新桥硫铁矿选硫工业生产实践

阐述了新桥硫铁矿增设的选矿工艺流程，对其技术操作条件进行了考查，硫精矿品位由29％提高到45％，滤饼水份降低至11％，并根据考查结果进行经济效益分析，年可获利润百万元。     

造气炉中有机硫转化的优化条件的热力学探讨

本文利用非线性参数估值算法——单纯形加速法对造气炉中有机硫转化的优化条件进行了热力学探讨。根据热力学计算结果得出了有机硫转比的最佳条件,并考查了造气温度、压力对有机硫平衡转化率的影响。通过与工业生产的对比可知造气炉中有机硫的转化主要受其转化动力学的影响。     

一种除铜新工艺在粗铅精炼中应用研究

针对西北铅锌厂粗铅火法精炼过程中,直接加单质硫进行除铜而出现硫损过大的问题,对除铜工艺中硫的利用方式进行了研究,提出一种除铜新工艺,即利用硫化铅代替单质硫进行除铜.在本实验中,对硫加入过量率、加热温度、加热时间等制备PbS的工艺条件进行了研究,并确定了加PbS除铜工艺的最佳硫化铅用量,最佳搅拌时间等技术条件.实验结果表明,粗铅中含铜量由0.814%下降至0.011%,除铜效率高达98.65%,且在除铜过程中,硫的利用率达92%以上.     

碳源对反硝化脱硫工艺碳氮硫同步脱除效果的影响

针对碳源对反硝化脱硫工艺运行效能影响不明问题,实验采用UASB反应器,考查两种不同碳源(乙酸钠和苯酚)条件下反硝化脱硫工艺碳氮硫去除效果及单质硫累积率,在此基础上,通过批次试验进一步探究碳氮硫降解及转化规律.结果表明:乙酸钠为碳源,HRT为2.5~10 h,NO_3~--N、S~(2-)和Ac~--C去除率分别保持在93%、90%和99%以上,单质硫积累率稳定在41%以上;而苯酚为碳源,HRT为10 h,NO_3~--N、S~(2-)和C_6H_5O~--C去除率分别达67%、85%和50%,但硫化物均转化为硫酸盐,无单质硫累积.批次试验表明,乙酸钠为碳源时,S~(2-)氧化速率(qS~(2-))乙酸盐氧化速率(qAcetate)S~0的氧化速率(q_S~0);而苯酚为碳源时,S~(2-)氧化速率(qS~(2-))S0的氧化速率(q_S~0)苯酚氧化速率(qPhenol),从而使得硫化物的氧化产物有所差异.     

莱钢120吨转炉冶炼超低硫钢工艺优化

结合脱硫反应热力学和动力学理论,对莱钢120t转炉冶炼过程及操作制度进行了分析研究,通过控制转炉回硫对深脱硫工艺流程进行了优化。结果表明:(1)通过控制转炉回硫,可将LF炉中钢水硫质量分数控制在0.005%以下,脱硫率可达80%以上,终点硫质量分数最低可达到0.001%,并且能够稳定生产硫质量分数小于0.005%的低硫钢种;(2)顶渣SiO2质量分数可控制在8%以下;(3)终点(FeO+MnO)质量分数和可降低到1%左右,碱度可控制在5～6之间。     

顶底复吹转炉冶炼45~#硬线钢终点硫的控制

对马钢70 t顶底复吹转炉冶炼45#硬线钢硫的物料平衡及转炉脱硫的影响因素进行分析,在此基础上,依据原辅料条件,控制入炉硫含量且对转炉冶炼脱硫操作参数进行优化,实现终点硫的有效控制。应用结果表明,控制入炉总硫量≤10 kg,转炉炉渣碱度在3.5～4.0,渣中(FeO)质量分数在10%～20%,转炉终点温度在1 630～1 650℃,转炉终点回硫得到改善,终点平均回硫质量分数由之前的0.007%下降至0.004%,终点硫合格率由之前的70%提高到96%以上。     

煤液化重质产物的催化加氢裂解研究

为了使煤直接液化的重质产物转化为轻质油类,利用管式高压反应釜,以四氢萘为溶剂、FeS和S为催化剂,对沥青烯进行了加氢裂解研究.考察了催化剂种类及加入量、反应温度和反应压力等因素对沥青烯加氢液化的转化率和产物分布的影响.利用FTIR与元素分析仪对原料沥青烯及残余沥青烯进行了结构表征.结果表明:在一定实验条件下,FeS加硫后使原料的转化率由30.76%增加至53.94%,油+气的产率也由6.01%增至38.39%,而逆向缩合程度减少了9%;两种催化体系下原料的液化转化率均随着温度的升高而增加,但不加硫时增加的幅度为15.20%,明显小于加硫时的23.83%;随着压力的增加,两种催化条件下原料的转化率均增加,而逆向缩合程度在不加硫时随着压力的增加而增加(16.17%,6～30.54%),加硫时则相反.     

