Extraction of chromium (III) from spent tanning baths

Extraction of chromium(III) from a model spent tanning bath of the leather industry has been investigated using ammoniated and non-ammoniated di(2-ethylhexyl)phosphoric acid (D2EHPA) and bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex® 272). Chromium extraction of 95% by 15% (v/v) D2EHPA, 10% (v/v) isodecanol in kerosene and 86.1% by 15% (v/v) Cyanex® 272, 10% (v/v) p-nonylphenol in kerosene was obtained at equilibrium pH values of 4.0 and 5.0, respectively. The separation of small amounts of iron (III) and aluminium (III) present in the solution along with the Cr(III), was also examined and it was found that Cyanex® 272 was a better reagent than D2EHPA. The slow kinetics of extraction and stripping observed in the case of AI(III) was advantageous for its separation from Fe(III) at low pH values. Difficulties faced in the stripping of loaded metals were also studied because only about 80% chromium recovery by 8 M HCl was obtained from both solvents. The incomplete stripping of the metal may be a result of the formation of a stable species in the organic phase and needs further investigation. The Cr(III) can be recovered as chloride from the strip liquor and recycled for retanning purposes.     

Study on a novel flat renewal supported liquid membrane with D2EHPA and hydrogen nitrate for neodymium extraction

The Nd(III) extraction in flat renewal supported liquid membrane(FRSLM),with polyvinylidene fluoride membrane and renewal solution including HNO3 solution as the stripping solution and di(2-ethylhexyl) phosphoric acid(D2EHPA) dissolved in kerosene as the membrane solution,was investigated.The effects of pH in the feed phase,volume ratio of membrane solution to stripping solution,concentra-tion of HNO3 solution and concentration of carrier in the renewal phase on extraction of Nd(III) were also studied,respectively.As a result,the optimum extraction conditions of Nd(III) were obtained when concentration of HNO3 solution was 4.00 mol/L,concentration of D2EHPA was 0.100 mol/L,and volume ratio of membrane solution to stripping solution was 1.00 in the renewal phase,and pH was 4.60 in the feed phase.When initial concentration of Nd(III) was 2.00×10-4 mol/L,the extraction percentage of Nd(III) was up to 92.9% in 75 min.     

Synergistic extraction of iron(III) at higher concentrations in D2EHPA-TBP mixed solvent systems

The extraction of iron(III) from chloride solutions at macrolevel concentration by different solvents such as tri-n-butyl phosphate (TBP), di(2-ethylhexyl) phosphoric acid (D2EHPA), and their mixture in various proportions has been investigated at different acid concentrations. The synergistic extraction of iron(III) with a mixture of TBP and D2EHPA was studied and the results were compared with that of the extraction by individual solvent alone. An increase in the concentration of the synergist, TBP, in the D2EHPA-TBP solvent system resulted in an increase in the synergistic co-efficient value. The experimental data are treated graphically to explain the formation of organic phase extracted species, and the equilibrium extraction constants for the species are determined. It is found that a maximum of two molecules of TBP are adducted to the extracted species of the corresponding nonsynergistic system. Stripping of iron(III) with hydrochloric acid from loaded D2EHPA was found to increase with an increase in acid concentration. In the case of D2EHPA-TBP mixtures, stripping efficiency was increased with an increase in acid concentration up to a certain level and then it was decreased. The experimental results indicate that an iron exchange reaction between loaded D2EHPA and TBP proceeds during stripping at a higher concentration of hydrochloric acid (from mixed loaded solvent system). A plausible mechanism for iron(III) extraction and stripping has been discussed.     

