Counter-current vs co-current flow in carbon-in-pulp adsorption circuits

Carbon-in-pulp (CIP) and carbon-in-leach (CIL) technology is applied successfully to recover gold from cyanided pulps. These plants are operated on a counter-current basis allowing for small concentrations of gold to be recovered at the expense of inefficiencies such as back-mixing, additional carbon breakage by interstage pumps and difficulties in carbon inventory management. In this study, linear regression techniques were utilised in order to study the adsorptive behaviour of carbon in gold bearing solutions with the aim of determining whether a partial co-current mode of operation will be feasible in CIP operations. It has been found that these empirical techniques are able to predict the adsorption rate of gold onto activated carbon and that the point of discontinuity of the constant rate adsorption period can accurately be determined. Thus, the behaviour of a single activated carbon particle can be predicted making use of standard linear regression techniques and using inputs such as, slurry density, rate of agitation, carbon loading and carbon and gold concentration. This information can then be utilised to maximise the use of the constant rate adsorption period by using a partial co-current mode of operation and reducing inefficiencies such as back-mixing and gold loss due to the abrasive action of interstage pumping on the adsorbent.     

煤液化残渣基炭材料吸附瓦斯实验研究

实验采用自行设计的单塔高流量、常压吸附装置和煤液化残渣基炭材料吸附剂,讨论了不同吸附剂用量、不同装柱方式对CH4/N2分离性能的影响。结果表明:在550℃,KOH活化下所制备煤液化残渣基活性炭的比表面积可达1721 m2/g,其中微孔占到开孔数量的89.5%;在相同吸附剂装填量下,分层装填方式对甲烷的吸附性能要优于混合式装填方式;在分层装填方式下,随着吸附剂装填数量的增加,甲烷的吸附量增加,饱和吸附性能提高20%。     

Modelling of gold (I) cyanide adsorption based on the properties of activated bagasse

Bagasse, the fibrous residue from sugar cane milling operation, was subjected to physical activation using CO₂ to establish its suitability as a precursor for gold adsorption, specifically for the recovery of gold from cyanide medium. Mathematical modelling, which correlates the effects of carbon properties on the adsorption behaviour, was conducted to formulate a basis for tailor making the adsorbent for this particular application. The developed model suggests carbon properties of alkali pH, high total surface area and small pore diameters are required for optimum adsorption capacity. The optimum adsorption capacity attained by the developed carbon in this study was 227% that of the test commercial activated carbon, which exhibited an adsorption of 101mg Au/g carbon. Hence this demonstrates bagasse as a promising precursor for the manufacture of activated carbon for gold cyanide adsorption.     

磁性活性炭的制备及其对选矿废水中丁基黄药的去除研究

通过共沉淀法将Fe₃O₄负载在活性炭上, 制备磁性活性炭MAC, 解决了普通活性炭存在的分离回收困难问题。将其用于吸附选矿废水中的丁基黄药, 考察了吸附时间、吸附剂用量和pH值等因素对吸附性能的影响, 结果表明, 在pH=7、吸附时间3 h、丁基黄药浓度100 mg/L、MAC用量0.6 g/L条件下, MAC对丁基黄药的去除率达99.73%。MAC对丁基黄药的吸附满足二级动力学方程和Langmuir等温模型。通过磁力对MAC进行回收, 回收率达98%。5次重复使用后MAC对丁基黄药去除率仍有76.59%, 是一种经济环保的吸附剂。     

Total recovery of gold,palladium, and platinum using lignophenol derivative

A tertiary amine type adsorption gel was prepared by the immobilization of dimethylamine onto crosslinked lignophenol (CLP) matrix. This novel product was studied for its adsorption behavior for Au(III), Pd(II), Pt(IV), Cu(II), Zn(II), Ni(II), and Fe(III) in 0.5–6 M hydrochloric acid medium. From our previous study, crosslinked lignophenol (CLP) is known to hold solo selectivity for Au(III). After modification to dimethylamine type adsorbent (DMA-CLP), an extended selectivity of Au(III), Pd(II), and Pt(IV) was observed. The maximum loading capacity for these three metal ions was evaluated by isotherm study. For Au(III) an impressive value of 7.2 mol/kg of DMA-CLP was observed. The feasibility of recovery of precious metals from a mixture containing several other metal ions was studied in batch mode by using both model solution and actual industrial solution obtained after aqua regia leaching of metal components in obsolate e-devices. In addition, a number of adsorption–elution cycles were produced so as to know the feasibility of multiple uses.     

