e) Fettling mixes Fettling mixes are also granular refractorymaterials, with function like to gunning mixes, but are applied by shovelinginto the kilns needing patching 43-51.f) Tap-hole mixesTap-hole mixes are resin bonded.
In these mixesthe higher strength which is normally desired for monolithic refractoryproducts, is not that important. Some criteria are necessary for all tap-holemixes. These criteria are consisting of: correct consistency, setting, andcarbonization at the right time, precisely controllable PLC, and above alldrilling capability 72-78. 1. Application ofNano-technology in refractory industrial: Nano-technology is usually introduced by sizeand consist of the visualization, properties, production and manipulation ofstructures which are lower than 100 nm 89- 90. Specific mechanical, optical,electrical, and magnetic properties which can differ substantially from theproperties of the same materials at larger dimensions can show for thestructures that the dimensions of which range from 100 nm down to approx. 0.
1nm. Hence, nano-technology is a very active research field and has applicationsin a number of areas. Today, considerable attention has been paid to the use ofnano-technology in the progress of refractories products 91-93.Nano-technology has been entered to refractories. It has been expressed thatthe efficiency ofthe refractories was extremely improved for the well dispersion of nano-sized grainin the microstructure and reaction activity.
Some efforts have been done by differentresearchers to enhance the properties of refractories (bricks and monolithic)by using Nano-particles. The application of nano-technology is aimed at achievingthe following specific properties of brick and monolithic refractories 90-95:ü Ultra-high compressive strength, ü Relatively high tensile strength andductility,ü More efficient cement hydration,ü Increased aggregate-paste bond strength, ü High corrosion resistanceü Control of cracks and self-healingü High thermal shock resistance and ü High Abrasion resistance ü High chemical corrosion résistance 2. Use of Nano-technology in monolithicrefractories:According tothe above, in this section, the results of carried out activities by various researchersusing nano-technology in monolithic refractories have been expressed (Table 1). It is observed that the use ofNano-technology has been heavily used by researchers in recent years.Conclusion:Recently, Nano-technology is used forproduction to refractory products and it is a necessary tool included in many activities.
A lot of research has been working on the adding of different types ofadditives in ceramic goods, and some of them have concentrated theirinvestigations on the use of Nano-additives, because of the mentionedadvantageous of adding nano-particles to the ceramic goods. In this review article, all researches which done to enhancethe performance of monolithic refractories is reported and it was concluded that theapplication of nano-additives has the best results. Results show that recently, researchershave been using nano-technology and have reached interesting results.