scholarly journals Selection of recycled water electrochemical conditioning parameters for preparation of diamond-bearing kimberlite for froth separation

2021 ◽  
Vol 6 (3) ◽  
pp. 170-180
Author(s):  
G. P. Dvoichenkova ◽  
V. V. Morozov ◽  
E. L. Chanturia ◽  
E. G. Kovalenko
Keyword(s):  
Thermal Treatment ◽  
Process Intensification ◽  
Surface Hydrophobicity ◽  
Electrochemical Treatment ◽  
Surface Cleaning ◽  
Diamond Surface ◽  
Maximum Effect ◽  
Processing Plant ◽  
Recycled Water ◽  
Diamond Crystals

The main reason of decreasing diamond recovery through froth separation is their surface hydrophilization by hypergene minerals and technogenic films, crystallized from the supersaturated aqueous phase, fixed on the surface structurally or by adhesion. Various types of physical actions, including thermal and ultrasonic treatment of the initial feed of froth separation, are recommended to increase the diamond-bearing kimberlite beneficiation process performance, providing cleaning of the surface of diamonds due to destruction of their accretions with rock minerals and removal of film hydrophilizing coatings from the surface of diamond crystals. A sample of kimberlite material with a given content of diamonds of 1.5–2 mm in size was used as a subject of research in the process of froth separation. The results of thermodynamic calculations and experimental research have substantiated the necessity of using electrochemical conditioning of recycled water for increasing the efficiency of diamond surface cleaning in froth separation operation when using the process of thermal treatment of initial ore feed. The use of diaphragmless electrochemical conditioning of recycled water increases the efficiency of thermochemical dissolution of hydrophilizing compounds on the surface of diamonds through reducing the concentration of calcium and carbonate ions as well as through shifting the medium pH to 6.1–6.5. The measurements of the limiting wetting angle showed that the maximum effect of increasing the diamond surface hydrophobicity was achieved when heat and electrochemical treatment were used together. Laboratory studies showed the possibility of increasing flotation diamond extraction from 65.7 to 91.4 % through application of electrochemical conditioning of recycled water. The optimum parameters of diaphragmless electrochemical treatment of recycled water of the froth separation cycle in conditions of application of pulp heat treatment: current density of 175–200 A/m2 and power consumption of 1.2–1.5 kWh/m3. Tests carried out at processing plant No. 3 of the Mirny GOK (Mining and Processing Complex) (Mirny, Yakutiya) showed that the application of the developed froth separation process intensification method with the use of thermal treatment of pulp and electrochemical diaphragmless treatment of recycled water allowed increasing the recovery of diamonds of +0.5–2 mm size by 4.9–5.1 %.

scholarly journals Intensification of diamond purification from hydrophilic minerals in foam separation process

2021 ◽  
Vol 57 (1) ◽  
pp. 19-26
Author(s):  
G.P. Dvoichenkova ◽  
V.V. Morozov ◽  
E.G. Kovalenko ◽  
Y.A. Podkamenny
Keyword(s):  
Thermal Treatment ◽  
Separation Process ◽  
Combined Method ◽  
Technological Research ◽  
Foam Separation ◽  
Diamond Crystals

The reason for diamond loss in foam separation process consists in the fact that the diamond crystals fed to the foam separation are coated with hydroxides and carbonates. A combined method to restore the diamond hydrophobicity through thermal and electrochemical destruction of the mineral coat was proposed. This method provides for the conditioning stage in the foam separation process to enable decreasing the amount of the minerals coating diamonds surface from 3 to 10 times. Technological research showed that using products of diaphragm less electrolysis of recirculating water, with the thermal treatment of the foam separation feed enables increasing the recovery of diamonds in the foam separation concentrate from 76.5% to 83.7%.

scholarly journals Designs of new operating copper processing plants: process types, equipment selection, industry trends

2021 ◽  
pp. 44-52
Author(s):  
V. F. Baranov
Keyword(s):  
Large Scale ◽  
High Capacity ◽  
Process Intensification ◽  
Processing Plant ◽  
Advantages And Disadvantages ◽  
Sulphide Ores ◽  
Flotation Cells ◽  
Ore Preparation ◽  
Processing Plants ◽  
Technical Solutions