高硅贝利特-硫铝酸盐水泥的热分析实验研究

为了探明在1200℃左右烧制时高硅贝利特硫铝酸盐水泥其强度高于烧成温度更高这一特性的原因,在文献[1,2]XRD的分析基础上,笔者对石膏、铝酸钙、无水硫铝酸钙、硅酸二钙和铁铝酸四钙、高硅贝利特硫铝酸盐水泥进行了热分析,研究表明:当水泥的煅烧温度低于1200℃时,硅酸二钙和无水硫铝酸钙并没有大量生成,石膏的化合率仅为4%,因此强度很低.当温度超过1250℃时,石膏开始分解,石膏、无水硫铝酸钙和高硅贝利特水泥在1375℃的石膏分解率分别为8%、30 5%、26 68%,不利于无水硫铝酸钙的稳定存在,甚至可导致无水硫铝酸钙的分解,最终降低水泥的强度.     

2-氨基-1,3,4-噻二唑合成新工艺及优化

甲酸与硫代氨基脲以催化活性较高的氢溴酸催化剂合成了2-氨基-1,3,4-噻二唑,并通过响应曲面法对催化剂的投加量、反应温度、反应时间等因素进行了优化及分析,得出了2-氨基-1,3,4-噻二唑合成的最佳工艺条件:甲酸与硫代氨基脲的摩尔比为1.2∶1,氢溴酸20mL(硫代氨基脲为0.022mol),反应时间为4.6h,反应温度为104℃,产率为74.44%.将得到的最佳工艺条件应用于乙酸、丙酸、正丁酸、正戊酸、氯乙酸等与硫代氨基脲合成2-氨基-1,3,4-噻二唑的反应中同样获得了较高产率,产率分别为70.08%,78.72%,78.72%,66.77%,72.11%.     

高效脱硫菌的筛选及脱硫性能研究

通过实验,从含硫土壤中分离到一株高效脱硫率的硫杆菌菌株T2,初步鉴定为硫杆菌属的那不勒斯硫杆菌。对其特性进行研究,结果表明:该菌细胞为革兰氏阴性杆菌,严格自养,好氧,最佳生长pH为6.0~8.0,能在NaCl浓度为0~20%的培养基中生长,在接种量为5%时,该菌株2天将硫代硫酸盐去除99%。     

煤与单一矿物质在摩擦电选过程中的分离

摩擦电选能够有效分选粒度小于74μm的微粉煤,为了探索煤中矿物质在摩擦电选过程中的分离规律,将净煤(ρ1.3g/cm3)与煤中常见伴生矿物质如石英、高岭土、黄铁矿、方解石等分别按照一定比例混合,进行摩擦电选研究,并对各组精煤产品进行了X射线荧光光谱分析.试验结果表明:4种矿物质都可以通过摩擦电选方法有效脱除,方解石、石英、黄铁矿和高岭土的脱除率可分别达74.871%,82.608%,96.169%,94.986%.     

Bioflotation of pyrite with Thiobacillus ferrooxidans

Bioflotation of pyrite with bacteria Thiobacillus ferrooxidans in the presence or absence of potassium ethyl xanthate was studied on a pure pyrite through microflotation and electrophoretic light scattering measurements. The experimental results showed that in the absence of xanthate, pyrite flotation is slightly enhanced by Thiobacillusferrooxidans. However, with xanthate as a collector, pyrite flotation is strongly depressed after being exposed to the bacteria. The longer is the time when the pyrite is exposed to the bacteria, the stronger the depression is. The mechanism of the depression might be due to the formation of the biofilms of Thiobacillus ferrooxidans on pyrite surfaces, preventing the adsorption of xanthate on pyrite surfaces in the form of dixanthogen or xanthate ions.     

Investigation of pyrite surface state by DFT and AFM

The surface states of pyrite(Fe S2) were theoretically investigated using first principle calculation based on the density functional theory(DFT). The results indicate that both the(200) and(311) surfaces of pyrite undergo significant surface atom relaxation after geometry optimization, which results in a considerable distortion of the surface region. In the normal direction, i.e., perpendicular to the surface, S atoms in the first surface layer move outward from the bulk, while Fe atoms move toward the bulk, forming an S-rich surface. The surface relaxation processes are driven by electrostatic interaction, which is evidenced by a relative decrease in the surface energy after surface relaxation. Such a relaxation process is visually interpreted through the qualitative analysis of molecular mechanics. Atomic force microscopy(AFM) analysis reveals that only sulfur atom is visible on the pyrite surface. This result is consistent with the DFT data. Such S-rich surface has important influence on the flotation properties of pyrite.     

