With the Chinese One Belt and One Road strategy, the economic exchanges between China and Central Asia, South Asia and Western Asia have greatly deepened the economic infrastructure of the region along the way, greatly improving the infrastructure, public service facilities and investment demand for housing construction, which has brought great development prospects to the construction industry, the building materials industry and the cement concrete industry. For example, the expressive way from Karachi to Lahar in Pakistan, the Yawan high-speed railway in Indonesia and the Tehran-Mashhad high-speed railway have greatly promoted the development of the local concrete industry.
Concrete refers to the engineering composite materials which are cemented by cementitious materials into a whole. Generally speaking, the term concrete refers to cement as cementing material, sand and stone as aggregate, and water (including admixtures and admixtures) in a certain proportion, the cement concrete obtained by mixing, also known as ordinary concrete, which is widely used in civil engineering industry. Concrete has the characteristics of abundant raw materials, low price and simple production process, so its consumption is increasing. At the same time, concrete has the characteristics of high compressive strength, good durability and wide range of strength grades. These characteristics make it widely used not only in various civil engineering, but also in ship-building, machinery industry, ocean development, Geothermal Engineering and so on. Concrete is also an important material. Ordinary concrete has its own advantages, but because of its self-weight, it is brittle material, easy to crack in construction; not easy to cut, planer;slow hardening after cast-in-place, long construction period and so on. The particle shape and surface characteristics of coarse aggregate also affect its bonding with cement and the fluidity of concrete mixtures. Crushed stone has edges and corners, rough surface, good bonding with cement, while pebbles are mostly round, smooth surface, and poor bonding with cement. Under the same cement and water dosage, concrete mixed with crushed stone has poor fluidity, but high strength, while concrete mixed with pebble has better fluidity, but low strength. Therefore, in order to improve some performance shortcomings of concrete, it is necessary to add appropriate additives and admixtures. Among them, adding slag and slag powder in concrete as admixture is more and more accepted by many enterprises.
Slag and slag powder is a kind of mineral admixture with potential activity, which can grind water-quenched blast furnace slag to a specified fineness. It is a new building material. The surface area can reach more than 400 cm2/g, which has the characteristics of ultra-fine particles and high activity. It can be used as a concrete admixture to replace part of cement, is one of the components of high performance concrete production, and is also one of the raw materials widely used by commercial concrete companies.
The composite use of concrete gel materials, especially slag and mineral powder admixture, has many advantages in technology and economy than in the past.
Adding appropriate amount of slag and slag powder can improve the fluidity, cohesion and water retention of concrete mixing material, make concrete mixing material easy to pump, pour and form, and reduce the economic loss of slump. Adding slag and slag powder can reduce the usage of cement, and the heat released by hydration of slag and slag powder is very little, which reduces the heat released by hydration. Therefore, when concrete is constructed, the temperature decreases and the temperature cracks can be reduced, which is especially beneficial to mass concrete engineering. The creep deformation of slag powder concrete is lower than that of ordinary concrete. The water reducing effect of slag and slag powder makes the dry shrinkage and early plastic cracking of slag and slag powder concrete basically consistent or slightly lower than that of ordinary concrete. The strength and hardness of slag and slag powder are higher, so the wear resistance of slag and slag powder is better than that of ordinary concrete. However, poor maintenance of concrete will lead to lower wear resistance. At the same time, adding slag and slag powder under the condition of equal strength grade can reduce the amount of cement by 10% - 15%, thus reducing the cost of concrete.
As concrete admixture, slag and slag powder need to be processed between 200 mesh and 325 mesh in fineness. The concrete industry generally uses a large amount of concrete and has a high degree of centralized operation, so the ordinary Raymond mill can not meet the production capacity requirements at all. The power consumption and investment of the ordinary ball mill can not reach the optimal investment effect. Therefore, based on the comprehensive study of the mill industry, the Zenith Mining Company has developed LM series vertical mills suitable for large-scale production, and has already been in Jakarta, Indonesia, as well as in Indonesia. Tehran Thermal Power Plant in Iran has established customer sites, so it has rich experience in the operation of LM vertical grinding slag and slag powder.
As an ideal equipment in the grinding industry engaged in crushing, drying, grinding, separating and transportation, the LM series vertical grinding mill is advanced grinding equipment designed and developed by our company based on our experience in mill production as well as wide range of adoption of and overseas advanced technology. The LM series vertical grinding mills can be widely used in cement, electric power, metallurgy, chemical industry, non-metallic mining and other industries to grind blocky, granular and powdery to powder as required
1.Low comprehensive investment. The equipment integrates the functions of crushing,drying,grinding,powder separating and transportation,featuring simple system and compact layout, with the floor space of about 50% of that of the ball mill system, And it can be arranged outdoors so as to greatly reduce the investment costs. The system design is simple and reasonable, saving unnecessary equipment investment so as to reduce total investment of the equipment
2. low operating costs. As the roller does not contact the grinding directly and the roller and lining board are made of high-quality materials. Therefore, they enjoy longer service life and less wear. The grinding rollers can directly grind materials on the grinding disc, featuring lower energy consumption (30%-40%) lower than that of ball-mill systems. A limiting device is provided to prevent direct contact between the roller sleeve and the lining plate of the grinding disc, so that destructive impacts and violent vibration could be avoided to lower the failure rate.
3. Automatic control system. The equipment is provided with an expert automatic control system, realizing free switching between remote and local control to achieve easy operation and save labor costs
4. High-quality finished products. The materials only stay in the mill for a short time, which can reduce repeated grinding, and facilitate testing and controlling the product particle size and chemical composition as well as stabilizing the product quality. The grinding roller does not directly contact the grinding,disc, so the product contains very little iron and the iron contents due to mechanical wear can be easily removed so that the whiteness and purity of the product can be effectively guaranteed. An efficient dynamic and static combined powder clash.er is adopted with the rotor speed adjustable, so that higher classification efficiency and top-quality finished products could be ensured to satisfy different requirements for fineness
5. High Environmental Protection Standard. The equipment can operate stably with little vibration. So its noise is fairly low. The system is wholly sealed and works under negative pressure, free of dust spillover and environmentally friendly with the emission meeting the national standard