Non-renewable mineral resources

The natural resources of the earth's crust upon which industry depends for metals, non-metallics and most of its energy, come from deposits in the crust carrying six to over 1000 times the normal content of the required elements. Such deposits have formed over such long periods of geological time that they must be regarded as non-renewable within the span of existence of the human species. These facts are briefly illustrated by reference to the cases of iron, copper, aluminium, titanium, magnesium, lead, zinc, flourine and the fossil fuels. The possibilities of exploiting much lower concentrations when considered in relation to the exponential rise in demand, lead to the conclusion that the scope is limited unless very cheap energy becomes available.     

Statistical estimation of global mineral resources

The concentration of minerals in the crust forms a continuous distribution between the higher grade reserves mined as ore and the low-grade background mineralization of waste rock. A lognormal distribution could be generated by a mineralization process compatible with the theory of plate tectonics. A computer model of this process is demonstrated. The discussion is extended to other base metals and in particular to the distribution of reduced carbon. Neither base metals nor fossil fuels are ever likely to be exhausted, but they may rise in cost and be superseded by cheaper substitutes.     

Tracking changes in the global impacts of metal concentrate acquisition for the metals industry in Finland

This article considers the environmental impacts and the governance framework of the domestic and international supply of iron, zinc, copper and nickel concentrates smelted and refined in Finland. The metals industry in the country is heavily dependent on imported concentrates, and the research is thus focused on defining the level of impacts related to mining and mineral processing abroad, and the change in the impacts between 2000 and 2010. The estimations of environmental impacts are based on waste minerals and CO_2eq emissions, and the quality of governance in the set of indicators measuring different aspects of governance. The total amount of waste minerals and CO_2eq emissions related to metal concentrates decreased over the ten-year period. At the same time, the quality of governance improved in all concentrate groups except nickel. Ore grade, mine type and transportation distance appear to be the most influential factors on environmental impacts. The results suggest that the country of origin can have a noticeable effect on the environmental impacts and the quality of governance of the mining and processing of metal concentrates.     

Imperatives for attracting investment and technology in the Indian mining sector

In India, the mineral resource inventory and the production of a large number of important minerals have registered significant increases during the last few decades. Yet the country continues to be a net importer of many high value and scarce minerals and metals, like gold, diamond, and several base metals. Exploration and development of the resources of these minerals are technology- and capital-intensive. To bring technology and capital through foreign direct investment (FDI) into the Indian mineral sector, it is imperative to lay stress on: accurate resource estimation and categorization, as well as realistic projection of the true values; rationalization of legislative measures based on R&D studies and reorganization of the implementation machinery; conducive tax structure; notification of acts and rules applicable to offshore mineral resources; time-frames for granting licences and leases; encouragement to labor productivity by rationalizing labor laws; reforms in the monetary system to increase market competitiveness of Indian minerals; and judicial reforms. FDI in the Indian mineral sector is important to firm up the knowledge-base of mineral resources and their optimum exploitation.     

Mobilization of trace metals and inorganic compounds during resuspension of anoxic sediments from Trepangier Bayou, Louisiana

The release of trace metals (Mn, Ni, Co, Cu, Zn, Pb, and Cd) and inorganic compounds (As) from initially anoxic Trepangier Bayou sediments, Louisiana and the sources of the released metals were investigated. After 1 to 2 d aeration, significant amounts of trace metals (Mn, Zn, Cd, Ni, and Co) were released to the aqueous phase with increased acidity, primarily due to the oxidation of acid-volatile sulfide and ferrous iron and iron sulfide minerals. The addition of a bacterial inhibitor, NaN,, to the Trepangier sediment during resuspension inhibited metal release, suggesting that microbial catalysis can regulate metal mobilization during sediment resuspension. In a well buffered system, oxidation of iron sulfides alone did not appear to induce trace metal release. Moreover, when Trepangier sediment was resuspended in anoxic conditions at neutral pH, <1% of the trace metal content was released, whereas a significant release of metal was observed under acidic anoxic conditions. Although oxidation of iron sulfide minerals is an essential prerequisite for the release of Zn, Co, Cd, and Ni, carbonates and oxides also play a role. The trace metals and inorganic compounds investigated could be classified into three groups according to their release characteristics: (i) Mn, Zn, Cd, Ni, and Co; (ii) Fe, Pb, and As; and (iii) Cu. The groupings appeared to depend on the sources of compounds and their relative affinity, after oxidation, to iron oxyhydroxides or organic matter.     

