Cent Copper Research Articles

Kitwe black mountain - Is Zambia realising the true value from it?

Nkana slag dump (The Black Mountain) in Kitwe, Zambia, has existed since 1931 when the copper smelter was commissioned. This 20 million tonnes of smelter slag contains about 0.34 per cent - 4.5 per cent cobalt and average 1.2 per cent copper. When Zambia Consolidated Copper Mines Limited was privatised, the slag dump was purchased by Anglo Vaal Mining (90% shareholding) who built a smelter in Chambishi in 2000 to recover the cobalt and copper in the slag. The smelter operations closed in 2006 and the slag dump was later sold to Nkana Alloy and Smelting Company Limited. Various small scale illegal miners (locally called Jerabos) started illegally reclaiming the slag and selling to Chinese buyers operating small scale mineral processing plants. In the recent past, the government surrendered its 10 per cent shareholding of the slag dump to Chapamo Minerals Processing Company owned by the small scale local community (Jerabos). The substandard technologies being used by these small scale plants yield very low recoveries of about 50-60 per cent for both cobalt and copper, thus discarding huge quantities of valuable cobalt and copper which could be recovered if appropriate technologies were applied. This potential revenue to the nation in taxes is being lost. These small scale plants have not invested in appropriate advanced technology which can yield above 90 per cent recoveries because of their quest to make quick and easy money. The serious safety shortcomings at the slag dump have resulted in unnecessary loss of lives. The recent incident on 21 June, 2018 claimed 11 lives. There is need to study the physical structure of the slag dump to provide clear understanding of the safety precautions to be taken while reclaiming the material. There is, therefore, an opportunity to increase recoveries of the cobalt and copper by applying appropriate advanced technologies to process the slag. This will result in improved revenue, thus realizing the true value.

Identification of chilli (Capsicum Annuum L.) cultivars based on chemical tests and Sds-page of total soluble proteins

Identification of chilli cultivar is prime importance to ensuring seed quality during seed production, certification and quality control. Fifteen cultivars were subjected to different biochemical tests Viz., phenol test, modified phenol test with FeSO4 and CuSO4, analysis of soluble seed proteins by SDS-PAGE. No single varieties were so distinct in case of phenol colour reaction, while it helped to group the cultivars. Based on modified phenol text with ferrous sulphates 1per cent (FeSO4) and 0.5 per cent copper sulphate (CuSO4) helped in further classification of cultivars. The cultivars Gouribidanur Local and Phule Jyothi showed unique bands at 14 (Rm: 0.624) and 2 (0.191) level of band. All the cultivars were distinct among each other showing SDS-PAGE as efficient method in chilli cultivar identification.

Transitioning to nontoxic antifouling paints

Purpose – The purpose of this paper is to reduce the amount of copper in antifouling paints by using eugenol as an additive. Biofouling leads to deterioration of any submerged material. The most widespread method for control is the application of cuprous oxide antifouling paints which are toxic. First of all, the paper describes the effect of eugenol on larvae of Balanus amphitrite (fouling organism) under laboratory conditions and then the preparation, application and performance of different types of antifouling paints in field trials. Design/methodology/approach – Three types of soluble matrix antifouling paints were prepared with different pigments. The first one containing 16 per cent v/v copper, the second with 1.6 per cent copper and the third with 1.6 per cent copper + 2 per cent eugenol. Findings – After 12 months of immersion in Mar del Plata harbour paints containing 1.6 per cent copper + eugenol and 16 per cent copper were the most effective. Although these formulations showed a similar performance, copper + eugenol-based paint contains 90 per cent lesser copper than a traditional copper-based formulation. Originality/value – The use of antifouling paints with copper + eugenol combination as pigment is a promising alternative due to its performance, low cost and reduction in copper leaching to environment.

