Transformation behavior of ferrous sulfate during hematite precipitation for iron removal

The transformation behavior of ferrous sulfate was examined during hematite precipitation for iron removal in hydrometallurgical zinc.Specifically,the effects of the method used for oxygen supply(pre-crystallization or pre-oxidation of ferrous sulfate)and temperature(170–190℃)on the redissolution and oxidation–hydrolysis of ferrous sulfate were studied.The precipitation characteristics and phase characterization of the hematite product were investigated.The results showed that the solubility of ferrous sulfate was considerably lower at elevated temperatures.The dissolution behavior of ferrous sulfate crystals was influenced by both the concentrations of free acid and zinc sulfate and the oxydrolysis of ferrous ions.Rapid oxydrolysis of ferrous ions may serve as the dissolution driving force.Hematite precipitation proceeded via the following sequential steps:crystallization,redissolution,oxidation,and precipitation of ferrous sulfate.The dissolution of ferrous sulfate was slow,which helped to maintain a low supersaturation environment,thereby affording the production of high-grade hematite.

Recovery of magnetite from waste ferrous sulfate using polyethylene glycol(PEG) as a dispersant

The effect of PEG dispersant on the magnetic separation of magnetite（Fe3O4） synthesized from ferrous sulfate solution via co-precipitation method with calcium hydroxide as the precipitant was investigated. The results indicated that a PEG dispersant could significantly affect Fe3O4 recovery. Adding PEG during the preparation of Fe3O4 was unfavorable for Fe3O4 recovery. When the PEG-6000 concentration was increased from 0 to 8 g/L, the iron grade and median particle size of the Fe3O4 product decreased from 65.58% and 2.35 μm to 57.79% and 1.35 μm, respectively. However, adding PEG during the wet milling of the mixed product promoted the subsequent recovery of Fe3O4. When the amount of PEG-200 increased from 0% to 4% of the powder mass, the grade of iron in the Fe3O4 product increased from 65.58% to 68.32%. While the relative molecular mass of PEG at an amount of 4% of the powder mass increased from 200 to 20000, the grade of iron was reduced from 68.32% to 66.70%.

Efficacy and Compliance of Oral Iron Poly-Maltose Complex versus Oral Ferrous Sulfate in the Treatment of Iron Deficiency Anemia in Pregnant Women

Objective: To compare the efficacy and compliance of the conventional therapy of iron deficiency anemia (ferrous sulfate) with the new forms of therapy chewable iron tablets: (iron polymaltose complex) in the treatment of iron deficiency anemia in pregnant women. Methods: This Randomized Control Trial study included 290 pregnant women with iron deficiency anemia, and they were randomly allocated to a control group who received ferrous sulfate capsules for two months and study group who received iron polymaltose complex chewable tablets for two months. Complete Blood Picture (hemoglobin level and hematocrit level) and Serum ferritin level were done after four and eight weeks to determine the efficacy. In addition, any complains or side effects had been reported to assess the tolerability of the drugs. Two-factor repeated-measures analysis of variance (ANOVA) was used to compare the change in hemoglobin and serum ferritin levels in both groups. Results: There was no statistical significant difference between the two research groups as regards baseline hemoglobin, and at week 4 from onset of treatment (p values = 0.990, 0.112, consecutively). However, there was statistical significant difference on week 8 of continuous drug intake in both groups in which the iron poly maltose complex research group had significantly higher hemoglobin levels (p value = 0.006). Conclusion: The results of the study showed oral iron polymaltose complex increases Hemoglobin and serum ferritin levels more than oral ferrous sulfate and produces less adverse effects than ferrous sulfate.

Preparation of microsized hematite powder from ferrous sulfate via microwave calcination

The preparation of microsized hematite powder from ferrous sulfate using microwave calcination was investigated based on the TG/DTG curves. The decomposition of industrial ferrous sulfate under air atmosphere was divided into three stages, and a ferrous sulfate sample added with 15% Fe_2O_3 could strongly absorb microwave energy. Therefore, preparing hematite powder from ferrous sulfate using microwave calcination was feasible. Hematite was obtained under the following optimized conditions: calcination temperature, 850 °C; microwave power, 650 W; and sample amount, 40 g. The obtained hematite satisfied the first-grade quality requirements. The total ferrum value was more than 58%, and the total sulfur and phosphorus contents were less than 0.5% and 0.2%, respectively. X-ray powder diffraction and scanning electron microscopy were used to characterize the structure and morphology of microsized hematite powder. The particles were non-spherical in shape, and the average particle size distribution was 10.45 μm. This work provides new potential applications for waste ferrous sulfate.

