What is an aac panel? AAC panel, also known as ALC panel, is the short term for autoclaved aerated concrete panels. According to the uses, it can be divided into partition panels, exterior wall panels, roof panels (floors), fireproof panels, etc. AAC panels are widely used in industrial and civil buildings such as concrete structures and steel structures. What is the manufacturing process of the AAC panel? It shares common steps with the AAC block making process while requiring steel bar and steel mesh cage preparation.
The AAC Panel Manufacturing Process
The main process of aac panel manufacturing includes several steps such as the preparation of raw materials, steel bar processing, steel mesh cage preparation, batching, pouring, pre-curing, cutting, autoclaving, out of autoclaving, packing, and storage.
- Preparation of raw materials
Firstly, sand, or fly ash, lime, gypsum, waste material, etc. are ground to make the corresponding slurry for storage.
- Sand or fly ash with waste material and gypsum are sent to the hopper and calculated then transferred to ball mills for grinding. Then the ground material is transported to the slurry tank which will be pumped into the storage tank for later use.
- The block lime is added to the lime hopper for crushing, and then the lime is lifted by the bucket elevator to the granular lime bin for storage. The whole process is equipped with a dust removal system. The lime is ground to a fineness of 200 mesh by a ball mill and then stored in a lime bin for use.
The raw material preparation process provides raw materials that meet requirements for reprocessing, storage, and homogenization process before batching process. It is the most basic process that directly affects whether the entire production can go smoothly and whether the product quality can meet the requirements.
- Steel bar processing
Steel bar processing is a unique process for the production of aac panels, including rust removal, straightening, cutting, welding, coating preparation, coating impregnation, and drying of steel bars. Steel bar is the structural material for the production of aerated concrete slabs. Process control not only affects product quality but also directly affects the structural performance and safety of buildings.
- Steel mesh cage preparation
The steel mesh assembly process is to combine the anti-corrosion treated steel mesh according to the size and relative position required by the inserting process after the pouring process.
Batching is to adjust the measurement, temperature, and concentration of various raw materials that have been prepared and stored for use. According to the process requirements, feed materials to the mixing equipment in sequence. Batching is a key step in the process of aerated concrete. It is related to the ratio of active ingredients among raw materials, whether the fluidity and viscosity of the slurry are suitable for the aluminum powder to gas and the body to harden normally.
The pouring process uses a pouring mixer to pour the prepared slurry into the mold. The slurry after the previous batching process has been measured and made necessary adjustments to meet the time, temperature, and consistency requirements specified in the process. Before entering the pre-curing room, the steel mesh cage is put into the mold by inserting and pulling out hoist machine. The slurry undergoes a series of physical and chemical reactions in the mold to generate air bubbles, making the slurry expand, thicken and harden. The pouring process is an important process for forming a good pore structure, and together with the batching process, it constitutes the core steps of the autoclaved aerated concrete production process.
The pre-curing process is mainly to promote the continuous thickening and hardening process of the poured slurry. This process starts after the slurry is poured into the mold, including gas expansion and green body maintenance. The process is to make the slurry complete gasification to form a green body, and to make the green body reach a certain strength for cutting. The steel mesh assembly is pulled out after pre-curing. There are not many operations in this process, and vibration should be avoided. At the same time, strict attention should be paid to the changes in the slurry during the gas generation process, and feedback to the batching and pouring processes, because the main defects of the green body are produced in this process, such as mold collapse, blank body cracking, suffocation, etc.
The cutting process is to divide and shape the aerated concrete body to make it meet the appearance size requirements. Cutting can be done mechanically or manually. To improve production efficiency and product quality, people have designed a special cutting machine, which constitutes the core of the aerated concrete production process and has formed different patented technologies. The cutting process directly determines the appearance quality and some internal quality of air-entrained concrete products.
- Autoclaved curing
The autoclaved curing process is to perform high-pressure steam curing on the aerated concrete body. For aac panels, only after a certain temperature and sufficient time of curing can the body complete the necessary physical and chemical changes, thereby generating strength and meeting the needs of building construction. This process usually needs to be carried out above 174.5°C. Therefore, a well-sealed autoclave is often used to heat saturated steam with a certain pressure, so that the green body can fully complete its hydration reaction under high temperature and high humidity conditions, and obtain the desired product. The autoclaved curing process determines the final formation of the intrinsic properties of aac panels.
- Out of the autoclave
Out of the autoclave is the last process in the production of aac panels. It includes products out of the autoclave, hoisting, splitting, inspection, packaging, cleaning, and oiling of trolleys and bottom plates. This ensures the supply of qualified products to the market and the normal operation of the next production cycle.