THE SEPARATION OF Pb-Sb ALLOYS BY VACUUM DISTILLATION

This paper summarizes the research results of vacuum distillation of Pb-Sb alloy and crude antimony.In our study,we have found the basic law which states that in Pb-Sb phase diagrams,the part which is rich in lead can be used to guide the purification of lead by distillation,while the part rich in antimony can be used to guide the purification of Sb.where the compositional point C is the azeotropic mixture.The technical experi-mental results at temperatures between 7OO-85OC are coincident with those of theorical study.The expanding experiment at the 100kg scale produced satisfactory results.

Supergravity separation of Pb and Sn from waste printed circuit boards at different temperatures

Printed circuit boards（PCBs） contain many toxic substances as well as valuable metals, e.g., lead（Pb） and tin（Sn）. In this study, a novel technology, named supergravity, was used to separate different mass ratios of Pb and Sn from Pb–Sn alloys in PCBs. In a supergravity field, the liquid metal phase can permeate from solid particles. Hence, temperatures of 200, 280, and 400°C were chosen to separate Pb and Sn from PCBs. The results depicted that gravity coefficient only affected the recovery rates of Pb and Sn, whereas it had little effect on the mass ratios of Pb and Sn in the obtained alloys. With an increase in gravity coefficient, the recovery values of Pb and Sn in each step of the separation process increased. In the single-step separation process, the mass ratios of Pb and Sn in Pb–Sn alloys were 0.55, 0.40, and 0.64 at 200, 280, and 400°C, respectively. In the two-step separation process, the mass ratios were 0.12 and 0.55 at 280 and 400°C, respectively. Further, the mass ratio was observed to be 0.76 at 400°C in the three-step separation process. This process provides an innovative approach to the recycling mechanism of Pb and Sn from PCBs.

Cyclomatic Complexity-Based Encapsulation, Data Hiding, and Separation of Concerns

Three design principles are prominent in software development-encapsulation, data hiding, and separation of concerns. These principles are used as subjective quality criteria for both procedural and object-oriented applications. The purpose of research is to quantify encapsulation, data hiding, and separation of concerns is quantified using cyclomatic-based metrics. As a result of this research, the derived design metrics, coefficient of encapsulation, coefficient of data hiding, and coefficient of separation of concerns, are defined and applied to production software indicating whether the software has low or high encapsulation, data hiding, and separation of concerns.

Music/voice separation based on the multi-repeating structure of Mel cepstrum coefficient

For the poor adaptability of the original repeating pattern, an improved music separation method of multi-repeating structure of Mel cepstrum coefficient （MFCC） is proposed. Firstly, the MFCC coefficient matrix （39-dimensional data） of the music signal was extracted. Then the cosine characteristic was applied to the count of similarity matrix of MFCC, and the fragments with consistent similarity are putted together. Next different repeating patterns are built for different groups. Thereby the spectrums of the background music and vocal were separated combined with ideal binary masking （IBM）, and the corresponding time domain signals were obtained by inverse Fourier transform. Fnally, the improved method was tested on the music database of different types and length, and the separation results were compared with repeating method of Rafii and the non-negative matrix factorization based on flexible framework method of Ozerov. The experimental results showed that the separation performance of improved method was improved about 3 dB, and the performance of music with melody changed larger was significantly improved. Experiments verified that the improved method was an effective music separation algorithm and more stability.

Study on separation of rare earth elements in complex system

The effect of the feed acidity,acetic acid concentration and rare earth concentration on the distribution ratio,separation coefficient and extraction capacity of light rare earth elements were studied in the P204(DEHPA)-HCl system and P507(HEH/EHP)-HCl system both containing acetic acid,respectively. The results showed that the distribution ratio and separation coefficient decreased with increasing of acidity,and increased with increasing of acetic acid concentration and rare earths concentration,and the extraction capacity increased with increasing of acetic acid concentration. When pH value of feed was 2.0,[RE]/[acetic acid] was 1:1 and rare earth concentration 0.35 mol/L,in P204(DEHPA) -HCl system with acetic acid,the maximum separation coefficient(β) reached to βCe /La=4.09,βPr/Ce=1.96 and βNd/Pr=1.53,and the separation ability of this extraction system was better than P507(DEHPA)-HCl system.

Impurity distribution in metallic dysprosium during distillation purification

The distribution rules of impurities contents in distilled metallic dysprosium were researched, and a theoretical analysis was carried out. The research results indicated that, the content of impurity in distilled metal, such as Al and Fe, was lower in the ini-tial stage, increased slowly in the middle stage, and increased rapidly in the last stage during the process of distillation purification. The calculated method of separation coefficient of impurity in crude metal by content of impurity in distilled metal was not suitable for high pure metals, and the modified separation coefficient was proposed, and it equaled 1/6.1 and 1/16.9 for impurity Al and Fe. The physical process of distillation was coincident with that of solidification essentially, and solute re-distribution theory in solidify-ing front could be used to describe the impurity distribution near evaporating surface. In the former stage of distillation purification, the diffusion of impurity in liquid metal could reach a quasi-equilibrium state, the calculated result of impurity content in distilled metal agreed well with experiments. In the latter stage of distillation process, the diffusion rate of impurity in liquid metal decreased, and the content in distilled metal was larger than the calculated result.