Leaching kinetics of zinc silicate in ammonium chloride solution

The leaching kinetics of zinc silicate in ammonium chloride solution was investigated. The effects of stirring speed （150？400 r/min）, leaching temperature （95-108 ℃, particle size of zinc silicate （61-150 μm） and the concentration of ammonium chloride （3.5-5.5 mol/L） on leaching rate of zinc were studied. The results show that decreasing the particle size of zinc silicate and increasing the leaching temperature and concentration of ammonium chloride can obviously enhance the leaching rate of zinc. Among the kinetic models of the porous solids tested, the grain model with porous diffusion control can well describe the zinc leaching kinetics. The apparent activation energy of the leaching reaction is 161.26 kJ/mol and the reaction order with respect to ammonium chloride is 3.5.

Effect of ammonium chloride on leaching behavior of alkaline anion and sodium ion in bauxite residue

This study focused on leaching behavior of alkaline anion and sodium in bauxite residue through ammonium chloride treatment.The results showed that the pH of bauxite residue decreased from 10.49 to 8.93,total alkaline anion(HCO3^-,CO3^2-,OH^-,AlO2^-)concentration reduced from 38.89 to 25.50 mmol/L,leaching rate of soluble sodium was 80.86%with ammonium chloride addition of 0.75%,liquid/solid(L/S)ratio of 3(mL/g),temperature of 30°C and reaction time of 18 h;L/S ratio was the main factor affecting the removal of alkaline anion and the leaching of sodium.Furthermore,ammonium chloride promoted the dissolution of diaspore and changed the micro/morphological characteristics with the increase of massive structure.The findings of this work will contribute to achieve soil-formation of bauxite residue.

Dissolution kinetics of low grade complex copper ore in ammonia-ammonium chloride solution

The leaching kinetics of Tang-dan refractory low grade complex copper ore was investigated in ammonia-ammonium chloride solution.The concentration of ammonia and ammonium chloride,the ore particle size,the solid-to-liquid ratio and the temperature were chosen as parameters in the experiments.The results show that temperature,concentration of ammonia and ammonium chloride have favorable influence on the leaching rate of copper oxide ores.But,leaching rate decreases with increasing particle size and solid-to-liquid ratio.The leaching process is controlled by the diffusion of the lixiviant and the activation energy is determined to be 23.279 kJ/mol.An equation was also proposed to describe the leaching kinetics.

Extraction of metals from complex sulfide nickel concentrates by low-temperature chlorination roasting and water leaching

The recovery of valuable metals from complex sulfide concentrates was investigated via chlorination roasting followed by water leaching. A reaction process is proposed on the basis of previous studies and the results of our preliminary experiments. During the process, various process parameters were studied, including the roasting temperature, the addition of NH4Cl, the roasting time, the leaching time, and the liquid-to-solid ratio. The roasted products and leach residues were characterized by X-ray diffraction and vibrational spectroscopy. Under the optimum condition, 95% of Ni, 98% of Cu, and 88% of Co were recovered. In addition, the removal of iron was studied in the water leaching stage. The results demonstrate that this process provides an effective approach for extracting multiple metals from complex concentrates or ores. © 2017, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.

Kinetics of Magnesium Slag Leaching by NH_(4)Cl

The leaching kinetics of magnesium slag in ammonium chloride solutions was investigated.The effects of initial ammonium chloride concentration,liquid-solid ratio and reaction temperature on the leaching rate of calcium were determined.The results showed that the leaching rate increased with the increase in initial ammonium chloride concentration,reaction temperature and liquid-solid ratio.It was determined that the leaching rate fit the Avrami equation,and the leaching process was controlled by diffusion.The activation energy was 13.22 kJ/mol.

