scholarly journals Flotation of Seafloor Massive Sulfide Ores: Combination of Surface Cleaning and Deactivation of Lead-Activated Sphalerite to Improve the Separation Efficiency of Chalcopyrite and Sphalerite

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 253 ◽  
Author(s):  
Kosei Aikawa ◽  
Mayumi Ito ◽  
Atsuhiro Kusano ◽  
Ilhwan Park ◽  
Tatsuya Oki ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Zinc Sulfate ◽  
Separation Efficiency ◽  
Massive Sulfide ◽  
Surface Cleaning ◽  
Water Soluble ◽  
Ethylene Diamine ◽  
Sulfide Ores ◽  
Seafloor Massive Sulfide

The purpose of this study is to propose the flotation procedure of seafloor massive sulfide (SMS) ores to separate chalcopyrite and galena as froth and sphalerite, pyrite, and other gangue minerals as tailings, which is currently facing difficulties due to the presence of water-soluble compounds. The obtained SMS ore sample contains CuFeS2, ZnS, FeS2, SiO2, and BaSO4 in addition to PbS and PbSO4 as Pb minerals. Soluble compounds releasing Pb, Zn2+, Pb2+, and Fe2+/3+ are also contained. When anglesite co-exists, lead activation of sphalerite occurred, and thus sphalerite was recovered together with chalcopyrite as froth. To remove soluble compounds (e.g., anglesite) that have detrimental effects on the separation efficiency of chalcopyrite and sphalerite, surface cleaning pretreatment using ethylene diamine tetra acetic acid (EDTA) was applied before flotation. Although most of anglesite were removed and the recovery of chalcopyrite was improved from 19% to 81% at 20 g/t potassium amyl xanthate (KAX) after EDTA washing, the floatability of sphalerite was not suppressed. When zinc sulfate was used as a depressant for sphalerite after EDTA washing, the separation efficiency of chalcopyrite and sphalerite was improved due to deactivation of lead-activated sphalerite by zinc sulfate. The proposed flotation procedure of SMS ores—a combination of surface cleaning with EDTA to remove anglesite and the depression of lead-activated sphalerite by using zinc sulfate—could achieve the highest separation efficiency of chalcopyrite and sphalerite; that is, at 200 g/t KAX, the recoveries of chalcopyrite and sphalerite were 86% and 17%, respectively.

Waste Rejection on Seafloor by Hydrocyclone for Economic Seafloor Massive Sulfide Mining

2016 ◽  
Author(s):  
Yosuke Takeda ◽  
Tetsuo Yamazaki ◽  
Rei Arai ◽  
Naoki Nakatani
Keyword(s):  
Specific Gravity ◽  
Separation Efficiency ◽  
Massive Sulfide ◽  
Exclusive Economic Zones ◽  
Waste Separation ◽  
Economic Zones ◽  
Sea Area ◽  
Seafloor Massive Sulfide ◽  
High Possibility ◽  
Disposal Cost

Many seafloor massive sulfide (SMS) deposits have been discovered in Japan’s exclusive economic zones (EEZ). They have some useful metals and are expected to become future metal resources. In Japan, because of an expensive waste disposal cost, it seems to be difficult to realize the SMS mining. Adding a function of primary waste separation from metal-rich parts of SMS ore on seafloor by a hyrocyclone is proposed to overcome the problem. The water flow structure in a model hydrocyclone is observed in the study at first. Secondly, the performance of separation using differences in specific gravities of particles by the hydrocyclone is experimentally examined. Finally, the application of hydrocyclone in the actual sea area is examined. The result shows that 67% of larger specific gravity are collected and 67% of smaller one are rejected. From the separation efficiency, the hydrocyclone method is recognized to have a high possibility of application in the actual sea area.

scholarly journals The Combined Effects of Magnesium Oxide and Inulin on Intestinal Microbiota and Cecal Short-Chain Fatty Acids

Nutrients ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 152
Author(s):  
Kanako Omori ◽  
Hiroki Miyakawa ◽  
Aya Watanabe ◽  
Yuki Nakayama ◽  
Yijin Lyu ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Dietary Fiber ◽  
Magnesium Oxide ◽  
Acid Concentration ◽  
Short Chain Fatty Acids ◽  
Water Soluble ◽  
Short Chain ◽  
Acetic Acid Concentration ◽  
Chain Fatty Acids

