantage for the most widely and frequently found kilns, those of the rotary type, as it achieves greater resistance and hardness 15 in the materials arranged inside the kiln to assist the circulation of the cement clinker being processed such as retainers and areas with shapes or in the satellite coolers, with staggered forms and elliptical inlets, respectively, and is consequently more efficient in maintaining their design and function. An embodiment of the invention will now be further explained and illustrated, by 20 way of example, with reference to the accompanying drawings in which: Figure 1 shows a schematic representation of a rotary kiln with satellite coolers for the cement industry, in a configuration comprising a heat exchanger (1) and a calcination area (2), safety area (3), transition area (4), sintering area (5), outlet area (6), coolers (7), kiln head (8) and flame burner (9); and, 25 Figure 2 shows a schematic representation of a rotary kiln with grate coolers for the cement industry, in a configuration comprising a heat exchanger (1) and a calcination area (2), safety area (3), transition area (4), sintering area (5), outlet area (6), coolers (7), kiln head (8) and flame burner (9). The refractory material can be made up and placed as follows: 30 As regards the chemical components, a percentage by weight of andalusite (Al 1 SiO 4 ) of 10-80%, a percentage by weight of silicon carbide (SiC) of 10-80% and a percentage by weight of clay of 10-15%. The preferable average composition is in the following proportions: Percentage by weight 35 Andalusite (Al 1 SiO 4 ): 55% dinwm A011R6926A4v1 ;05966734 4 Silicon carbide (SiC): 35% Clay: 10% Given its cost advantages, kaolinite (Al 4

[(OH)

8 (Si0 4

)

4 ]) can also be used instead of andalusite, in equal proportions. 5 As regards its location in the kilns, the areas where this refractory material is used are: the calcination area (2), the safety area (3), the transition area (4), the kiln outlet (6) and the coolers (7). The word 'comprising' and forms of the word 'comprising' as used in this description, and in the claims which follow, do not limit the invention claimed to exclude 10 any variants or additions. Modifications and improvements to the invention will be readily apparent to those skilled in the art. Such modifications and improvements are intended to be within the scope of this invention. ,n An 1R6426R4v1 AO%66724

Claims (5)

1. A refractory material for use with cement industry kilns and its use for resistance to thermal, physical and chemical deformation, the material comprising a chemical composition that combines a percentage by weight equal to or greater than about 10 5 of andalusite (AlnSiO 4 ), a percentage by weight equal to or greater than about 10 of silicon carbide (SiC) and a percentage by weight equal to or greater than about 5 of clay.

2. Use of a refractory material as claimed in claim 1, for lining a portion of the inside of a kiln in one of the following areas: in a calcination area, in a safety area, in an outlet 10 area, or in an area having coolers.

3. A refractory material for use with cement industry kilns and its use for resistance to thermal, physical and chemical deformation, the material comprising a chemical composition that combines a percentage by weight equal to or greater than about 10 of kaolinite (A1 4 [(OH)a (SiO 4 )4]), a percentage by weight equal to or greater than 15 about 10 of silicon carbide (SiC) and a percentage by weight equal to or greater than about 5 of clay.

4. A refractory material for use with cement industry kilns substantially as hereinbefore described and with reference to any of the accompanying drawings.

5. Use of a refractory material substantially as hereinbefore described and with reference 20 to any of the accompanying drawings. duwm AO118692684v1 305966734