铁基改性生物炭对Sb污染土壤稳定化修复效果的研究

以某冶炼生产废弃场地土壤为对象,研究了不同稳定剂对Sb污染土壤的稳定化修复效果。试验结果表明:三种稳定剂对土壤Sb的稳定化效果依次为铁基改性生物炭>三氯化铁>未改性生物炭。当使用三氯化铁作为稳定剂时,将显著降低土壤的pH值,造成土壤酸化。最佳的稳定剂添加量为3%,养护时间在3~5d左右可实现土壤Sb的稳定化平衡。基于Tessier连续提取法分析了不同稳定剂施加后土壤中Sb的形态和比例,当施加三氯化铁和铁基改性生物炭后,原土中的可交换态(EX)Sb的占比显著降低,与施加三氯化铁相比,施加铁基改性生物炭后土壤Sb的可交换态(EX)仍进一步降低20%左右,表明铁基改性生物炭充分发挥了生物炭和铁基稳定剂各自的优点,不仅表现出最好的土壤Sb稳定效果,而且对土壤pH的影响也最小,具有良好的潜在应用前景。     

氯化铁浸出铅冰铜的工艺研究

研究了氯化铁湿法浸出铅冰铜的工艺,主要分析了FeCl₃浓度、温度、浸出时间、鼓入空气等因素对浸出的影响,得出试验最优条件为:FeCl₃浓度400 g/L,液固比5∶1,温度75℃,时间7 h,空气流量150 L/h。此时铜的浸出率为92.5%,铅的浸出率为1.54%。     

黏土型锂矿中锂的浸出实验研究

黏土型锂矿是一类重要的锂资源,目前关于该类锂矿的研究相对较少。采用氯化铁溶液对碳酸盐黏土型锂矿中的锂元素进行浸出,研究了焙烧温度、氯化铁质量分数、浸出温度和反应时间对锂浸出率的影响。结果表明,氯化铁溶液对样品中的锂元素有较好的选择性浸出作用。当焙烧温度为600 ℃,氯化铁质量分数为15%,浸出液固比为5 mL/g,浸出温度为80℃,反应时间为240 min,转速为240 r/min时,锂浸出率可达82.78%。浸出前后样品的XRD和SEM分析表明,锂的浸出可能是氯化铁溶液中的铁离子与黏土样品中的锂离子进行交换的结果。     

蒸馏—臭氧酸浸处理高硫渣浮选尾矿

采用蒸馏—臭氧氧化—稀硫酸浸出工艺路线处理氧压浸锌的浮选硫尾矿,主要为蒸馏法回收单质硫,臭氧氧化—稀硫酸浸出浮选硫尾矿回收其中有价元素。在温度400℃、保温时间0.5 h、载气流量400 mL/min条件下,浮选硫尾矿中硫元素的回收率可达到92%以上。臭氧对硫尾矿中Fe、Cu、As、Zn等元素的浸出具有很好的促进效果。在温度80℃、时间2 h、液固比6、氧气流量400 mL/min、硫酸浓度1.6 mol/L、搅拌速度400 r/min的条件下,Fe、Cu、As、Zn的浸出率分别可达到73.08%、90.97%、89.69%、99.03%。     

正交实验法优选钛白粉沉降絮凝剂

通过选择钛液浓度、钛液温度、絮凝剂种类、絮凝剂浓度、絮凝剂加入量和搅拌时间等作为因素,采用L25(56)正交表,以过滤速度为指标对钛白粉酸解沉降钛液用絮凝剂进行正交优选实验。实验得到的最佳工艺参数为:钛液浓度为130 g/L,钛液温度为60℃,絮凝剂为7035,絮凝剂加入量为40 mg/L,絮凝剂浓度为0.5 g/L,搅拌时间1 min。该优选的絮凝剂絮凝效果好,不仅能满足质量方面的要求,而且生产效率也能得到保证。     

难处理钨矿尾砂沉降性能研究

解决难处理钨矿尾砂的沉降问题对优化白钨矿山的充填工艺具有重要意义。研究论述了难处理钨矿尾砂沉降性能与粒级组成、表面形状及矿浆连续相的关系,研究结果表明:矿浆连续相性质对尾砂的沉降性能影响最大。选矿工艺中的碳酸钠和水玻璃使矿浆p H值适合起泡剂的发泡作用,阻碍细颗粒尾砂的下沉;采用酸中和矿浆至中性、聚合氯化铁消解水玻璃并初步凝聚尾砂颗粒,添加FA6000s絮凝剂使尾砂快速沉降。最终优选的药剂制度为聚合氯化铁75 g/t、FA6000s絮凝剂25 g/t,该方法实现了对该难处理白钨尾砂的快速沉降。     

硅藻土与常规调理剂改善污泥沉降及脱水性能的比较

本实验比较了硅藻土和无机絮凝剂对剩余污泥沉降性能和脱水性能的改善效果,通过对污泥各性能指标的变化分析,硅藻土处理剩余污泥较传统絮凝剂具有一定的优势,其对污泥各指标性能均有提升,污泥沉降比和污泥比阻减小效果明显。对于四种污泥调理剂,硅藻土最佳投加量为0.8g/L污泥,聚合氯化铝最佳投加量为0.1 g/L污泥,氯化铁最佳投加量为0.3 g/L污泥,硫酸铝最佳投加量为0.8 g/L污泥。     

