磷酸钠-氢氧化钠浸出氟化钙动力学研究

针对现行主流氢氧化钠和碳酸钠浸出低品位白钨矿存在浸出剂用量大,浸出率低的弊端,提出磷酸钠-氢氧化钠-氟化钙协同高效浸出低品位白钨矿的新工艺.氟化钙作为固体氟源,在浸出过程中首先发生溶解并释放出游离的氟离子,再参与白钨矿的浸出反应生成氟磷酸钙沉淀.因此,氟化钙的溶解速率对白钨矿浸出速率有较大影响.文章使用等浸出率法,对磷...     

（NH4）3PO4-NH3·H2O-H2O体系中磷酸铵溶解度

采用等温溶解度法测定了10～70℃时（NH4）3PO4-NH3·H2O-H2O三元系中磷酸铵的溶解度,并绘制成相应的相图。结果表明：磷酸铵的溶解度随温度降低和氨浓度升高而下降。当溶液中氨浓度相同时,温度越低,则磷酸铵的溶解度越小。采用氨溶析结晶法从磷酸铵溶液中除去钾、钠杂质时,可通过提高溶液中氨浓度以及降低温度的方式,使得磷酸铵结晶析出,钾和钠留在结晶母液中,除去钾、钠,以达到净化提纯磷酸铵的目的。     

高磷高钼复杂白钨矿的脱磷-除钼处理工艺

利用磷灰石、钼酸钙和钨酸钙等含钙矿物与盐酸反应的差异性规律,首先在温和的盐酸浸出条件下预处理高磷高钼复杂白钨矿,即反应温度为50 ℃,盐酸浓度2.5 mol/L,反应时间2 h,液固比（指液体体积与固体质量之比,单位为L/kg,下同）5:1的条件下实现杂质磷的高效选择性浸出,磷的浸出率达到99%以上,同时实现钨钼的初步分离,钼浸出率为44.76%,钨浸出率仅为1.84%。然后,再利用钨酸和钼酸在盐酸体系中溶解度的性质差异,进一步提高盐酸浓度和反应温度强化浸出,在盐酸浓度4 mol/L,反应温度80 ℃,反应时间2 h,液固比5:1的条件下,钼的浸出率达到95%,而钨以钨酸的形式留在固相,此步骤的钨浸出率只有1.55%,实现了钼的深度分离和钨矿的转型。      

WO3–CaSO4在HCl–Na2SO4溶液中的平衡溶解

目前钨冶炼的碱分解工艺,存在用水量大、废水量大、加工成本高等问题,使钨冶炼企业面临着经济与环保的双重压力,不能继续满足行业发展需求。对此,在大量白钨焙烧分解工艺研究的基础上,提出了酸法焙烧思路,开发出了硫酸盐焙烧分解白钨工艺,一步转型生成WO₃。由于白钨矿焙烧产物的主要杂质为Na₂SO₄与难溶CaSO₄,可采用盐酸浸出方式进行钨钙分离,本文采用等温平衡法,考察对比了WO₃、CaSO₄与WO₃–CaSO₄在HCl–Na₂SO₄溶液中的溶解行为,结果表明:WO₃与CaSO₄在盐酸中的溶解度相差较大,CaSO₄在盐酸中溶解度随温度、盐酸浓度的升高而增大,在温度80 ℃、盐酸浓度3 mol·L–1的条件下,硫酸钙在盐酸中的溶解度达到峰值55 g·L–1,而Na₂SO₄可显著降低CaSO₄在盐酸中的溶解度,缩小CaSO₄与WO₃在盐酸中的溶解差,WO₃溶解度则维持在0.3～3 g·L–1范围内,结合目前成熟的低钨回收工艺,能将该部分溶解钨有效地回收,即控制一定的溶解条件有利于钨钙高效分离。      

Treatment of a Nigerian covellite ore. Part I: Dissolution kinetics study by ammonia solution

In the present work, the leaching kinetics of covellite ore in ammonia solution was studied and the following variables, the solution concentration, reaction temperature and particle size were considered. A kinetics model representing the effects of these variables on the leaching rate was developed and it was ascertained that the leaching rate increases with increasing solution concentration, reaction temperature and decreasing particle size. At optimal conditions, 75.1% of covellite ore was reacted within 120 min and the leaching reaction was diffusion controlled by surface chemical mechanism. The calculated activation energy of 56.98 kJ/mol supported the proposed dissolution process.     

