Building the working principle of calcined gypsum grinding burn integration

                        Building the working principle of calcined gypsum grinding burn integration

Grinding sintering integrated calcination equipment is an annular ball mill equipment integrating grinding, drying, calcination and screening. It was developed by claudis Peters of the former Federal Republic of Germany and used in the gypsum industry in the 1960s. It is called Peters calcining mill, or Peters mill for short. It is characterized by high equipment volume, high production efficiency, low energy consumption and stable product quality. It is suitable for products with a large number of hydrated gypsum. Such as paper gypsum board, fiber gypsum board, gypsum block and other production lines. At present, it has been widely used in the calcination of gypsum, and some gypsum plants newly built and rebuilt in many countries in Europe and America in the 1990s also use this mill. For example, James hardre company in the United States dismantled the frying pan and used Peters mill to increase production and save energy. Since 1963, Peters has provided more than 110 sets of Peters vertical ball milling and calcination systems for the global gypsum industry. Beixin building materials group has introduced three sets of Peters mills from 1997 to 2007, which are respectively used for the paper gypsum board production line with an annual output of 20 million m2, 30 million m2 and 50 million m2. The mill can calcine the mixed paste of natural gypsum, natural gypsum and by-product gypsum. In recent years, the company has developed HIC transverse crushing calciner to adapt to the calcination of 100% industrial by-product gypsum. The mill can use gas, oil and coal as fuel.
Working principle: the bottom of the mill is the main driving device. The base is equipped with a gearbox. The gypsum production line is driven by conical gear and equipped with fan-shaped thrust bearing, which is used to bear the pressure of the grinding plate and drive the lower grinding plate on its upper part to rotate. The rotating speed is generally (45 ~ 55) R / min. there are five hollow balls with a diameter of 95600mm ~ 800mm on the grinding plate. The rotating speed of the balls is generally (30 ~ 40) R / rain. The weight of each ball is 300 ~ 1000kg, and the upper part of the ball is a non rotating upper grinding plate, There are evenly distributed spring groups on the disc, and the grinding pressure is adjusted hydraulically or mechanically. The top of the mill is a separator, with a circle of blades arranged at a certain angle and a screener composed of regulating devices. During the operation of the mill, the blade angle can be adjusted to obtain the required particle size. The lower side of the ring mill is the hot air inlet.
Raw gypsum is sent to the center of the grinding body from the upper side feed pipe. Under the action of centrifugal force, the gypsum powder equipment pushes the material outward to be crushed and ground between the lower part of the ball and the grinding ring. At the same time, 500 ~ 600 ℃ high-temperature medium (hot gas) is sprayed into the grinding body from the annular nozzle located between the lower grinding ring and the grinding shell. In this way, the hot gas flow is in direct contact with the material, and the gypsum is dehydrated rapidly after heating to mature the gypsum. In this process, the free water and crystal water of gypsum absorb a lot of heat energy due to endothermic evaporation, so that the high-temperature medium cools down rapidly. When the high-temperature medium leaves the lower grinding ring with the ground gypsum powder, its temperature drops below 180 ℃, and the upward hot gas with the gypsum powder flows to the separator at the upper part of the mill for screening. The oversized particles are separated and fall into the grinding body for grinding until the required fineness is reached. The particles with suitable particle size are sent to the dust collector by the air flow, separated from the air flow, cooled and put into the clinker silo for standby. The residence time of powder in the mill is very short. Generally, the drying, calcination and screening processes are completed within 5 ~ 10 seconds, and the retention in the raw material flow in the mill is generally only a few hundred kilograms. The circulation rate of powder in the mill is about 20%, and 80% of powder can meet the requirements.