氯化铵浸取电石渣中钙离子的研究

电石渣是工业生产乙炔气过程中电石水解后产生的废渣,主要成分是Ca(OH)_(2)。文章以氯化铵为浸取剂,提取电石渣中的钙离子,以达到提纯钙和资源化利用的目的。实验探究了不同用水量、氯化铵用量、反应温度及反应时间下Ca^(2+)浸取率,探讨了氯化铵浸取机理,同时对浸取液和滤渣的成分进行了详细分析。结果表明,当浸取温度25℃,浸取时间40min,电石渣∶氯化铵∶用水量=5∶6∶35时,电石渣中的Ca^(2+)浸取率最高,为76.58%。经氯化铵浸取,电石渣中的Mg、Al、Fe、C等杂质被去除,Ca^(2+)纯度达到98%,滤渣中的主要成分为炭黑、碳酸钙、水铝钙石、钙矾石。

含钛高炉渣氯化铵焙烧活化试验

针对钒钛磁铁矿高炉冶炼副产的含钛高炉渣成分复杂、难以处理特点,采用氯化铵焙烧活化—浸出提质处理工艺进行钙铝镁等杂质金属元素的脱除,获得钛富集物。考察焙烧和浸出过程中各参数对杂质脱除的影响。结果表明,在焙烧温度450℃、焙烧时间1 h、氯化铵配比40%、原料-0.074 mm占比83%,盐酸浓度9%、液固比5、浸出时间4 h、浸出温度90℃的优化条件下,含钛高炉渣中钙、铝、镁脱除率分别达到73.22%、90.04%、91.39%,钛损失率仅有0.34%,达到选择性脱除炉渣中杂质元素,提高含钛高炉渣品质的目的。

密闭机械活化浸出电石渣制备高纯钙溶液

电石渣是工业生产过程产生的碱性危废,利用于CO_(2)固化,将有助于“碳达峰、碳中和”目标早日实现。在碱性环境中,用氯化铵浸出剂可选择性浸出Ca,使电石渣中的Ca与其他杂质分离开来,从而制备高纯度含钙溶液,之后将所得富钙液与CO_(2)反应制备高纯碳酸钙,从而实现固废资源化。以氯化铵为浸出剂,球磨机为浸出反应设备,采用密闭机械活化手段进行处理,探究了浸出剂用量、机械搅拌转速、反应时间和液固比等工艺参数对电石渣中Ca浸出率的影响。结果表明,在氯化铵用量为理论用量的1.1倍、球磨机转速500 r/min、反应时间10 min和液固比4∶1最佳反应条件下,Ca浸出率可达到89.76%,滤液Ca浓度高达79.4 g/L。相较于常规浸出,采用密闭机械活化手段可提高Ca浸出率3个百分点,且可大幅度降低氨气挥发,保证良好操作环境。

白云石炼镁收尘灰制备碳酸钙工艺研究

以白云石炼镁收尘灰为原料,利用铵浸-碳化法制备碳酸钙。采用XRD、SEM和EDS对制备的样品进行表征。研究了制备碳酸钙的3个过程中消化水量、消化时间、消化温度、氯化铵浓度、铵浸温度、碳化时间、碳化温度及二氧化碳流速对样品产率影响。得到了制备碳酸钙的最佳工艺:水和炼镁收尘灰的质量比为7∶1、消化温度30℃、消化时间80 min,氯化铵浓度2 mol·L^(-1)、铵浸温度55℃、铵浸时间15 min、二氧化碳流速250mL·min^(-1)、碳化温度30℃、碳化时间9min。最佳工艺下制备的碳酸钙由物质的量比为1∶1的方解石和球霰石两相组成,产率86.62%,纯度97.5%。

煅烧-铵盐两步浸出法对磷矿浮选尾矿钙镁回收研究

采用煅烧-铵盐两步浸出法对磷矿浮选尾矿中的钙和镁进行回收,考查了铵盐种类及用量、固液比、反应温度、反应时间等对氧化钙和氧化镁浸出率的影响。磷矿浮选尾矿的最佳煅烧温度为1000℃、煅烧时间为60 min。在氧化钙与氯化铵摩尔比为1∶2.2、固液比为1∶7、反应温度为35℃、反应时间为20 min的条件下,氧化钙的浸出率为56.69%,氧化镁的浸出率为4.29%,较好地实现了钙镁分离。在氧化镁与硫酸铵摩尔比为1∶1.4、固液比为1∶10、反应温度为90℃、反应时间为60 min的条件下,氧化镁的浸出率达83.43%。煅烧-铵盐两步浸出法能有效实现对磷矿浮选尾矿的二次利用。

