硫酸铵焙烧与浸出提取碳素铬铁冶炼渣中有价金属

用(NH4)2SO4焙烧分解碳素铬铁冶炼渣,提取有价金属,考察了焙烧温度、硫酸铵用量和焙烧时间对有价金属浸出率及过程相变的影响. 结果表明,焙烧过程中250~435℃间失重达65.5%,主要为NH3,H2O,SO3释放及(NH4)2SO4挥发. 优化的焙烧条件为(NH4)2SO4与铝镁渣质量比5:1、焙烧温度350℃,焙烧时间3.5 h. 有价金属转变为其相应的硫酸金属铵盐,且与(NH4)2SO4分解产物共存;该条件下的焙烧料90℃下浸出1 h,Mg, Al, Cr, Fe的浸出率分别为92%, 80%, 82%, 93%. 推测新生成的硫酸金属铵盐的片状聚集体阻碍碳素铬铁渣内部完全被(NH4)2SO4侵蚀.     

高磷高铁氧化锰矿硫酸化焙烧与水浸制备锰电解液

为克服传统工艺的缺点,采用氧化锰矿硫酸化焙烧-水浸方法制备电解锰电解液,将氧化锰矿与硫铁矿混合高温焙烧,使四价锰还原成水溶性的二价锰,并在焙烧过程中完成硫酸化过程,生成水溶性MnSO4,而其他杂质元素生成难溶性的氧化物用水直接浸出,避免其进入电解液,不用传统工艺中的酸浸,有利于环保. 通过实验得出在S/Mn摩尔比为3、焙烧温度600℃、焙烧时间270 min的最优工艺条件下,Mn的综合浸出率可达85.6%. 表明本工艺路线是完全可行的.     

钒渣钙化焙烧参数对钒浸出率的影响

在分析钒渣(V2O3 8.07%)钙化焙烧过程反应机理的基础上,采用钙化焙烧-酸浸法研究了钙化焙烧过程中CaO/V2O3(质量比)、焙烧温度、焙烧时间对钒浸出率的影响. 结果表明,焙烧温度在600~900℃之间时,V2O5等钒氧化物可与CaO发生反应,形成以CaV2O6, Ca3V2O8, CaV3O7为主的钒酸钙. 当CaO/V2O3由0.48提高到约1.125时,钒浸出率由55.3%提高到69.2%,当CaO/V2O3>1.125时,钒浸出率开始下降. 焙烧温度由750℃提高到825℃时,钒浸出率由56.3%提高到69.7%,温度进一步升高,物料开始烧结,浸出率逐渐下降. 随焙烧时间延长,钒浸出率逐渐提高,2 h后达最大;时间继续增加,钒浸出率会因物料间发生二次反应而下降.     

焙烧酸浸渣中铜的形态对铜、金浸出率的影响

以某黄金冶炼厂含铜金精矿为研究对象,采用铜化学物相分析及浸出方法研究了焙烧?酸浸?氰化工艺处理含铜金精矿过程中焙烧酸浸渣中铜形态对铜、金浸出率的影响. 结果表明,含铜金精矿焙烧酸浸及氰化浸出时,铜形态对铜、金浸出率有显著影响,当酸浸渣中氰化易溶铜(氧化铜、次生硫化铜)含量大于0.10%时,金浸出率降低. 以原生硫化铜矿为主的含铜金精矿,适当提高焙烧温度、延长焙烧时间、增加初始酸浸酸度可有效降低酸浸渣中氰化易溶铜含量,提高铜浸出率,减弱其对金浸出率的影响.     

粉煤灰酸浸提铝及其动力学

对KF为助剂焙烧活化粉煤灰酸浸提铝过程进行了研究,考察了粉煤灰焙烧活化和盐酸浸出条件对粉煤灰中铝浸出率的影响及其浸出过程动力学. 结果表明,焙烧活化优化条件为：时间1 h、温度800℃、粉煤灰与KF质量比为20:4. 浸出温度90℃、浸出时间2 h、盐酸浓度4 mol/L、液固比4 mL/g的条件下,铝提取率达到92.46%. 粉煤灰烧结产物加热酸浸过程符合收缩未反应核模型,反应级数为0.3718,反应活化能为43.49 kJ/mol,过程速率为化学反应速率控制.     