The article describes the largest operating processing plants for lowgrade copper sulphide ores of our time: 10 plants using the semi-autogenous grinding (SAG) technology and 10 plants using high-pressure grinding rolls (HPGR), with the output of 18 to 100 Mtpa. The unfavorable natural and economic factors are balanced by improved ore preparation and concentration technologies and high-capacity equipment units, combined with cost-saving layout solutions. The ore preparation sector is currently divided between the competing technologies of semi-autogenous grinding and HPGR. The article contains an overview of their advantages and disadvantages. The world’s largest monosection with the capacity of 55.5 Mtpa, that uses the SAG technology, is described. The role of the Drop Weght Test JKSimMet (A×b) parameter in the selection of the ore preparation method and the trend for using HPGR in the processing of strong ores are shown. Examples are provided for the consequences of an inadequate assessment of the feed strength in SAG-based plant designs. Examples of ore preparation process intensification through the use of HPGR in semi-autogenous grinding circuits are also given. The volume of impeller flotation cells installed has reached 600 m3. An overview of the two largest processing plants of our time with the output of 88 and 100 Mtpa of ore is presented. The innovative technical solutions of a newest low-capacity copper plant are highlighted. Based on the results of the overview, a future processing plant is predicted to use ∅12.8–13 m SAG mills, HPGRs with the roll diameter of 3 m, vertical VTM-7000 mills in ore grinding cycles, large fine screens, large-scale impeller flotation cells, and staged SFR and DFR flotation reactors.

scholarly journals Low-temperature Direct Bonding of Inp and Diamond Substrates Under Atmospheric Conditions

2021 ◽  
Author(s):  
Takashi Matsumae ◽  
Ryo Takigawa ◽  
Yuichi Kurashima ◽  
Hideki Takagi ◽  
Eiji Higurashi
Keyword(s):  
Low Temperature ◽  
Heat Dissipation ◽  
Surface Cleaning ◽  
Diamond Surface ◽  
Atmospheric Conditions ◽  
Low Temperature Annealing ◽  
Power Operations ◽  
Inp Substrate ◽  
Bonding Method ◽  
Inp Surface

Abstract An InP substrate was directly bonded on a diamond heat spreader for efficient heat dissipation. The InP surface activated by oxygen plasma and the diamond surface cleaned with an NH3/H2O2 mixture were contacted under atmospheric conditions. Subsequently, the InP/diamond specimen was annealed at 250 °C to form direct bonding. The InP and diamond substrates formed atomic bonds with a shear strength of 9.3 MPa through an amorphous intermediate layer with a thickness of 3 nm. As advanced thermal management can be provided by typical surface cleaning processes followed by low-temperature annealing, the proposed bonding method would facilitate next-generation InP devices, such as transistors for high-frequency and high-power operations.

Comparison of Surface Cleaning Processes for Diamond C(001)

1994 ◽  
Vol 339 ◽  
Author(s):  
Peter K. Baumann ◽  
T. P. Humphreys ◽  
R. J. Nemanich
Keyword(s):  
Chromic Acid ◽  
Surface Cleaning ◽  
Electrochemical Process ◽  
Diamond Surface ◽  
Chemical Cleaning ◽  
Cu Films ◽  
Force Microscopy ◽  
Atomic Force ◽  
Acid Etch ◽  
Semiconducting Diamond

ABSTRACTTwo wet chemical cleaning processes (a conventional chromic acid clean and an electrochemical etch) and a H-plasma exposure have been employed to clean natural type lib semiconducting diamond C(001) wafers. The effects of these processes on the diamond surface have been assessed and compared. As evidenced by Auger electron spectroscopy (AES), an oxygen free surface could be obtained following annealing to 900°C for the electrochemical process compared to 1050°C for the chromic acid etch. In addition, the technique of Atomic Force Microscopy (AFM) demonstrated the presence of oriented pits on the surface of samples electrochemically etched for long times at high currents. Furthermore, heteroepitaxial Cu films have been grown on the diamond substrates cleaned by a process as described above. By means of Ultraviolet Photoemission Spectroscopy (UPS) a Schottky barrier height of ΦB≊ 1.0 eV was measured. Furthermore, the presence a negative electron affinity (NEA) has been determined.

