我国铜矿资源形势及其可持续供应对策

通过对我国铜矿资源的供需形势进行分析,得知其安全供应问题已经处于高度紧张状态,年进口量在不断增加,对外依存度在不断升级,进而成为制约我国铜工业健康发展的"瓶颈".为了保障我国铜矿资源可持续安全供应与促进铜工业的健康发展,就其可持续供应的对策问题进行了探讨.     

A novel extractant for removal of hazardous metals from preservative-treated wood waste

The purpose of this study was to develop a one-step metal extraction process that would effectively remove hazardous elements from wood powder or chips of western hemlock [Tsuga heterophylla (Raf.) Sarg.] treated with chromated copper arsenate (CCA) preservative. In addition, we tested this method for wood treated with other copper-based preservatives such as ammoniacal copper quaternary (ACQ) and copper, boron, and azole (CuAz). A bioxalate solution consisting of 0.125 M oxalic acid adjusted to pH 3.2 with sodium hydroxide was tested for its ability to extract chromium, copper, and arsenic from wood treated with CCA and copper from ACQ, CuAz, or a mixture of CCA-, ACQ-, and CuAz-treated wood in single step. The extraction proceeded efficiently with 6 h of treatment, and was insensitive to the differences in chemical characteristics, including solubility of individual elements. After 6 h of treatment, approximately 90% of chromium, copper, and arsenic were effectively removed from wood treated with CCA or a mixture of CCA, ACQ, and CuAz and 90% of copper from ACQ- and CuAz-treated wood. These results demonstrate that the solvent extraction technique using pH-adjusted bioxalate solution with sodium hydroxide is a promising method for pollution minimization by various types of wastes contaminated with heavy metals and arsenic.     

Characteristics of a bioxalate chelating extraction process for removal of chromium,copper and arsenic from treated wood

The disposal of wood waste treated with chromated copper arsenate (CCA) is a problem in many countries. We have proposed a novel chelating extraction technique for CCA-treated wood using bioxalate, a solution of oxalic acid containing sufficient sodium hydroxide to adjust the pH to 3.2, which is an effective way to obtain an extraction efficiency of 90% for chromium, copper, and arsenic. The purpose of the present study was to investigate the characteristics of bioxalate extraction of CCA-treated wood. Extractions of CCA-treated western hemlock chips with solutions of bioxalate, oxalic acid, and sodium hydroxide were carried out. The use of bioxalate was confirmed as the most effective extraction technique for chromium, copper and arsenic, with an efficiency of 90%. Extraction with simple oxalic acid was ineffective for copper (less than 40% extraction efficiency), but effective for chromium and arsenic, with 90% efficiency. Sodium hydroxide showed a similar tendency, being ineffective for chromium and copper (less than 20% extraction efficiency), but relatively effective for arsenic (around 70–80% efficiency). We also discovered an interesting phenomenon whereby the addition of sodium hydroxide to a simple oxalic acid solution during the oxalic acid extraction progress resulted in dramatically increased extraction efficiency for copper, chromium and arsenic, up to 90%. Although oxalic acid was ineffective for copper extraction, the addition of sodium hydroxide during the oxalic acid extraction process rendered it effective.     

Tracking effective measures for closed-loop recycling of automobile steel in China

Closed-loop recycling of steel in automobiles is particularly difficult because of the low tolerance for impurities and the use of composites of various types of steel products. Technologies that reduce impurities or increase impurity tolerance must be developed and introduced to the steel recycling system at the appropriate time. This study evaluated the feasibility of closed-loop recycling in the automobile industry in China. Material pinch analysis combined with dynamic modeling of the life cycle of steel sheets used in the manufacture of automobiles was employed to estimate the amount of steel sheet scrap available for closed-loop recycling and the amount of copper contamination in the scrap. The results indicate that by 2050, more than half of the old steel sheet scrap generated annually will have to be down-cycled because of its high copper contamination. However, scenario analyses of three types of technologies for mitigating the problem of copper contamination showed the potential for increasing the amount of old scrap used in closed-loop recycling. In particular, improving copper tolerance in the steel production process could be effective both now and in 2050.     