Two-stage cyclic ammonium sulfate roasting and leaching of extracting vanadium and titanium from vanadium slag

Compared with traditional sodium or calcification roasting process for vanadium extraction from raw vanadium slag (V-slag), ammonium sulfate (AS) roasting could reduce about 470℃ roasting temperature and avoid Cl₂, HCl, sodium-containing waste-water and waste gypsum discharging. To reduce the amount of AS added in vanadium extraction process, an efficient AS two-stage cyclic roasting and acid leaching process was proposed. The result of TG analysis indicates V-slag could be decomposed in 275-380℃ using AS roasting process. Using 2.03:1 total mass ratio of AS to V-slag, 90.86% V and 80.54% Ti could be extracted after 380℃ roasting for 30 min and 8% initial concentration of H₂SO₄ leaching at 70℃ for 100 min. XRD analysis indicates V-containing spinel phase in the 1st stage leaching residue would be efficiently decomposed by the cyclic two-stage roasting and leaching process. Furthermore, the valence of V(III) in raw V-slag was not changed after the 1st AS roasting stage, but a part of V(III) in the 1st leaching residue was oxidized to V(V) after 2nd roasting process.     

Preparation of high-purity graphite from a fine microcrystalline graphite concentrate: Effect of alkali roasting pre-treatment and acid leaching process

Removal of silicate minerals from microcrystalline graphite ores is important to achieve high-purity graphite product. Alkali roasting pre-treatment and acid leaching process was used to prepare high-purity graphite from a fine microcrystalline graphite concentrate. The results showed that the alkali roasting pre-treatment and acid leaching process could enhance the fixed carbon of microcrystalline graphite to a higher level. Under the optimum conditions selected, a graphite product with fixed carbon content of 99.0% was obtained from microcrystalline graphite concentrate with carbon content of 90.2%. According to XRD and SEM-EDS analysis, impurities mainly composed of Fe, Si, and Al were decomposed to water soluble or acid soluble components during alkali-roasting pre-treatment and acid leaching process. The crystal structure and surface topography of microcrystalline graphite showed no change.     

微波焙烧预处理难浸金矿物

采用微波焙烧法对难浸金矿进行了预处理,并对金的赋存状态、物相及焙砂的微观组织进行了分析.结果表明,金以微粒金和次显微金存在,赋存状态为以硫化物包裹金和石英包裹金为主,需进行预处理打开硫化物包裹金,才能有效提高金浸出率.微波焙烧预处理,焙烧时间为15 min、温度为480℃时,氰化浸出率为92.03%;常规焙烧预处理,焙烧时间为35 min、温度770℃时,氰化浸出率为86.63%.经微波焙烧预处理后的焙砂,矿物界面变得疏松,颗粒表面产生了大量的孔隙,有利于矿物内的金与浸出剂接触,提高金的氰化浸出率;采用常规焙烧预处理后的焙砂,颗粒表面形貌没有明显的变化.     

The role of silver minerals on the cyanidation of gold particles embedded within multi‐sulphidic mineral matrices

The effect of silver minerals on the dissolution behaviour of gold particles embedded within multi‐sulphidic minerals was investigated. A multi‐layer packed‐bed reactor approach was used to study the leaching behaviour of free gold (within silica) and gold associated with a series of synthetic multi‐mineral systems consisting of pyrite, silica, and successively, X = chalcopyrite, sphalerite, and stibnite. The reactor was filled with sieved powders of sulphidic minerals (pyrite, X), gold and silica and arranged as electrically‐isolated three‐layer //Pyrite//X//Silica// and two‐layer //Pyrite + X//Silica// systems. Gold powder was introduced successively in each layer of the three‐ and two‐layer mineral systems and the gold leaching behaviour was studied. The highest gold recovery was achieved for the gold particles within the pyrite layer while the lowest was within the silica layer. In case of the //Pyrite//Stibnite//Silica// system, the surface passivation inhibited gold leaching strongly. Gold cyanidation experiments were also performed with the addition of silver minerals, with both Au and Ag minerals dispersed in a three‐layer //Pyrite//X//Silica// and two‐layer //Pyrite + X//Silica// systems. Silver minerals addition proved beneficial for the pyrite‐sphalerite‐silica system. Gold leaching was severely retarded for the pyrite‐chalcopyrite‐silica and pyrite‐stibnite‐silica systems. Passivating films were observed at the surface of gold particles in case of gold cyanidation with pyrite‐chalcopyrite‐silica and pyrite‐stibnite‐silica systems.