Effect of phosphate on lead removal during a copper recycling process from wastes using ammoniacal chloride solution

Techniques for the removal of lead have been studied in order to develop a hydrometallurgical copper recycling process consisting of copper leaching from wastes using an ammoniacal chloride solution and subsequent copper electrowinning. The solubility of Pb(II) in the ammoniacal chloride solution increased with ammonia concentration; this was attributable to the formation of a lead ammine complex. The lead dissolution was depressed from the order of 10^− 3 M to the order or 10^− 5 M by the addition of phosphate into the leaching solution because of the precipitation of chloropyromorphite (Pb₅(PO₄)₃Cl), while no significant effect was observed by the addition of carbonate. Linear sweep voltammetry and potentiostatic electrolysis in the solution containing Pb(II) revealed that lead was deposited during the copper electrowinning, even in the potential region more positive than the equilibrium redox potential for the Pb/Pb(II) couple on the lead electrode, because of the alloy formation with copper. In a galvanostatic electrolysis, however, the lead content at the electrodeposited copper cathode was found to be lower than 5 ppm at the current density range of 125–400 A/m², when the Pb(II) concentration in the electrolyte was 5 × 10^− 5 M. Since this Pb(II) concentration was achieved by the phosphate addition, these results indicated the effectiveness of phosphate for lead removal in the copper recycling process using the ammoniacal chloride solution.     

仲钨酸铵蒸发结晶过程中杂质元素的析出行为

仲钨酸铵(APT)主要采用蒸发钨酸铵溶液的方式制取,是钨冶炼中最重要的中间产品,其化学质量将直接影响后续钨产品的质量.以硫磷混酸协同分解白钨所得钨酸铵溶液为原料,通过研究APT蒸发结晶过程中主要杂质离子的析出规律,获得了制备APT-0级产品所要满足的钨酸铵原料液中各杂质的浓度上限,既为钨酸铵净化工序提供了除杂深度的数据...     

磷酸法中稀土溶出的动力学模型研究

利用磷酸浸出伴生稀土磷矿,研究了温度、时间、酸度、粒度与稀土浸出动力学的关系。结果表明,升高温度、延长反应时间、增大酸度、减小初始粒度均有利于稀土的浸出。界面化学反应控制为稀土浸出的控制步骤,表观反应级数0.993,表观活化能44.6kJ/mol,稀土浸出过程近似为基元反应。按反应核收缩核模型通过统计分析建立了关联温度、浓度、粒度三因素的稀土浸出数学模型。     

依靠技术进步提高钨冶炼离子交换工艺技术水平

简述了赣州华兴钨制品有限公司在提高钨冶炼离子交换工艺技术水平的几项工艺的研发与应用，其中包括白钨矿碱分解新工艺、矿浆碱回收、离子交换串柱吸附工艺、除钼技术、APT结晶母液回收，蒸发结晶废气回收氨等。这些新技术或措施的采用，使每吨APT生产成本降低1000元左右。同时，对工艺今后的发展提出了建议。     

Selective Leaching-Recovery of Re and Mo from Out-Gas Dust of Molybdenite Roasting Furnace

Selective leaching and recovery of Mo and Re present in out-gas dust of molybdenite roasting furnace was quantitatively investigated. The effects of solid to liquid (S/L) phase ratio, sulfuric acid concentration and solution temperature on the selective extraction were determined. Considerable Mo and small amount of Re were detected in the out-gas dust of the industrial roasting furnaces. Recovery percentage of both Re and Mo increased by increasing acid concentration and solution temperature. The results also showed that the recovery percentage of Re decreased by increasing the S/L ratio. The best conditions for selective leaching was obtained as 20 min mixing in water (0 g/L sulfuric acid) with S/L ratio of 0.2 in the temperature range of 40–60 °C.     

氨溶高纯仲钨酸铵的生产工艺参数研究

热离解后氨溶与直接氨溶研究表明,APT固体在280±5℃热离解50 min,加1∶3的氨水溶液200 mL在95℃溶解6 h,浸出率为85.1%,离解时间对S(Fe)/WO3影响不大,热离解后氨溶比直接氨溶溶出率要高,但是S(Fe)/WO3基本相同。     

Selective leaching kinetics and upgrading of low-grade calcareous phosphate rock in succinic acid

Selective leaching kinetics of calcareous phosphate rock in succinic acid solution was investigated. Using a known particle size range of the sample, liquid/solid ratio and acid concentration, the influence of various reaction temperatures was studied in order to elucidate the kinetics of calcareous material in the rock. The leaching rate increased with increasing temperature. A kinetic model was suggested to describe the selective leaching process of calcareous material analyzing the kinetic data. The selective leaching curves were evaluated in order to check the validity of shrinking core models for liquid–solid systems. The experimental data were tested by graphical and statistical methods and it was found that the leaching of calcareous material in the rock was controlled by chemical reaction, i.e., 1 − (1 − x)^1/3 = 1.47 × 10⁶e^−64.92/RTt. The apparent activation energy of the leaching process was found as 64.92 kJ mol⁻¹ over the reaction temperature range from 313 to 353 K.     

