Electric selection equipment and process technology---Drum type electric sorter (1)

This electric sorter has been developed from a single drum to a multi-drum, and the small drum diameter has developed into a larger diameter. Domestically, the small drum diameter is called the roller or roller type electric separator. The minimum drum diameter of the electric separator produced in China is only 120 mm, and the maximum is 320 mm. The existing single drum, double drum and three drums The cylinder has a maximum drum diameter of 350 mm and a maximum of 10 drums. The electric sorter is completely sorted according to the conductivity of the mineral, and is a dry operation for sorting in the air, and the power source used is a high-voltage DC power source.
Except for a very small number of electrode structures using only electrostatic fields and a few using only corona electric fields, most of them use a composite electric field. According to the author's induction, various types have emerged, and Figure 1 is a typical representative at home and abroad.

There is only one high-voltage negative electrostatic electrode in kind A, which does not produce corona discharge. The trajectory of falling from conductors and non-conductors shows that the efficiency is very low. It is rarely used at present. The domestic electro-selector is not produced. The principle is pure dependence. Inductive charging causes the mine B to adopt a corona pole. From the difference of the trajectory of the mineral falling, it is known that it is significantly different than the A species, but only one corona pole, especially the non-conductor will have too little charge due to adsorption. The mirror suction is small and falls into the conductor ore, resulting in a low conductor grade. Of course, the grade of non-conductor ore will be higher, but the recovery rate is too low.
The C structure is further advanced than the A and B types, which concentrates the advantages of both, but still reflects the weakness of the B species, so the efficiency is still not high.
The D species are obviously different, and the corona pole is increased to 5 or even 7, which greatly enhances the corona electric field. It is obvious that the non-conductor ore particles will adsorb more electric charges in the electric field, which inevitably produces a larger mirror suction force. Falling into the conductor ore increases the sorting effect. The obvious disadvantage is that there is no static electrode, and there are too many coronas, which will inevitably cause some of the conductors to be mixed into the non-conductor. The reason is that the conductor adsorbs too much electric charge, and it is not enough to conduct it. This residual electric charge will inevitably produce specular suction. In the non-conductor, the result is a high conductor grade and low recovery.
E is an electrode developed by Capco in Florida, USA. It has 2 static electrodes and 2 corona electrodes. The sorting efficiency is improved. The static electrode is just above the two corona poles, which prevents the corona from fully functioning, and the corona pole is still too small, so the amount of medium ore is relatively large.
The F species concentrates on the advantages of the above various electrode structures, strengthens the role of the corona electric field, and gives the ore particles ample opportunity to obtain more electric charges, but does not adsorb too much charge as in the D species; Using static electrodes, practice has repeatedly proved that this electrode structure is much better than the above various types, conductor grade, recovery rate and non-conductor grade and recovery rate have reached a very high level, and the amount of medium ore is very small, generally only It is 10 to 20%.
Drum The drum represents the grounding pole, however it is one of the important factors that directly affect the sorting effect. At present, various types of electric separators produced at home and abroad have various diameters of 120, 130, 150, 200, 250, 300, 320 and 350 mm. The theory and practice at home and abroad prove that under the same conditions, the drum diameter is better than the small drum diameter.
At present, the domestically produced electric separators are all drum type, but there are no other types, but the sorting effect is also distinct due to the difference in electrode structure and other conditions. [next]
(1) Double roller ф120×1500 electric separator
The structure of this electric sorter is shown in Figure 2. It is the first electric sorter used in production in China.

The advantage of this equipment is that it is simple in structure and large in processing capacity, and is used in the selection of tungsten ore, coastal sand mine and land sand mine in some mines and selected plants in China. However, due to the fact that it was a product in the early 1960s, it was in a state of phase-out due to historical conditions. The reason is that the voltage is too low, only 20,000 volts, and the drum diameter is too small (ф = 120mm), resulting in separation efficiency is very low, such as less than 1 mm separation scheelite cassiterite, which require sorting ~ 7 More than 8 times, but still can not meet the product quality requirements, Xi Shi selection must be reluctant to pass many times, in addition to the adjustment of the electrode position and speed is also extremely inconvenient, they need to be adjusted after parking. [next]
(II) DXJф320×900 high-voltage electric separator This is a kind of equipment developed in combination with the needs of domestic small and medium-sized mines and selected plants. It was successfully developed in the early 1970s and was first applied in the selection of antimony ore.

The electrode structure is shown in Figure 1. The corona electrode can be used in 3 to 5, and there is a static electrode, which can be changed according to different minerals and requirements. This structure not only fully considers the role of the corona electric field, but also considers the static electrode, but also has its characteristics in the selection and installation position of the static electrode, just installed on the second corona pole; It uses a higher DC power supply (0~60 kV); and it uses a larger drum diameter (ф=320 mm), which is the largest drum diameter in China. The drum is designed with a heater, which is different from any domestic and foreign. The electric drum method of the electric separator is extremely safe and reliable. The position of the electrode can be adjusted not only in the horizontal direction during production, but also up and down along the arc of the drum surface. Thanks to these improvements, the sorting effect is significantly improved, with its own characteristics, and its application range is also wider. For example, some minerals that were not able or effectively sorted by ordinary double-roller electric separators in the past can be effectively divided. Selection, not only the conductor and non-conductor grade and recovery rate are very high (97 ~ 99%), and the amount of medium ore is very small, the result of a single sorting is at least equal to 5 to 7 times of the double-roller electric separator. The structure is shown in Figure 3. The heating of the drum and the bucket is automatically controlled. The disadvantage is that only one drum is designed, and the processing amount is small, which brings inconvenience in the re-election of the middle mine. The device is suitable only for small selection of mining use, has been widely used beach placer scheelite and cassiterite separation of tantalum and niobium ore selection.