【作者】 郑雅杰；

【导师】 龚竹青； 陈白珍；

【作者基本信息】 中南大学 ， 冶金物理化学， 2002， 博士

【摘要】 硫铁矿烧渣是硫酸工业的固体废弃物，硫铁矿烧渣的综合利用既能消除烧渣对环境的危害，又作为资源进行了利用。因此，硫铁矿烧渣的综合利用具有十分重要的意义。本研究利用硫铁矿烧渣制备得到高质量的硫酸亚铁、聚合硫酸铁（PFS）和新型絮凝剂聚磷硫酸铁（PPFS）。 为了提高烧渣中铁的回收率，采用了熟化法处理烧渣。烧渣与硫酸混合后经过熟化和水浸，铁浸出率达到91％以上。适宜的熟化条件是熟化温度200～300℃、熟化时间1～2h、硫酸浓度65～85％、硫酸用量系数为1～1.2。 研究证明在适当条件下，烧渣直接与硫酸反应后铁的浸出率也可达到90％。适宜的酸浸条件为反应温度95～115℃、反应时间3～4h、硫酸浓度40～50％、硫酸用量系数0.9～1.1。酸浸工艺比熟化工艺简单、反应温度低。 经XRD实验首次发现烧渣和硫酸混合后固化料和熟化料均有FeHSO₄ 4H₂O晶体物质生成，SEM证实熟化料为晶体状。烧渣与硫酸反应时，Fe₃O₄的反应活性高于Fe₂O₃，烧渣中Fe₂O₃与硫酸反应受扩散控制，符合颗粒收缩芯模型，动力学方程为1-（1-x_B）^2／3=kt。反应速度常数与温度的关系式为k=8.33×10⁴_e^-6.936／RT，反应活化能E₀为6.936kJ／mol。 烧渣酸浸液中加入铁皮，反应温度高于50℃、Fe³⁺浓度低于2mol／L、反应4h后，酸浸液中Fe³⁺被完全还原，9～17℃冷却还原液，得到绿矾。首次采用胶体分散法和氯酸钠部分氧化法由烧渣酸浸液制备得到液体PFS，在PFS溶液中加入磷酸钠得到PPFS。将液体PFS蒸发浓缩后，于60～80℃下搅拌干燥7h得到固体PFS，采取同样的方法也可制备得到固体PPFS。氯酸钠部分氧化法优点是工艺简单，减少了氧化剂用量，降低了成本，有利于产业化。 TG-DTA实验发现加热PFS和PPFS凝胶样至500℃，出现2次吸热和失重变化，吸热和失重温度区间分别大致为27～160℃和170-290℃。通过XRD首次发现固体PFS和PPFS主要物相为Fe_4.67（SO₄）₆（OH）₂·20H₂O，经过130℃以上温度处理后，Fe_4.67（SO₄）₆（OH）₂·20H₂O物相消失。因此可知失重是由于失去游离水、部分结晶水和Fe_4.67（SO₄）₆（OH）₂·20H₂O的分解而产生。FTIR分析说明固体PFS和PPFS有3400cm^-1、1635cm^-1OH基团吸收峰和998cm^-1 Fe-OH弯曲振动吸收峰。XRD和FTIR实验结果证实PFS和PPFS含有羟基。 PFS和PPFS与盐酸反应非常迅速，酸解液pH值不随时间变化。PFS和PPFS中形态比依次为Fe（a）／Fe_总＞Fe（b）／Fe_总＞Fe（c）／Fe_总。固体PFS、液体PPFS、液体PFS的Fe（b）和Fe（c）百分含量依次增加，Fe（b）和Fe（c）百分含量并随盐基度和中南大学博士学位论文摘要，;（P）:n（Fe）增加而增加。固体PFS、液体PPFS和液体PFs最高Fe（a）zFe:比分别为56，76%、76.99%、79.57%，最高Fe（b）/Fe总比分别为27.8x%、21.72叹、一8.7x%，Fe（e）/Fe总比分别为21.71%、13.76%、13.77%。电中和能力由强到弱依次为固体PFs>液体PPFS>液体PFS。絮凝硅藻土悬浊液，胶体杏电位变化范围为一60mv一+3omV。絮凝生活污水，胶体咨电位变化范围为一30mV一+l ZmV PFS和PPFS去除CODcr和浊度的能力为固体PFS>液体PPFS>液体PFS .PFs和PPFS絮凝规律表现出与PFS和PPFS的电中和能力和形态变化相似的规律。B=14.40%的固体PFS、B=9.33%和n（P）:n（Fe）=0.05的液体PPFS、B=14.40%液体PFs具有最佳絮凝效果，这些絮凝剂处理浊度为55.3mg/L、pH=7 .46的硅藻土悬浊液，加人的剂量（Fe，+）为2.76mg/L时，浊度去除率分别为90.78%、88.61%、84.99%。 pH值为7.49、浊度56mg/L、CODer为163.5mg/L的城市生活污水经固体pFS、液体PPFs、液体PFs、FeZ（504）3、PeA处理，剂量为o.smmol/L(以Fe3+或A13+、}一。时，浊度去除率大于99%， CODc:去除率分别为70.00%、69.00%、66.60%、62.13%、60.00%，PFS和PPFS处理生活污水后达到了8978一1996综合污水排放的一级标准PFs处理总磷含量为4.1 lmg/L的生活污水，剂量（Fe3+）为11.lmg/L时，，曾、磷去除率为68.12%。PPFs絮凝总磷为0.37 mg/L的自来水，剂量（Fe3+）达到27.6mg/L时，总磷下降到。.17 mg/L。 液体PPFs去除euZ+和PbZ+的效果好于液体PFs。终点pH值为6.8、齐}J量(Fe又+。为27 .6mg/L时，模拟重金属污水经PPFS和PFs处理后，cuZ十去除率分别为93.。%和88.7%，Pb2+去除率分别100%和99.2%。 实验结果说明PFS和PPFS处理硅藻土悬浊液和城市污水效果好，并能够有效地去除重金属和总磷。更多还原

