Reviews of Metallurgical Technology to Recovery Platinum Group Metals from Secondary Resource in China

China is extremely poor in mineral resources of Platinum Group Metals (PGMs), productive output of PGMs from mineral resource is 2.5 tons per year. At the same time, China is the biggest PGMs consumption country in the world, the mineral resource of PGMs is critical shortage, it shows the importance of recycling the secondary resource of PGMs. Sino-Platinum Metals Resource (Yimen) Co., Ltd. is the leader in recycling of PGMs from secondary resource, and has made outstanding contributions to China PGMs secondary resources recycling. This article elucidates the current situation of secondary resources recovery and development of metallurgical technology for PGMs.

‘‘Complexation–precipitation'' metal separation method system and its application in secondary resources

Recovery processes of secondary resources usually encounter problems because of the diverse com- positions of wastes. To enhance the applicability of tradi- tional hydrometallurgical process toward secondary resources, the adjustment of components is necessary. In traditional hydrometallurgical separation, precipitation and complexation are extensively used. However, their com- bination as a specific metal separation method has not yet been studied in detail. This approach is very promising for solving problems caused by changeable components during recycling processes of secondary resources. This paper reviews the effects of precipitation and complexation in metal separation processes, and a metal separation method system of ＂complexation-precipitation＂ developed to adjust the components of secondary resources is introduced.

Formation of AlN from Secondary Al Resources

Synthesis of AlN by NH4Cl-assisted direct nitridation of secondary Al resources was studied. Aluminum alloy scrap contained Mg and Zn element was used. Milled Al scrap （-1 mm） was mixed with NH4Cl and heated at 1000℃ for 1 h in presence of 1 L/min N2 flow gas. The nitrided product was evaluated by X-ray diffraction semi-quantitative analysis and scanning electron microscopy （SEM）. Aluminium nitride of 90.5% concentration was obtained with a hexagonal crystalline form. AlN is mostly formed in nano-whisker morphology （50～150 nm） which is homogenously distributed.

English Language Corpora as a Secondary ELT Resource for Indian Learners

The author proposes here for utilizing ELC （English Language Corpora） as a secondary resource for developing ELT （English Language Teaching） materials for teaching English to Indian learners. We argue for using ELC as one of the most authentic representative collections of modem English language from where we extract necessary linguistic data, information, and examples to develop basic as well as additional resources of ELT, such as, text books, reference materials, syllabuses, grammar books, dictionaries, and terminology databases, etc., for Indian learners. Keeping the requirements of individual learners in mind we propose to customize materials to make these maximally useful within the broader scheme of CALT （Computer Assisted Language Teaching）. In our view, ELT resources developed from ELC are more useful for Indian learners, because ELC represents diversified varieties of usage of modem English in real situations, which Indian learners need to assimilate to be at par with others across the globe. Also ELC-based ELT resources are more interesting and beneficial to Indian learners, if instructors carefully utilize these resources keeping in mind the requirements of learners. If Indian ELT learners want to compete in global frame, then utilization of ELC-based ELT resources is the most useful solution, which we can ignore at the cost of our own peril.

Quantitative estimation of social stock for metals Al and Cu in China

Social stock for metal determines secondary or recoverable resources to a certain extent.Top-down analysis method for the studying of metal in social stock was given.Influences of metal consumption under three circumstances,that is keeping constant,varying in a linear trend and in an exponential trend,on one kind of metal’s social stock,recyclable ratio and average age were analyzed.Al-contents and Cu-contents in social stock for China during the period 2006-2009 were calculated.The results reveal that Al-contents and Cu-contents in social stock kept increasing and reached 88.9 million tons and 51.4 millions tons in 2009,respectively,their average recyclable ratios are 1.45% and 0.30%,and the average ages are 4.65 years and 6.89 years,respectively.The recyclable ratios and average ages of Al-contents and Cu-contents in social stock will rise in future along with the decline of the increasing rate of aluminum consumption and copper consumption.

Research on Experimental and Application for the High Efficient Enrichment of the Low-grade Precious Metal Materials

On the basis of reviewing the progress in the high efficient enrichment from secondary resources of low grade precious metals at home and abroad, a process route of the high efficient enrichment precious metals from secondary resources of low-grade metals by adding iron oxide as the trapping agent, reducing agent, additive, mixing uniformly and grinding, pelletizing, reduction, grinding and separation, and selectively acid leaching iron has been put forward in this paper. The experiments of reduction, grinding and separation, and selectively acid leaching iron were carried out mainly. Under the decided experiment parameters and conditions, iron generated during the reduction can trap precious metals during reduction, high active alloy powders were obtained from the reduced products by grinding and separation, the concentration of precious metals was obtained by acid leaching high active alloy powders. The better enrichment effect was obtained by adopting the technical route of processing. Other low grade noble metal materials and enrichment ratio of precious metals from the materials to acid products was high through acid leaching. This process has the advantages of simple process, environmental-friendly, strong adaptability of raw materials, high concentration ratio, which was regarded as a kind of the general efficient enrichment technology of low grade precious metal materials.

The practice of using LT dust and BOF slag as hot metal dephosphorizing fluxes at Baosteel

In order to meet the requirements for environmental protection and achieve sustainable development for the steel industry, Baosteel＇ s secondary resources should be utilized in production. Hot metal dephosphorizing factors are analyzed and the practice of a dephosphorizing agent for molten iron pretreatment with LT dust and BOF slag is introduced. Experimental results show that LT dust and BOF slag can be substituted for traditional raw materials, such as sinter and quicklime, etc in molten iron dephosphorization. The proper addition of LT dust or BOF slag and the proper control over basic agents, oxidizing agents and fluxes can achieve the same effect as traditional dephosphorizing agents. BaO can reduce the activity of P2O5 and form stable dephosphorizing products. Using a BaO dephosphorizing agent as a kind of harmless dephosphorizing agent will be one of the trends of molten iron dephosphorization.

The practice of clean production in the Ironmaking Plant of Tangshan Iron & Steel Co.,Ltd.

The Ironmaking Plant of Tangshan Iron & Steel Co.Ltd.takes clean production as its orientation. It decreases silicon to smelt through increasing the entering furnace sinter ratio,stabilizing coke quality by tackling key problems,increasing coal injection ratio,as well as keeping the blast furnace smooth running and so on.The energy consumption of sinter working procedure has been greatly reduced through optimizing the ore blender structure,enhancing the quality of fuel and flux,increasing the quicklime amount,reclaiming the remaining heat of the annulus cooling system and deepening the material layer to sinter.We have achieved the repetition economy and the secondly resource has been used synthetically with advanced producing technics.The environment around the plant has been greatly improved by preventing,monitoring and fathering the moving pollution root,at the same time,the economy and environment development in phase has been greatly accelerated.