In recent years, scientists have found that various electromagnetic waves in the electromagnetic spectrum range (see Figure 1) can be used for sorting. Although different electromagnetic waves generate different mechanisms (radio waves are generated by the periodic motion of free electrons in the oscillating circuit; infrared rays, visible rays, and ultraviolet rays are generated by the outer electrons of the atoms; χ-rays are The electrons in the inner layer of the atom are excited; γ-rays are generated after the nucleus is excited, but they all obey the common law of electromagnetic waves. Different electromagnetic waves have different frequencies and wavelengths, exhibit different characteristics, and can be used for sorting in different forms. The sorting method classification table based on the wavelength of the radiation source used for picking is shown in Table 1. The table is divided into seven categories and 13 sorting methods. According to the electromagnetic spectrum, it can be seen that the wavelength ranges of various electromagnetic waves have been connected. Therefore, the wavelength division limits of each category in the classification table are not very strict. The second type of neutron flux in the table is not exactly the same as other electromagnetic waves. It has obvious quality because neutrons are particles, but according to the study of the laws of microscopic particle motion in modern physics, not only light has waves. Granularity, microscopic particles also have wave-particle duality. According to the mass and speed of the neutron, the wavelength can be determined, so the picking method using neutrons is also listed in Table 1. [next] Whether the ore of a mining area can pick up large pieces of waste rock or large pieces of useful ore by picking method is mainly determined by the characteristics of the ore. Depending on the different characteristics of the ore, there are different picking methods. Figure 2 shows several graphs of the degree of mineralization uniformity and ore body shape. In Figure a, the useful minerals are uniformly distributed in the ore body, and the ore is not optional; in Figure b, the useful minerals are in the form of granular inlays, and the mineralization is uneven, which can be sorted; in Figure c, the ore body is small and the shape is not Rules, the boundary between the ore body and the surrounding rock is obvious, easy to choose; in Figure d, the ore body is thin, the boundary between the ore body and the surrounding rock is obvious, easy to choose; in Figure e, the ore body is thick, the boundary between the ore body and the surrounding rock is not obvious, it is difficult selected. Therefore, from the geological conditions of the mine, the possibility of picking can be preliminarily estimated. Optional curves can also be utilized to evaluate mineralization non-uniformities. This method is simpler and clearer. First, based on the shape of the optional curve, the difficulty of picking can be qualitatively evaluated. Figure 3 is a discretionary washability several typical graph where a very homogeneous ore mineralization, grade of ore useful components of each block is equal to ore grade, can not be chosen, d is the easy dressing stone, ore by a Most of the waste rock (or low grade ore) and a small number of ore grades are easy to sort; Figure b and c are the optional curves of general ore, where b is refractory ore, c is easy Ore. (II) Granularity characteristics of ore Picking is a method of coarse-grained ore dressing. Different sorting methods and equipment have a range of ore sizes. Under the premise of determining the ore selectivity, the greater the yield of coarse-grained grades, the more waste rock that can be sorted out, and the more obvious the economic benefits of sorting. Christmas Cookie Boxes,Christmas Cracker Gift Boxes For Cookies,Christmas Cookie Gift Boxes,Holiday Christmas Cupcake Cookie Boxes Dongguan Tielangtou Hardware Products Co., Ltd , https://www.tinboxtlt.com
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The ore characteristics and the theoretical basis of the main sorting methods commonly required by various sorting methods are briefly described below.
I. Influence of ore characteristics on picking The optional ore characteristics are: heterogeneity of the distribution of useful components in the ore; grain size composition of the ore; sorting characteristics used in the sorting and useful components in the ore Relevance.
(I) Non-uniform distribution of useful components in ore The difference in distribution of useful components in ore is the basis for sorting. The presence of useful components in the ore, the distribution characteristics of useful minerals in the ore body (whether it is coarse-grained or disseminated), the shape and size of the ore body, and the contact state of the ore body and the surrounding rock, etc. The grade distribution of the mined ore is very different, and it has an important influence on the process indicators that can be obtained by picking and sorting.
The mineralization of large marine sedimentary deposits is uniform, and the grades of the ore mined are very small and cannot be sorted. Hydrothermal deposits, vein deposits, ore bodies with complex ore bodies and thin ore bodies have uneven mineralization, and the grades of ore produced are very different and are easy to sort. [next]
After the ore is produced, in order to understand the unevenness of the distribution of useful element grades, it is necessary to take hundreds of representative ores, determine the grade by block, and then calculate the average relative deviation M of each grade and the original grade. According to the size of the M value, the unevenness of the ore grade distribution can be quantitatively evaluated, and the formula is [next] [next]
The main factors affecting the size composition of the ore produced are. The physical and mechanical properties of ore and rock; the heterogeneity of ore, rock, joints and fissures; the blasting parameters during mining; the mode and link of ore from the stope to the sorting machine. The first two are the natural characteristics of the ore, and the latter two can be manually controlled.
Based on the rock strength and fracture characteristics, the coarse fraction yield can be roughly estimated by referring to the values ​​listed in Table 2.