Adsorbing flocs in expanded/fluidised bed reactors: A new basis for pollutants removal

The present work describes studies concerning a new adsorption technique based on the use of adsorbent flocs in an expanded/fluidised bed reactor for the removal of pollutants from aqueous solutions. The technique, based on flocculation of aqueous suspensions of powdered adsorbent materials, when conducted in an expanded/fluidised bed reactor takes advantage of conducting adsorption and solid–liquid separation in one single stage. Studies were performed using flocculated powdered activated carbon and natural zeolites, alone and in mixtures, for phenol and ammonia adsorption. A reactor with cylindrical–conical geometry was used for the pollutants adsorption in flocs beds (pure and mixed), as well as the regeneration/recycle of the exhausted adsorbents. Results proved the high adsorption efficiency of powdered natural zeolites and activated carbon flocs for the uptake of ammonia (11 mg NH₃–N g⁻¹) and phenol (132 mg g⁻¹), at 38 and 19 m h⁻¹ loading rates, respectively. Regeneration/recycle of the pollutant-saturated beds was possible for the ammonia/natural zeolites adsorption case, using sodium sulphate as regenerator. Use of mixed flocs beds was efficient, showing advantages such as multiple-pollutants adsorption in one single stage, higher loading rates when using light materials (activated carbon) combined with heavier ones (natural zeolites) and use of small adsorbent concentrations (not possible otherwise). Economical and environmental issues regarding the technique are also discussed in the paper. The new technique shows great potential as an alternative physicochemical adsorption process for pollutant removal from aqueous solutions using low-cost and highly-available powdered adsorbent materials.     

山东某风化壳型金矿氰化浸出试验研究

针对山东某风化壳型金矿进行了氰化浸出试验研究,考察了磨矿细度、氰化钠用量、石灰用量、液固比、搅拌时间等对金浸出效果的影响规律。试验结果表明,较粗的磨矿细度和较低的矿浆浓度对浸出更有利,在最佳的试验条件下,该矿石的金浸出率可达到95.87%,炭吸附率可达到99.58%。     

石棉尾矿酸浸渣对废水中Zn2+的吸附性能研究

石棉尾矿酸浸渣经煅烧提纯处理,对废水中Zn2 有较好的吸附性能.一定范围内,增加酸浸渣用量、延长吸附作用时间、升高吸附温度、提高pH值,均可改善对Zn2 的吸附去除效果,其中pH值是影响吸附的主要因素.酸浸渣对废水中Zn2 的等温吸附,符合Langmuir模型,为化学吸附.     

壳聚糖负载膨润土处理含磷废水的试验研究

利用壳聚糖负载膨润土吸附处理含磷废水,考察了吸附剂投加量、吸附时间、振荡强度、pH值等对磷去除率的影响。结果表明:投加量为0.5g、吸附90min、振荡强度为100 r/min、pH值为7,25℃下对25mL质量浓度为2mg/L的磷溶液去除率为78.25%。壳聚糖负载膨润土对磷的吸附符合Langmuir等温吸附模式。     