CuSO4 treatment of nuisance algal blooms in drinking water reservoirs

Since the turn of the century, copper sulfate has been used extensively as an algicide to control nuisance algal blooms in drinking water reservoirs Recent experimental results have shown that the toxicity of copper to algae is determined by the activity of ionic copper, and not the total copper concentration The sensitivity of algae to ionic copper has been found to vary considerably for different algal species Chemical processes such as precipitation, complexation by dissolved organic substances, and adsorption by suspended material can be important in controlling the chemical speciation of copper added to drinking water reservoirs The copper sulfate dosage required for effective treatment of a reservoir is shown to depend on water chemistry and the copper sensitivity of nuisance algal species By evaluating copper chemistry and copper sensitivity of nuisance algal species it may be possible to obtain effective treatment with lower copper sulfate dosages in some reservoirs     

INPUTS OF COPPER‐BASED CROP PROTECTANTS TO COASTAL CREEKS FROM PASTICULTURE RUNOFF1

ABSTRACT: Inputs of copper‐based crop protectants from tomato fields grown under plastic mulch agriculture (plasticulture) to an estuarine creek were investigated. Copper was measured in runoff from diverse land‐uses including conventional agriculture, plasticulture, residences, and natural areas. Water column and sediment copper concentrations were measured in plasticulture and control (nonagriculture) watersheds. Copper concentrations in plasticulture‐impacted creeks exceeded background levels episodically. High concentrations occurred during or immediately after runoff‐producing rains. Concentrations of 263 μg/L total copper and 126 μg/L dissolved copper were measured in a tidal creek affected by plasticulture; concentrations exceeded the shellfish LC₅₀ values and the water quality criteria of 2.9 μg/L dissolved copper. Control watersheds indicated background water column levels of ≤ 4 μg/L dissolved copper with similar copper levels during periods with and without rain. The copper concentrations in tomato plasticulture field runoff itself contained up to 238 μg/L dissolved copper. Copper concentrations in runoff from other land‐uses were less than 5 μg/L dissolved copper. Creek sediment samples adjacent to a plasticulture field contained significantly higher copper concentrations than sediments taken from nonplasticulture watersheds.     

Copper cycle in China and its entropy analysis

Copper cycle analysis approaches have been broadly investigated for sustainable development of copper industry in China. There are four stages in the life cycle of copper products, including mining & processing, fabrication & manufacture, use and reclamation. The 2005 copper cycle in China, analyzed by copper-flow diagram of the copper products life cycle with time factor, indicates that the copper ore index and copper scrap index were 0.78 t/t and 0.063 t/t, respectively; and copper resource efficiency was 1.3 t/t. To ascertain the degree of both aggregating and dispersing of the copper in the life cycle of copper products, the substance flow analysis with the index of entropy and the calculating method of entropy was presented. The variation of entropy along copper cycle was calculated based on the analysis of the life cycle of copper products in China in 2005. The entropies at the five nodes along copper cycle were 0.26, 0.046, 0.24, 0.60 and 0.25, respectively. The variation ratio of relative entropy in the whole system was −2.9%, which showed the copper-contained materials were congregated after the whole products life cycle. The same method was also applied to the variation of entropy along copper products life cycle in China in 2002. The discussion was focused on the results of these two years. The values of entropy at the five nodes along copper cycle in 2005 were all lower than those in 2002. The entropy at the five nodes along copper products life cycle in 2005 was extracted through two scenes under different technical indices, including scene one: 0.26, 0.032, 0.23, 0.60 and 0.17, respectively; and scene two: 0.26, 0.023, 0.23, 0.60 and 0.096, respectively. The values of entropy are effectively reduced, especially from the fourth to the fifth node, which is the obsolete copper products reclaiming stage.     

Viability of processing in copper-mining areas : An economic analysis

Although copper is exported mainly in the form of semi-refined or refined copper, exports of copper in the form of ores and concentrates increased their share of world copper exports in the 1970s. These exports mainly originate from copper-mining areas with limited access to the inputs required for stages subsequent to mining. This article surveys the options open to copper-producing countries to increase their revenue from copper, and concludes that changes in the composition of exports to favour the export of more processed forms of copper would require substantial changes in the economic structure of a country. Trade barriers are not felt to constitute a substantial obstacle to world trade in refined or semi-fabricated copper.     

EVALUATION OF COPPER ACCUMULATION IN PART OF THE CALIFORNIA AQUEDUCT1

ABSTRACT: Copper sulfate has been used extensively in the California Aqueduct to control phytoplankton and the alga Cladophora. Since 1969 more than 250,000 pounds of copper sulfate has been added to a part of the aqueduct. Although copper sulfate is effective in controlling algae, copper tends to accumulate in the system in which it is applied. Samples of water, biota including plants, clams, and snails, as well as sediment were analyzed for copper. Results of these analyses showed that copper concentrations in the water, with three exceptions, were less than 10 micrograms per litre. Samples of plant tissue showed a 198 percent increase in copper concentration in the treated reach of the aqueduct, and clam tissue showed a 68 percent increase. Snails in the treated reach had 77 percent more copper than in the untreated reach whereas copper concentrations in the sediment doubled. None of the concentrations found are considered to be harmful to the biota.     