【Abstract】 Pyrite cinders are the solid waste of sulfuric acid industry. The comprehensive utilization of pyrite cinders is very important because the comprehensive utilization can not only control the cinders pollution, but also recover the resource. Ferrous sulfate, polyferric sulfate and phosphoric polyferric sulfate have been prepared from pyrite cinders.The maturation method has been adopted to treat the cinders in order to raise the recovery rate of iron. The rate of iron recovery is up to 91% by means of maturating the cinders. The suitable factors of maturation are as follows, that maturation temperature is 200-300 C , maturation time is l~2h, H2SO4 concentration is 65-85% and cost coefficient of H2SO4 is 1-1.2.The recovery rate of iron is also up to 90% by leaching cinders with sulfuric acid .There are suitable factors of leaching that reaction temperature is 95-115 C, reaction time is 3~4h, H2SO4 concentration is 40-50% and cost coefficient of H2SO4 is 0.9-1.1. The leaching technology is simpler than the maturation technology.XRD proves first time that FeH(SO4) 4H2O is produced after mixing cinders with H2SO4 and maturating the mixture of cinders and H2SO4. SEM demonstrats that the globular cinders become crystal grains after maturation. Fe3O4 is more reactive than Fe2O3 when cinders react with H2SO4. The reaction between Fe2O3 and H2SO4 is controlled by diffusion and the reaction is applicable to the shrinking core model. Theleaching kinetics equation was 1-(1-xB)2/3 =kt. k = 8.33x104e-6.936/RT. the activeenergy Eo is 6.936kJ/mol.Fe3+ is completely reduced to Fe2+ after putting iron sheet into the leaching liquid and reacting for 4h When reaction temperature is above 50C and Fe3+ concentration is below 2mol/L. FeSO4 7H2O is crystallized from Fe2+ solution by cooling at 9C-17C. PFS solution has been prepared first by dispersing Fe (OH) 3 colloid in the leaching liquid or by oxidizing FeSO4 in the leaching liquid with NaClO3. Phosphoric polyferric sulfate has been obtained by putting Na3pO4 in the PFS solution. Solid PFS has been produced by drying and stirring at 60~80C for 7h after concentrating PFS solution. Solid PPFS has been also prepared in this way.TG-DTA tests show there are tow TG weight loss peaks and tow DTA exothermic peaks in the TG-DTA curves. The temperature ranges of the peaks are respectively 27-160C and 170~290C. Fe4.67(SO4)6(OH)2 20H2O in the solid PFS and PPFS has been discovered by XRD tests. Fe4.67(SO4)6(OH)2 2OH2O disappears after heating above 130C. The first loss weight occurs and the second loss weight is resulted because of losing free water by heating and losing crystal water and Fe4.67(SO4)6(OH)2 2OH2O decommission .FTIR spectroscopy shows that absorption bands at 3400cm-1 and 1635 cm-1 arise from OH and absorption bands at 998cm-1 came from Fe-OH in the solid PFS and PPFS.PFS and PPFS react with HCl rapidly and pH value of the solution is not dependent on the time. The species percentage of Fe(a), Fe(b) and Fe(c) of the same PFS andPPFS are up in order. The percentages Fe(b) and Fe(c) increase and The percentage of Fe(a) decreases as alkali degree and the mole ratio of P and Fe increase. The ratios of Fe(b) and Fe(c) increase from solid PFS, liquid PPFS to liquid PFS. The highest Fe(a) ratios of solid PFS, liquid PPFS and liquid PFS are 56.76%,76.99% and 79.57%.The highest Fe(b) ratios of them are 27.81%,21.82% and 18.71%,.The highest Fe(c) ratios of them are 21.71%,13.76% and 13.77% respectively. Charge neutralization effects increase in the same order as solid PFS, liquid PPFS and liquid PFS. When solid PFS, liquid PPFS and liquid PFS flocculate dialomile suspensions and municipal wastewater the ranges of zeta potentials are from -60mV to +30mV and from -30mV to +12mV respectively.The effects of COD and turbidity removal are such as the order of charge neutralization and the species ratios. These coagulants have highest rates of COD and turbidity removal when alkali degree of solid PFS is 14.40%, alkali degree and mole ratio P/Fe of liquid PPFS are 9.33%更多还原