湿法炼锌溶液中臭氧氧化除铁工艺及动力学研究

以臭氧为强氧化剂、ZnO为中和剂进行湿法炼锌溶液中Fe2+脱除的试验及动力学研究。考察初始Fe2+浓度、溶液pH、反应温度和O3流量等因素对除铁效果的影响。结果表明：增大pH、温度和O3流量可以显著增加除铁效率,而增加初始Fe2+浓度会降低除铁效率。宏观动力学研究表明,对比常用的拟一级、拟二级、Higbie和Avrami等动力学方程,臭氧氧化—沉淀除铁符合拟一级反应特征,受扩散控制,反应表观活化能为28.57 kJ/mol,动力学方程为r_(Fe^(2+) )=8.22[Fe^(2+) 〖]_0〗^(-0.74) [H^+ ]^(-0.51) Q_(O_3)^1.89 exp?〖(-3436/T〗)。     

湿法提取铅阳极泥中的铋锑技术研究

正介绍了湿法提取铅阳极泥中铋锑的技术研究,考察了铅阳极泥的氧化温度、盐酸浓度、反应温度、反应时间、液固比、三氯化铁用量和氯化钠用量对铋锑浸出率的影响。实验结果表明,铅阳极泥预处理对铋锑浸出率影响较大,在铅阳极泥经粉磨过-200目筛后,当氧化温度为220℃,盐酸浓度为5mol/l,液固比为5∶1,反应温度为80℃,反应时间为3h,三氯化铁浓度为10g/l,氯化钠浓度为45g/l时,铋锑的浸出率分别达到99.44%和99.69%。     

空气氧化法生产高浓度聚合硫酸铁

聚合硫酸铁是新近出现的水处理絮凝剂,广泛用于工厂的给水处理和各行业的废水处理。其絮凝效果优于硫酸铝、三氯化铝、三氯化铁等传统絮凝剂,也优于新型水处理剂聚合氯化铝。目前国内有一些单位在研制和生产聚合硫酸铁,但大都采用氧气催化氧化法工艺。由于使用价格较贵的氧气,使产品成本较高,且氧气贮运不便。该法生产的产品中有效成分 Fe~(3 )的含量也较低,大多在90～140克/升。     

The leaching of nickeliferous laterite with ferric chloride

Several experiments were conducted to investigate the extraction of nickel from nickeliferous laterite by ferric chloride solutions as a function of pulp density, solution composition, and temperature. Solubility relationships for goethite and nickel laterite in aqueous solution were reviewed in terms of leaching rates and reaction mechanisms. Generally, the amount of nickel extracted increased with temperature, the amount of “free acid,” and ferric chloride concentration; however, the amount was inhibited by ferrous chloride. In this investigation, as much as 96 pct of the available nickel was extracted by ferric chloride solution. Nickel extraction was found to be more dependent on ferric chloride concentration than on the concentration of hydrochloric acid. Mechanistically, nickel extraction occurred by the formation of an intermediate ferric chloride complex, which was then hydrolyzed to hematite.     

新型TMT-硫酸铁固定剂对重金属污染土壤的修复研究

以新型TMT（三巯基均三嗪三钠盐）-硫酸铁复配混合物为化学固定剂,考察了其对湖南郴州某重金属污染土壤中铅、镉、砷的固定效果.结果表明,单一使用TMT（含15 %（质量分数）TMT的水溶液）为固定剂时,土壤中的有效态铅、镉去除率高于60 %,但对砷没有固定效果.使用TMT-硫酸铁复配固定剂时,控制硫酸铁投加量为35.7 g/kg,TMT投加量为0.1 L/kg时,有效态铅、镉去除率达到90 %以上.随着土壤含水量的增加,土壤中有效态铅、镉的含量显著降低.当控制硫酸铁投加量为35.7 g/kg,TMT投加量为0.04 L/kg,控制土壤含水量至田间持水量的70 %,固定60 d,有效态铅、镉的去除率在80 %以上,有效态砷的去除率可达到60 %.      