LONG-TERM COPPER PRODUCTION OPTIONS OF THE DEVELOPING COUNTRIES

After petroleum, copper is the most important foreign exchange earner of the developing countries. Supply of copper from developing nations is heavily concentrated in six countries. The production strategies of these countries can, therefore, have a significant impact on world copper trends as well as on their own copper earnings. The author, former Chief Economist of CIPEC, examines the implications of two alternative growth paths for long-term copper production in these countries.     

Interparticle diffusion and thermodynamic modeling studies for the removal of heavy metals using mixed adsorbents in industrial effluents

Pollution of water, air, and soil by industrial effluents is a major problem nowadays. A variety of contaminants are too responsible for changing the physicochemical properties of the receiving body. There are practical treatment solutions available to clean up contaminants from various resources. The term “adsorption” refers to one of them. The purpose of the research work is to remove heavy metals from industrial effluent. Mixed adsorbents prepared from activated charcoal and bone charcoals were used to remove the copper and cadmium ions. The experiment carried out in a batch operation and modeling of these data for intraparticle diffusion and thermodynamic calculations were reported in this research work. At optimum operating condition pH 6; metal ion concentration 50 mg/L; dose 5 g/L; agitation 180 rpm and temperature 40°C maximum 99.41% copper ions and 88.12% cadmium ion removal was achieved. Cadmium ions were well fitted in the thermodynamic model compared to copper ions, as demonstrated by the higher correlation coefficient R² (0.9824) value. Intra particle diffusion demonstrated that film diffusion was a rate-limiting step at the start of the reaction, while microporous intraparticle diffusion was the rate-determining phase later on. A Fourier transformation infrared spectroscopy, X-ray diffraction, and scanning electron micrography analysis confirmed the suitability of mixed adsorbents for the removal of cadmium and copper metal ions.     

State ownership and the price sensitivity of supply: The case of the copper mining industry

The paper attempts to verify the claim that output in state owned copper mining industries is less sensitive to price changes than in private ones. This is done by comparing the price sensitivity of copper supply in countries with state and privately owned copper industries and by testing whether nationalization leads to changes in the supply behaviour of copper mining industries. It is found that low supply elasticities and nationalizations are both the result of a country's high dependence on copper and are not themselves causally related.     

Modelling future copper ore grade decline based on a detailed assessment of copper resources and mining

The concept of “peak oil” has been explored and debated extensively within the literature. However there has been comparatively little research examining the concept of “peak minerals”, particularly in-depth analyses for individual metals. This paper presents scenarios for mined copper production based upon a detailed assessment of global copper resources and historic mine production. Scenarios for production from major copper deposit types and from individual countries or regions were developed using the Geologic Resources Supply-Demand Model (GeRS-DeMo). These scenarios were extended using cumulative grade-tonnage data, derived from our resource database, to produce estimates of potential rates of copper ore grade decline.The scenarios indicate that there are sufficient identified copper resources to grow mined copper production for at least the next twenty years. The future rate of ore grade decline may be less than has historically been the case, as mined grades are approaching the average resource grade and there is still significant copper endowment in high grade ore bodies. Despite increasing demand for copper as the developing world experiences economic growth, the economic and environmental impacts associated with increased production rates and declining ore grades (particularly those relating to energy consumption, water consumption and greenhouse gas emissions) will present barriers to the continued expansion of the industry. For these reasons peak mined copper production may well be realised during this century.     

Optimization of the electrocoagulation process for the removal of copper, lead and cadmium in natural waters and simulated wastewater

Chemical, electrochemical and flow variables were optimized to examine the effectiveness of the electrocoagulation process for the removal of copper, lead and cadmium. The electrochemical process, which uses electrodes of commercial laminate steel, was applied to simulated wastewater containing 12 mg dm(-3) of copper, 4 mg dm(-3) of lead and 4 mg dm(-3) of cadmium. The optimum conditions for the process were identified as pH=7, flow rate=6.3 cm(3) min(-1) and a current density between 31 and 54 A m(-2). When the electrode geometric area and time of electrolysis reached critical values, the copper removal reached a maximum value of 80%. A linear relationship was identified between the current density and the mass of generated sludge. In addition, a linear relationship was found between specific energy consumption and current density. The results of this investigation provide important data for the development of an industrial-scale electrolytic reactor.     

