A cleaner production strategy for acid mine drainage prevention of waste rock:A porphyry copper case

An in-process technology approach is proposed to identify the source of acid mine drainage(AMD)generation and prevent its formation in a porphyry copper waste rock(WR).Adopting actions before stockpiling the WR enables the establishment of potential contaminants and predicts the more convenient method for AMD prevention.A WR sample was separated into size fractions,and the WR’s net acidgenerating potential was quantified using chemical and mineralogical characterization.The diameter of physical locking of sulfides(DPLS)was determined,and the fractions below the DPLS were desulfurized using flotation.Finally,the WR fractions and tailing from the flotation test were submitted to acid-base accounting and weathering tests to evaluate their acid-generating potential.Results show that the WR’s main sulfide mineral is pyrite,and the DPLS was defined as 850μm.A sulfide recovery of 91%was achieved using a combination of HydroFloat^(®)and Denver cells for a size fraction lower than DPLS.No grinding was conducted.The results show that size fractions greater than DPLS and the desulfurized WR are unlikely to produce AMD.The outcomes show that in-processing technology can be a more proactive approach and an effective tool for avoiding AMD in a porphyry copper WR.

From Less or No Waste Manufacturing and Cleaner Production to Recycle Economy -- A Review on the Theoretical Research and Practice of Ecological Enterprises in China

Based on systematical research on the conception evolution of ecological enterprise, theoretical and practical development of constructing ecological enterprise, the paper makes conclusion that ecological enter- prises are developing into a new stage in which governments are launching some pilot projects about construct- ing ecological enterprises. And after that, governments should make policies to spread construction of ecological enterprises, to construct ecological enterprises in legal system and conforming to the standard as soon as possibly. So that, the basic units of ecological economy that fit to the conditions of China will be set up.

Relationship between ecological economics and circular economy,eco-industry,cleaner production,and other relevant categories

Eco-industry, circular economy, cleaner production, industrial ecology or industrial ecosystem and other subjects are all categories related to sustainable developinent. This paper studies the relations and differences between the four categories and sustainable development as well as ecological economics. Circular economy, eco-industry, industrial ecosystem and cleaner production were put forward during the revolution in “end treatment pattern” of traditional industrial society. Industrial ecology, eco-industry and circular economy theory are three content expansions of cleaner production. Ecological economics is of instructive function theoretically and methodologically for circular economy, eco-industrial, cleaner production and industrial ecology. Circular economy theory is easier to be accepted, compared with ecological economics theory. And circular economy in nature is the complete application of ecological economics theory.

Study on the evaluation system for the cleaner production of the mine

It is important to establish the evaluation system of the cleaner production of the mining enterprise, which canprovide the technical support and guidance for the cleaner production evaluation and facilitating the promotion ofcleaner productive techniques so as to realize the integration of economic development and environmental protection.This paper, according to the characteristic of mining and Analytic Hierarchy Process (AHP), establishes the evaluationindex system, puts forward the overall quantitative evaluation method based on Fuzzy Mathematics and the experts’experience, and establishes the evaluation system of cleaner production. The main problems in cleaner production of themine are analyzed by calculation, and some countermeasures and suggestions are proposed.

Cleaner production for continuous digester processes based on hybrid Pareto genetic algorithm

Pulping production process produces a large amount of wastewater and pollutant emitted, which has become one of the main pollution sources in pulp and paper industry. To solve this problem, it is necessary to implement cleaner production by using modeling and optimization technology. This paper studies the modeling and multi\|objective genetic algorithms for continuous digester process. First, model is established, in which environmental pollution and saving energy factors are considered. Then hybrid genetic algorithm based on Pareto stratum\|niche count is designed for finding near\|Pareto or Pareto optimal solutions in the problem and a new genetic evaluation and selection mechanism is proposed. Finally using the real data from a pulp mill shows the results of computer simulation. Through comparing with the practical curve of digester,this method can reduce the pollutant effectively and increase the profit while keeping the pulp quality unchanged.