Effect of purification pretreatment on the recovery of magnetite from waste ferrous sulfate

The present study was conducted to elucidate the influence of impurities in waste ferrous sulfate on its recovery of magnetite. Ferrous sulfate solution was purified by the addition of Na OH solution to precipitate impurities, and magnetite was recovered from ferrous sulfate solution without and with purification pretreatment. Calcium hydroxide was added to the solution of ferrous sulfate as a precipitator. A mixed product of magnetite and gypsum was subsequently obtained by air oxidation and heating. Wet-milling was performed prior to magnetic separation to recover magnetite from the mixed products. The results show that with the purification pretreatment, the grade of iron in magnetite concentrate increased from 62.05% to 65.58% and the recovery rate of iron decreased from 85.35% to 80.35%. The purification pretreatment reduced the conglutination between magnetite and gypsum, which favors their subsequent magnetic separation. In summary, a higher-grade magnetite with a better crystallinity and a larger particle size of 2.35 μm was obtained with the purification pretreatment.

Quality of Drugs Based on Ferrous Sulfate Dispensed in a Basic Health and Commercial Pharmacy in a City in the Amazon Region

Background: For the WHO, anemia is a serious public health problem, with an emphasis on deprivation anemia, which has socioeconomic conditions as determining factors for its development. Among nutritional anemias, the most relevant is iron deficiency, whose main form of prevention and treatment is supplementation with ferrous sulfate dispensed in the public health system, with the need to periodically check whether the drug has the quality required by regulatory health agencies. Thus, the objective of this study was to analyze the quality of the ferrous sulfate medication, from the same laboratory, and dispensed in a basic health unit (BHU) and a commercial pharmacy (CF). Materials and Methods: An analytical, qualitative and quantitative study of ferrous sulfate heptahydrate (25 mg/mL in 100 mL syrup), carried out on 20 BHU and 10 from CF, both from the same laboratory, but in different batches. Samples were subjected to organoleptic analysis and verification of iron content, pH, volume and density. Data were compared with values recommended by the Brazilian pharmacopoeia 5th edition. Results: Three batches were evaluated: 4659 of from the CF;4574 from the BHU1, and 4576 from the BHU2, stored in accordance with RDC 304/19 of ANVISA. All showed compliance with some organoleptic characteristics;and stable values in pH (3.61 - CF;3.67 - BHU1;3.65 - BHU2), density (1.079 - CF;1.088 - BHU1;1.086 - BHU2) and individual volume (not less than 95% of the declared value). However, it was not possible to detect the odor of herbs;the average volume of batch BHU1 was below the declared value, and the iron content of both BHUs was above the maximum value of pharmacopoeia standards. Conclusion: Samples did not show full compliance with the physical and chemical parameters evaluated, suggesting deviation in the quality of the medication.

A Mild and Practical Procedure for Tetrahydropyranylation of Alcohols and Phenols Catalysed by Anhydrous Ferrous Sulfate

An easy preparation of tetrahydropyranyl (THP) ethers of alcohols and phenols with 3,4-dihydro-2H-pyran (DHP) in refluxing dichloromethane has been carried out in good to excellent yields under catalysis of anhydrous ferrous sulfate.

Physicochemical, structural characterization, and antioxidant activities of chondroitin sulfate from Oreochromis niloticus bones

In this study,chondroitin sulfate was extracted from Oreochromis niloticus bones(OCS)and isolated to three fractions(OCS-1,OCS-2,and OCS-3).The physicochemical properties and structure characterization including monosaccharide,disaccharide compositions,molecular weight(Mw)of OCS were determined by HPAEC,HPLC-SAX,HPGPC,FT-IR spectra,and 1D/2D NMR.Moreover,their thermal properties,crystalline structure,and microstructure were also analyzed.Results showed that their Mw were between 10 kDa and 50 kDa.CS-6 was the predominant disaccharide unit in four OCS,and the CS-4/CS-6 ratios were close to CS from shark cartilage.Besides,the results of antioxidant activity showed that different fractions of OCS had a distinct DPPH radical,hydroxyl radical,and ABTS+radical scavenging activity.OCS-1 has the highest scavenging activities in DPPH and hydroxyl radical compared with other fractions,which showed a higher medicinal value.Those findings may lay some theoretical basis for the potential application development of OCS.