Constipation is a common condition that occurs in many people worldwide. While magnesium oxide (MgO) is often used as the first-line drug for chronic constipation in Japan, dietary fiber intake is also recommended. Dietary fiber is fermented by microbiota to produce short-chain fatty acids (SCFAs). SCFAs are involved in regulating systemic physiological functions and circadian rhythm. We examined the effect of combining MgO and the water-soluble dietary fiber, inulin, on cecal SCFA concentration and microbiota in mice. We also examined the MgO administration timing effect on cecal SCFAs. The cecal SCFA concentrations were measured by gas chromatography, and the microbiota was determined using next-generation sequencing. Inulin intake decreased cecal pH and increased cecal SCFA concentrations while combining MgO increased the cecal pH lowered by inulin and decreased the cecal SCFA concentrations elevated by inulin. When inulin and MgO were combined, significant changes in the microbiota composition were observed compared with inulin alone. The MgO effect on the cecal acetic acid concentration was less when administered at ZT12 than at ZT0. In conclusion, this study suggests that MgO affects cecal SCFA and microbiota during inulin feeding, and the effect on acetic acid concentration is time-dependent.

Economic Seafloor Massive Sulfide Mining by Japan’s Model

2016 ◽  
Author(s):  
Tetsuo Yamazaki ◽  
Yosuke Takeda ◽  
Rei Arai ◽  
Naoki Nakatani
Keyword(s):  
Papua New Guinea ◽  
Waste Disposal ◽  
Mining Operation ◽  
Massive Sulfide ◽  
Sea Surface ◽  
Flexible Link ◽  
Private Companies ◽  
Mining Site ◽  
Seafloor Massive Sulfide ◽  
Disposal Cost

Because of the higher Au, Ag, and Cu contents, seafloor massive sulfides (SMS) have received much attention as future commercial mining targets by private companies and nations. One of them, Solwara 1 Project in Papua New Guinea (PNG), is scheduled to start the commercial mining operation from 2018. Because the mining site is inter-island area and almost no cost is necessary for the waste disposal in PNG, the economy of the mining is expected very well. In contrast with this, because all the SMS distribution sites in Japan locate outer ocean areas and the waste disposal cost on land in Japan is very expensive, the economy of SMS mining in Japan is quite negative. In order to overcome the problems, a self-standing riser with flexible link to the sea surface platform and a primary ore separation on the seafloor prior to the ore lift-up are proposed. The improved SMS mining concept named Japan’s model is examined.

scholarly journals Synthesis of Water-Soluble 7-O-Carboxymethyl-Genistein

2017 ◽  
Vol 41 (3) ◽  
pp. 183-185
Author(s):  
Zhiling Cao ◽  
Qiao Wu ◽  
Jing Cheng ◽  
Dandan Zhu ◽  
Wengqi Teng ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Sodium Salt ◽  
Water Solubility ◽  
Clinical Chemistry ◽  
Water Soluble ◽  
Aqueous Acetic Acid ◽  
Carboxylate Group ◽  
Target Compound ◽  
Catalysed Reaction

A three-step synthesis from genistein of the water-soluble sodium salt of 7-O-carboxymethyl-genistein is described. Base-catalysed reaction of genistein with t-butyl bromoacetate gave 7-O-(carbo-t-butoxy)methyl-genistein, which was hydrolysed by aqueous acetic acid to 7-O-carboxymethyl-genistein and neutralised (NaHCO3) to give the target compound. The carboxylate group enhanced the water-solubility of genistein more than a thousand-fold and the new derivate will be useful as a candidate compound in pharmacological and clinical chemistry studies of isoflavones.

scholarly journals Chemical Mass Balance, Depositional Efficiency, and Rates of Formation of Seafloor Massive Sulfide Deposits

2020 ◽  
Author(s):  
John Jamieson ◽  
Dennis Sanchez Mora ◽  
Ben Peterkin ◽  
Thibaut Barreyre ◽  
Javier Escartin ◽  
...  
Keyword(s):  
Mass Balance ◽  
Massive Sulfide ◽  
Chemical Mass Balance ◽  
Sulfide Deposits ◽  
Massive Sulfide Deposits ◽  
Seafloor Massive Sulfide

scholarly journals Subseafloor Alteration of a Modern Mafic-Volcaniclastic Hosted Seafloor Massive Sulfide Deposit

2020 ◽  
Author(s):  
Melissa. O Anderson ◽  
Mark Hannington ◽  
Timothy McConachy ◽  
John Jamieson ◽  
Thor Hansteen ◽  
...  
Keyword(s):  
Massive Sulfide ◽  
Sulfide Deposit ◽  
Massive Sulfide Deposit ◽  
Seafloor Massive Sulfide
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