Mixed solvent systems for the extraction and stripping of iron(III) from concentrated acid chloride solutions

The extraction of concentrated iron(III) from acid chloride solutions has been investigated with methyl isobutyl ketone (MIBK), tri-n-butyl phosphate (TBP), di(2-ethylhexyl) phosphoric acid (D2EHPA), and their mixtures in various proportions, at different acid concentrations. On comparing the extraction of iron(III) with mixed and individual extractant, it was found that both D2EHPA-MIBK and D2EHPA-TBP mixtures exhibit synergism, the latter having better extraction ability. The synergistic coefficients, at different initial acid concentrations for each mixed extractant system, were evaluated and compared. An increase in the concentration of MIBK and TBP in the mixed organic resulted in higher synergistic coefficient. The stripping of iron(III) from loaded D2EHPA was found to increase with the strip feed acid concentration, while from loaded organic mixtures, it initially increased and then decreased. Stripping of iron(III) from D2EHPA-MIBK loaded solvent is better then D2EHPA-TBP. The extracted iron species formed and the stripping reactions have been proposed. Ultraviolet visible spectra of the stripped organic phase support the result and the proposed mechanisms.     

Extraction of vanadium from black shale using pressure acid leaching

The extraction of vanadium from black shale was attempted using pressure acid leaching. The effects of the several parameters which included reaction time, concentration of sulfuric acid, leaching temperature, liquid to solid ratio and concentration of additive (FeSO₄) upon leaching efficiency of vanadium were investigated and a two-step counter-current leaching approach was developed. The results showed that the leaching efficiency of vanadium in the two-step process could reach above 90%. Vanadium was effectively separated and enriched by solvent extraction after leachate pretreatments, including the reduction of Fe³⁺ and adjustment of pH value. The extraction and stripping yields of vanadium were both > 98%. Ammonia was added to a stripping liquor to precipitate vanadium and then the ammonium poly-vanadate produced was calcined at 550 °C for 3 h to produce the high purity V₂O₅ powder. The overall yield of vanadium through all process stages was about 85%.     

电感耦合等离子体原子发射光谱法测定铁矿石中16种元素

准确、快速地测定铁矿中各种杂质元素含量,对铁矿石质量判定具有重要意义。试验采用“酸溶-碱熔回渣”的方法消解样品,先用硝酸、盐酸溶解样品,再过滤,滤渣及滤纸灰化后再用碳酸钠-硼酸混合熔剂熔融,溶液中的总固体溶解量(TDS)为2.5mg/mL。采用基体匹配法绘制校准曲线消除基体效应的影响,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定铝、砷、钙、铬、铜、钾、镁、锰、镍、磷、铅、硅、锡、钛、钒、锌等16种元素。各待测元素校准曲线的线性相关系数均大于0.999;方法检出限为0.00018%~0.034%。实验方法用于2个铁矿石实际样品中铝、砷、钙、铬、铜、钾、镁、锰、镍、磷、铅、硅、锡、钛、钒、锌的测定,结果的相对标准偏差(RSD,n=8)为0.40%~9.8%;按照实验方法测定4个铁矿石标准样品,测定值与认定值相吻合;测定4个铁矿石生产样品中铝、砷、钙、铬、铜、钾、镁、锰、镍、磷、铅、硅、锡、钛、钒、锌,测定值与GB/T 6730系列标准方法测定值相吻合。     

电感耦合等离子体原子发射光谱法测定铁矿石中16种元素

准确、快速地测定铁矿中各种杂质元素含量,对铁矿石质量判定具有重要意义。试验采用“酸溶-碱熔回渣”的方法消解样品,先用硝酸、盐酸溶解样品,再过滤,滤渣及滤纸灰化后再用碳酸钠-硼酸混合熔剂熔融,溶液中的总固体溶解量(TDS)为2.5mg/mL。采用基体匹配法绘制校准曲线消除基体效应的影响,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定铝、砷、钙、铬、铜、钾、镁、锰、镍、磷、铅、硅、锡、钛、钒、锌等16种元素。各待测元素校准曲线的线性相关系数均大于0.999;方法检出限为0.00018%~0.034%。实验方法用于2个铁矿石实际样品中铝、砷、钙、铬、铜、钾、镁、锰、镍、磷、铅、硅、锡、钛、钒、锌的测定,结果的相对标准偏差(RSD,n=8)为0.40%~9.8%;按照实验方法测定4个铁矿石标准样品,测定值与认定值相吻合;测定4个铁矿石生产样品中铝、砷、钙、铬、铜、钾、镁、锰、镍、磷、铅、硅、锡、钛、钒、锌,测定值与GB/T 6730系列标准方法测定值相吻合。     

Purification of Cobalt Solutions from Manganese by Extraction with Mixture of Organic Acids

extraction on pH and composition of the aqueous phase, and concentration of extractants have been investigated. D2EHPA was shown to extract the metals, but monocarboxylic acids took part in extracting the complex formed by means of additional solvation.