Separation of macro amounts of tungsten and molybdenum by precipitation with ferrous salt

In order to develop a low-cost approach for separating macro amounts of Mo and W, the effects of parameters on the separation using FeSO4 as precipitation reagent were studied. The results show that the optimum reaction temperature is 10 °C, and the separation factor does not further improve after a reaction time of 7 h. Moreover, slow dropping speed of the precipitation reagent is beneficial for improving the separation efficiency. When the H＋/W molar ratio is below 1/1, the addition of acid to a neutral solution is favorable to the separation. For the solution with an ammonium concentration below 3 mol/L, the separation factor is high due to the high W-precipitation rate. Furthermore, the method is also effective when it is applied to industrial solution containing some other impurities. All these indicate the ferrous salts have great potential for removing W from Mo on a commercial scale.

A study on simultaneous removal of NO and SO2 by using sodium persulfate aqueous scrubbing

Nitric oxide （NO） removal and sulfur dioxide （SO2） removal by sodium persulfate （Na2S2O8） were studied in a Bubble Column Reactor. The proposed reaction pathways of NO and SO2 removal are discussed. The effects of temperatures （35-90℃）, Na25208 （0.05-0.5 mol·L-1）, FeSO4 （0.5-5.0 m mol·L-1） and H2O2 （0.25 mol·L-1） on NO and SO2 removal were investigated. The results indicated that increased persulfate concentration led to increase in NO removal at various temperatures. SO2 was almost completely removed in the temperature range of 55-85 ℃. Fe2 ＋ accelerated persulfate activation and enhanced NO removal efficiency. At 0.2 mol· L- 1 Na2S2O8 and 0.5-1.0 mmol· L-1Fe2 ＋, NO removal of 93.5%-99% was obtained at 75-90 ℃, SO2 removal was higher than 99% at all temperatures. The addition of 0.25 mol. L i H202 into 0.2 mol·L-1· Na2S2O8 solution promoted NO removal efficiency apparently until utterly decomposition of H2O2, the SO2 removal was as high as 98.4% separately at 35 ℃ and 80 ℃.

Effect of Sulfate on an Iron Manganese Catalyst for Fischer-Tropsch Synthesis

The effect of sulfate on Fischer-Tropsch synthesis performance was investigated in a slurryphase continuously stirred tank reactor （CSTR） over a Fe-Mn catalyst. The physiochemical properties of the catalyst impregnated with different levels of sulfate were characterized by N2 physisorption, X-ray photoelectron spectroscopy （XPS）, H2 （or CO） temperature-programmed reduction （TPR）, Mossbauer spectroscopy, and CO2 temperature-programmed desorption （TPD）. The characterization results indicated that the impregnated sulfate slightly decreased the BET surface area and pore volume of the catalyst, suppressed the catalyst reduction and carburization in CO and syngas, and decreased the catalyst surface basicity. At the same time, the addition of small amounts of sulfate improved the activities of FischerTropsch synthesis （FTS） and water gas shift （WGS）, shifted the product to light hydrocarbons （C1-C11） and suppressed the formation of heavy products （C12＋）. Addition of SO4^2- to the catalyst improved the FTS activity at a sulfur loading of 0.05-0.80 g per 100 g Fe, and S-05 catalyst gave the highest CO conversion （62.3%）, and beyond this sulfur level the activity of the catalyst decreased.

农药氟虫腈与钛白粉副产盐资源化生产电池用磷酸铁工艺

针对农药氟虫腈与钛白粉生产过程中副产盐的处置难题,提出以副产磷酸钠为磷源,以副产硫酸亚铁为铁源,制备电池级磷酸铁的工艺路线。采用连续催化氧化的方法将磷酸钠废盐中的亚硫酸钠氧化为硫酸钠,副产硫酸亚铁经过除杂后,用双氧水将硫酸亚铁氧化为硫酸铁,再与上述的磷酸钠反应得到磷酸铁。结果表明:亚硫酸钠的氧化率接近100%;副产硫酸亚铁经化学除杂和水解除杂后,杂质镁、锰、钛的质量分数分别降低至80 mg·kg^(-1)以下,杂质铝则被完全去除;除杂后的硫酸亚铁溶液经双氧水氧化后,硫酸亚铁的氧化率达到100%;制备得到的二水合磷酸铁的各项指标均满足标准HG/T 4701-2021《电池用磷酸铁》的要求。

