Alumina Silicate Used in Braiding of Refractory
INSTRUCTIONS FOR USE OF BRAID MORTARS
Production Technology of Braid Mortars; It is in the form of the addition of refractory clay, which has a binding feature, into the sintered refractory material in powder thickness. They are packaged ready to be used in 25 or 50 kg kraft paper bags.
MATTERS TO BE CONSIDERED IN USING:
It should be thoroughly mixed dry before adding water. Mixing should be continued while adding water slowly until the mortar, which will be applied on the brick surface with a thickness of max.
APPLICATION METHODS:
The most common methods are;
Trowel Method: Mortar is applied with a trowel, not exceeding 2 mm thickness, on one of the bricks to be built, and the other brick to be adhered is placed on this brick properly without wasting any time, ensuring that it is adhered.
Dipping Method: In this method, one of the bricks to be adhered should be dipped into the mortar prepared in a chamber or a boat, and it should be placed on the wall to ensure it’s adhesion.
Monolithic Refractories
INSTRUCTIONS FOR USE
The mixture consisting of sinter and special binding materials is mixed very well during production and bagged. Generally, binders and additives are in the same bag. Bags are 25 or 50 kg.
If monolithic materials (Ready-Fire Concrete) need to be stored for a long time; The binder and sinter material should be placed in separate bags but two separate bags in another bag so that the substances in the mixture in the bag are not affected by the environment. During use, care should be taken to mix the two bags in one bag very well to make a mortar.
PREPARATION
The amount of water to be used during the preparation of bulk monolithic materials varies according to the properties of the material.
Mixture with High Water Amount: Using more water than necessary will prolong the setting and freezing times of cast refractory materials, and will have very negative effects on the porosity and thus strength during drying and stewing. The most important of these negativities is that large cracks will occur.
Mixture with Less Water: In case of using less water than necessary, a homogeneous mixing will not be achieved and early freezing will start.
While adding water during the preparation of monolithic materials (Fire Concretes), it should be controlled by hand, it should be tried to achieve the appropriate consistency and it should be paid attention not to agglomerate. This process should be completed within 3-5 minutes, otherwise, as a result of the reaction of water and cement, the mortar sets and starts to set in a short time, and difficulties are experienced in terms of application and it causes the performances expected from the refractory to not be achieved where it is applied.
PLACEMENT
After the mixing process is finished, the monolithic material is ready for processing. After the molds prepared according to the process area are wetted, the monolithic material (Fire Concrete) is quickly poured into these molds.
It is placed in the mold according to the way it is processed. In the placed material;
Reaction starts in 3-5 minutes, freezing starts in 3-5 hours, min. It should be kept at 95% relative humidity (at 35 oC). This can be achieved by keeping it covered with nylon for 24 hours. Or; This process can also be done by spraying water on the material. However, if it cannot be kept moist, heat will occur as a result of the reaction and the increased heat will cause the concrete to crack.
ANCHORAGE SYSTEM
An anchor system suitable for the shape should be applied so that it remains inside the concrete on movable or flat walls or floors. Anchors are designed in Y and V shape from “stainless steel”. The concrete to be poured has a length of 2/3 of it’s thickness and their thickness can be in diameters such as 6, 8, 10, 12, etc.; depending on the condition of the concrete. In environments with lower temperatures, anchors can also be made of iron.
There is a distance of 200 to 300 mm between each anchor, and they are mounted to the sheet (mantle) by welding or bolts, one in the opposite direction of the other and staggering each other. The anchoring method is shown in the picture below.
DILATATION
During the pouring of the monolithic material (Fire Concrete), dilatation allowance should be left in order to easily take the expansions caused by high heat. For an application area of 1 to 2 m2, it is necessary to leave a dilatation gap of 3 – 25 mm. Materials such as; Ceramic blankets, rock wool, cardboard, etc. can be added to this range.
DRYING AND STEWING
After the concrete has completely hardened and formed, the molds are removed. The drying and accessing temperature program is given in the table below.
For temperatures above 800 degrees Celsius, the stewing regime can be increased. But; Going above 400 degrees Celsius/hour is always very risky.
Low Cement Monolithic Materials
INSTRUCTIONS FOR USE
Low Cement Castables (Low Cement Monolithic Materials) must be applied with vibration. It is very difficult to apply in bulk because of the low water content in it.
Vibrating Materials;
* Low porosity,
* High strength,
* Their Volume Weights are high and therefore their performance is quite high. Their performance can be increased even more depending on the usage situations. In unfavorable conditions, performance degradation may occur. To avoid this; mixing should be homogeneous, a good mixer should be used and the mixers should be very clean. Mixing time should be maximum 4 minutes. The prepared mortar should be stocked in a dry environment and this environment should be artificially ventilated.
The water that used should be very clean, attention should be paid to it’s temperature, and the temperature should be 5-25 oC. The water ratio to be used in materials to be vibrated is 5.5 – 6.5 %. With this ratio, the mixture becomes almost dry. If water collects on the surface as a result of vibration application, the amount of water should be reduced in other applications.
Vibration processing time should be maximum 5 minutes. If air bubbles are seen in the mold during process, the vibration should be stopped immediately. Vibrations that are too long can also disrupt the homogeneity of the mixture. If the application is made with immersion vibration, the vibration tool should be pulled out of the concrete very slowly.
Freezing starts after 4 hours of mixing and lasts for 48 hours. The formwork should be dismantled after 12-14 hours so that the concrete should be in contact with the air for the continuation of the freezing or hardening process.
Low Cement Refractory Castables
HEATING REGIME DIAGRAM (VIBRATION)
