Production process and equipment of aerated autoclave concrete block

Firstly, silica materials such as sand and fly ash are ground. According to the requirements of raw materials and process characteristics, some are dry ground into powder, some are wet ground with water, and some are mixed with some lime. There are two ways of mixed grinding: one is dry mixed grinding to prepare cement; One is wet grinding with water, mainly to improve the characteristics of fly ash or sand, which is called hydrothermal ball milling. Most of the lime purchased is massive, so the lime must also be crushed and ground. Generally, gypsum is not ground separately, or mixed with fly ash, or mixed with lime. It can also be ground with a ball mill with lime wheel. Other auxiliary materials and chemicals are often prepared and used. Raw material preparation process is the preparation process of batching, the reprocessing of raw materials to meet the process requirements and the storage homogenization process before batching. It is the most basic process link that directly affects whether the whole production can be carried out smoothly and whether the product quality can meet the requirements.

According to the production sequence, aerated concrete blocks and plates are divided into several stages: raw material preparation, reinforcement processing (aerated plates), batching, pouring, static stop, cutting, autoclave curing and discharging.

1. Raw material preparation

In the production of aerated concrete, silica materials such as sand and fly ash are ground first. According to the requirements of raw materials and process characteristics, some are dry ground into powder, some are wet ground with water, and some are mixed with some lime. There are two ways of mixed grinding: one is dry mixed grinding to prepare cement; One is wet grinding with water, mainly to improve the characteristics of fly ash or sand, which is called hydrothermal ball milling. Most of the lime purchased is massive, so the lime must also be crushed and ground. Generally, gypsum is not ground separately, or mixed with fly ash, or mixed with lime. It can also be ground with a ball mill with lime wheel. Other auxiliary materials and chemicals are often prepared and used. Raw material preparation process is the preparation process of batching, the reprocessing of raw materials to meet the process requirements and the storage homogenization process before batching. It is the most basic process link that directly affects whether the whole production can be carried out smoothly and whether the product quality can meet the requirements.

2. Reinforcement processing

Reinforcement processing is a unique process for the production of aerated concrete slab, including derusting, straightening, cutting, welding, coating preparation, coating impregnation and drying. Reinforcement is the structural material for the production of aerated concrete slab. Process control not only affects the product quality, but also directly affects the structural performance and safety of buildings.

3. Reinforcement mesh assembly

The assembly process of reinforcement mesh is to assemble the anti-corrosion reinforcement mesh into the mold according to the size and relative position required by the process, and fix it for pouring.

4. Ingredients

Batching is to measure various raw materials prepared and stored for use, adjust temperature and concentration, and prepare a small amount of added materials on site, and then feed them to the mixing equipment in turn according to the process requirements. Batching is a key link in the process of aerated concrete, which is related to the proportion of effective components between raw materials, the fluidity and viscosity of slurry, whether it is suitable for aluminum powder aeration and normal hardening of green body, etc. In short, it has the most direct impact on the gas expansion, hardening process and product properties.

5. Pouring

Pouring process is one of the unique production processes of aerated concrete, which is different from other kinds of concrete. The pouring process is to mix the materials put into the mixer after metering and necessary adjustment in the previous batching process, make the slurry that meets the time, temperature and consistency requirements specified in the process, and pour it into the mold through the pouring port of the mixer (so it is also called pouring mixer). At this time, if the plate is produced, the assembled reinforcement mesh has been placed in the mold. The slurry carries out a series of physical and chemical reactions in the mold to produce bubbles to expand, thicken and harden the slurry. Pouring process is an important process for forming good pore structure. Together with batching process, it constitutes the core link of aerated concrete production process.

6. Quiet stop

The static stop process is mainly to promote the slurry after pouring to continue to complete the thickening and hardening process. In fact, this process starts after the slurry is poured into the mold, including gas expansion and green body maintenance, so as to make the slurry gas to form the green body, and make the green body reach a certain strength for cutting. There is not much operation in this process, so vibration should be avoided. At the same time, pay strict attention to the change of slurry in the gas generation process and feed it back to the batching and pouring process, because the main defects of green body are produced in this process, such as die collapse, green body cracking, gas holding, etc.

7. Cut

The cutting process is to segment and shape the aerated concrete blank to meet the appearance and size requirements. The cutting process reflects the characteristics of aerated concrete, which is easy to form in large volume, flexible and diverse in overall dimensions and can be produced in large-scale mechanization. It is also a prominent advantage of aerated concrete different from other concrete. Cutting can be carried out mechanically or manually. In order to improve the production efficiency and product quality, people have designed a special cutting machine, which constitutes the core of the production process of aerated concrete, and formed different patented technologies. The cutting process directly determines the appearance quality and some internal quality of aerated concrete products.

8. Autoclave curing

Autoclave curing process is to carry out high-pressure steam curing for aerated concrete blank. For aerated concrete, only after curing at a certain temperature and sufficient time can the green body complete the necessary physical and chemical changes, so as to produce strength and meet the needs of building construction. This process is usually carried out above 174.5 ℃. Therefore, autoclaves with good sealing are often used to heat the green body with saturated steam with a certain pressure, so that the green body can fully complete its hydration reaction under the conditions of high temperature and high humidity, so as to obtain the required hydration products and make the aerated concrete have certain strength and other physical and mechanical properties. Autoclave curing process determines the final formation of the internal performance of aerated concrete.

9. Outlet kettle

Autoclave discharge is the last process of aerated concrete production. It includes product delivery, lifting, inspection, packaging, cleaning and oiling of trolley and bottom plate, so as to ensure the normal operation of providing qualified products to the market and the next production cycle process. With the requirements of the market for the appearance of products and the requirements of urban management, more and more aerated concrete plants have begun to package aerated concrete products. The corresponding packaging has also changed from simple packaging to adding packaging machinery and thermoplastic packaging.