人造沸石和PFS去除城镇生活污水氨氮和总磷的实验研究

采用人造沸石和聚合硫酸铁(PFS)处理污水中氨氮和总磷,人造沸石实验采取连续进水模式,从沸石投加量、曝气量和流速(水力停留时间)多角度考察对污水中氨氮的去除,PFS实验从浓度、搅拌转速、混凝时间、沉降时间和取样深度多方面考察对污水中总磷的去除。结果表明:对于NH_(3)-N去除,单独曝气或人造沸石均效果不佳,去除率分别达10.01%±1.69%和49.49%±5.08%,但两者共同作用可极大提升去除效率,达90.55%±1.41%;水力停留时间在2.4~5.5 h范围内越长氨氮出水浓度越低,5.5 h时最低为(2.81±0.14)mg/L。对于TP去除,低浓度PFS(50、100 mg/L)表现出的去除效果不明显,去除率仅达6.62%~10.39%,至400 mg/L时去除率达89.58%±0.79%;转速110 r/min增加至205 r/min,TP去除率仅相差0.27%~3.77%;混凝时间由1 min增至10 min,去除率由52.36%±3.84%提升至87.30%±0.99%,且15 min为最佳沉降时间,之后TP质量浓度趋于平衡;不同取样深度对TP去除无较大影响;最佳实验参数组为PFS浓度400 mg/L,转速110 r/min,混凝10 min后沉降15 min,液面以下池深10%(约2 cm)处取样,出水TP质量浓度可达(0.17±0.01)mg/L,去除率达(89.58±0.79)%,明显优于GB 18918-2002一级A标准。人造沸石和PFS在城镇生活污水氮磷突发状况及深度处理,如某些工艺阶段设备突发事故导致不能运转的紧急情况或出水有深度处理需求的场合具有一定的技术研究和实际应用价值。

罗非鱼养殖尾水絮凝去除效果研究

罗非鱼养殖尾水中含有大量的残饲和粪便等颗粒悬浮物,这些物质是氮、磷营养元素的主要载体。将养殖尾水外排会导致周边水体富营养化。当前常见的尾水处理方式具有占地面积大、投资高、效率低等缺点,影响其推广使用。为解决这一问题,探索采用絮凝工艺对罗非鱼养殖尾水进行处理,选取聚合硫酸铁、三氯化铁、壳聚糖和碳酸镁等4种絮凝剂,通过比较浊度、总悬浮物和化学需氧量的去除效果,筛选出适合用于养殖尾水处理的絮凝剂。结果显示:聚合硫酸铁的效果优于其他3种絮凝剂。在投加量0.4 g/L、pH=8、絮凝时间15 min时,聚合硫酸铁对养殖尾水的浊度、总悬浮固体颗粒物(TSS)和化学需氧量(COD)的去除率分别达到了96.7%、92.6%和95.1%。对絮凝后絮体评价发现,絮体的沉降高度与浊度去除率具有一定相关性,絮体的成长受成核作用的影响。尾水处理前后的zeta电位说明聚合硫酸铁通过破坏尾水中的悬浮物的稳定结构而净化尾水。研究表明,在罗非鱼养殖尾水处理时,可选择聚合硫酸铁作为絮凝剂。

硫酸亚铁铵制备的绿色化改进与创新设计

硫酸亚铁铵的制备是一个经典的无机化学实验。但由于传统实验设计的缺陷,导致产物纯度低、环境污染等不足。本文从绿色化学的理念出发,把传统的两步法制备硫酸亚铁铵改为“一锅法反应”;同时增设了Fe^(3+)杂质定量分析、单晶培养、显微镜下观察产物形貌和颜色三个板块;改进后的实验不仅提高了产品纯度和实验课效率,减少了实验室污染,而且将绿色化学理念贯穿于实验的全过程,提升了学生的实验技能和从事科学研究的兴趣。

