摘要
熵,是描述热力学系统平衡态的一个状态函数。为确定铜产品生命周期中含铜物质的聚集和散失程度,将热力学中"熵"这一指标引入到物流分析中,给出了物流分析中"熵"的分布及其计算方法,在中国2005年铜产品生命周期分析的基础上,计算了铜循环整个过程中,即精炼铜的生产阶段、铜制品的加工制造阶段、铜制品的使用阶段和报废铜制品的回收阶段的熵的变化,得到5个节点处的相对熵值分别为0.25596,0.04562,0.23690,0.60470和0.24866,整个过程中的相对熵变化率为-2.85%,即经过一个生命周期,含铜物质聚集度在提高,并与2002年铜产品生命周期的熵分析结果进行了比较。在2005年铜产品生命周期熵分析的基础上,通过两种不同技术指标下的情景分析,得出了减少采、选矿环节和熔炼环节尾矿和熔渣中铜的损失量,提高报废铜制品的回收率和折旧废铜的含铜百分比等措施,将会有效地降低铜产品生命周期的熵值增加。相信随着物质流分析方法和理论研究的进一步深入,熵在物质流分析中的应用范围和程度也会愈来愈广泛和深入。
Entropy is used to describe the balanced state of a system in thermodynamics. In order to ascertain the aggregating and dispersing degree of copper in the life cycle of copper products, the index of entropy in thermodynamics was introduced to analyze the material flow, and the methods for analyzing entropy distribution and calculation in material flow were given. The variations of entropy in copper life cycle from refining, processing, manufacturing, products use, disposal and recycling were calculated based on the analysis of copper products life cycle in China in 2005. Results show that the entropy at the five stages mentioned above was 0. 25596, 0.04562, 0. 23690, 0.60470 and 0. 24866, respectively. The variation rate of relative entropy in the whole life cycle is - 2.85 %, which implies that the congregating degree of copper-contained materials is increasing. The entropy variations of copper products life cycle in China in 2002 were also calculated by using the same method, and the results were compared with that in 2005. The values of entropy at the five stages of copper life cycle in 2005 are lower than the values in 2002. Two scenarios analysis were conducted based on entropy analysis of copper life cycle. Scenario Ⅰ： losses of copper in mining, milling and smelting process are reduced to 70% of the original quantities of them in 2005, recycling rate of used copper products are raised from 70% to 80% and copper-contained ratio in reclaimed copper scraps are increased from 60% to 70%. Scenario Ⅱ ： losses of copper in mining, milling and smelting process are reduced to 50% of the original quantities of them in 2005, recycling rate of used copper products are raised from 70% to 90% and copper-contained ratio in reclaimed copper scraps are increased from 60% to 80%. The entropies at the five stages of copper life cycle were calculated under scenario Ⅰ and scenario Ⅱ . Under scenario Ⅰ , the entropy at the five stages of copper life cycle is 0.25596, 0.03193, 0. 23225, 0. 60418 and 0. 17287, respectively. Under scenario Ⅱ ： the entropy at the five stages of copper life cycle hey is 0.25596, 0.02281, 0.22916, 0. 60383 and 0. 09637, respectively. The values of entropy are effectively reduced, especially in copper products recycling stage. Entropy will be used widely and deeply for analyzing material flow with the improvement of the methods and theories in the future.
出处
《资源科学》
CSSCI
CSCD
北大核心
2008年第1期140-146,共7页
Resources Science
基金
国家重点基础研究计划(973项目):"现代城市"病"的系统识别理论与生态调控机制"(编号:2005CB724206)
东北大学材料与冶金学院青年教师基金资助
关键词
产品生命周期
铜流
熵
节点
相对熵
Products life cycle
Copper-flow
Entropy
Stage
Relative entropy