Tribological characteristics at running‐in of repaired tractor engines using friction modifiers

PurposeThe purpose of this paper is to determine and compare the tribological characteristics (weight wear and friction moment) of a friction couple C45/C330 at running‐in with motor oil SAE 30 and different friction modifiers of copper oleate and zinc oleate.Design/methodology/approachFriction couples are tested using the model “roller‐sector” and they are lubricated with oil SAE 30 and two other samples of SAE 30 containing 0.6 per cent copper oleate and 0.6 per cent zinc oleate, respectively. Graphic dependencies are drawn for the weight wear of the sectors, rollers and couples; as well as for the running‐in moment, the friction moments at the end of the loading and at the end of the test.FindingsThe weight wear, running‐in moment and friction moments are evaluated for friction with SAE 30 as reference and oils containing copper oleate and zinc oleate as friction modifiers. The best performing material is the oil with zinc oleate.Originality/valueFrom a practical point of view this paper offers a new idea about a friction modifier – zinc oleate. Data for tribological characteristics and suitable concentration in the oil composition are given in the paper.

English

The influence of fullerene additives on the combustion behaviour of cyclotrimethylene trinitramine/ammonium perchlorate composite modified double-base (RDX/AP-CMDB) propellants are investigated by thermogravimetricdifferential thermogravimetric (TG-DTG) analysis, burning rate tests, and scanning electron microscopy observations. The difference between lead salicylate (F-Pb) and bismuth citrate acid (CP-Bi) as combustion modifiers has also been examined. TG-DTG investigations show that the addition of all additives advanced and accelerated the evaporation of nitroglycerin (NG). The addition of Extracted Fullerene Soot (EFS), C60 and carbon black (CB) additives obviously accelerated the liquid phase decomposition of NG. Also, the solid phasedecomposition of nitrocellulose (NC) and the liquid phase decomposition of RDX were accelerated by 0.5 per cent Fullerene Soot (FS)/2.5 per cent CP-Bi/0.5 per cent copper adipic acid (J-Cu) composite catalyst. The addition of all composite catalysts promoted the decomposition of ammonium perchlorate (AP) except 0.5 per cent EFS/2.5 per cent CP-Bi/0.5 per cent J-Cu composite catalysts. It is well known that there exists dark zone in the flame structure of RDX-CMDB propellant, but in our observation, the dark zone vanished with the addition of 10 per cent AP to the forenamed propellant. The burning rates were increased at low pressure but reduced at high pressure by all catalysts except 0.5 per cent EFS/2.5 per cent CP-Bi/0.5 per cent J-Cu and 0.5 per cent C60/2.5 per cent CP-Bi/0.5 per cent J-Cu which reduced the burning rates at every tested pressure. The pressure exponents of tested propellants were reduced by 0.5 per cent FS/2.5 per cent CP-Bi/0.5 per cent J-Cu with a factor of 17 per cent . The quenched surface observations significantly differed with the additions of diverse composite catalysts, which were consistent with the burning rate results.Defence Science Journal, 2009, 59(3), pp.284-293, DOI:http://dx.doi.org/10.14429/dsj.59.1522

Synthesis of Corrosion-resistant Nanocrystalline Nickle-copper Alloy Coatings by Pulse-plating Technique

Bright and smooth nanocrystalline Monel-type Ni-Cu alloy gets deposited from complex citrate electrolyte by pulse electrolysis. Transmission electron microscopy studies have revealed that the deposited Ni-Cu alloy was nanocrystalline in nature and it comprised a two-phase (fcc+Ll,) mixture. The presence of twins could be seen in the nanocrystals. The Ni-Cu alloys prepared by pulse electrolysis were finer grained (- 2.5-28.5 nm) than those deposited by direct current method. Nelson-Riley function has been used to calculate the lattice parameters for both the pulse current-plated and direct current-plated alloys from x-ray diffraction analysis. The microhardness values for pulse current-plated alloys were higher than for the direct currentplated alloys. The internal stresses of both the pulse current-deposited and the direct currentdeposited alloys have also been measured; the values were lower for pulse current-plated alloys. Potentiodynamic polarisation studies were carried out in aerated and deaerated neutral 3.0 Wt per cent NaCl solution and instantaneous corrosion current density of the plated alloy was determined and compared with the Monel-400 alloy. It was found that nanocrystalline pulse current-N,-35 8 Wt p;r cent copper alloy uxh~bited lower instantaneous value of corros~on current densirv than that of soeclrnens with direct current method and Monel-400 allov The d~ssolut~on ~ ~~~~-~ behaviour ofthe deposited nanocrystalline material was found to be more like general corrosion rather than localised corrosion as in the case of Monel-400 alloy.