再生润滑油吸附除臭的实验研究

以活性白土、分子筛、硅胶和活性炭为吸附剂,对再生润滑油进行吸附除臭处理;比较了用吸附剂直接吸附除臭和先絮凝再吸附除臭2种方法对再生润滑油的除臭效果,考察了影响絮凝、吸附的各种因素。结果表明,先絮凝再吸附,效果均较直接吸附除臭有明显的提高,活性白土、硅胶和活性炭的除臭去除率均可达96%以上,分子筛的除臭去除率也可达87%以上;最佳絮凝条件:温度80℃、150mL再生润滑油所需2种絮凝剂用量分别为3.7g和1.3g;最佳吸附条件:吸附温度为70℃,吸附时间为5min(分子筛为30min),吸附剂的用量为2g(活性白土为4g),pH值为10。     

活性炭吸附回收浸出液中金络合物的研究进展

矿石中的金常用氰化物和非氰化物作为浸出剂,形成金络合物浸出到浸出液中。由于活性炭具有耐腐蚀、较强的吸附能力、可循环利用等优点,常用来吸附回收浸出液中金络合物。本文在前人研究的基础上,重点分析了氰化炭浆法中活性炭吸附Au(CN)2-的机理和研究进展,概述了非氰浸出液(硫代硫酸盐浸出液、硫脲浸出液、卤素浸出液、硫氰酸盐浸出液)中活性炭吸附回收金络合物的机理及研究进展。为活性炭在提金工业中的更好应用提供参考。     

基于活性炭的真空变压吸附提浓煤层气甲烷的实验研究

测试了活性炭的平衡吸附特性,在此基础上研究筛选出了适合煤层气提浓的活性炭,其比表面积为1 706 m2/g,并建立了两塔真空变压吸附提浓煤层气甲烷的实验装置,对甲烷体积分数为20%的低浓度煤层气提浓进行了实验。结果表明：利用真空变压吸附的方法,吸附压力在209 kPa以内,解吸压力为21 kPa时,可以将体积分数为20%的煤层气提浓到30%以上且产率超过80%;适当的延长吸附时间有助于提高甲烷的体积分数;降低解吸压力有助于提高甲烷的体积分数和产率;均压有助于提高甲烷的体积分数,既有上均压又有下均压的均压过程对甲烷体积分数的增大效果最好,实验中下均压02 s、上均压04 s时甲烷体积分数最大;维持吸附时间不变,存在一个最佳的产品气与原料气之比（Qc/Qin）,使得甲烷体积分数达到最大值。     

贵州某钡渣盐酸浸出回收钡离子实验研究

大量钡渣堆积会对环境造成极大的危害。对钡渣采用盐酸浸出,能有效回收钡渣中剩余可溶性钡盐,还能大大减少钡渣对环境的危害,是一种较好的利用钡渣的方法。本文通过实验,得出了较好的钡渣盐酸浸出条件,在钡渣磨矿细度为-0.074 mm 80%,盐酸浓度为3 mol/L,浸出固液比为1∶7,浸出时间为2 h,浸出温度为40℃,浸出搅拌速度480 r/min时,得到了较佳的钡离子浸出率,钡离子总浸出率达到了38.88%,仅考虑可溶性钡盐时,钡离子浸出率达到90.30%。     

Modelling of an autoclave used for high pressure sulphuric acid/oxygen leaching of first stage leach residue,Part 2: Model application

In this study, the application of models to predict the steady state and dynamic behaviour of the pressure leaching stages at a Base Metal Refinery (BMR) is discussed. Part I of this communication provides background about the context of the study, and presents a complete overview of the process concerned and the model development strategy. The steady state model allows the prediction of the operating temperature and the slurry composition in the different autoclave compartments as a function of pressure, feed rates, and the flow rate of the flash recycle stream. The dynamic response of the temperature and stream compositions to changes in the above mentioned process variables can also be predicted. It has been illustrated how interdependencies between process variables can be determined and an improved understanding of the process can be developed by means of the process models. The importance of controlling the relative leaching rates of digenite and covellite to minimise precious metal leaching, for example, was illustrated by modelling the system behaviour at different operation conditions.     