Depressing effect of hydroxamic polyacrylamide on pyrite

The performance of hydroxamic polyacrylamide(HPAM) in mineral flotation was tested on the samples of calcite, diaspore and pyrite. It is found that HPAM expresses intensive depression on pyrite and can be used as effective depressants for pyrite. The depression mechanism of HPAM to pyrite was investigated by the determination of contact angle, zeta potential, adsorptive capacity for collectors and infrared spectrum. A lower contact angle,more negative zeta potential, less xanthate adsorptive capacity, and the formation of chemical bonding were determined, which reveals that the strong chemical interactions exist between HPAM and pyrite surface. The group electronegativity of HPAM was calculated to explain the differences of interaction between reagent and minerals.     

Influencing factors of pyrite leaching in germ-free system

The effect of mineral particle size, pulp potential and category of oxidant on pyrite leaching was studied. The results show that a smaller mineral particle size leads to a higher leaching rate of pyrite, and the optimum result with pyrite leaching rate of 2.92% is obtained when mineral particle size is less than 0.037 mm. The pulp potential reflects the leaching process. The increase of pulp potential can improve pyrite leaching. The leaching rate and velocity of pyrite can be enhanced rapidly by adding strong oxidant. The kind and the method of adding oxidant have important effect on the pyrite leaching. Appropriate concentration of Fe3 can enhance pyrite leaching but the precipitation generated by high concentration of ferric ion covers the surface of pyrites and prevents the leaching process. The leaching rate increases with the constant addition of H2O2.     

黄铁矿伴生金回收研究进展

Pyrite is one of the most important minerals bearing gold, and also the major resource of the gold production in China. However, the gold associated with pyrite is reported to be finely disseminated in complex structure, resulting in great recovering difficulty. This article reviews the mineralogical characteristics of gold associated with pyrite, and the research progress of common physical and chemical beneficiation processes for it. The principle of each gold extraction method and its applications in the recovery of gold associated with pyrite were illuminated, the merits and demerits of each method were discussed as well from the aspects of process cost, environmental hazard and gold leaching efficiency, etc. It is pointed out that, for refractory gold associated with pyrite, developing effective pretreatment process and highly selective leaching aids will be the future research directions to improve the gold leaching efficiency.
     

Interfacial interaction of bio-leaching of pyrite mineral

Electrokinetic and contact angle measurements were used to discuss the interfacial interaction on bio-leaching of pyrite mineral. Surface energy parameters of pyrite mineral and thiobacillus ferrooxidans were obtained by calculating according to formula of Young's equation and contact angle measurements. The results show that surface energy of thiobacillus ferrooxidans is much higher than that of pyrite mineral, and the reaction of pyrite mineral with thiobacillus ferrooxidans causes the reduction of the pyrite surface energy. The interfacial interaction energies between pyrite mineral and thiobacillus ferrooxidans were also obtained based on polar interfacial interaction theory and electrokinetic and contact angle measurements. The thermodynamics approach only considering Lifshitz-van der Waals and Lewis acid-base interaction fails to explain the adhesion behavior of the bacteria, but the extended Derjaguin-Landan-Verwey-Overbeek theory concerning Lifshitz-van der Waals and Lewis acid-base and the electrostatic can exactly predict interfacial interaction.     

Effect of organic depressant lignosulfonate calcium on separation of chalcopyrite from pyrite

In order to selectively separate chalcopyrite from pyrite, the effect of organic depressant lignosulfonate calcium (LSC) on the flotation separation of chalcopyrite from pyrite was investigated by flotation tests. The depression mechanism was studied by Fourier-transform-infrared (FTIR) analysis. The flotation tests of single mineral show that LSC can depress the flotation of pyrite in a certain pH range, but it has little effect on chalcopyrite flotation. Flotation separation of a mixture of chalcopyrite and pyrite can be completed to obtain a copper concentrate grade up to 24.73% with a recovery of 80.36%. IR analysis shows that LSC and butyl xanthate compete in absorption on pyrite surface, and there exists an LSC characteristic peak on pyrite surface. There is little adsorption of LSC on chalcopyrite.     

Influences of collector DLZ on chalcopyrite and pyrite flotation

The interaction mechanism of collector DLZ in the flotation process of chalcopyrite and pyrite was investigated through flotation experiments, zeta potential measurements and infrared spectrum analysis. Flotation test results indicate that DLZ is the selective collector of chalcopyrite. Especially, the recovery of chalcopyrite is higher than 90% in neutral and weak alkaline systems, while the recovery of pyrite is less than 10%. When using CaO as pH regulator, at pH=7-11, the floatability of pyrite is depressed and the recovery is less than 5%. Zeta potential analysis shows that the zeta potential of chalcopyrite decreases more obviously than that of pyrite after interaction with DLZ, confirming that collector DLZ shows selectivity to chalcopyrite and pyrite. And FT1R results reveal that the flotation selectivity of collector DLZ is due to chemical absorption onto chalcopyrite surface and only physical absorption onto pyrite surface.