Britain's First Brass

Stamps on the blade of a sword from the Thames, originally considered to be Anglo-Saxon, now place the sword stylistically in the La Tène II period (late third to early second century BC). X-ray fluorescence tests have shown that the gold-coloured foil covering the stamps consists of 80 per cent copper and 20 per cent zinc, this being the formula for brass. The sword therefore represents the earliest known use of brass in Britain.

Microgravimetry on the high temperature oxidation of short range ordered crytals of near Au 2CU 3 composition

For gold + copper alloys of composition near 60 atom per cent copper the process of oxidation of copper to copper (I) oxide has been studied by microgravimetry in ultrahigh vacuum over the 775-885 K temperature range and the 5 μTorr to 2 mTorr oxygen pressure range for (100) surfaces. For an approximately constant oxide coverage a linear rate equitation applies and near linear pressure dependence was found.

Recherche d'un modele pour l'evolution de la limite elastique d'un alliage AlCu 4% a l'etat θ′

This article examines the evolution of the elastic limit of an aluminium alloy with 4 weight per cent copper, in the θ′ state. Various treatments allow the distribution and the geometrical characteristics of the precipitates to be changed. Among the proposed models, of “cellular” or “Lamellar” types, we show that only a lamellar model accounts for elastic limit changes in every studied state. In this model we have to consider clusters of θ′-precipitates of the same family, with an average interval h ̄ . To describe the change R E in elastic limit associated with precipitation, we establish the relation ΔR E = ΔR E 0 + α h ̄ −1 2 . The precipitates spacing seems to determine alone the change in elastic limit, even if clusters have a very small extent and contain only a few precipitates.

Nitric oxide reduction with hydrogen on copper-nickel and chromium-nickel catalysts

The reduction of NO with H 2 on copper-nickel and chromium-nickel catalysts has been investigated. Both CuNi and CrNi catalysts were prepared by impregnation on Al 2O 3 pellets. Dry-pressed catalysts, CrNi with Al 2O 3 powder, were formed with several catalysts containing the NiCr 2O 4 spinel. A pressed nickel oxide catalyst was highly active for the reduction of NO while impregnated nickel oxide was much less active. Copper oxide and chromium oxide were relatively inactive. Addition of small amounts of copper to impregnated nickel oxide improved the activity of the latter catalyst, but above about 24 atomic per cent copper, activity decreased with increase in copper content. The activity of the pressed chromium-nickel catalysts increased with increase in nickel content. Production of NH 3 maximized at intermediate Ni content for the impregnated CuNi catalysts, and, in general, decreased with increase in Ni content for the impregnated CrNi catalysts and increased with Ni content for the pressed CrNi catalysts.

ChemInform Abstract: SOLID‐STATE IONICS, HIGH‐CONDUCTIVITY SOLID COPPER ION CONDUCTORS, N,N′‐DIALKYL (OR DIHYDRO)‐TRIETHYLENEDIAMINE DIHALIDE‐COPPER(I) HALIDE DOUBLE SALTS

New solid electrolytes with high copper ion conductivity at ambient temperature have been found in the system N,N'‐dialkyl (or dihydro)‐triethylenediamine dihalide‐copper(I) halide in the composition range of 94–80 mole per cent (m/o) copper(I) halide. For example, the solid‐state reaction product between copper(I) bromide 94 m/o and N,N'‐dimethyl‐triethylenediamine dibromide 6 m/o exhibited the conductivity of 0.035 (ohm‐cm)−1 at 20°C, which was essentially ionic. X‐ray diffraction investigations indicated that these new solid electrolytes are unique and not the mixtures of their constituents.

The phosphorus burn and its specific treatment (a biochemical, histological, electron microscopy and radioactive study)

Yellow phosphorus is known to cause a severe specific burn, which may result in death even when a relatively small area (12–15 per cent) of the body surface is affected. Biochemical studies and both light and electron microscopy as well as radioactive phosphorus study indicate primary renal damage followed by functional alterations, diffuse liver changes and severe aberrations in the blood and urine composition of experimental animals with phosphorus burns. The early death is more likely to be caused by primary renal alterations and cardiac standstill from potassium intoxication rather than by hypovolaemic shock and septicaemia. A suspension of 5 per cent sodium bicarbonate plus 1 per cent hydroxyethyl-cellulose plus 2 per cent copper sulphate was shown to fulfil the requirements of a satisfactory antidote.