     

含金粉尘中阻金元素的鉴定及提金工艺的选择

金精矿焙烧过程中产生的含金粉尘是一种有价值的二次金资源。在矿物学分析的基础上,研究了不同预处理方法对含金粉尘氰化脱除有害元素和提金的影响。结果表明,该粉尘属于难处理金矿石,砷、碳、铁对提金的不利影响是导致提金率低的主要原因。当NaOH浓度为6 moL/L时,对砷和碳的去除率分别为99.7%和60.6%;金浸提率为58.9%,仅比直接氰化提高了4.60%;在H₂SO₄质量分数为15%时,铁、砷和碳的去除率分别为33.7%、80.4%和12.6%,金的萃取率达到80.4%;在650℃、0.2 m³/h气流速率下焙烧4 h后,砷和碳的去除率分别为54.7%和95.0%,金的提金率达到84.5%。结果表明,碳对金从尘埃中浸出的影响最大,其次是铁和砷。     

废旧锂离子电池正极活性材料的焙烧及其浸出

采用湿式破碎分选、钴酸锂与碳粉混合物预焙烧、钴酸锂预焙烧产物与硫酸钠和浓硫酸混合体系焙烧、热水浸出焙烧产物中的钴,研究了钴酸锂的焙烧及浸出过程。实验结果显示:锂离子电池经湿式破碎分选后铜箔的回收率大于97%,钴酸锂粉末回收率大于98%;钴酸锂与碳粉混合物经700℃预焙烧2 h后再与硫酸钠和浓硫酸在200℃下焙烧4 h,焙烧产物用70℃热水浸出30 min,钴的浸出率可达97%;XRD分析焙烧产物发现生成了Na2Co(SO4)2和Na6Co(SO4)4。     

高铝粉煤灰碳酸钠焙烧与酸浸提铝的动力学

以内蒙古高铝粉煤灰(Al2O3/SiO2质量比1.24)为原料,采用Na2CO3焙烧活化-盐酸浸取法提铝,考察了焙烧温度、时间和碳酸钠/粉煤灰质量比的影响,对焙烧活化及酸浸提铝动力学进行研究,分析了提铝机理. 结果表明,高温活化条件下,粉煤灰中的莫来石及SiO2与Na2CO3反应生成NaAlSiO4, Al2O3和Na2SiO3,酸浸后铝浸出率超过94.99%;活化过程符合Crank-Ginstling-Braunshtein模型,表观活化能为117.06 kJ/mol,活化反应受固膜扩散控制.     

钒矿石活化焙烧-酸浸新工艺的研究

对河南某钒矿进行了活化焙烧-酸浸实验,系统考察了添加剂种类与用量、焙烧温度、焙烧时间、浸取酸度、液固比、浸取温度及时间对钒浸取率的影响。实验结果表明:焙烧过程中,采用氧化钙为添加剂,控制添加量为10%,850～900℃下焙烧3h,矿样的活化效果较好;酸浸过程中,硫酸酸度为5%,液固比为2.5∶1,70～80℃,浸出3h的条件下,钒的浸出率最高,可达80%以上。     

难浸含砷炭金精矿预先酸浸-焙烧-氰化工艺实验研究

某地难浸含砷炭金精矿采用预先酸浸,然后进行焙烧,氰化浸出,研究了酸浸条件对金浸出率的影响。结果表明,较优酸浸条件为硫酸浓度100 g/L,添加氯酸钠活化剂5 g/kg,酸浸温度50℃,酸浸时间6 h;630℃焙烧2 h;氰化浸出采用二浸二洗流程,氰化钠浓度控制在0.15%~0.20%,氰化浸出时间为(24+12)h。在此条件下,金的浸出率可高达93%。     

借鉴硫酸法钛白生产工艺提高黄金回收率的设想

为了提高难浸金矿中黄金的回收率,提出了借鉴硫酸法钛白生产工艺,利用70％左右浓度硫酸浸出焙烧矿中的铁,使铁进入酸浸液中,剥离铁中的包裹金,从而提高难浸金矿中黄金产率,对黄金行业具有一定的开拓和创新意义,具有良好的经济效益和社会效益。     