Global competition for strategic mineral supplies

The USA's dependence on imported sources of strategic minerals has grown substantially since the second world war, while its ability to protect the sealanes critical to foreign supplies has deteriorated. Domestic production has been severely hampered by a lack of access to mining on public lands, and by excessive environmental regulations. No major purchases have been made for the strategic stockpile in 20 years. Concern has been growing in Western Europe and in Japan about secure supplies of strategic minerals. Being even more dependent on foreign sources of supply than the USA, some of these countries have recently initiated their own strategic stockpilling programmes. The USSR, long an important exporter of metals, appears to have changed its mineral trade policy, and has sharply reduced exports while entering the market as an importer of a number of key metals. These developments foreshadow growing competition for world supplies of strategic minerals.     

World supply of non fuel minerals: The geological constraints

The feasibility of trebling production of essential non fuel minerals by AD 2000 is considered in relation to a rise in world population to 6 billion (10⁹). Adequate supplies of common bulk ‘minerals’ like sand and gravel, brick clays and saline deposits, are assured, but mining will place additional strains on local environments. Ores of the metals that can be regarded as available in sufficient quantities include iron, aluminium, chromium, titanium, copper and nickel, and possibly also lead and zinc. In spite of the geological constraints imposed by complexity of geometry and genesis, reasoned resource estimates are possible for these, but they may not be feasible for rarer necessary minerals, such as those of the precious metals, mercury, niobium and flourine. The extraction of even the commonest of the non fuel minerals is conditioned by the availability of abundant energy at economic prices – this should be regarded as the critical factor.     

Metal scarcity and sustainability,analyzing the necessity to reduce the extraction of scarce metals

There is debate whether or not further growth of metal extraction from the earth's crust will be sustainable in connection with geologic scarcity. Will future generations possibly face a depletion of specific metals? We study whether, for which metals and to what extent the extraction rate would need to be reduced in order to be sustainable. To do so, we propose an operational definition for the sustainable extraction rate of metals. We have divided 42 metals in 4 groups according to their geologic scarcity. Applying the proposed sustainability definition to the 17 scarcest metals, shows that for almost all considered metals the global consumption of primary resources needs to be reduced to stay within sustainable limits as defined in our analysis. The 8 geologically scarcest metals are antimony, bismuth, boron, copper, gold, molybdenum, rhenium and zinc.     

Long-term perspectives on world metal use—a system-dynamics model

In this paper, a system dynamics model is described, which simulates long-term trends in the production and consumption of metals (i.e. iron/steel and an aggregate of metals of medium abundance) in relation to impacts such as ore-grade decline, capital and energy requirements and waste flows. This metal model can be of assistance in exploring the issue of sustainability of metal resource use. Application of the model to historical trends shows it to be fairly capable of reproducing the long-term trends in the 1900–1990 period, among others on the basis of two intensity of use curves applied to 13 world regions. For future trends, a set of perspective-based long-term scenarios has been constructed that represent the major paradigms in resource use. These scenarios highlight some of the uncertain factors in the relation between economic growth, metal resource exploitation and use, and energy and environmental consequences. They also indicate that apparently similar metal flows in society may be the result of quite different and sometimes contrary assumptions on metal demand, production patterns and resource base characteristics. Such analyses contribute to a more open and transparent discussion on the issue at hand by adding quantitative explications to qualitative views.     

Resources policies in Australia

Developments in Australia's resource industries in recent years have raised policy issues not previously encountered, and their consideration has been superimposed onto traditional policies affecting resource production and use. This review of Australia's policies on resources - here meaning minerals and energy policies - looks at the objectives of these policies and their interrelationships. It considers issues such as management, development objectives, investment, taxation, environment and processing, and likely future developments.     

The role of the Australian minerals industry in world mineral supplies

Australia is one of the world's main producers and exporters of both fuel and non-fuel minerals. Among the main commodities produced for export are bauxite/alumina, iron ore, and nickel—Australia is also an increasingly important source of supply of black coal, especially for Japan, and is a significant producer and exporter of a number of base metals. Resources are adequate to support a substantial expansion of both non-oil fuels and other minerals. The potential for growth, both in terms of specific commodities and in the overall role of Australia in the world mineral industry, will depend to a very large extent on the cost competitiveness of Australian mining and on continuing inflow of capital.     