IMPLEMENTATION OF CLEANER PRODUCTION STRATEGIES TOWARDS A SUSTAINABLE CITY

Rapid urbanization and growing size of cities will have an increasing impact on the global environment in the 21st century. As an engine of urban development to drive economic growth and technological innovations, industry has moved its focus from controlling environmental hazards to stimulating sustainable industrial development throughout the entire product lifecycle. These process- and technology-driven innovations for industrial production are prerequisites for enhancement of urban environment and sustainable development of cities. In this review, problems of environment and resources scarcity associated with rapid urbanization are demonstrated. And, on the basis of expatiations on the concepts and policies of the cleaner production(CP) and other similar initiatives with the goal of preventing pollution at the source and of managing the raw material more efficiently, two different ways to link the practice of cleaner production in industrial sector with performance of urban environment are discussed in detail. Then, the introduction, practice and legislation of CP strategies in China are outlined, and possibility for China to develop CPC (Cleaner Practices for Cities) approaches in the demonstration cities is discussed. Finally, some suggestions on implementation of CPC strategies are put forward.

Design of policy mechanism to promote cleaner production in China

In order to promote cleaner production in China, a package of policy options was presented based on the identification of the barriers encountered in the CP demonstration project and the effectiveness and feasibility of policy options for the CP implementation were analyzed. Furthermore, the policy mechanism framework was given, which composes of compulsory, economic incentive, social pressure and supportive function. Finally, the implementation strategy of the policy mechanism, in which the emphasis will be changed from compulsory policy options towards economic and social pressure policy options, was proposed.

Can environmental regulations achieve both profitability and profit quality?A natural experiment based on the China Cleaner Production Standards

Numerous studies evaluated the effects of end-of-pipe control environmental regulations(EER).However,few scholars discussed the effects of process management environmental regulations(PER),such as the China Cleaner Production Standards(CCPS)implemented by the country's Ministry of Ecology and Environment.Using data on China's manufacturing enterprises,this paper adopts the CCPS policies as quasi-natural experiments and uses differences-in-differences(DID)methods to analyze their effects on enterprise profitability and profit quality,respectively.The results show that:first,the CCPS significantly improve both profitability and profit quality;that is,the implementation of the environmental regulation policy plays a significant role in improving enterprise profit rates and cash flows.Second,for the profitability mediator effects,the short-term Porter effect of CCPS is not significant but shows the opposite during the lag period and significantly reduces the management cost and wage levels,comprehensively promoting enterprise profitability.Third,for the profit quality meditator effects,environmental regulations improve the enterprises'cash flow by reducing management costs and increasing government subsidies;however,its effect on bank credit subsidies is not significant.Fourth,for the moderator effects,the environmental regulations'effect on enterprises profitability and profit quality depends on the strategic interaction among local governments,the scale and ownership of the enterprise,and regional differences.That is,the strategic interaction weakens the effect of environmental regulations on enterprise performance.Environmental regulations have a stronger influence on profitability and profit quality for large-scale,state-owned,and coastal enterprises.

Cleaner Production Assessment in Textile Industry

Cleaner Production focuses on environmental improvement with economic benefits. Based on the benefit assessment home and abroad, the assessment method and process in textile industry is discussed, including maneuverable indicator system, mathematics model. According to corresponding principles of Cleaner Production, representative problems are mentioned. With Analytic Hierarchy Process and Fuzzy Mathematics, some enterprise is collected to attain the economic, environmental and social benefit of Cleaner Production. The results show that Cleaner Production improves utilization efficiency of resources, energy sources even waste, and creates conditions of Sustainable Development in textile industry.

Level and potential of cleaner production in Baosteel's sintering process

It is necessary for the sintering process to carry out cleaner production, which is also of great significance to the iron and steel enterprises of a long-flow process. According to the cleaner production standard recently issued by China＇ s Ministry of Environmental Protection, the research detailed in this study has analyzed and estimated the level of cleaner production at Baosteel in the aspects of technical equipment, resource and energy utilization, product quality, emissions, recycling and environmental management, etc. The research also expatiated some effective measures with which cleaner production can be carried out in Baosteel＇s sintering process, and discovered some potential opportunities of cleaner production.

Research on Development Status and Countermeasures of Agricultural Cleaner Production

In the study,the connotation and objectives of agricultural cleaner production were introduced firstly,and then the development status of agricultural cleaner production in China was analyzed,and the problems existing in the development of agricultural cleaner production were pointed out.From the strategy of agricultural sustainable development,the necessity and feasibility of implementing agricultural cleaner production in China were discussed.Finally,some related countermeasures were put forward according to the problems existing in the development of agricultural cleaner production,so as to provide theoretical references for the realization of agricultural sustainable development in China.

