In Brand Collection 3, the brand of crushers has been sorted out. This chapter will provide a detailed introduction to the mill brand. The products of the mill series include automatic mills, semi mills, ball mills, rod mills, high-pressure roller mills, etc. Due to different ore properties and design processes, the selection of mills also varies. There are many SAG Mills, ball mills, and high-pressure roller mills used in mineral processing plants, while the grinding equipment in coal preparation plants mainly involves the preparation of heavy media (magnetite powder).

Process Overview

In the past few decades, the design of mineral processing plants using semi-automatic grinding technology has replaced conventional multi-stage crushing and rod/ball mill grinding circuits, becoming the preferred crushing and grinding process. The circuit using semi-automatic grinding technology is simpler, with lower investment and overall operating costs. The semi self-grinding process is an ideal process for treating wet, sticky, and clay rich ores and their oxidized ores.

For harder and more wear-resistant primary ores, energy efficiency is gradually becoming increasingly important from an economic and environmental perspective. At this time, the introduction of high-pressure roller milling technology into the field of hard rock crushing represents a return to the traditional concept of crushing ball milling grinding circuit. Compared with circuits using semi-automatic grinding technology, the increased complexity of the circuit can be compensated for by the high energy efficiency of high-pressure roller mills.

In the late 1970s, the conventional crushing and grinding process was mostly a "three stage (or two stage) one closed circuit crushing+grinding" process. The coarse crushing of the raw ore was carried out using a rotary crusher or jaw crusher, while the intermediate and fine crushing were carried out using a cone crusher. The final product P80 of the crushing circuit was generally 12-20mm. After entering the 21st century, with the maturity of high-pressure roller mill technology, the third stage cone crusher in the original process of more crushing and less grinding has been replaced by high-pressure roller mills, and the final product particle size can also be reduced to a lower level, minimizing the energy consumption of ball mills in subsequent processes.

Self-Grinding Machine

Self-grinding machine is a new type of grinding equipment that combines both crushing and grinding functions. It uses the ground material itself as the medium and achieves grinding through mutual impact and grinding effects. Currently, wet self-grinding machine is widely used.

SAG Mill

Semi-automatic grinding is the process of adding a small amount of steel balls to the automatic grinding machine, which can increase the processing capacity by 10-30% and reduce the energy consumption per unit product by 10-20%. However, the wear of the lining plate increases by 15%, and the fineness of the product also becomes coarser. The SAG Mill has a large diameter and a small length, resembling a flat circular drum, with a length to diameter ratio (L/D) generally ranging from 0.3 to 0.35.

Ball Mill

When the cylinder rotates, the grinding medium (steel ball) inside the cylinder is lifted to a certain height as the cylinder rotates, and then thrown down at a certain linear speed. The ore is crushed by the impact of the falling steel ball and the additional crushing and grinding effects between the steel ball and the steel ball, as well as between the steel ball and the lining plate. With the help of the impact of water, the qualified material that has been ground is sent out of the cylinder.

The above series of mills, if they are small equipment, can be made by many factories. Although the quality varies, they can meet the basic working conditions requirements; However, for medium-sized and large mills, there are relatively high requirements for equipment performance and manufacturing, which ordinary factories cannot handle. At present, foreign brands mainly include FFE Minerals under FLSmidth, Outokumpu from Finland, Mesto from Finland, ThyssenKrupp from Germany, and others.

In terms of medium to large equipment, China's mill brands are mainly CITIC Heavy Industry and Northern Heavy Industry. At the end of the 20th century, CITIC Heavy Industries collaborated with Fowler and Mesto in the United States to complete the production of 5.5m diameter ball mills and 8.53m SAG Mills, respectively. The diameter of overflow type ball mills increased from 4.27m to 8.2m and the diameter of SAG Mills increased from 5.5m to 12.2m. They have delivered more than 1700 sets in total. Currently, they have fully demonstrated the advantages of domestic brands in the international market. Northern Heavy Industries has produced more than 9000 mining mills, with products distributed worldwide. Among them, two sets provided for Laos Φ 9.15m × 5m SAG Mill and two sets Φ 6.4m ×10m ball mill with an installed power of 8000 kilowatts is the first time in China to adopt the "one driven two" variable frequency drive scheme for the mill.

High Pressure Grinding Roll ( HPGR)

High Pressure Grinding Rolls are developed on the basis of roller crushers and were first applied in the 1980s, initially in the cement industry. With the emergence of roller nail wear-resistant systems, the application scenarios of High Pressure Grinding Roll are also increasing. If the ore has high hardness and strong wear resistance, and the specific energy consumption of using a SAG Mill for processing is greater than 8-9kW. h/t, it is more suitable to use a high-pressure roller mill at this time.

Due to the initial origin of high-pressure roller mills from smooth roller crushers, in the field of small equipment, the technical difficulty is relatively low, and there are many factories that can complete production and production. Once large-scale equipment manufacturing is achieved, the value of large brands is also reflected.

The main foreign brands include ThyssenKrupp's Polysius, KHD, and Koppern, all of which have made outstanding contributions to the development of high-pressure roller mills.

The main brands in China include Chengdu Lijun, Hefei Cement Institute, CITIC Heavy Industry, Northern Heavy Industry, etc. Among them, Chengdu Lijun has developed rapidly in research and development, market development, large-scale equipment, and process optimization in the past decade, and has demonstrated its unique brand style. From the perspective of large-scale production, Chengdu Lijun's high-pressure roller mill has achieved the world's largest in the field of iron ore grinding, with a roller sleeve diameter of up to 2.6m and a roller width of 1.6m. A production line that processes 40000t of iron ore per day can be met with just one set.

We have made outstanding contributions on the road to the brand of grinding machines, and can compete with foreign first tier brands in the international market. However, we still have many shortcomings in equipment standardization, after-sales service, brand presentation, and other aspects. We hope to get better and better.

BUTTRESS ROOTS will provide the latest brand collection and supply to global mining users.

www.brt-link.com