Imperial Smelting Research Articles

Intelligent integrated optimization and control system for lead–zinc sintering process

The lead–zinc sintering process (LZSP) is an important step in imperial smelting. This paper presents an intelligent integrated optimization and control system (IIOCS) for the LZSP. The optimization and control scheme has a hierarchical configuration. First, the requirements of process control and the configuration of the IIOCS are described. Then, models for predicting quantity and quality (Q&Q) are established using correlation and mechanism analysis, and are implemented by improved back-propagation neural networks. Based on the models, an integrated algorithm combining c-means clustering, genetic, and chaos approaches is employed to optimize the operating parameters of the process. Finally, the control of the process state is carried out by a distributed control system to control the Q&Q of the product.

Ｉｍｐｅｒｉａｌ Ｓｍｅｌｔｉｎｇ Ｐｒｏｃｅｓｓの焼結工程における鉱層の圧力損失変化の検討

Change in the blowing pressure applied to the sintering bed (for the preparation of row materials for ISP) was examined by the experiment using a sinter pot and a mathematical model considering gas-flow across the bed. The results obtained were as follows: (1) A pressure drop of the sintering bed changes as the sintering reaction proceeds. It increases at the beginning of the oxidized reaction when the temperature of the bed is still low.Then it decreases as the progress of reaction accompanied by the increase in the bed temperature. (2) The pressure drop of the bed during the sintering process was mainly attributed to a drying zone, and was comparatively low in the reaction and the cooling zones. (3) Based on the Erugen's equation, the change in the pressure drop during sintering can be explained by assuming the decrease of an apparent fractional void volume in the drying zone.

Technological Assessment of Alternative Processes: The Processing of Sulphide Minerals

AbstractThe theory of cumulative exergy analysis of complex technological processes is summarized. Technological assessments are made of a proposed Sulphation Roast Leach (SRL) process, and commercial Imperial Smelting (IS) and Roast Leach Electrowin (RLE) processes for zinc production. Assessments are made in terms of the specific cumulative exergy consumption and cumulative degree of thermodynamic perfection for zinc production.The IS process is found to be superior in terms of these criteria when the steps for the preparation of the feed material to the processes are not taken into account. This results from the low usage of electricity in the process relative to the SRL and RLE processes.For the total processing of a complex mineral sulphide ore, a selective sulphation (e.g. SRL process) is superior due to its ability to handle wide variations of feed composition. Adoption of the process could essentially eliminate discharge to the environment of harmful metal sulphides with concomitant improved metal...

Whither Zinc?

AbstractPresent technology for production of primary zinc by the Imperial Smelting and electrolytic zinc processes followed long and expensive process development, driven by the need to improve on inefficient, small scale and labour intensive retorting processes. These newer processes are complementary, very efficient and continue to develop to meet evolving needs, with no sign of a shortage of suitable concentrates to force major change to newer technology.Several proposed intensive zinc processes to treat calcines, and an innovative direct process treating polymetallic sulphide concentrates, all need to condense bulk metallic zinc from a dust‐ or fume‐laden gas, e.g. by absorption in a lead or zinc condenser. Efficient metal recovery and process control will meet major engineering and operating difficulties. Successful commercialisation to bulk zinc, if ever achieved, will require long and expensive development, and present need does not justify the costs and effort involved.Whither zinc? Most likely down an evolutionary path from present technology, with added environmental protection whose costs must be carried by the industry, then by society.

Zinc blast-furnace operation

The zinc furnace permits treatment of complex zinc-lead ores. Earlier attempts with high CO furnace gas resulted in low thermal efficiency and reduction of iron oxides. The lead splash condenser, developed by Imperial Smelting, has permitted zinc to be condensed from blast-furnace gas high in CO2.