空气氧化—氨浸出废旧电路板中的铜

提出了在氨水—硫酸铵体系下鼓入空气浸出废旧电路板中铜的新工艺。考察了氨水浓度、硫酸铵浓度、固液比、反应温度、通入空气流量和浸出时间对铜浸出率的影响。结果表明,在下述最佳浸出条件下,渣计铜浸出率达到96.67%:氨水浓度2mol/L,硫酸铵浓度2mol/L,固液比1∶20,反应温度25℃、通入空气量8m3/h、浸出时间4h。     

废旧镍氢电池负极板中稀土的回收

采用湿法冶金工艺,回收废旧镍氢电池负极板中的稀土（RE）元素,用硫酸浸出负极板中的有价金属,分析硫酸浓度、浸出温度、浸出时间等因素对稀土元素浸出率的影响,在硫酸浓度为2.0 mol/L、浸出温度为60℃、浸出时间120 min下,RE的浸出率为92.31%.采用磷酸二异辛酯（P204）为萃取剂萃取浸出液中的稀土,当P204在煤油中的比率为20%时,萃取率为92.86%.用硫酸钠沉淀溶液中的稀土,浸出液中稀土元素回收率可达98.78%.采用XRD和SEM分析表征回收的稀土氧化物的物相和表面形貌,结果表明,回收产物为铈系稀土氧化物,为立方晶系,呈面心立方结构,表面形貌为棱柱形.     

难选氧化锌矿氨浸的热力学

计算了锌在不同pH、不同温度下氨溶液中氧化锌的溶解度和氨溶液中锌的水溶物种的热力学平衡及其分布规律,得到等温熔解度图;试验测定了等压溶解度图,得出pH值、压力和时间对浸出锌的影响的规律。     

一种从废旧电路板中回收铜的新工艺

介绍了一种从废旧电路板中分离提取铜并产出超细铜粉的新工艺。首先采用物理分选法分离出含铜的重密度组分,之后采用氧化氨浸—溶剂萃取工艺获得CuSO4溶液,最后以次亚磷酸钠为还原剂,以PVP为保护剂和分散剂,采用二次还原法,获得粒度1.5μm左右的抗氧化铜粉。浸出阶段优化条件为:温度35℃,时间2h,氨水和硫酸铵起始浓度均为2mol/L,空气流量8m3/h,固液质量体积比1∶10。铜萃取及反萃阶段优化条件为:萃取剂Lix84,萃取剂体积分数50%,相比1∶1,TBP浓度0.1mol/L,常温,以500次/min的速度震荡3min;反萃取剂硫酸,浓度0.2mol/L。在优化条件下,浸出、萃取及反萃取阶段的铜提取率分别为96.67%、98.87%及93.34%,效果良好。     

陈化除钼渣处理工艺试验研究

针对某地APT厂堆存的除钼渣的特点,提出采取碱性浸出-硫化沉钼-人造白钨的工艺,提取其中的铜、钼、钨。系统地考察了碱浸工序的工艺参数,确定碱性浸出的最佳条件。结果如下：碱用量为除钼渣的50％,添加剂A用量为除钼渣的5％,液固比L／S=3／1,温度为70℃,时间为3h,钨钼浸出分别为99．12％和98．42％,铜保留率～100％。对浸出液采用硫化沉钼,钼的沉淀率达到98．03％,钨的沉淀率为4．19％。沉钼后液采用人造白钨,钨的沉淀率达98．29％,产品WO,品位达50．10％。     

核桃壳还原浸出软锰矿的动力学

探究以核桃壳为还原剂硫酸浸出氧化锰矿过程的动力学。考察了搅拌速度、反应温度、硫酸浓度、反应时间以及核桃壳用量对锰浸出率的影响。结果表明,锰的浸出率随着搅拌速度、硫酸浓度、核桃壳用量的增大和温度的升高而增大。浸出前60 min浸出率的增长速度较快。在反应温度为369 K、硫酸浓度3.5 mol/L、核桃壳加入量40 g/L、反应时间2.5 h、转速200 r/min时,锰浸出率达93.18%。浸出过程属于化学反应控制,对应的活化能为45.5 kJ/mol,硫酸浓度和核桃壳用量的反应级数分别为0.897、0.2。     

印刷厂废胶片上银的回收

以硝酸和过氧化氢的混合溶液为银的溶解液,对印刷厂废胶片上银的回收进行了研究.考察了硝酸的浓度、溶解温度对银溶解速度的影响,结果表明:硝酸的浓度为7 mol/L、溶解温度为60℃时,溶解速度较好,且在银的溶解过程中不产生NO、NO2有毒气体,有利于环境保护.