Electronic adsorption spectra of extracts of cobalt and manganese di (2-ethylhexyl) phosphates in SMA show that there are mainly octahedral complexes in extracts. It confirms the formation of a mixed extracted complex in organic phase. In contrast to the systems with “inert” solvents, manganese oxidation by air does not occur due to stabilization of manganese (II) in octahedral complex. The conditions of purification of cobalt chloride and cobalt sulphate solutions from manganese were determined and tested on a pilot scale. According to the technological scheme the cobalt solution after purification from iron was purified from manganese by extraction with 0.6-0.8 M D2EHPA in a monocarboxylic acids (C₁-C₉ solution. Scrubbing of extracts from cobalt and stripping of manganese were conducted by hydrochloric or sulhpuric acids depending on the type of initial solution. Purified cobalt solution practically does not contain manganese and cobalt recovery was 99.5%. The suggested scheme of purification has been applied at the Norilsk Mining and Metallurgical plant for processing of manganese by-product.     

The application of Primene 81R for the purification of concentrated aluminium sulphate solutions from leaching of clay minerals

A method of separating iron(III) and aluminium by solvent extraction treatment of sulphate leach liquors produced by the acid leaching of domestic non-bauxitic ores is reported. The principal impurity to be eliminated was iron(III). The amine Primene 81R was investigated for both synthetic solutions and leach liquors. The effect of aluminium, sulphuric acid, amine concentrations and other variables upon extraction was studied. The use of sulphuric acid and basic solutions as stripping agents was also studied. Extraction and stripping isotherms were used as a basis for laboratory-scale tests in single-stage and multi-stage studies. The iron concentration in the aqueous solution can be decreased from 2 kg/m³ to 0.015 kg/m³.     

Iron(III) removal from base-metal electrolyte solutions by solvent extraction

The use of a novel synergistic solvent extraction mixture based on an alkylated derivative of 8-hydroxyquinoline (Kelex 100) and di(2-ethylhexyl) phosphoric acid (D2EHPA) for the selective removal of iron(III) from strong sulphuric acid solutions is described. Stripping of the iron from the loaded organic solvent is effected by reacting with hydrogen to reduce iron(III) to iron(II), which subsequently is easily stripped with a weak acid solution. The applicability of the process for iron removal from an actual copper electrolyte is also demonstrated.     

从石煤酸浸液中萃取分离钒钼

采用P204作为萃取剂富集分离石煤酸浸液中的钒和钼,考察了溶液pH值、反萃剂种类、反萃剂浓度、反萃相比对钒钼富集分离的影响.研究结果表明：经过Na2S2O3还原后的溶液,钒的萃取率可以达到84.1%,钼的萃取率可以达到81.1%;采用1.5 mol/L的硫酸溶液反萃负载钒和钼的有机相,钒的反萃率可以达到99%以上,钼不能被反萃;在O/A为（体积比）3∶1的条件下采用60 g/L的碳酸氢铵溶液可以将钼反萃,其反萃率为76.4%.采用不同的反萃剂,可以实现钒和钼的分离.     

