2020 China cement industry research report

China Cement industry market Overview - Definition and classification of cement

Definition of cement: Cement is a powdery hydraulic inorganic cementing material. After mixing with water, the slurry can be hardened in air or in water, and can firmly bond sand, stone and other materials together. Early mixtures of lime and volcanic ash, similar to modern lime-pozzolanic cement, were used to cement concrete made of crushed stone, which was not only stronger when hardened, but also resistant to erosion by fresh water or salt water. For a long time, as an important cementing material, it has been widely used in civil construction, water conservancy, national defense and other projects.

Cement performance indicators: cement is the most commonly used important material for construction projects, and is widely used. The quality of cement will greatly affect the construction project. Therefore, it is of great significance to the performance indexes that affect the strength of cement and cause damage within the structure. The appropriate use of cement varieties with different indexes can effectively reduce or even avoid major defects in engineering construction

China cement industry market overview - the origin history of cement industry

After more than 200 years of development of cement production technology, through continuous improvement and progress, the modern new dry method of pre-decomposition kiln was finally invented. The production process of cement needs to go through "two grinding and one burning", and is also closely related to "kiln". Looking back at the development process of cement in the world, kilns are often used as clues. In the past two hundred years, cement production has experienced the development stages of warehouse kilns, vertical kilns, dry rotary kilns, wet rotary kilns and new dry rotary kilns, and finally formed the new dry method of modern pre-decomposition kilns. China's cement industry started late but developed rapidly after the 21st century. The development process can be divided into five stages: the initial exploration stage, the planned transformation to the market stage, the elimination and transformation of the development stage, the high-speed leapfrog development stage, and the innovation and improvement beyond the leading stage.

China Cement Industry Market Overview - cement components and raw materials

The components of cement:

Cement clinker: raw material with appropriate composition is burned to partial melting, resulting in calcium silicate as the main component of the product;

Gypsum: mainly natural gypsum or industrial by-product gypsum, the content of 2-5%;

Cement mixture: In the cement production process, the mineral material added to cement to improve the performance of cement and adjust the cement label is called cement mixture material, which is divided into active and inactive two kinds. Active mixtures are those with pozzolanic properties or potential hydraulic properties, such as granulated blast furnace slag, fly ash, etc. Inactive mixtures, that is, potential hydraulic or pozzolanic mixtures with activity indexes that do not meet the requirements of the standard, as well as sandstone and limestone;

Kiln ash: refers to the dust collected from the exhaust gas of the cement rotary kiln;

Grinding aid: An admixture used to aid the grinding of cement without damaging the properties of cement, adding less than 1%.

Chinese cement industry process technology - "two grinding and one burning" cement process

Introduction of cement production process:

"Two grinding and one burning", respectively for raw material preparation, clinker calcination and cement grinding. The preparation of raw materials is to combine calcareous raw materials, clay raw materials and a small amount of correction raw materials after crushing, grinding and grinding according to a certain proportion, and then combine into raw materials with appropriate composition and uniform quality; Clinker calcination refers to the clinker of Portland cement with calcium silicate as the main component, which is obtained by calcination of raw material in cement kiln to partial melting. Cement grinding is to add an appropriate amount of clinker gypsum, and sometimes add an appropriate amount of mixed materials or admixtures to grind into cement.

Limestone and cement kiln introduction:

Sand and stone are important raw materials for producing clinker. At present, China's cement production is basically covered by the new dry cement production technology. Different types of cement kilns produce a large difference in heat consumption, of which the new dry cement production technology is based on suspension preheating and pre-decomposition technology as the core, the use of modern fluid mechanics, combustion dynamics, thermal engineering, powder engineering and other modern scientific theories and technologies, and the use of computer and its networked information technology for cement industrial production of comprehensive technology. Because of its characteristics of high-tech, environmental protection and sustainable development, it fully meets the needs of large-scale production and automation of modern cement industry, and gradually replaces the production technology of vertical kiln, wet kiln production technology, dry hollow kiln production technology and semi-dry production technology, and has become the mainstream technology used in the cement industry.