钡渣氯化铵浸出工艺试验及过程机理研究

针对大量堆存的危险固体废弃物钡渣,作者开展了氯化铵浸出工艺试验研究,通过氯化铵循环浸出从钡渣中提取碳酸钡产品,并实现浸出渣的无害化。结果表明,在最佳浸出条件下(球磨时间15 min、氯化铵浓度3 mol/L、液固比10∶1、反应温度90℃、反应时间3 h),钡渣中碳酸钡一次浸出率可达到60%,通过3次循环浸出,可使钡渣中碳酸钡含量由25.09%降低至3%以下,浸出渣中Ba2+浸出毒性及碳酸钡毒性物质含量均低于相关危险废物鉴别标准限值。最后,采用扫描电子显微镜和电子微探针探究了浸出前后钡渣的表面形貌及化学组成变化,揭示了钡渣与氯化铵的作用过程机制。

Process optimization of rare earth and aluminum leaching from weathered crust elution-deposited rare earth ore with compound ammonium salts

In order to intensify the leaching process of rare earth（RE） and reduce the impurities in the leachate, ammonium chloride（NH4Cl） and ammonium nitrate（NH4NO3） were mixed as a compound leaching agent to treat the weathered crust elution-deposited RE ore. Effects of molar ratio of NH~＋_4Cl and NH_4NO_3, ammonium（NH_4） concentration, leaching agent pH and flow rate on the leaching process of RE were studied and evaluated by the chromatographic plate theory. Leaching process of the main impurity aluminium（Al） was also discussed in detail. Results showed that a higher initial ammonium concentration in a certain range could enhance the mass transfer process of RE and Al by providing a driving force to overcome the resistance of diffusion. pH almost had no effects on the mass transfer efficiency of RE and Al in the range of 4 to 8. The relationship between the flow rate and height equivalent to a theoretical plate（HETP） could fit well with the Van Deemter equation, and the flow rate at the lowest HETP was determined. The optimum conditions of column leaching for RE and Al were 1：1（molar ratio） of NH_4Cl and NH_4NO_3, 0.2 mol/L of ammonium concentration, pH 4–8 of leaching agent and 0.5 mL /min of flow rate. Under this condition, the mass transfer efficiency of RE was improved, but no change was observed for Al compared with the most widely used ammonium sulfate. Moreover, the significant difference value（around 20 mL） of retention volume at the peak concentration between RE and Al provided a possibility for their separation. It suggested the potential application of the novel compound leaching agent（NH_4Cl/NH_4NO_3）. It was found that the relative concentration of RE in the leachate could be easily obtained by monitoring the pH of leachate.

用NH_4Cl溶液浸出氧化锌矿石

研究了用氯化铵溶液浸出氧化锌矿过程中反应条件对锌浸出率的影响。结果表明,在搅拌速度300 r/min,矿样平均粒径0．075mm,反应温度90℃,氯化铵浓度5mol/L,反应时间4h条件下,锌的浸出率近90%,浸出液中铁质量浓度仅为0．61mg/L。

机械活化对氧化锌矿碱法浸出及其物化性质的影响

研究了不同活化时间、活化方式对云南兰坪低品位氧化锌矿碱法浸出的影响.结果表明,当浸出液NH4Cl浓度2.0mol/L、NH3·H2O浓度1mol/L、温度30℃、浸出液与浸出矿样液固比为10L/g时,未活化矿样浸出90min浸出率仅为60.08%,而活化90min矿样浸出90min的浸出率为69.36%,为可浸出含锌物相的103.97%;先磨后浸的强化效果优于边磨边浸.不同活化时间、活化方式不仅造成矿物的形貌、粒度分布不同,而且使矿样在球磨过程中的物相转化存在差异:活化与浸出步骤分离时,球磨过程发生了机械化学反应,矿样中ZnS被氧化成利于浸出的物相,从而比两步骤合并的浸出效果好.