Enhancing phytoextraction: the effect of chemical soil manipulation on mobility, plant accumulation, and leaching of heavy metals

For heavy metal-contaminated agricultural land, low-cost, plant-based phytoextraction measures can be a key element for a new land management strategy. When agents are applied into the soil, the solubility of heavy metals and their subsequent accumulation by plants can be increased, and, therefore, phytoextraction enhanced. An overview is given of the state of the art of enhancing heavy metal solubility in soils, increasing the heavy metal accumulation of several high-biomass-yielding and metal-tolerant plants, and the effect of these measures on the risk of heavy metal leaching. Several organic as well as inorganic agents can effectively and specifically increase solubility and, therefore, accumulation of heavy metals by several plant species. Crops like willow (Salix viminalis L.), Indian mustard [Brassica juncea (L.) Czern.], corn (Zea mays L.), and sunflower (Helianthus annuus L.) show high tolerance to heavy metals and are, therefore, to a certain extent able to use the surpluses that originate from soil manipulation. More than 100-fold increases of lead concentrations in the biomass of crops were reported, when ethylenediaminetetraacetic acid (EDTA) was applied to contaminated soils. Uranium concentrations could be strongly increased when citric acid was applied. Cadmium and zinc concentrations could be enhanced by inorganic agents like elemental sulfur or ammonium sulfate. However, leaching of heavy metals due to increased mobility in soils cannot be excluded. Thus, implementation on the field scale must consider measures to minimize leaching. So, the application of more than 1 g EDTA kg(-1) becomes inefficient as lead concentration in crops is not enhanced and leaching rate increases. Moreover, for large-scale applications, agricultural measures as placement of agents, dosage splitting, the kind and amount of agents applied, and the soil properties are important factors governing plant growth, heavy metal concentrations, and leaching rates. Effective prevention of leaching, breeding of new plant material, and use of the contaminated biomass (e.g., as biofuels) will be crucial for the acceptance and the economic breakthrough of enhanced phytoextraction.     

What caused the slack demand for metals after 1974?

This paper explores the general reasons for the sudden decline in the growth of world metal demand which began after 1974 and continues to impact the metal industries. For all of the eight metals studied, except aluminium, the dominant cause of this atrophy in demand is the stagnation in total world economic growth, which has caused reduced demand for all goods and services. In addition, consumer preferences have shifted away from metal-intensive goods, further reducing the need for metals. However, materials substitutions and manufacturing technologies have continued to evolve towards lower use of metal in each product at much the same rate after 1974 as before. Therefore, these aspects do not explain the sudden shortfall after 1974 except in the case of aluminium which experienced a dramatic change during the energy crisis years.     

Life cycle inventory of recycling portable nickel–cadmium batteries

In this study, the environmental impact of recycling portable nickel–cadmium (NiCd) batteries in Sweden is evaluated. A life cycle assessment approach was used to identify life cycle activities with significant impact, the influence of different recycling rates and different time boundaries for emissions of landfilled metals. Excluding the user phase of the battery, 65% of the primary energy is used in the manufacture of batteries while 32% is used in the production of raw materials. Metal emissions from batteries to water originate (96–98%) from landfilling and incineration. The transportation distance for the collection of batteries has no significant influence on energy use and emissions. Batteries manufactured with recycled nickel and cadmium instead of virgin metals have 16% lower primary energy use. Recycled cadmium and nickel metal require 46 and 75% less primary energy, respectively, compared with extraction and refining of virgin metal. Considering an infinite time perspective, the potential metal emissions are 300–400 times greater than during the initial 100 years. From an environmental perspective, the optimum recycling rate for NiCd batteries tends to be close to 100%. It may be difficult to introduce effective incitements to increase the battery collection rate. Cadmium should be used in products that are likely to be collected at the end of their life, otherwise collection and subsequent safe storage in concentrated form seems to offer the best solution to avoid dissipative losses.     

