What are the Mixing Steps of Ladle Refractory Castable

Ladles are used in steelmaking plants and foundries to receive molten steel and carry outpouring operations before open-hearth, electric furnace or converter. 45% of the ladle castables are aluminum-magnesium spinel castables. The alumina-magnesia spinel castables for ladle are mainly used on large, medium, and small ladles. Ladle castable refers to a mixture of granular and powdery materials made of refractory materials and a certain amount of binder for a ladle. This product has a long service life, safety, and stability, and is an ideal refractory material for a ladle. Therefore, it needs to be stirred before the ladle castable is used. Next, Rongsheng monolithic refractory castable manufacturer will introduce the mixing steps of ladle refractory castable for you.

The Mixing Steps of Ladle Refractory Castable

As we all know, the construction process of ladle castables includes construction preparation, mixing, pouring, demolding, baking, etc. The mixing of ladle castables is a very critical step after construction preparation.

1. The mixing of ladle castables must be mixed with a forced mixer. When mixing, do not mix in packaging bags, rope ends, and other sundries, so as not to affect the pouring effect and performance.

2. The ladle castable used for mixing must be unpacked after arriving on site. The mixing capacity of the mixer should be determined according to the capacity of the mixer. The amount of castable used should be accurately measured before being poured into the mixer.

3. When mixing, the process of dry mixing first and then wet mixing is required. After the castable is added to the mixer, first dry mix for 2 minutes, then add about 5.2~5.5% of water, add water while stirring, first add 80% of the total. Then, add as appropriate depending on the consistency of the mixture, and note that the mixing water must be clean tap water, not sewage. Wet mixing for 4 minutes, one-time mixing should not be less than 6 minutes, until the castable is uniform. Discharge after the surface is flooded. Generally speaking, the bottom of the package is slightly dry and the wall of the package is slightly thinner. The above-mentioned water addition is a reference value.

4. When mixing, strictly control the water consumption and mixing time to ensure the consistency required for construction. If the castable is too thin, it will seriously affect the performance and quality of the material. The amount of mixing, mixing time, and the amount of water added each time are uniform and should not be thick and thin. If it is found that the consistency of the mixing material does not meet the requirements, it should be returned to the mixer to add water or dry material to mix properly. It is strictly forbidden to temporarily add water during pouring.

5. The evenly stirred material should be poured within 20 minutes. In order to avoid being hardened for a long time and cannot be poured, it will affect the structural strength of the ladle lining.

6. The mixer should be cleaned every time the construction is completed or the variety of castables is changed.

7. It is strictly forbidden to stop the mixing operation halfway and put the materials that have already started mixing in the mixer. If the mixer breaks down during work, if it can be repaired in a short time, you must clear a part of the material before turning on the machine before it can be turned on. Put this part of the material into it after starting up. If it cannot be repaired in time, all the castables in the machine must be cleaned.

The above is the mixing steps of refractory castable for a ladle. Hope to help you with your construction. We are a Rongsheng Alumina Bricks manufacturer. http://www.aluminabricks.com/. Our main products are various types of refractory bricks and monolithic refractory materials. If you want to know our company or want to buy refractory castables for ladle, please contact us. We will provide you with services according to your specific needs. 

 

 

How to Reserve Expansion Joints for Refractory Bricks and Castables?

When refractory bricks or castables are used in the refractory lining of industrial kilns, due to the influence of temperature changes and thermal stresses formed by temperature gradients, the lining structure will deform and expand. Therefore, expansion joints should be left during the construction of refractory bricks and castables.

The raw materials used in refractory bricks and castables are different, and the expansion coefficients produced after heating are also different. During masonry, the size of expansion is mainly determined by the nature of refractory bricks or castables and the temperature it withstands. 

Reserved Expansion Joints for Refractory Bricks in Rotary Kiln

The expansion of refractory brick and castable heating surface at the highest temperature is (unit: mm):

• Clay brick masonry: 5-6
• High alumina brick masonry: 7-8
• Corundum brick masonry: 9-10
• Silica brick masonry: 12-13
• Magnesia brick masonry: 10-14
• Clay castable masonry: 4-6
• Phosphorus salt castable: 5-8
• High alumina cement castable: 6-8
• Water glass castable: 4-6

Rules for reserved expansion joints

Clay bricks and lightweight brick masonry whose temperature is lower than 800°C do not need to leave expansion joints. However, expansion joints are still required for clay bricks with too long dimensions. The location of the expansion joint must avoid the stressed part. If there are holes in the furnace body frame and lining, the expansion joints should be separated and the spacing should not exceed 2m.

The expansion joints of refractory bricks or castables at the bottom of the furnace should be staggered in the upper and lower bricklayers and the furnace bottom of the same layer. When building the furnace wall, the left expansion joints can also be left in a staggered pattern between the inner and outer layers and in the upper and lower layers. When the circular wall is constructed, a gap should be left between the shells to compensate for expansion.

In the vault construction, the expansion joints of the refractory bricks and the castable should be left straight at both ends. Consider the vertical expansion of the vault and the upward expansion of the furnace wall when setting it aside. When the length of the dome is greater than 5 meters, in addition to leaving expansion joints at both ends, expansion joints must be set in the middle of the dome according to the segmentation of the arch length. The expansion joints of the staggering vault are left straight through.

The expansion joints of each layer of the multi-layer vault should be staggered, and the expansion joints should be covered with a layer of flat bricks. If it is a dome made of silica bricks, cardboard of 1-2mm should be inserted every 3-5 bricks in the radial joint of the dome to compensate for expansion.

If refractory bricks or castables are used for suspended furnace roofs, expansion joints should be left around the furnace roof.

Rongsheng refractory material manufacturer provides high-quality refractory brick lining and castable lining for various thermal furnace equipment. For detailed price information, please contact us, http://www.aluminabricks.com/contact-us/.