Catalysis in Nickel Electroless Plating

The kinetics of the metal deposition from electroless plating baths has been studied. In addition, transition metal doped nickel electroless plating baths have been formulated which exhibit increased rates of metal deposition. Among all dopants examined, copper proved to be most effective. Addition of 10–20 mole per cent copper to a nickel‐dimethylamineborane electroless plating bath leads to a considerable increase in the rate of metal deposition. This increase is due to the deposition of Ni‐Cu alloys of a significantly improved catalytic activity in comparison with pure nickel. X‐ray photoelectron spectroscopy has been employed to demonstrate the autocatalytic nature of the nickel deposition process. It is proposed that this improvement arises because the presence of copper leads to the promotion of weak chemisorption of hydrogen on the catalytic surface.

Solid‐State Ionics: High‐Conductivity Solid Copper Ion Conductors: N,N′‐Dialkyl (or Dihydro)‐Triethylenediamine Dihalide‐Copper(I) Halide Double Salts

New solid electrolytes with high copper ion conductivity at ambient temperature have been found in the system N,N′‐dialkyl (or dihydro)‐triethylenediamine dihalide‐copper(I) halide in the composition range of 94–80 mole per cent (m/o) copper(I) halide. For example, the solid‐state reaction product between copper(I) bromide 94 m/o and N,N′‐dimethyl‐triethylenediamine dibromide 6 m/o exhibited the conductivity of 0.035 (ohm‐cm)−1 at 20°C, which was essentially ionic. X‐ray diffraction investigations indicated that these new solid electrolytes are unique and not the mixtures of their constituents.

Thermodynamic considerations of copper smelting

AbstractCombining the knowledge of the phase relations with thermodynamic calculations, the basic problems in copper smelting are discussed on the Cu-Fe-S-O-SiO2 system in terms of sulphur-oxygen chemical potential diagrams. During the matte smelting stage, the variation in the activities of Fe3O4 and Cu2O is found to be small, even though the matte is oxidized up to 70 per cent copper. However, when white metal of 70 per cent copper is oxidized to 80 per cent copper matte coexisting with molten copper, drastic variations in such activities, are observed. On the basis of these facts, reasonable explanations are given for the smelting principles involved in both the conventional and newly-developed continuous smelting processes. Dissolution of copper oxide and sulphide, and behaviour of impurities are also elucidated thermodynamically. Resume L'auteur traite du smeltage du cuivre en termes des diagrammes de potentiel chimique soufre-oxygene et des diagrammes de phase du systeme Cu-Fe-S-O-SiO2. Pendant l' e...

Phosphorus burns: The antidote: A new approach

Summary Two sets of experiments were carried out in an attempt to find a simple, efficient antidote for phosphorus burns. It was realised that the use of a 5 per cent solution of copper sulphate was highly toxic. A solution of 5 per cent sodium bicarbonate + 1 per cent hydroxi-ethyl-cellulose + 3 per cent copper sulphate fulfils all criteria outlined in our introduction. Lauryl sulphate when added to the solution in order to decrease surface tension of the phosphorus granules, completes the neutralisation process of the burning phosphorus.

A Staining Technique to Demonstrate Erythrocyte Refractile Bodies in Cat Blood

SUMMARY Erythrocyte refractile (ER) bodies in feline blood can be readily recognized in thin dry unfixed smears stained by the myeloperoxidase staining procedure of Sato and Sekiya. A staining technique to demonstrate ER bodies was developed combining a brief exposure to 0 · 5 per cent copper sulphate solution and the Wright–Leishman staining procedure. The technique clearly reveals ER bodies and produces a permanent preparation. The smear is also suitable for a differential leucocyte count and examination of morphologic features of leucocytes.