煅烧菱镁矿在氯化铵乙二醇溶液中的浸取动力学

系统地研究了菱镁矿的煅烧条件以及煅烧粉在氯化铵乙二醇溶液中的浸取动力学.菱镁矿在750℃下煅烧2h左右能使MgCO3分解完全而CaCO3不分解,过烧会使晶粒长大,从而降低浸取速率.在消除外扩散影响的前提下,浸取过程在反应物(NH4Cl与MgO)以化学计量比反应、氯化铵的初始浓度为0～1.23mol/L时符合未反应收缩核模型(Unreacted shrinking coremodel),且浓度为1.23mol/L时浸取速率达到最大;浸取速率受表面化学反应控制,活化能为44.74kJ/mol.

高炉瓦斯灰氨浸脱锌

研究用氨水+氯化铵浸出高炉瓦斯灰脱锌工艺过程。最佳浸出工艺条件为:室温、浸出时间3h、搅拌速度600r/min、液固比为4∶1、氨水与氯化铵浓度均为2.5mol/L。在此条件下,浸出液锌浓度为23.36g/L,锌浸出率高达89%。浸出渣含锌量1.168%,经水洗后可直接作为高炉烧结原料。

氯化铵溶液中还原浸出海洋锰结核

采用亚硫酸钠作还原剂对氯化铵溶液中海洋锰结核的浸出行为进行研究，探讨Ｎａ２ＳＯ３加入量、ＮＨ４Ｃｌ浓度及初始ｐＨ值、浸出温度和时间等对锰结核中铜、镍、钴、锰、铁浸出率的影响。结果表明５．０ｍｏｌ／ＬＮＨ４Ｃｌ溶液中，初始ｐＨ值约５．０及８０℃、１８０ｍｉｎ，锰结核与Ｎａ２ＳＯ３等量加入时，铜、镍、钴、锰的浸出率分别为８８．５６％、９６．１４％、７８．５７％、３５．２％，铁几乎未被浸出。而在同样的条件下，控制浸出过程的ｐＨ值４．０左右，１２０ｍｉｎ后铜、镍、钴、锰、铁的浸出率分别为９０．２１％、９８．８０％、９１．４３％、９８．１１％、２０．１３％。

NH_4Cl-NH_3-H_2O体系浸出氧化锌矿

介绍了氯化铵 氨配合浸出法直接从氧化锌矿提取锌新工艺 .该工艺采用氯化铵 氨水溶液作浸出剂 ,使之与氧化锌矿反应得锌氨配合离子 ,在浸出的同时将杂质砷、锑、铁、硫酸根和碳酸根除去 .实验结果表明 :时间、液固比对锌浸出率影响显著 ,而温度对锌浸出率影响不大 ;在综合浸出条件下 ,锌浸出率大于 6 8% ,氨溶锌浸出率大于 93.88% (质量分数 ) ;胶体吸附除砷、锑效果明显 ,浸出液中砷、锑质量浓度可降至 0 .2 5mg·L- 1 ,铁质量浓度可降至 0 .15mg·L- 1 以下 ,氯化钙、氯化钡可将碳酸根和硫酸根几乎除尽 ,其他杂质元素含量也极低 .该浸出液净化容易 ,特别适合制电锌或锌粉 .本法具有工艺简单、能耗低、污染小、原料适应性广等优点 .

氯化铵浸出低品位菱镁矿试验研究

以辽宁海城低品位菱镁矿为原料,在750℃煅烧2 h,再进行磨矿,筛分,氯化铵溶液浸出镁试验。采用单因素变量法得到了该菱镁矿的最佳实验条件为:-74μm煅烧后氧化镁4 g,浸出温度90℃,固液比1∶11(g/m L),反应时间为60 min,氯化铵用量32.094 g,反应过程中,采用间隔加药方式,每10 min加一次氯化铵,添加量为5.394 g,浸出率可达89%,镁离子质量浓度为49.09 g/L。该工艺无腐蚀性,时间较短,浸出率较高,镁离子浓度高,应用前景广阔。

低品位氧化锌矿的氨—铵盐浸出研究

对某难选低品位氧化锌矿的氨法浸出进行了研究。结果表明,以NH3-NH4Cl为浸出剂,在适宜的条件下浸出该低品位氧化锌矿,锌的浸出率可达87.51%。该浸出过程所需温度为35℃左右,能耗较低。