复合添加剂对石煤提钒焙烧与浸出工艺研究

利用复合添加剂焙烧、低浓度酸浸出法对石煤矿进行提钒研究,考察了焙烧、浸出两个过程中各种工艺参数对浸出率的影响。实验结果表明,适宜的焙烧、浸出工艺条件为:复合添加剂中添加剂硫酸钠、氯化钠、碳酸钠的最佳质量比为7∶1∶11,焙烧温度为750℃,焙烧时间为2.5 h,浸出温度为50℃,浸出时间为5 h。最佳工艺条件下钒的浸出率可达81.9%,明显高于传统的钠法焙烧工艺。     

废SCR催化剂钠化焙烧回收钨和钒的机理探究

文章从热力学角度,分别以温度和碳酸钠加入量为变量,用热力学软件HSC Chemistry计算了蜂窝状废SCR催化剂钠化焙烧的过程,得到了相应的相图,并分析了其对钨和钒浸出率的影响。研究了不同动力学条件下钨和钒的浸出率,得到最佳焙烧条件为：碳酸钠加入量为30%、焙烧温度为800 ℃、粒度为75～100 μm、焙烧时间为2～2.5 h。采用XRD和SEM进行物相和形貌分析。从理论和实验上探究了失效SCR催化剂钠化焙烧过程的机理。     

利用铅锌废渣制备纳米ZnO的试验研究

以铅锌废渣为锌源,通过浸取、除杂、蒸发、干燥和焙烧等步骤制备纳米ZnO.ZnO前驱体的X射线衍射(XRD)、红外光谱分析(IR)、热重(TGA)和差热分析(DSC)分析表明:ZnO 前驱体是无定型碱式碳酸锌(Zn5 (CO3)2(OH)6),加热过程中它先分解成ZnO和Zn(OH)2,然后Zn(OH)2进一步分解成ZnO.焙烧产物的XRD、扫描电镜(SEM)和粒度分析显示:在400 ℃的温度下下焙烧时,ZnO前驱体分解产物是红锌矿(ZnO)和Ashoverite (Zn(OH)2);在500 ℃和600 ℃焙烧时,前驱体完全转化为红锌矿,其形貌不规则,但是前驱体在500 ℃焙烧时,产物ZnO的粒径较小,主要分布在80~150 nm,在600 ℃焙烧时,产物的颗粒团聚严重.     

硼泥活化焙烧-浸取综合回收硅、镁有价组分

以硼化工行业固体废物--硼泥为原料,在TG-DSC热分析基础上,采用马弗炉和微波炉对其进行活化焙烧,再将焙烧产物进行碱浸和酸浸综合回收硅、镁有价组分。研究了两种焙烧方式对硼泥中SiO₂和MgO浸出率的影响。采用化学分析、X射线衍射和扫描电镜对焙烧产物以及白炭黑和氧化镁制品的化学成分、物相组成和微观形貌进行表征分析。结果表明：两种焙烧方式均可提高硼泥活性,促进硼泥中硅、镁组分的浸取。其中,马弗炉最佳焙烧条件为600℃、30 min,此时硼泥中SiO₂和MgO浸出率分别为97.65%和98.81%;微波炉最佳焙烧条件为500℃、10 min,此时SiO₂和MgO浸出率分别为98.03%和98.83%。白炭黑制品中SiO₂含量为92.20%,颗粒多呈近球状,粒径100～200 nm。氧化镁制品中MgO含量为93.05%,晶粒呈圆片状,粒径约2 mm。     

焙烧-浸出黄钾铁矾渣中多种有价金属

实验研究了中低温焙烧-NH4Cl浸出-碱浸同时回收湿法炼锌黄钾铁矾渣中有价金属及Fe的新工艺. 黄钾铁矾渣在650℃下焙烧1 h后,渣中Zn, Pb的主要物相KFe3(SO4)2(OH)6分解为Fe2O3, ZnSO4和PbSO4. 在105℃、液固比10:2(w)条件下用6 mol/L NH4Cl浸出2 h,Zn, Pb和Cd的浸出率均在95%以上,同时Fe含量由焙烧后的23.21%提高到40%. 所得浸出渣再于160℃下用23.08%(w)的NaOH溶液浸出1 h,Fe含量可提高到54%左右,且As含量可降低到0.1%. 最终的浸出渣可作为铁精矿使用.