Assessment of the implementation status of best available techniques for cleaner production in the textile industry

The draft Integrated Pollution Prevention and Control(IPPC)regulation mandates compliance with best available techniques(BATs)for textile manufacturers.A study in Turkish textile facilities,covering 56 units across four sub-sectors,assessed the status of 488 BATs through on-site visits and surveys.The aim was to gauge the sector’s adherence to BATs.The findings revealed that 37% of surveyed BATs were fully implemented,rising to 88% when considering potential future implementations.This suggests a strong industry inclination toward adopting BATs for cleaner production and competitiveness.The study highlighted significant BAT-related investments in the textile sector,driven by environmental concerns,regulations,customer demands,resource efficiency,competition,and cost-benefit considerations.However,the study results also indicated that there is still much work to do for the implementation of some BATs.It was found that 60 BATs had lower implementation ratios(IR:0%-43%).Lower IR values for these BATs are mainly due to factors like specificity,high costs,long payback periods,operational difficulties,limited expertise,space constraints,customer requirements,quality concerns,operational issues,and sector-specific challenges.The study recommends similar assessments in other European industrial sectors to evaluate compliance with mandatory BATs outlined in the Industrial Emissions Directive.The insights from this study on the Turkish textile sector can serve as a valuable guide for future evaluations.

Cleaner production of ammonium paratungstate by membrane electrolysis-precipitation of sodium tungstate solution

The production of ammonium paratungstate(APT) is riddled with the generation of wastewater,which causes environmental problems.To solve the problem of wastewater generation at source,a membrane electrolysis-NH3·H2O precipitation method,which prevents wastewater generation and recycles the reagents used in the process,was proposed and investigated in this study.The electrolysis process was investigated based on parameters such as initial cathodic and anodic NaOH concentrations,and current density.The results showed that an increase in current density and initial cathodic NaOH concentration and a decrease in the initial anodic NaOH concentration would enhance the separation of tungsten and sodium.The optimum condition was found at a current density of 666 A·m^(-2),initial anodic and cathodic NaOH concentrations of 69 g·L^(-1) and 40 g·L^(-1),with a current efficiency of 75.40%,and energy consumption for producing 1 ton of NaOH was 2184 kW·h.The precipitation process was investigated based on the acidic high W/Na molar ratio solution obtained by the electrolysis process with NH3·H2O as the precipitant.Parameters such as excessive coefficient,temperature,and W/Na molar ratio were studied.The result showed that the variation of excessive coefficient and solution temperature had an opposite effect on the purity of the APT,while an increase in the W/Na molar ratio would increase the product purity.The precipitation product obtained had a purity of 99.6% and was characterized using X-ray diffraction,inductively coupled plasma,and scanning electron microscopy.The methods proposed in this study could provide fundamental information for the design of a cleaner APT production process.

Technical measures to achieve a cleaner production mode for recycled paper mills

China’s paper production reached 79.8×10^(6) t in 2008 and ranked number one in the world.Because of its high consumption of water,energy and materials and its serious pollution,the present processes are not likely to be sustainable.An alternative,the closed Water Loop-Papermaking Integration(WLPI)method,is put forward in this paper.The WLPI method can be realized in a recycled paper mill by adding technologies and using recycled water.Many industrial case studies have shown that a large quantity of water,energy and materials can be saved,and the quantity of waste sludge and wastewater discharge was minimized by using the WLPI method.The design of the water reuse system,control of calcium hardness,water recycling and minimal waste sludge are discussed.Anaerobic technology plays an important role in the WLPI method to lower cost,energy use and waste.In the brown paper and coated white board production,zeroeffluent discharge can be realized.Fresh water consumption is only 1-2m^(3)·t^(-1).For the paper mills with deinking and bleaching processes,about 10 m^(3)·t^(-1) of fresh water and a similar amount of effluent discharge are needed.Power saving using anaerobic technology is 70%when recycled water is used in comparison with the conventional activated sludge process.Waste sludge can be decreased to about 5%of the initial process due to reuse of the waste sludge and the lower bio-sludge production of the anaerobic process.

Green chemistry of chromate cleaner production

Research topics and methods of green chemistry in chromate production are introduced in this paper. New original green chemical process of the heterogeneous reaction and separation system of liquid phase oxidation of chromite in molten salt of sodium hydroxide—one way separation in high concentration medium—metastable phase separation—carbonate recycle conversion has been developed. The green commercial process for comprehensive utilization of mineral resources—reactant recycle inside the process—zero emission was established.

