The heavy medium beneficiation process includes ore preparation, medium preparation, stone sorting, medium removal, and medium regeneration. Pictured silicon iron magnetite suspension or as a suspension medium typically sorting process. (1) Ore preparation In the production process, it is necessary to have a good understanding of the mineral ratio (the ratio of the tonnage or cubic meter required for 1 ton of ore). The general drum type sorting machine has a tonnage ratio of 1:0.7~0.8; the cone concentrator is 1:1; the heavy medium cyclone is 1:6; the heavy medium vortex vortexer is 1:8; the cannula swirl The device is 1:4. Merry Christmas Decoration,Merry Christmas Balloons,Merry Christmas Ornament,Merry Christmas Wall Hanging NINGBO ART TALK CRAFTS CO LTD , https://www.just-arts-crafts.com
After the ore is crushed to a suitable particle size, it is also washed and sieved to remove the slime adhering to the ore and control the lower limit of the ore size. These two tasks can be done simultaneously on the screening machine by spraying water. Screening machines in China use linear vibrating screens and self-centering vibrating screens. The washing water pressure is 100~125 kPa, and the water consumption is 0.2~0.9 m32/ton ore. The fine fraction in the product on the sieve should not exceed 0.2 to 0.3%.
(2) Medium preparation
When bulk ferrosilicon or magnetite is used as the weighting material, it is broken and ground in advance. The crushing and grinding process is basically the same as that of the general ore dressing plant. After the jaw crusher and the sieving machine are used to form a closed circuit to a certain particle size, the ball mill and the spiral classifier are used for closed-circuit grinding until the required particle size.
When sprayed granular ferrosilicon or magnetite or pyrite concentrate is used for weighting, it is generally not necessary to regrind unless the particle size is coarse.
The grounded weight is then magnetically selected (excluding non-magnetic impurities) or concentrated (when iron sulfide or the like is used as a medium), and then stored in a concentrated medium tank for sorting application.
(3) Ore sorting
The ore sorting is the separation of light and heavy minerals in the sorting machine. The key issue in operation is to keep the density of the suspension stable. Commonly used suspension density measuring instruments include differential pressure or density measuring instruments and radioactive density meters.
The figure is a schematic diagram of the operation of the differential pressure suspension density measuring instrument. Two pressure measuring tubes are inserted at different depths of the tested suspension, and the upper ends of the two tubes are in communication with the source of compressed air, and the throttle valve is adjusted to control the amount of air entering the tubes so that they can be discharged from the bottom port. The pressure measuring tube is connected with the indicator tube and the electrode group, and the pressure difference at the bottom end of the two pressure measuring tubes is displayed on the liquid level of the indicator tube and the electrode group. Let h1 and h2 be the insertion depth of the long pipe and the short pipe respectively, H is the rising height of the water column in the index pipe, Ïsu is the density of the suspension, and Ï is the density of the water in the pipe. When the pressure is balanced, the following relationship exists:
The viscosity of the suspension should also be controlled so as not to increase excessively. For this purpose, the micro-mud content in the suspension should be minimized. The measures can be taken as follows: (1) The freshly ground medium is first purified and decontaminated to remove extremely fine mud and impurities; (2) a part of the concentrated medium separated from the product is sent to the purification system for treatment (see production below) Process example).
(four) medium out
The light and heavy products discharged from the sorter are separately fed into the screening machine to take off the entrained suspension. The de-screening is divided into two sections: the first section screens out the concentrated medium and returns directly to the process; the second section sprays water on the screening machine to wash away the heavy mass adhered to the ore, and the two sections can be On the same sieve, the front part is 25~30% of the length of the concentrated medium, and the back part is rinsed with water. The sieves used are linear vibrating screens, self-centering vibrating screens and resonant screens. The sieve surface is mostly a slit screen with a slit width of 2 to 3 mm or less. The unit production capacity of de-screening is about 10-20 tons of ore/hour meter 2.
(5) Medium regeneration
Generally, the amount of concentrated medium that is released is about 90% to 95% of the total working medium, and the rest of the weight adhered to the ore is flushed to the dilute medium. This part of the medium is seriously polluted and needs to be purified and concentrated. This operation is called Media regeneration. The regeneration method differs depending on the nature of the addition:
(1) using pyrite as a weighting purification system, including de-packing, washing, one to three de-roughening, cyclone and concentrator concentration, and periodically removing impurities by flotation;
(2) Purification system of ferrosilicon suspension, including de-packing, washing, magnetic dehydration tank, magnetic separator to recover ferrosilicon, cyclone concentration and the like. The working system of the purification system adopts a split continuous work system;
(3) The coarse-grained (2-0 mm) hematite is used as the aggravating purification system. Only the de-packing, washing and concentrating operations are carried out. There is no medium purification operation, and all new media are replaced regularly.
A portion of the newly added weighted and concentrated medium is also sent to the media purification system for purification before use to prevent viscosity increase. According to foreign experience, the weight loss of ferrosilicon is generally 0.2-0.3 kg/ton, and the consumption of pyrite is 0.5-0.8 kg/ton.