Adsorption of 2,4-dichlorophenoxyacetic acid by an Andosol

To identify the important soil components involved in 2,4-dichlorophenoxyacetic acid (2,4-D) adsorption on Andosols, 2,4-D adsorption on a surface horizon of an Andosol was compared with that on hydrogen peroxide (H2O2)-treated (soil organic matter [SOM] was removed), acid-oxalate (OX)-treated (active metal hydroxides and SOM were removed), and dithionite-citrate-bicarbonate (DCB)-treated (free and active metal [hydr]oxides and SOM were removed) soil samples at equilibrium pHs ranging from 4 to 8. Although the untreated soil contained a large amount of organic C (71.9 g kg-1), removal of SOM had little effect on 2,4-D adsorption. Active surface hydroxyls, which were attached to the active and free metal (hydr)oxides and metal SOM complexes, were identified as the most important soil functional group for 2,4-D adsorption. The dominant mechanism of the 2,4-D adsorption was a ligand exchange reaction in which the carboxylic group of 2,4-D displaced the active surface hydroxyl associated with metals and formed a strong coordination bond between the 2,4-D molecule and soil solid phase. The ligand exchange reaction reasonably accounted for the selective adsorption of 2,4-D over Cl-, competitive adsorption of phosphate over 2,4-D, reduction in plant-growth-inhibitory activity of soil-adsorbed 2,4-D, and the high 2,4-D adsorption ability of Andosols. Although a humic acid purified from the soil did not adsorb 2,4-D, the presence of the humic acid increased 2,4-D adsorption on Al and Fe, probably by inhibiting the hydrolysis and polymerization of Al and Fe resulting in the preservation of available adsorption sites on these metals. The adsorption behavior of 2,4-D on soils could be a good index for predicting the adsorption behavior of other organic acids in soils.     

Natural materials for treatment of industrial effluents: comparative study of the retention of Cd, Zn and Co by calcite and hydroxyapatite. Part I: batch experiments

This work explores the heavy metal retention capacity of materials developed from minerals that are abundant in nature, with low cost and minimum environmental impact. To accomplish this objective we have: (a) characterized commercial samples of calcite (CA) and hydroxyapatite (HAP)--including their surface properties (BET area, electrophoretic mobility, SEM, and X-ray energy dispersive spectroscopy); and, (b) qualified and quantified the interaction of Cd, Zn and Co with calcite (CaCO3) and hydroxyapatite [Ca5(PO4)3OH] through batch experiments, in a range of metal concentrations (4Zn>Co and Cd>Zn approximately Co, respectively. Retention increased with pCa and pH and could be modeled by: (a) a non-ideal ion exchange mechanism (Me/Ca) for the adsorption of Cd, Zn and Co onto CA; and, (b) a mechanism of non-ideal ion exchange and specific adsorption (Me/Ca and identical with PO4O-Me) in the case of HAP. The pH dependence is indirect in CA and is related to its solubility changes (pCa increases with pH, and so does sorption of Cd, Zn and Co). Both materials, HAP and CA, can be used for heavy metal retention. The former has better performance for water treatment due to its greater efficiency for the retention of Cd, Zn and Co (over two orders of magnitude per gram of material) and its lower solubility in a wide range of pH (6相似文献   

Resource conservation and pricing

The belief that forests, minerals, fisheries, and other exhaustible assets are being depleted at excessive rates in a free enterprise society has led to recurrent demands for the regulation of resource exploitation. Many have believed that further regulations are necessary — for example, the conservation movement accepted as basic tenents that most resources were too cheap, were wastefully exploited, and would become exhausted soon. This paper surveys several interrelated issues in resource depletion from an economist's perspective, in particular, whether the articles of faith of the conservation movement are borne out by economic theory and available empirical evidence. Are resources too cheap? Are they wastefully exploited? Will resources become exhausted prematurely? Are we neglecting the needs of future generations?     

烟气海水脱硫排水水质对周边海域的影响分析

从理论计算和国内外已投运工程的实际运行监测两方面,对海水脱硫排水水质进行了分析,结果表明在采用成熟工艺的前提下,海水脱硫的排水水质包括重金属等指标,全部可以达到我国海水三类标准,绝大部分指标满足海水一类标准,而且通过对国内外已经投运项目的长期监测,也未发现对周围海域的生态环境造成不利影响。