Comparisons of Vacuum Ceramic Disc Filter and Disk Filter
1. The advantages of Vacuum Ceramic Disc Filters
The most significant feature of Vacuum Ceramic Disc Filter is to use ceramic material as the filtering media instead of filter cloth. The external layer of ceramic filter plate is covered by micro-porous membrane and internal is supporting body with big pore diameter, and the size of micro-pore can reach 0.5μm. Under capillary effects, filtrate goes to ceramic filter plate continuously through micro-pores, and is absorbed into the plate under vacuum pressure difference and then discharged by filtrate pipe. For there is no air entering the micro pores, the vacuum ceramic disc filter can keep an extra high vacuum degree during working process. The specific features are as follows:
1.1 Compared to using traditional filters, using VCF will result in lower moisture of filter cake which is normally less than 8%.
1.2 Greatly decreased energy consumption, only reach 20-30% of that of traditional filters.
1.3 High degree of automation, compact structure, small foundation, easy to install, operate, and maintain.
1.4 The turbidity value is low, particle content is 21ppm, and filtrate can be directly recycled.
1.5 High recovery rate, fine particles under -10μm can be recycled.
2. Comparisons of Vacuum Ceramic Disc Filter and Disk Filter
Case study：After renovation and expansion in 2004, Ansteel Dagushan Beneficiation Plant’s yearly concentrate output is 3.8 million tons and the second beneficiation workshop daily concentrate output is 7000 tons. For the concentrate particle size is superfine ( -200 mesh takes up 94%, moisture 9.5-11%), the former installed 10 sets of 72m2 disk filters cannot meet the needs of yearly pellet output 4 million tons lately. After second renovation, they adopts 7 sets of our 60m2 vacuum ceramic disc filters, the performances are good and they can meet production requirements completely. The comparisons to the two kinds of filters as follows:
Comprehensive Benefit: If the beneficiation plant wants to keep the moisture below 8% but still use disk filter, to lower 1%
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moisture of iron concentrate by drying, the cost of coal and other consumptions is USD1.47/T; while the second workshop filtering 2.4 million tons of iron concentrate each year by using vacuum ceramic disc filter, saves dry cost USD3, 528,000 and ultrafine powder concentrate is additionally collected (15 thousand tons each year) valued USD 1,764,706.
3. Operating cost estimates
Internal drum filter, external magnetic filter and vacuum disc filter, etc are usually used for the filtration of iron concentrates. In recent years, the vacuum ceramic disc filter is widely used in various types of ore beneficiation for filtering products, especially iron concentrates. Several large iron mining companies have been using vacuum ceramic disc filter to process iron ore because of the distinct advantages of vacuum ceramic filter. The first is lower cake moisture, which is the traditional filter before-mentioned are not comparable. The second is small installed capacity, effective energy-saving. In addition, its environmental advantages are obvious, since the filtrate water is clear and could be recycled directly.
3.1 Operating Costs Comparison
Under the same ore feed condition, granularity is under 200Mesh, 85%. It should choose three sets of 20 M2 Disc Filters or choose three sets of 21 M2 vacuum ceramic disc filters. It is good enough for the theoretical efficiency of 0.85 T/m2 H or the actual requirements of 0.748T/m2 H.
3.1.1 .Operation Cost of 20M2 disc filters:
(1) Power consumption: two sets work and one for spare, the install capacity is 62Kw × 2 = 124Kw Power Cost: USD0.088/Kw•H×124/29.92T=USD0.366/ton
(2) Filter cloth: two sets of disc filter should use 120 pieces filter cloth, one piece of filter cloth is USD6.6, and the average service life is 14 days.
Cost should be: USD6.6×120pieces/10053T=USD0.079/ton Total Cost: USD0.366/ton+ USD0.079/ton= USD 0.445/ton
3.1.2 .Operation Cost of 21M2 vacuum ceramic disc filter:
1. Power consumption: two sets work and one for spare, the install capacity is 26Kw×2=56Kw
Power Cost: USD0.088/Kw•H×52Kw/29.92T=USD0.153/ton
2. Consumption of ceramic filtering plate：
Two sets of vacuum ceramic disc filters should use 168 pieces of ceramic filtering plate, Cost of one piece is USD176, average service life is 18 month, process capacity is 29.92T×21×547.5days=393148.8T.
3. Acid consumption: Working vacuum ceramic disc filter should be stopped and cleaned by nitric acid after every 7 hours.
Amount of nitric acid is 21Kg, concentration should be 40%, and the Cost is USD382/ton.
USD0.382/Kg×21/ (29.92×7) = USD0.038/T Total Cost: USD0.153 +USD0.075 + USD0.038=USD0.266/ton
3.1.3 We can see from the above comparison result that vacuum ceramic disc filter could reduce the Cost of filtering the iron concentrate, USD 0.445/T- USD0.266/T=USD0.179/T the annual handling capacity is:
29.92T×330days×24hour=236,966.4tons Cost reduces: USD0.179×236966.4=USD42,417/year
3.2 Cake Moisture: Under the ore feeding conditions described above, the cake moisture filtered by vacuum ceramic disc filter should be under 7.5%, but the cake moisture of disc filter will be about 8.5%.
Compared between disc filter and other filter cloth type vacuum filters, the main change is on the equipment structure. It reduces the area occupied and a slight decrease in cake moisture. But it does not solve the existent drawbacks of the filter cloth-type vacuum filter. Ceramic filtering technology is the world's most advanced filtering technology. East Anshan Iron and Steel sintering plant took use of vacuum ceramic disc filter and made significant economic benefits. Wuhan Iron and Steel Plant’s three beneficiation plant all use vacuum ceramic disc filter to replace the original disc filters. Shandong Lunan Mining Company, Shandong Laiwu mining company, Wuyang Mining Corporation of Henan, Hebei Yuantong company, Sijiaying Iron ore Beneficiation Plant, Miyun Iron ore Company located in Beijing, Tangshan Iron and Steel Miaogou Iron ore Plant, Inner Mongolia Hongxin Mining Company and so. Totally more than 30 companies’ reconstruction projects or new projects are using vacuum ceramic disc filters. Vacuum Ceramic Disc Filter’s superiority has been widely recognized by the domestic iron ore beneficiation.