A Portion of the System Fe-S-O between 900 and 1080 C and its Application to Sulfide Ore Magmas

The portion of the Fe–S–O system including pyrrbotite, wüsite, magnetite, and iron has been studied between 900 and 1080 °C by modifed silica-tube techniques. At 900 °C, tie lines extend from pyrrhotite containing between 63.53 and 62.8±0.2 wt. per cent Fe to wüstite solid solution and form pyrrhotite containing between 62.8 and 60.0 wt. per cent Fe to magnetite. A ternary eutectic, troilite-wüstite-iron-liquid occurs at 915±2 °C. A ternary invariant point, where pyrrhotite (composition 62.8±0.2 wt. per cent Fe)+wüstite ⇌ magnetite+liquid occurs at 934 °C. Pyrrohotite composition strongly influences the temperature of thee magnetite-pyrrhotite solidus. Magnetite-pyrrhotite assemblages begin to melt at 934 °C when the pyrrhotite contains 62.8 wt. lper cent Fe, at 1010 °C when it contains 62.5 wt. per cent Fe, at 1030 °C when it contains 62.0 wt. per cent Fe, and at 1050 °C when it contains 60.5 wt. per cent Fe. Craig & Naldrett (1967) have shown that up to 20 wt. per cent nickel substituting for iron in pyrrhotite solid solution on a weight per cent basis has little effect on magnetite-pyrrhotite solidus temperature and that up to 2 wt. per cent copper substituting in a sunukar way lowers the solidus less than 20 °C. By redetermining the solidus in the presence of H2O at 2 kb total pressure Naldrett & Ricahrdson (1967) have show that, within experimental accuracy (± 10 °C), water has no effect on melting temperature. since natural iron-sulfide magmas rarely crystallize pyrrhotites containing more than 62.5 wt. per cent total metal, the temperature range of from 1010 to 1050 °C determined in this study is probably within 20 °C of the minimum temperature of introduction of a large number of magnatic sulfide ores. Comparison of the melting temperatures of ores with those of the rocks with which they are associated suggest that crystallization under different water pressures is responsible for the presence of sulfides disseminated as rounded ‘buck-shot’ type spherules in some rocks ans as an interstittial filling in others. The composition of an iron sufide-oxide ore magma settling from its associated silicate magma is controlled by the sulfur and oxygen fugacities of the silicate magma at the moment when equilibration between the two ceases. In the case of large bodies of massive sulfide ore, equilibration probably ceased when the ore settled out of its host; the sulfide to magnetite ratio of such ore will depen on how far below its liquidus temperature the sulfide-oxide liquid was at the moment of separation. In the case of sulfide-rich droplets remaining disseminated throughtot the plutonic host rock, equilibration probably continued to subsolidus temperatures; under these conditions it is possible that the droplets may lose all of their oxygen to the host rock. Finally in the case of sulfife-rich droplets trapped within rapidly cooled volcanic rocks complete re-equilibration was probably prevented by the rate of cooling and consequently these droplets retain much of their original oxygen as magnetite.

Copper distribution in Octopus vulgaris lam. Hepatopancreas

1. 1. The copper content of Octopus vulgaris Lamarck hepatopancreas was found to be 4880 ± 2549 p.p.m./dry wt. 2. 2. Fifty per cent of the total hepatopancreas copper was extracted after homogenization in 1 M sucrose. 3. 3. Twelve per cent of the soluble copper was separated after 24,500 g centrifugation. 4. 4. The extracted copper was entirely in the cuprous state. 5. 5. The molecular weight distribution of the copper binding substances was studied by gel chromatography. 6. 6. Ninety-six per cent of the copper was bound to substances with a molecular weight higher than 1500 and 50–60 per cent to substances with a molecular weight between 5000 and 30,000, while only 10 per cent was bound to substances with a molecular weight greater than 70, 000.

The Background to the Weldable Al‐Zn‐Mg Alloys

THE alloys under consideration contain only zinc and magnesium as the major alloying additions. The total alloy content varies between 5 and 7 per cent whereas the high strength aircraft alloys have a total content of 8 to 10 per cent and may also contain up to 2 per cent of copper. A wide range of mechanical properties can be obtained with the weldable alloys and some of these properties closely approach those of the aircraft alloys. Problems associated with weld metal cracking and heat affected zone recovery arc normally severe with age hardening aluminium alloys but are greatly attenuated with the weldable alloys.