普鲁士蓝类钠电池正极生产废水预处理工艺研究

钠离子电池作为新兴产业,有关其生产工艺的研究较多,但是鲜少见到关于钠电池生产废水处理工艺的研究。因此,本文对普鲁士蓝类钠电池正极废水的预处理工艺进行实验研究,探究最佳处理工艺。最终确定了母液废水采用直接氧化法预处理工艺,即先加入H_(2)O_(2)(1.18倍理论投入量),然后用质量分数为30%的NaOH溶液调pH至9左右,静置30 min,再经过管式超滤膜过滤,母液中铁锰元素的去除率分别约为99.93%和99.99%。洗水废水采用两段式沉淀法预处理工艺,即第一阶段采用固氰除铁法,先用质量分数为30%的NaOH溶液调pH至7左右然后加入硫酸亚铁(硫酸亚铁投入量与废水中铁元素质量比为5.2),反应静置30 min。主要去除废水中绝大部分的铁元素和少部分锰元素。在一段处理的基础上再采用氧化沉淀法,先加入H_(2)O_(2)(0.83倍理论投入量),然后用质量分数为30%的NaOH溶液调pH至9,反应静置30 min,再经过管式超滤膜过滤,最终铁和锰元素的去除率分别约为99.87%和99.99%。为实际工程中钠电池废水预处理提供了重要技术参考。

钛白副产硫酸亚铁中镁离子的含量分析

本文研究以酸性铬蓝K为指示剂,以草酸铵为沉淀剂排除Fe^(2+)干扰,用紫外分光光度法测定钛白副产物FeSO_(4)中的Mg^(2+)的含量。实验结果表明,Mg-铬蓝K的最大吸收峰波长为540nm,最佳pH值为9.5,最佳沉淀剂草酸铵的用量为10mL。经加标回收的方法验证了方法的可行性,测出钛白副产物FeSO_(4)中Mg^(2+)含量为1.07%。

硫酸亚铁对铝酸盐水泥浆体性能及水化产物的影响

铁相对水泥混凝土耐久性具有显著的积极作用,为拓宽铁相来源,本文研究了铁盐对铝酸盐水泥性能及水化产物的影响。通过将铝酸盐水泥和硫酸盐(二水石膏和硫酸亚铁)复合,使铝酸盐水泥水化生成以钙矾石为主的产物,在此基础上,研究了硫酸盐中硫酸亚铁比例对铝酸盐水泥浆体凝结时间、抗压强度以及体积稳定性的影响规律,并采用XRD和SEM分析水化产物类型以及微观形貌,阐明硫酸亚铁对水泥浆体性能的影响机理。结果表明:适量的硫酸盐可提升铝酸盐水泥浆体的抗压强度;硫酸亚铁对铝酸盐水泥表现出轻微的促凝作用,对膨胀率具有显著的抑制作用;硫酸亚铁对钙矾石的形成具有明显的抑制作用,适量的硫酸亚铁使得所生成的钙矾石尺寸较小,且分布均匀,有利于提升硬化浆体的抗压强度。

微波耦合硫酸亚铁对铬渣的稳定化效果和机制研究

安全处置的铬渣常出现“返黄”现象,这与未溶解的含六价铬(Cr(Ⅵ))矿物再次释放Cr(Ⅵ)有关,因此在修复过程中,彻底溶解不稳定的含Cr(Ⅵ)矿物,使其充分释放Cr(Ⅵ)是实现铬渣长效稳定的关键。该研究利用微波(MW)快速溶解铬渣中Cr(Ⅵ)矿物——钙钒石,再耦合硫酸亚铁(FeSO_(4))实现了铬渣的高效稳定。MW辐照显著降低了钙矾石溶解的表观活化能(35.8 k J/mol),促进钙矾石快速溶解释放Cr(Ⅵ)。而FeSO_(4)水解酸化产生的硫酸(H2SO_(4))在MW场下进一步促进了含Cr(Ⅵ)矿物水滑石的溶解,实现了铬渣中Cr(Ⅵ)矿物的完全溶解。同时,MW显著提升了FeSO_(4)对Cr(Ⅵ)的还原效率,在低功率MW(462 W)耦合低剂量FeSO_(4)(w=21.5%)处理下,Cr(Ⅵ)的还原率达到100%。更为重要的是,MW促进了生成的三价铬(Cr(Ⅲ))固定在Cr(Ⅲ)矿物(Fe O·Cr_(2)O_(3)和Cr_(2)O_(3))晶格中,1年后未出现“返黄”,实现了铬渣的长效稳定。该研究为MW耦合FeSO_(4)在铬渣稳定化处理领域的应用提供了数据支持和理论基础。