Study on Cleaner Production Subsidies, Income Distribution Imbalance and Carbon Emissions Permit Reallocation Mechanism

The allocation mechanism for carbon emissions permit(CEP)is an institutional guarantee for advancing the development of China’s unified carbon trading market.The initial allocation of carbon quotas fails to solve new inequalities stemming from subsidizing cleaner production.This paper constructs a theoretical framework that describes China’s progressive decline in carbon intensity,calculates the equilibrium solution on the neoclassical saddle point path using the shooting method,and studies the income distribution imbalance caused by cleaner production subsidies and the reallocation mechanism of carbon emissions permit The main conclusion is that the incremental cleaner production subsidy policy meets the goal of maximizing welfare on the saddle point path,but it may lead to over-investment in the clean sector,thus causing the income distribution imbalance among entities.Further research suggests that the amount of carbon emissions permit acquired by the clean sector should be higher than the actual emissions in the trading market and that,as the cleaner support increases,the share of carbon emissions permit acquired by the sector should be constantly increased through reallocation mechanism.This helps achieve the Pareto improvement in all parties’economic benefi ts.

Sulfur resource recovery based on electrolytic manganese residue calcination and manganese oxide ore desulfurization for the clean production of electrolytic manganese

An environmentally friendly and resource-conserving route to the clean production of electrolytic manganese was developed,in which the electrolytic manganese residue(EMR)was initially calcined for cement buffering;then the generated SO2-containing flue gas was managed using manganese oxide ore and anolyte(MOOA)desulfurization;at last,the desulfurized slurry was introduced to the electrolytic manganese production(EMP).Results showed that 4.0 wt%coke addition reduced the sulfur of calcined EMR to 0.9%,thereby satisfying the cement-buffer requirement.Pilot-scale desulfurization showed that about 7.5 vol%of high SO2 containing flue gas can be cleaned to less than 0.1 vol%through a five-stage countercurrent MOOA desulfurization.The desulfurized slurry had 42.44 g·L-Mn2+and 1.92 g·L-1 S2 O62-,which was suitable for electrowinning after purification,and the purity of manganese product was 99.93%,satisfy the National Standard of China YB/T051-2015.This new integrated technology fulfilled 99.7%of sulfur reutilization from the EMR and 94.1%was effectively used to the EMP.The MOOA desulfurization linked the EMP a closed cycle without any pollutant discharge,which promoted the cleaner production of EMP industry.

Process Development and Design of Chlorine Dioxide Production Based on Hydrogen Peroxide

This paper presents a process development and design of chlorine dioxide production based on hydrogen peroxide. The process is characterized by cleaner production, high efficiency, and waste minimization. Optimization of process conditions, selection of equipment, and experiment of recycle of waste acid are carried out. The process design is realized in consideration of several aspects such as operation, material, equipment design and safety. An industrialized process flowsheet is developed according to experiment. A pilot testing is carried out to confirm the lab results. Process design of chlorine dioxide production based on hydrogen peroxide is realized.

Studies on Barriers for Promotion of Clean Technology in SMEs of China

After more than 10 years efforts on awareness raising and promotion, the concept of cleaner production (CP) has been adopting as a strategic approach to balance economic benefits and environmental protection for China’s industries. However, it is also found that clean technology is difficult to be adopted and implemented in Chinese Small and Medium-sized Enterprises (SMEs) because of certain barriers. This paper investigates these barriers among three stakeholders--governments, enterprises and experts. The Analytic Hierarchy Process (AHP) was employed to prioritize the relative importance of the twenty fine-selected barriers, which were classified into four barrier categories. The findings reveal that the exterior barriers of policy and financial barriers should be stressed rather than the inner barriers of technical and managerial barriers, although they are also very important. Absence of incentives on economic policies, lax enforcement of environmental regulations and high initial capital cost were the most important barriers to adoption of Clean Technologies (CT) in China.

Controlled Entropy and Gauge Theory in Recycling Condensed Matter by Solar Energy

This article discusses the physical principles to be considered in a thermodynamic engineering solar system running under operational control algorithms designed to minimize entropy rates. The proposed plant is based on scientific foundations established by thermodynamics and classical field theory, and empirical disciplines that deal with properties of chemical elements and with technologies of calorific capture from remote sources. The gauge principle was applied in theoretical formalization as an essential tool in the control background of the entropy rates involved. The industrial system presented was planned to recycle condensed matter within the scope of a solid waste management policy.