萃取法提取铬(Ⅲ)分离铁(Ⅱ)的研究

采用皂化的P204+磺化煤油体系共萃铬、铁,选择性反萃分离铬、铁工艺,从电镀污泥硫酸浸出液中回收富集铬.考察皂化率、P204浓度、料液初始pH值、萃取时间、温度、相比等因素对于萃取效果的影响,考察反萃剂组成、浓度、相比等因素对反萃效果的影响.结果表明:P204皂化率及浓度是影响铬的萃取率重要因素.在萃取有机相组成为30 %P204+70 %磺化煤油,皂化率为70 %,料液pH=2.42,V_O/V_A=1/1,萃取温度28 ℃,振荡时间5 min条件下,经6级逆流萃取达到平衡之后,出口水相铬浓度为0.9 mg/L左右,铬萃取率为99.99 %.采用2段反萃工序有效的分离铬铁:采用2 mol/L硫酸反萃,相比V_O/V_A=5/1,温度32 ℃,振荡时间5 min,经过3级逆流反萃,铬反萃率为97.5 %,铬浓度富集到29.5 g/L,铁浓度为10 mg/L;反萃铬后负载有机相再用氢氧化钠溶液反萃铁.      

Extracting iron from aluminum sulfate solution

A solvent extraction process using Primene JMT (Rohm & Haas Company) as the extractant was investigated in this study in order to remove iron(III) (3–4 g/L) from an aluminum sulfate solution. The iron-loaded amine solution was regenerated by first stripping with 3.0 M NaOH solution, followed by neutralization with 1.5 M H₂SO₄ solution. To improved its extractability of iron, the amine solution was contacted again with a weak NaOH (0.275 M solution to adjust its pH value to between 6 and 7. A subsequent continuous experiment showed that the iron(III) concentration in the acid solution can be decreased from 3.18 to 0.0124 g/L, i.e. a 99.6% reduction, in a four stage counter-current extraction operation using the proposed regeneration procedure.     

X射线荧光光谱法测定钒渣、钒渣熟料和提钒尾渣中主次组分

以四硼酸锂-碳酸锂为熔剂,碘化铵做脱模剂,熔融法制备样品,建立了X射线荧光光谱法(XRF)测定钒渣、钒渣熟料、提钒尾渣中二氧化硅、三氧化二铝、氧化钙、氧化镁、氧化锰、五氧化二钒、氧化铬、磷、二氧化钛和全铁的分析方法。试验表明,在试样量为0.25 g、稀释比(m_样品∶m_熔剂)为1∶20、脱模剂用量为20 mg时熔样效果最佳。采用经验系数法对基体效应进行校正及谱线重叠干扰校正,测定钒渣样品各组分的相对标准偏差(RSD,n=10)在0.10%~1.9%之间,检出限在35~460 μg/g之间。用标准物质和实际样品验证,测定结果与标准物质认定值和实际样品湿法测定值相符,能够满足日常分析的要求。     

硫酸亚铁铵滴定法连续测定铝钒锡铬合金中钒和铬

铝钒锡铬合金是冶炼钛合金的一种中间合金,为了准确、快速测定该合金中钒和铬,对硫酸亚铁铵滴定法连续测定该合金中高含量钒和高含量铬的条件进行研究并建立了测定方法。试样以硫酸-磷酸-硝酸的混酸分解后,在常温下,以高锰酸钾氧化钒,亚硝酸钠还原过量的高锰酸钾,同时用尿素分解多余的亚硝酸钠,用硫酸亚铁铵标准滴定液滴定钒,根据消耗的硫酸亚铁铵标准滴定液体积,求得钒含量;在加热情况下,将滴定钒后的溶液在硝酸银的催化作用下,用过硫酸铵溶液将钒和铬同时氧化至高价,再用硫酸亚铁铵标准滴定液滴定钒和铬的合量,两次滴定所消耗滴定液的体积之差即为滴定铬所需滴定液的体积,据此求得铬的含量。方法用于铝钒锡铬合金样品中钒和铬的测定,测定结果的相对标准偏差(RSD,n=10)分别为0.22%和0.75%,加标回收率分别在101%～105％和96％～101％之间。     

N1923萃取钒渣无焙烧浸出液中钒的实验探究

针对传统提钒技术中焙烧段能耗巨大和污染严重等问题,提出了用钛白废酸为浸出剂,无焙烧加压浸出钒渣的新工艺.通过正交设计实验及单因素实验考察 N1923 对此工艺体系中浸出液中钒萃取的状况.正交试验结果表明,常温下,20 %N1923-5 %仲辛醇-75 %磺化煤油体系中,水相初始 pH=1.4,水相有机相体积比（V_A/V_O）=1:3,萃取时间为 2 min 时,钒单级萃取率可达 77.69 %以上,经 4 级逆流萃取,钒总萃取率达 99.9 %,并与杂质元素分离效果明显.      