再生铜行业环境管理问题的若干思考和建议

随着我国铜冶炼(原生铜和再生铜)行业对含铜二次资源需求量的增加,集废旧资源回收、拆解和分选、二次资源出售、铜再生利用于一体的产业链逐渐发展壮大起来。然而高能耗、高污染、低质量、低产出的特点在再生铜行业依然存在,环境监管政策和标准也不健全不完善。随着人们对美丽生态环境诉求的增加,必须加强有色金属行业的环境管理。本文对再生铜行业发展和环境管理做了一些思考,特别是对再生铜行业环境管理存在的问题进行了分析,并针对问题提出了几点政策性建议,以期为我国再生铜产业的环境友好发展和环境监管提供借鉴。     

New mine capacity from yet-to-be found copper deposits

The copper industry in the USA is declining, but exploration for copper has been particularly promising in western Montana. The potential copper mine capacity of the area was estimated by using an interdisciplinary geological-economical assessment technique that categorizes deposits on the basis of development probability. Development probability is quantified and aggregated into potential new mine supply curves, which summarize resource potential of the region. The results suggest that copper resources in Montana and elsewhere are potentially large and that these resources probably will be mined at higher copper prices. This mineral assessment technique increases the usefulness of traditional methods for planners and policy makers.     

Secondary copper recovery

Following a brief review of the economics of copper recycling, the technical details of secondary copper recovery are given, from classification and sampling of scrap through to the production of blister copper ready for electrolytic refining.     

MODELING FRAMEWORK FOR MANAGING COPPER RUNOFF IN URBAN WATERSHEDS1

ABSTRACT: A modeling framework was developed for managing copper runoff in urban watersheds that incorporates water quality characterization, watershed land use areas, hydrologic data, a statistical simulator, a biotic ligand binding model to characterize acute toxicity, and a statistical method for setting a watershed specific copper loading. The modeling framework is driven by export coefficients derived from water quality parameters and hydrologic inputs measured in an urban watershed's storm water system. This framework was applied to a watershed containing a copper roof built in 1992. A series of simulations was run to predict the change in receiving stream water chemistry caused by roof aging and to determine the maximum copper loading (at the 99 percent confidence level) a watershed could accept without causing acute toxicity in the receiving stream. Forecasting the amount of copper flux responsible for exceeding the assimilation capacity of a watershed can be directly related to maximum copper loadings responsible for causing toxicity in the receiving streams. The framework developed in this study can be used to evaluate copper utilization in urban watersheds.     

Managing the Use of Copper-Based Antifouling Paints

Copper is the biocide of choice for present-day antifouling (AF) paints. It is also a major source of copper loading in to the marine environment and, as such, might cause local copper levels to exceed water quality criteria. The present study is multifaceted and looks into the overall impact of copper-based AF paints on copper concentrations along a 64-km stretch of the Indian River Lagoon and at Port Canaveral, Florida. This preliminary study is one of the first to outline issues and present background evidence on the current status of copper and copper-based AF usage in Florida and to address the need for management. Previous measurements of copper levels in these waters show a history of copper contamination close to marinas, boatyards, and at Port Canaveral that often exceed state and federal water quality standards. Further, we estimate that the total annual copper input into the Indian River Lagoon is between 1.7 tons/year (sailboats) and 2.1 tons/year (powerboats) from boats in 14 marinas. We estimate the copper input into Port Canaveral to be about 1.4 tons/year from seven cruise ships. A brief survey of marina operators and boat owners revealed attitudes and practices associated with AF paint usage that ranged from excellent to inferior. Management recommendations are made for a proactive approach to improving AF paint selection and application, assessing the environmental status of copper, and redefining existing management practices for sustainable AF paint usage and environmental health.     

MOBILITY AND AQUATIC TOXICITY OF COPPER IN AN URBAN WATERSHED1

ABSTRACT: Abundant use of copper based products has resulted in increased violation of copper water quality criteria in runoff from urban storm water systems. The objectives of this work were to understand the mobility and toxicity of copper in an urban watershed and to apportion the amount of copper entering the freshwater receiving stream from different urban land covers using a mass balance approach. Sixteen rainfall events collected from the University of Connecticut study watershed between August 1998 and September 2000 were analyzed to assess copper flux in an urban storm water system. Mean flow weighted dissolved copper concentrations observed in the study for copper based architectural material runoff, pervious area runoff, impervious area runoff, and in the receiving stream were 1210 ± 840, 9 ± 3, 8 ± 2, and 14 ± 7 μg/L, respectively. Mean dissolved copper concentrations in the receiving stream exceeded Connecticut's water quality criteria. Despite exceeding the dissolved concentration based criteria, cupric ion concentrations at the system outlet remained below 0.05 μg/L for all storms analyzed, and no acute toxicity (using Daphnia pulex as the test organism) was measured in samples collected from the stream.