Manfredini & Schianchi proposes solutions for the processing and milling of barytes.
Thanks to a technology based on the interaction between different machines offered by Manfredini & Schianchi, it is possible to realize the dry milling of the barytes, nowadays used as weighing additive in drilling fluids or muds for petroleum industry. The dry milling proposed by Manfredini & Schianchi takes to a final product in accordance to the actual technical specifications issued by API (American Petroleum Institute), and it allows to use types of barytes now rejected due to inadequate technological featur
The barytes
The barytes is a barium mineral (barium sulphate, BaSO4), with a medium-low Mohs hardness (3) and specific gravity (SG) of 4,5 kg/dm3. The main use of the mineral is towards the petroleum industry, in which it is use as weighing additive for the drilling muds (thanks to the high SG), in order to helps the earth crust drilling and reach the oil deposits.
The actual reference norms regarding the nature and the processing of the pretroleum barytes are nowadays issued by the API (American Petroleum Institute), and they impose restrictive specifications on the SG of that material (due to its role as weighing additive), and on the grain size distribution of the grinded barytes to be used for the petroleum industry.
Today, the imposed technological parameters are the followings
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Peso specifico minimo: 4,2 kg/dm3
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Residuo > 75µm: 3,0% massimo
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Residuo < 6 µm: 30,0% massimo
Dry milling of barytes
We take as example two samples of barytes with different SG (4,1 kg/dm3 and 4,2 kg/dm3), milled only with pendular mill: at the end of the milling process, it comes out a material with an extreme fine grain size distribution, whose apparent gravity (calculated on a dm3 of milled material and not on a dm3 of ideal material) will be different between the sample with initial SG of 4,1 kg/dm3 and the one with initial SG of 4,2 kg/dm3.
Due to this difference, the barytes with SG of 4,1 kg/dm3 comes out to be not usable for the petroleum industry. To solve this problem and allow the exploitation of the existing huge natural reserves of barytes with SG - 4,1 kg/dm3, Manfredini & Schianchi proposes a combined dry milling based on the match primary hammer mill + finishing pendular mill, able to provide a material whose grain size distribution is completely standard to the API specifications (Residue > 75µm: 3,0% max), but showing a lower percentage of fine fraction. In this way, milling a type of barytes with a SG of 4,1 kg/dm3 will takes to a grain size distribution showing around 12% < 10 µm and 100% between 20 ande 75 µm.
The final apparent gravity of material with that grain size distribution is absolutely identical to the one shown by types of barytes with SG of 4,2 kg/dm3, milled only with the pendular mill. The couple primary hammer mill + finishing pendular mill proposed by Manfredini & Schianchi for the barytes allows to get a milled material 100%< 75 µm, that shows a grain size distribution less fine: this solution makes also the barytes with SG of 4,1 kg/dm3 suitable for applications in the petroleum industry.
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Barite 4.1 only pendular mill |
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Barite 4.1 primary hammer mill + finishing pendular mill |
Moreover the results regarding the grain size distributions, that makes potentially available huge natural reserves of raw materials nowadays not used, the use of the couple primary hammer mill + finishing pendular mill proposed by Manfredini & Schianchi allows to accept also big size of feeding materials (up to 200-250 mm), eventually with impurities. In addition, in the primary hammer mill and in the finishing pendular mill proposed by Manfredini & Schianchi both, it is possible to put thermal devices for managing raw materials with high rate of moisture.