某地浸采铀矿山低流量钻孔O2加注方式优化

针对CO₂+O₂原地浸出采铀过程,通过对氧气溶解机制、氧气喷射混合、氧气静态混合及钻孔氧气溶解情况等因素的分析,提出了一种适用于低流量钻孔的O₂加注方式,实现了低流量钻孔的O₂加注,提高了低流量钻孔浸采单元浸出效果,缩短了浸出周期,提高了资源回收率,降低了浸采成本。     

浅析活性炭在湿法炼锌中对锗的吸附效果

国内某厂采用湿法炼锌,其原料中含有锗,在酸性浸出过程中锗元素随之被浸出,锗元素含量超标会造成硫酸锌电解过程烧板,严重影响锌电解过程正常运行。阐述了活性炭吸附硫酸锌浸出液、净化液中锗的部分条件试验,研究了活性炭吸附温度和酸性浸出液在不同锗浓度条件下对吸附效果的影响,目的在于利用物理方法提高焙砂浸出过程中锗的脱除率和降低净化过程中锌粉的单耗。     

某难浸浮选金精矿碱式预处理-氰化提金工艺

某浮选金品位65．20g／t，含砷15．40％、硫25．64％。84％以上金被黄铁矿、毒砂和脉石包裹，为难浸金精矿。在常温常压下进行碱式预处理。再接氰化和炭吸附提金。结果表明。在NaCN用量6．5kg／t和炭浆浓度17．5g／L。炭浸24h条件下，金浸出率达93．42％。金吸附回收率达99．67％。     

云南某氧化金矿石氰化浸出渣对金和银氰络合物的吸附

研究某褐铁矿型金矿石氰化浸出渣对银和金氰络合物的吸附过程.结果表明,随吸附时间延长,溶液中金络合物浓度降低,而银络合物浓度有所增加.浸出渣对金和银络合物的吸附特点不同,活性炭与浸出渣对金和银络合物的吸附特性也不同.浸出渣对被浸出的铜络合物也有一定的吸附作用,对滤液中的氧化钙有比较大的吸附作用,从而导致矿浆的pH下降.     

Mn-Cu吸附剂脱除模拟烟气中NO的研究

采用超声辅助加压浸渍法在半焦上负载金属组分锰和铜,研究锰铜吸附剂在模拟烟气中脱除NO的性能。重点考察了金属组分和锰铜摩尔比对Mn-Cu吸附剂脱除NO性能的影响。通过XRD,BET,XPS,AAS等表征手段对Mn-Cu吸附剂NO脱除机理进行初步探索。结果表明,双金属锰铜吸附剂脱除NO的能力远高于单金属锰吸附剂和铜吸附剂,在锰吸附剂中添加适量铜可以使锰铜组分之间产生协同效应从而显著提高吸附剂的脱硝性能;金属组分锰铜最佳浸渍摩尔比为3∶1,且实际负载量在1∶1时脱硝性能最佳,吸附剂M3C1在脱除效率为80%以上的穿透硝容高达10.07 mg/g,穿透时间长达300 min。在模拟烟气中含O2气氛下,吸附剂中的Mn3+是脱除NO的主体,碳骨架提供化学吸附的反应场所,组分Cu起到催化的作用。     

蒸汽相中煤矸石自转变合成AI-MFI型吸附剂

以煤矿的废弃物煤矸石为原料,研究了373~400 K温度范围内,煤矸石在乙胺和水的蒸汽相中自转变合成了纯度、结晶度均较高的AI-MFI 型吸附剂的过程, 并对其吸附性能做了初步研究, 用氮吸附静态容量法(BET)测得该矸石基吸附剂的氮吸附等温线、比表面积和孔分布曲线.用XRD和孔隙率等手段对所得的AI-MFI型吸附剂进行表征.通过AI-MFI型吸附剂对苯酚的吸附实验,给出AI-MFI 型吸附剂对它的吸附等温线.实验结果表明：由煤矸石在蒸汽相中自转变合成的AI-MFI 型吸附剂颜色为灰白色,有较好的吸附性能.并指出合理的吸附温度、大的比表面积对提高矸石基吸附剂的吸附量都是有效的.