Iron ore crushing technology (1)

Steel iron mines aspects of research institutions and iron ore processing enterprises in recent years for iron ore crushing of scientific research and production technology, mainly around reducing the final crushing product size, increase mill capacity, save energy, reduce consumption , the crushing process, the transformation of the process, the crushing and screening equipment and the transformation of auxiliary equipment.
I. Reconstruction of the crushing process The large and medium-sized iron ore dressing plant in China, the original designed crushing system is mostly three-stage open road, which has been gradually transformed into three sections and one closed road, and is still developing in four sections and one closed road. More typical examples are the Donganshan plant.
1. Improvement of the crushing process of the Donganshan plant. The first process process transformation, also known as the basic transformation of the process. In 1959, the original three-stage open crushing and screening process was transformed into a three-stage one-pass crushing and screening process (see the figure below), and a fine crusher was added, totaling six fine crushers. After the transformation, the particle size of the crushed product was significantly improved, and the fractional content of -12mm was increased from 28.2% to 58%, which increased the utilization factor of the mill from the original 1.8t/m ³ •h. to 2.2t/m ³ • h. Above.

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The second process is transformed. Mainly on the basis of the basic transformation, in 1965, the process was improved. The transformation measures are to expand a screening and two screening plant, one of which adds 2 sets of 2000×4000mm fixed rod screens, which solves the problem of newly increasing output of 1 million t75~20mm lump ore. The original five 1500×3000mm vibrating screens were cancelled, and nine 1800 × 3600 vibrating screening plants were built separately. The flow is shown in the figure below. After the transformation, the crushing and screening capacity is balanced. When the final product particle size is -12mm, the annual output is 4.6 million tons.

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The next step is to use a superfine crusher and change the process to a four-stage, closed-circuit crushing process. The original three sections are broken and sieved. Sub-system, coarse and medium-crushing system does not need to be modified, retaining the original fine crushing, changing the original closed-circuit system to open circuit, adding the fourth-stage closed-circuit crushing system, and introducing two 2134mm high-efficiency hydraulic cone crushers from American A-C company . As the fourth stage of crushing equipment. The sieve is made up of 6 sets of 2YAH2460 seat vibrating screens. The comprehensive production capacity of crushing has increased from 5 million t/a to 7 million t/a. If there is a lump output, the output is calculated at 1 million t/a, and the new fourth-stage crushing capacity is 6 million t/a. The crushed final product has a particle size of 7.5 to 0 mm and 95%.
2. Renovation of crushing process of Shuigang, Dashihe Iron Ore Plant, Shougang Waterworks Iron Ore Plant and Dashihe Iron Ore Plant, the original design process of the crushing system is a three-stage and one closed-circuit process (Figure 1 below) . In order to implement the technical policy of “breaking more and less grinding”, the Dashihe Concentrator has changed the three-stage crushing process to four sections (Fig. 2a). The waterworks concentrator was broken in the second section of the process in December 1986. Install a 1800×1400mm rod screen (Fig. 2b) in front of the machine. After the transformation, the load of the medium crusher is reduced by 29.89%.

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The results obtained through the transformation of the process and equipment are shown in the following table:

High precision double side surface grinding or fine grinding is a super finishing process performed by removing material from two surfaces of a component resulting in extremely precise geometric accuracy and surface finish. Typically, it is the last grinding step of a mechanical production chain utilized to improve and/or correct the geometry of parts coming from sintering, sawing, molding or similar operations. Depending on the application, the stock removal also can be taken from just one surface.