微波消解-电感耦合等离子体原子发射光谱法 测定脱硝催化剂中13种元素

脱硝催化剂中各元素是评估和改善催化剂效能的重要研究对象,准确、快速地测量其中各元素含量,对催化剂性能评价、失活与再生、催化剂中毒等深入研究具有重要意义。采用微波消解在酒石酸-氢氟酸-硝酸体系中消解试样,结合动态背景校正技术,采用基体匹配法消除基体效应,在选定的最佳分析谱线和仪器合适的工作条件下,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定钒、钨、钼、硅、铝、钙、钡、铁、锰、铬、镁、磷、砷,从而建立了电感耦合等离子体原子发射光谱法同时测定脱硝催化剂中13种元素的分析方法。在各元素线性范围内,校准曲线的线性相关系数均在0.999以上;方法中各元素检出限为0.001%~0.021%(质量分数)。实验方法用于测定脱硝催化剂样品中钒、钨、钼、硅、铝、钙、钡、铁、锰、铬、镁、磷、砷,结果的相对标准偏差(RSD,n=7)均小于2.0%,加标回收率在94%~103%之间。按照实验方法测定3个脱硝催化剂样品中13种元素,同时采用其他方法进行比对(其中钼、钨、硅、钒、铝、钡、钙采用国家标准GB/T 31590—2015 X射线荧光光谱法测定;镁、铁、铬、磷、锰、砷采用国家标准GB/T 34701—2017电感耦合等离子体原子发射光谱法测定),测定结果相符合。     

复杂铜钴矿浸出溶液处理试验

以复杂铜钴矿浸出溶液为原料,采用M5774萃取铜,硫酸反萃,铜的萃取率和反萃率均大于99%,萃余液用SO_2/空气混合气氧化中和除铁、锰,除铁后液铁和铝均小于0.005g/L,锰没有完全除掉,采用活性氧化镁沉淀镍和钴,在较优条件下,镍、钴沉淀率分别为97.73%和94.33%,用活性氧化钙沉淀锰和镁。     

提钒尾渣中钒铬的浸出与萃取

采用硫酸浸出和萃取分离从提钒尾渣中回收有价元素。结果表明,尾渣经80%质量浓度的硫酸溶液浸出后,钒、铬浸出率分别达98.2%、84.8%;以20%P204+80%磺化煤油(体积百分数)为萃取剂,对浸出液进行三级萃取并反萃后,钒的回收率可达56.2%,萃取过程中铬的损失率低于4%,萃余液水解后可得到纯度为89.6%的Cr_2O_3产品。实现了浸出液中钒、铬的分离和回收。     

Alumina extraction from northeastern red soils of Argentina

A laboratory-scale acid process to produce alumina with a purity higher than 98.4% from the northeastern red soils of Argentina is proposed. Leaching was carried out with 6 M hydrochloric acid at several molar ratios both with and without previous thermal treatment of the mineral. The relationship between the extent of dissolution of iron (II), iron (III), aluminium (III) and titanium (IV) and the structure of the principal minerals of the soils were analyzed. The solutions obtained after leaching, containing about 30 g/l of aluminium and iron oxides and 1 g/l of titanium oxide, were purified by solvent extraction and hydrolytic precipitation. The related behavior of the system aluminium (III) - iron (III) in hydrochloric acid with the organic solvent tributyl phosphate and the conditions suitable for titanium hydrolysis were studied. Then, hydrated aluminium chloride was obtained by crystallization and thermal decomposition of the salt was carried out to produce alumina.