scholarly journals Low-temperature direct bonding of InP and diamond substrates under atmospheric conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takashi Matsumae ◽  
Ryo Takigawa ◽  
Yuichi Kurashima ◽  
Hideki Takagi ◽  
Eiji Higurashi
Keyword(s):  
Low Temperature ◽  
Heat Dissipation ◽  
Surface Cleaning ◽  
Diamond Surface ◽  
Atmospheric Conditions ◽  
Low Temperature Annealing ◽  
Power Operations ◽  
Inp Substrate ◽  
Bonding Method ◽  
Inp Surface

AbstractAn InP substrate was directly bonded on a diamond heat spreader for efficient heat dissipation. The InP surface activated by oxygen plasma and the diamond surface cleaned with an NH3/H2O2 mixture were contacted under atmospheric conditions. Subsequently, the InP/diamond specimen was annealed at 250 °C to form direct bonding. The InP and diamond substrates formed atomic bonds with a shear strength of 9.3 MPa through an amorphous intermediate layer with a thickness of 3 nm. As advanced thermal management can be provided by typical surface cleaning processes followed by low-temperature annealing, the proposed bonding method would facilitate next-generation InP devices, such as transistors for high-frequency and high-power operations.

Identity of Mesophilic Anaerobic Sporeformers Cultured from Recycled Cannery Cooling Water

1983 ◽  
Vol 46 (5) ◽  
pp. 400-402 ◽  
Author(s):  
PAUL J. THOMPSON ◽  
MARY A. GRIFFITH
Keyword(s):  
Food Processing ◽  
Cooling Water ◽  
Water Reservoir ◽  
Clostridium Butyricum ◽  
Processing Plant ◽  
Recycle Water ◽  
Recycled Water ◽  
Clostridium Species ◽  
Clostridium Sticklandii ◽  
Selection For

Chlorinated, recycled water for cooling of containers in still retorts was sampled over a 27-month period at one food processing plant. Of 274 samples taken, 28 contained mesophilic, anaerobic spores in numbers that ranged from 0.04–4.6/ml (MPN). Though all isolates were characterized as Clostridium species, 11% could not be matched with named species. Clostridium butyricum and Clostridium barati (synonyms: C. paraperfringens, C. perenne) comprised 55% of isolates. Excepting Clostridium sticklandii, which is neither proteolytic nor saccharolytic, all isolates were saccharolytic. This contrasted with the finding of both proteolytic and saccharolytic clostridial spores in the municipal water feeding the recycle water reservoir. An apparent selection for saccharolytic strains could not be explained on the basis of published resistance of anaerobic spores to free available chlorine.

scholarly journals Survival of Escherichia coli O157:H7 on Cattle Hides

2011 ◽  
Vol 77 (9) ◽  
pp. 3002-3008 ◽  
Author(s):  
Terrance M. Arthur ◽  
Xiangwu Nou ◽  
Norasak Kalchayanand ◽  
Joseph M. Bosilevac ◽  
Tommy Wheeler ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Intervention Strategies ◽  
Maximum Effect ◽  
Processing Plant ◽  
Escherichia Coli O157 ◽  
Content Type ◽  
E Coli ◽  
Time Of Application ◽  
Time Period ◽  
Contamination Events

ABSTRACTThe objective of this study was to determine the time period thatEscherichia coliO157:H7 survives on the hides of cattle. Extensive research has been conducted and is ongoing to identify and develop novel preharvest intervention strategies to reduce the presence ofE. coliO157:H7 on live cattle and subsequent transfer to processed carcasses. If a reduction ofE. coliO157:H7 levels in feces can be achieved through preharvest intervention, it is not known how long it would take for such reductions to be seen on the hide. In the study presented herein, three trials were conducted to followE. coliO157:H7 hide prevalence over time. For each trial, 36 animals were housed in individual stanchions to minimize or prevent hide contamination events. Through prevalence determination and isolate genotyping with pulsed-field gel electrophoresis, survival ofE. coliO157:H7 on the hides of live cattle was determined to be short lived, with an approximate duration of 9 days or less. The results of this study suggest that any preharvest interventions that are to be administered at the end of the finishing period will achieve maximum effect in reducingE. coliO157:H7 levels on cattle hides if given 9 days before the cattle are presented for processing. However, it should be noted that interventions reducing pathogen shedding would also contribute to decreasing hide contamination through lowering the contamination load of the processing plant lairage environment, regardless of the time of application.

