Preface
After the glass furnace is shut down and removed, a large amount of waste refractories will be produced. Disposal of it as garbage will not only pollute the environment, but also cost it very high. The rational reuse of refractory materials has always been a common concern of our glass factories, refractory recycling companies and designers. Experienced glass factories are more or less trying to reuse valuable refractory materials to reduce investment in glass furnace construction and reduce environmental pollution.
One. The principle of recycling refractory materials in glass furnaces
The glass furnace uses refractory materials, regardless of whether it is new or old, the principle of separate acceptance and evaluation should be grasped. Referred to as "examination score opening".
In specific applications, it is recommended that the glass factory refer to the "Rules for Judging the Obligations and Responsibilities of Suppliers and Buyers Before and After the Use of Fused-cast Zirconium Corundum Products for Glass Furnace" and "Production of Dense Shaped Refractory Products for Glass Furnace" compiled by the Technical Advisory Committee of China Daily Glass Association. Sign a business contract with technical specifications such as "Rules of Use". When purchasing old bricks, it is necessary to sign a "Processing Contract" with the supplier in accordance with the actual situation and with reference to relevant technical standards.
The principle of scoring is that refractory materials that do not meet the requirements for use shall not be used for the construction of kiln projects. After the acceptance of the glass furnace ignited, even if there is a problem, the quality of the refractory material will no longer be traced, unless otherwise agreed in the contract.
Using old refractory materials, the glass factory saves a lot of money while also taking on possible risks. Objectively, the glass factory must improve the level of technical management.
The glass factory adopts the principle of scoring, and in the actual construction of the kiln project, it overcomes the phenomenon that old refractory materials are not used. In the actual kiln operation and management, more and more kiln repairs have been made, and many new kilns have also used some old materials, which has saved a lot of money for the glass factory and reduced environmental pollution.
Two, several points for attention in the reuse of refractory materials
1. Know the source of the material. Whether it is the owner’s own furnace refractories or outsourcing old refractories, the supplier of the production materials must understand clearly, especially the fused bricks that are in contact with molten glass. It is best to ask the owner of the furnace to provide or display the refractory material purchase contract for outsourcing of used materials.
2. Understand whether there is any abnormality during operation, and whether the cooling operation of the kiln is standardized. It is necessary to consult its kiln supervision data and kiln cooling and kiln protection records.
3. Understand the types of products that have been produced, and observe the corrosion status of refractory materials.
4. If a large number of refractory materials are reused, a professional kiln dismantling company shall be entrusted to dismantle the kiln and supervise the whole process. At the same time, the "Refractory Material Processing Contract" can be signed.
5. Do targeted sampling testing or re-burning experiments.
6. Make key marks for important fused bricks.
7. Appropriately reduce the requirement of periodic output.
8. Choose an experienced construction team.
Three, some experience in the reuse of refractory materials
1. Replacement and repair of electrofusion hook bricks
The parapet wall is judged to be reusable. If the hook brick cannot be used due to a U-turn, the parapet wall may not be moved and only the hook brick can be replaced.
If the hook bricks have fewer U-turns, they can also be repaired with special amorphous materials.
2. Use fused zirconia corundum bricks to build the flame space parapet
It is a common practice in many glass factories to build the flame space parapet with the dismantled fused bricks. When designing, only the overall size is issued, the minimum geometric size of the fused brick is specified, and it can be processed on-site or commissioned by a refractory material factory. The eroded surface faces the inside of the kiln and can be filled with ramming material. Contaminated glass should be carefully cleaned up.
It is worth noting that the flame space reuses refractory materials, and special attention should be paid to the reinforcement and repair of the steel structure. Carefully adjust the verticality of the kiln column during construction, and never allow the column to tilt into the kiln before the kiln is baked. Especially the kiln with a brace structure.
3. Use old fused bricks to build the pool wall
Pay special attention that the wall of the fused brick pool cannot be poured into the kiln. When processing, pay attention to the regularity of the bottom surface to meet the requirements.
When the multi-layer pool walls are spliced, the heat preservation gives way to the vertical seams. It is better to have a steel plate on the outermost side to withstand the insulation layer.
Fill the kiln with molten glass and turn on the cooling air according to the regulations.
If you have the conditions, you can use the pool wall to cut online.
4. Pool bottom repair
For kilns with deep erosion at the bottom of the pool, the glass must be cleaned, and zircon series materials are generally used to repair to the specified elevation.
5. Big scorpion
Some kilns do not run for a long time, and the large bricks can still be reused after they are removed. The mud must be cleaned up, and try to choose large and regular bricks, and the mud joints shall be considered as 2mm.
The central angle of the large slabs should be designed at 60 degrees, so that the slabs can be easily processed and configured.
After the top of the big chrysalis is treated with fine quartz powder, it will be insulated.
In the kiln, it is safer to do the first loose top wire or loose strip operation after the opening of the big chute appears.
6. Magnesia brick
If the old magnesia checker bricks are suspected of being damp, they should be sampled and reburned to above 450℃, generally 600℃, to see if the strength meets the requirements.
Magnesium checker bricks must be reprocessed and organized to ensure that the construction meets the standards. Leave a sufficient distance outside the wall of the regenerator to prevent the kiln from hitting the wall of the regenerator after baking.
Straight bricks are used to build the wall of the regenerator, and clay fire clay can be used for the medium and low temperature parts.
Four, the actual case
Some of the glass furnaces that produce ordinary soda lime glass, glass wool and other products have been reusing refractory materials. Taking the construction of an 80 square meter horseshoe flame kiln in a factory as an example, based on the current refractory material prices, the matching of mid-range refractory materials will cost about 18 million yuan. The plant uses refractory materials removed from a float kiln that has been running for about a year, with a design life of three years and only about 9 million yuan.
The 80-square-meter horseshoe flame kiln was repaired and the investment was reduced by one-half.
Five, concluding remarks
Reasonable reuse of refractory materials must grasp the principle of inspection and scoring, formulate an operable refractory material matching plan based on formal technical standards, ensure product quality and furnace safety, distinguish priority and reduce investment. In fact, experienced glass factories reuse refractory materials, and many furnaces have reached the design life and achieved good economic benefits.
