【作者】 姚坡；

【导师】 董岁明；

【作者基本信息】 长安大学 ， 环境工程， 2007， 硕士

【摘要】 本文以安徽某硫酸厂生产硫酸产生的硫铁矿烧渣为研究对象,通过对硫铁矿烧渣的分析可知,烧渣中金的品位为3.2g/t到6.5g/t,铁的含量为35%-60%,具备氰化提金和酸浸提铁并制备聚铁的条件,研究表明:烧渣常规氰化法浸金,由于烧渣中砷、铜等浸金有害杂质的影响,金的浸出率不足30%。针对此砷铜烧渣,成功研制了在预处理过程中能有效掩蔽铜干扰的SNO助剂,使烧渣中金的回收率达80%以上。确定了预处理的最佳条件:烧渣细磨粒度为-300目,每吨烧渣需加入20LSNO助剂,SNO助剂可以循环使用,SNO助剂与烧渣的搅拌反应时间为150min。并对氰化浸金过程的条件控制进行了研究,发现在氰化体系中加入活化剂SMD能有效提高金的浸出率。试验确定的最佳氰化条件为:NaCN用量为3kg/t烧渣;活化剂SMD用量为3kg/t烧渣;氰化体系pH控制10-11范围;氰化浸出温度保持在15℃以上;氰化搅拌浸出时间为24h-30h。最终可使烧渣中金从3.2g/t-6.5g/t下降到0.3g/t-0.5g/t。回收金后的烧渣经除氰后可以直接酸浸提取其中铁并制备聚合硫酸铁。正交试验、单因素试验确定的最佳制备工艺条件为:酸浸试验的硫酸浓度为70%;硫酸过量系数为1.3;酸浸时间40min,可使铁的浸出率达到91.69%;催化氧化聚合体系所用催化剂为氯酸钾4%、硝酸0.9%、碘化钾0.2%;亚铁和硫酸的物质的量之比为:n（H₂SO₄）/n(Fe²⁺)=0.29-0.36;反应时间为30min并保温2h;经此工艺可以制备出合格的聚合硫酸铁。用自制的PFS对洗煤废水和高岭土悬浊液进行了絮凝试验,试验结果表明,自制的PFS水处理效果良好。PFS处理洗煤废水的最佳投加量为2mg/L,废水pH的适用范围为6-10;处理高岭土悬浊液的最佳投加量为4mg/L,悬浊液pH的适用范围为5-12。试验还对氰化浸金、烧渣制备聚合硫酸铁时各步的反应以及PFS的絮凝机理进行了探讨。研究表明,氰化浸金是在碱性条件下,有氧存在下金与氰化物的络合反应;烧渣中的伴生组分对氰化浸金影响不同,铁的氧化物几乎没有影响,砷和铜是氰化浸金的极为有害物质;自制PFS对洗煤废水和高岭土悬浊液的絮凝机理主要为吸附电中和、吸附架桥和压缩双电层的作用。本研究对固体废物资源化回收利用、环境污染控制以及减轻资源短缺的危机等都具有重要的现实意义。更多还原

【Abstract】 The pyrite cinder,accompanied by the production of calcining pyrite in a sulfuric acid plant in Anhui province,contains 35%to 60%iron,gold,silver and other precious metals, and the grade of gold is 3.2g/t to 6.5g/t,so such pyrite cinder possesses qualities to leach gold and synthesize polyferric sulphate.Study shows that the cinder contains harmful impurities for leaching gold such as arsenic,copper etal.,the leaching rate of gold is less than 30%only by conventional methods,therefore,a kind of particular aiding agent has been prepared to mask interaction from copper aiming at such problem.In this experiment, the cinder was fine grinded firstly,mixed 2 hours with Self-synthesized SNO promotion agent in pretreatment process,and then acceded activating agent SMD in cyanidation system keeping appropriate conditions,the leaching rate of gold can be above 80%.The optimum condition was defined as follows:fine grinded granularity is -300 mesh;20L SNO agents should be acceded and reacted for 150min with per ton cinders in pretreatment process;the amount of sodium cyanide is 3kg/t cinder in cyanidation;activating agent SMD is 3kg/t cinder;pH between 10 to 11 in cyanidation;cyanide leaching temperature maintained above 15℃;cyanide leaching time is 24 to 30h.The grade of gold would drop from 3.2 or 6.5g/t to 0.3g/t cinder.The cinder can be directly extracted iron with sulfuric acid to prepare PFS after being removed the cyanide.The preparation process was divided into three steps-acid leaching,reduction and catalylytic-oxidation polymerization.The iron in the cinder were leached out by sulfuric acid at atmospheric pressure in acid leaching process;potassium chlorate-nitrate-potassium iodide compound catalytic oxidizer was used in the catalylytic-oxidation polymerization process,it not only avoided the secondary pollution by conventional catalyst-sodium nitrite,but also shortened the reacting time to prepare qualified PFS.This paper determined the best preparation conditions by orthogonal and single factor experiments.The sulfate acid concentration is 70%in acid leaching process;excessive coefficient of sulfuric acid is1.3;acid leaching time is 40 min;the leaching rate of iron can reach 91.69%;the catalyst is potassium chlorate 4%,nitric acid 0.9%and potassium iodide 0.2%in catalylytic-oxidation polymerization process;the reactants molar ratio n（H₂SO₄）/n(Fe²⁺)=0.29-0.36;stirring reaction time is 30 min and preserves the temperature 2h.Experiments show that PFS has a good result in dealing with coal-washing waste water and kaolin suspension.All indications of PFS were qualified to reach the state standards.The best PFS dosage for Coal-washing wastewater is 2mg/L; scope of pH is 6 to 10;the best PFS dosage for kaolin suspension is 4mg/L,scope of pH is 5 to 12.The principle of cyaniding leaching gold and the influences on leaching process of iron,copper,arsenic and other impurities in the cinder was discussed.SNO agent and activating agent SMD would eliminate the influence of arsenic and copper to insure that gold can be leached out effectively.Moreover,the main reaction behaviors in the preparation process of PFS were studied so as to achieve the advancement and rationality of the preparation process.Finally,the flocculation principle of PFS was discussed.Study shows that cyaniding leaching gold is complexing reaction between gold and cyanide with the existence of oxygen in alkalescence,there are inferences in leaching gold from arsenic and copper rather than other constituents in the pyrite cinder.Furthermore,PFS has main function in adsorption electrical neutraligation,adsorption bridging and compressing electric double layer to treat with coal-washing waste water and kaolin suspension,which has importance of realistic significances in recovering and using solid waste,controlling environmental pollution and alleviating stress from the shorten of resource.更多还原