scholarly journals Plasma Electrolyte Polishing of Titanium and Niobium Alloys in Low Concentrated Salt Solution Based Electrolyte

Mechanika ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 88-93
Author(s):  
Yuri ALIAKSEYEU ◽  
Algimantas BUBULIS ◽  
Vladimir MINCHENYA ◽  
Aleksandr KOROLYOV ◽  
Vladimir NISS ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Metal Removal ◽  
Electrochemical Treatment ◽  
Surface Cleaning ◽  
High Tech ◽  
Labor Costs ◽  
Electrochemical Polishing ◽  
Niobium Alloys ◽  
Plasma Electrolyte ◽  
Low Efficiency

Today, world enterprises specializing in the production of titanium and niobium alloy products and having modern high-tech equipment are still forced to use outdated, costly and environmentally unsafe methods of polishing and surface cleaning, based on electrochemical treatment in toxic solutions. The complex geometric shape of the processed products does not allow the use of mechanical polishing methods, due to high labor costs and low efficiency. These materials are difficult to process, and the processes of their polishing require the use of toxic electrolytes. An alternative to existing methods of electrochemical polishing is plasma electrolyte polishing in aqueous solutions of salts with a concentration of up to 5%. We have developed fundamentally new modes of plasma electrolyte polishing of products from titanium and niobium alloys using simple electrolytes based on an aqueous solution of fluoride salt, the use of which can significantly increase the surface quality class. The advantage of the plasma electrolyte polishing over classical electrochemical polishing is its safety due to the use of an electrolyte based on an aqueous solution of salt. The paper presents the results of an investigation of the characteristics and morphology of the surface after processing using the developed method. Modes that provide the maximum change in roughness with minimal metal removal were obtained.

scholarly journals MODIFICATION OF DIAMOND SURFACE DURING PHOTOLITHOGRAPHY, PLASMA-CHEMICAL CLEANING, AND MAGNETRON DEPOSITION

2020 ◽  
Vol 63 (11) ◽  
pp. 49-56
Author(s):  
Anton V. Golovanov ◽  
Nicolay V. Luparev ◽  
Boris P. Sorokin
Keyword(s):  
Surface Treatment ◽  
Surface Topography ◽  
Oxygen Plasma ◽  
Surface Cleaning ◽  
Aluminum Film ◽  
Diamond Surface ◽  
Plasma Cleaning ◽  
Plasma Chemical ◽  
Bias Power ◽  
Magnetron Deposition

An influence of the conventional planar technology of the semiconductor surface treatment operations (photolithography, plasma-chemical surface cleaning in radio frequency low-pressure oxygen discharge, and thin metal films growth) on monocrystalline diamond surface topography and roughness is investigated. It is preliminary shown that photolithography without the plasma cleaning and magnetron deposition of an aluminum film do not induce any diamond surface changes which could be found by the optical profilometry, electron and optical microscopy. However, as a result of the lithography some organic contaminants can decrease the adhesion of the aluminum film and have to remove from the surface. Further, the influence of the above-listed surface treatment operations separately and in combinations on the synthetic diamond surface is investigated. It is found that an even short oxygen plasma cleaning during 5 min with a low bias power of 20 W leads to etching the grooves on the diamond surface The depth of the etching grooves varies by more than an order of magnitude in different experiments (0.3 - 19 nm), and by 10-20% within the same substrate under the influence of the poorly controlled external factors. Also, oxygen plasma treatment changes its secondary electron emission coefficient. Deposition of aluminum film after plasma cleaning does not induce noticeable changes in the diamond surface topography. The quality of diamond surface polishing (in “hard” of “soft” direction), the diamond’s type (IIa or IIb) as well as producing method (HPHT or homoepitaxial CVD) do not affect the result of grooves formation.

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