Representation of the Kinetics of Leaching of Galena by Ferric Chloride in Concentrated Sodium Chloride Solutions by a Modified Mixed Kinetics Model

Galena (PbS) is leached by a solution concentrated in NaCl and containing ferrous and ferric chloride. The ferric ion concentration is kept constant by adding KMnO₄ or the potential is kept constant by adding a concentrated ferric chloride solution. The ferrous concentration of the solution has no effect upon the kinetics, the temperature and the chloride concentration have only a weak effect, whereas the radius of solid particles and the concentration of the ferric ion have the major influences. The kinetics are represented by a shrinking core model for up to 99 pet of ore dissolved. Both the aqueous diffusion of ferric ion in the pores of the sulfur layer and the chemical reaction at the surface are involved in the kinetic model. Taking into account the self blockage improves the representation of the end of reaction and yields a more consistent set of parameters. D. MORIN, formerly with the School of Mines, Paris. France     

The kinetics of dissolution of sphalerite in ferric chloride solution

The dissolution of sphalerite in acidic ferric chloride solution was investigated in the temperature range 320 to 360 K. Both sized particles from three sources and polished flat surfaces were used as samples. The effect of stirring rate, temperature, ferric and ferrous ion concentration, purity, and particle size on the dissolution rate were determined. During the initial stages of the process chemical reaction at the mineral surface is rate controlling while during the later stages diffusion through the product sulfur layer is rate controlling. Overall the process follows the mixed-control model embodying both chemical reaction and diffusion. The activation energy for the dissolution of sphalerite particles was found to be 46.9 kJ/mol.     

Mass Transfer of Ozone in Semibatch Stirred Reactor

The mass transfer of ozone from the gaseous phase into the aqueous phase plays an important role in determining the efficiency of ozonation. In this study, a mass-transfer model has been developed to simultaneously predict concentrations of the dissolved and outlet gaseous ozone in a semibatch reactor. A model in which the liquid phase is described as well mixed and the gas phase is described as a plug-flow system was used to estimate the mass transfer of ozone in both laboratory and pilot reactors. The self-decomposition of ozone was also incorporated into the model. The mass-transfer coefficient was found to increase with increasing gas flow rate, temperature, and ionic strength in the solution. Using a sensitivity analysis, the partition coefficient α was found to be the most sensitive factor that affects the concentration profile of dissolved ozone. However, the outlet gaseous concentration of ozone is quite insensitive to all physical parameters investigated in this study.     

萃取法从废旧锂离子电池正极材料 浸出液中提取锂

废旧锂离子电池正极材料浸出后,溶液中的镍、钴等有价金属十分容易回收,但一直没有很好的方法来回收锂.实际上,这种浸出液和盐湖卤水都为锂盐溶液,所不同的只是盐湖卤水中锂的浓度往往要低一些,并有大量的氯化钠、氯化镁伴生,因此可将废旧锂离子电池浸出液看做一种特殊的“盐湖卤水”,并进一步调整其Cl－的浓度,进而成功地采用盐湖提锂中常用的萃取法.该方法以磷酸三丁酯（TBP）为萃取剂,磺化煤油为稀释剂,在三氯化铁（FeCl₃）存在的条件下,实现选择性提取锂. TBP首先与FeCl₃-NaCl的酸性溶液接触, 形成了锂的专属萃取剂;并将浸出液中氯化钠的浓度进一步调整到250 g/L,在相比（V_O/V_A）为3,温度为室温条件下萃取5 min, 锂的单级萃取率可达到75 %左右,而Ni2+、Co2+、Mn2+几乎没有被萃取.根据平衡等温线,通过4级逆流萃取,锂的萃取率可达到99 %.      

从净水剂液体三氯化铁中去除钙

将酸浸含钙量较高的氧化铁物料得到的氯化铁和氯化亚铁混合溶液加工成净水剂液体三氯化铁时必须把溶液中的钙除去。采用聚合硫酸铁去除液体三氯化铁中的钙离子，钙去除率几乎可达100％，产品质量较高，而且除钙工艺成本低，流程易于控制。     

New colorimetric method for quantitative determination of protein in urine

Total urinary protein is rapidly precipitated at room temperature by tannic acid. The tannic acid/protein precipitate, dissolved in aqueous triethanolamine/ferric chloride solution, gives a purple-violet color of high absorptivity. Absorbance at 510 nm is linearly related to concentration from 0.05 to 1.50 A for a protein content of 0.05 to 1.50 g/liter, and less than 5 mg/liter can be detected. The CV and analytical recovery ranged from 0.5 to 1.8% and 98 to 103%, respectively. Nonprotein urinary constituents do not interfere.     

Kinetics of galena dissolution in ferric chloride solutions

A leaching investigation of galena with ferric chloride has been carried out as a function of concentration of ferric chloride and sodium chloride, temperature, and particle size. Three size fractions were considered in this investigation, namely, 48 × 65, 35 × 48, and 28 × 35 mesh. The concentration ranges of ferric chloride and sodium chloride used in this investigation were 0 to 0.25 M and 0 to 3 M, respectively. The reaction rate mechanism has been discussed in terms of a shrinking core model developed for cubic systems. Mass transport of ferric chlorocomplex through the product sulfur layer appears to be responsible for establishing the overall leaching rate under most of the conditions used in this investigation. The apparent activation energy for the leaching of 28 × 35 mesh galena with 0.1 M FeCl₃, 1 M HC1, and 3.0 M NaCl was found to be about 8.05 kcal/mol (33.7 kJ/mol), which was partially contributed by diffusion and partially by the heat of reaction of the formation of ferric chlorocomplexes. Rate of dissolution at both 50° and 90 °C is greatly affected by ferric chloride concentration up to 0.2 M and is essentially constant with ferric chloride concentration above this value.