杂卤石中钾的提取工艺

以四川渠县农乐杂卤石为原料，进行溶浸实验，并确定了最佳溶浸条件，实验表明，当溶浸剂质量分数为5％，固液比为1：4，在温度为40摄氏度条件下，溶浸10h，钾的浸出率可达95％以上，通过蒸发实验考察了溶浸液中钾的收率及钙，镁的去除率，并提出了从杂卤石中提取K2SO4的工艺方法，为我国深层杂卤石矿资源的开发利用提出了一条新的途径。     

杂卤石地浸开采实验室模拟

采用CaCl2溶液作溶浸剂,通过柱浸渗滤试验考察了矿石粒度、溶浸剂氯化钙溶液质量分数、渗滤速度、渗滤路径长度等参数对杂卤石中钾的溶出的影响.试验表明,矿石粒度的大小对体系浸出影响较大.当粒度由2～3mm增大至5～8mm时,K 的浸出率由80.19%降低至42.17%;K 的浸出事随溶浸液的渗滤速度、渗滤路径长度增加而增大;在相同的渗滤速度下,增加渗滤路径长度可提高浸出液中K 的体积质量.试验测得,K 在授出液中的最大体积质量12.1g/L.浸出过程符合金属浸出动力学模型.浸出液中K 体积质量同渗滤速度与渗滤路径长度之比呈指数关系.根据试验结果计算得到模型中相关参数:当渗滤速度由0.159 m/h提高至0.318 m/h时,浸出速率常数由0.278 h-1增大至0.6725 h-1,金属充分浸出开始到进入液所需的时间由2.333 h降为0.951h.研究结果为地浸开采埋藏较深的杂卤石提供了初步的试验基础.     

杂卤石溶解行为及制备矿物复合肥可行性分析

本文以渠县农乐杂卤石为原料,通过对比实验考察了杂卤石与过磷酸钙制备复合肥的可行性。采用正交实验考察了温度、pH、固液比、P2O5与K2O质量比等因素对杂卤石和过磷酸钙混合溶浸过程的影响,结果表明:在温度为27℃,pH为7.5,杂卤石∶水=1∶10,P2O5∶K2O质量比=2∶1时,K+的浸出率最高,达到90.32%,P2O5浸出率为56.45%。     

杂卤石制备硫酸钾工艺研究

采用Ca(OH)2溶液作溶浸剂,通过溶浸实验考察了温度、溶浸剂用量(液固比)、反应时间、溶浸剂浓度对杂卤石中K+浸出率的影响,按照优化的溶浸工艺条件,溶浸剂选5％ Ca(OH)2,液固比4:1,40℃下搅拌反应3h,K+的浸出率可达90.06％.提出了可行的杂卤石提取硫酸钾的工艺.     

杂卤石生产硫酸钾工艺研究北大核心

本文以渠县农乐杂卤石为原料,研究K2SO4的制备工艺。在反应温度70 0C,反应时间2 h的条件下,考查了不同溶浸剂和固液比对杂卤石中K+浸出率的影响。结果表明:以CaO为溶浸剂,反应温度70℃,固液比1∶4时,K+浸出率为78.8%,将浸出液进行蒸发结晶制备K2SO4,产品纯度达到94.3%。杂卤石矿焙烧后以水为溶浸剂、反应温度70℃、固液比1∶6时,K+浸出率为73.0%,在浸出液中加入KOH和K2CO3混合溶液以除去Ca2+、Mg2+等杂质,固液分离后蒸发结晶制得K2SO4产品的纯度可达99.5%。最后得出由杂卤石生产硫酸钾的工艺路线。     

杂卤石,一种潜在的钾肥资源

对杂卤石这种多元素的钾肥在我国的分布、开采、加工技术以及在农业上的应用等进行综述。杂卤石在我国分布广泛,储藏量大,对作物产量、品质及土壤理化性质均具有很好的影响,可视为一种潜在的钾肥资源。对其开发利用,可有效解决我国钾肥短缺问题。     

钾矿资源现状与杂卤石的开发应用分析

通过对世界钾盐资源储量及生产利用特征分析,指出中国钾盐行业亟待解决的问题以及杂卤石的应用前景。研究发现世界钾盐储量的56.98%高度集中于加拿大、俄罗斯和白俄罗斯,中国钾矿总储量丰富,但是可利用的钾不足20%,需要长期依靠进口满足内需;中国钾盐行业发展中存在可利用钾量少、国外找钾项目多处于建设阶段、钾肥生产能耗大、钾盐种类受限等问题。近年随着钾矿资源的消耗、传统化肥价格的攀升、硫肥需求量的增加,杂卤石作为一种成本低廉的缓释性多元素钾肥受到人们的关注,中国对优质杂卤石的需求量也将大幅度增加。因此,有必要进一步了解杂卤石的结构特点,加大杂卤石在农业上的应用分析并指出现有研究的不足,以实现杂卤石在中国的推广应用,缓解中国钾肥短缺的压力,实现农业的绿色发展。     

溶解结晶法加工云南钾石盐

我国云南有一个钾石盐矿藏。上海化工研究院在溶解结晶法方面做过许多工作,文章简要地进行了介绍。文章详细叙述了溶解结晶法的典型流程,作为比较的依据,然后介绍了全溶法、部分溶解法、半溶法和常温溶浸流程的主要实验结果。通过比较,作者认为用溶解结晶法加工云南钾石盐,适宜的方法是部分溶解法,而半溶法也有希望。     

正交试验在杂卤石溶浸工艺研究中的应用

在单因素条件试验的基础上,利用L9(3^4)正交试验法对杂卤石浸出过程的优化工艺条件进行了研究。结果表明,该过程的优化工艺条件为：矿样粒度100目、浸出温度323K、溶浸剂质量分数10％、液固比10：1。而且方差分析所得的结论与极差分析所得的结论相近,说明数据波动主要是由因素水平变化引起的。     

Mg-Al水滑石的溶解动力学及热力学

研究了Mg-Al水滑石在水溶液中的溶解性能及其机理,考察了温度和pH对其溶解性能的影响,探讨了溶解过程中动力学和热力学规律。动力学研究表明,Mg-Al水滑石在水溶液中的溶解符合外扩散及表面化学反应控制模型,且不同pH区间其控制步骤不同。pH=1.0~3.8,水滑石完全溶解,其溶解速率随pH的提高而减小,受解吸控制。而pH=4.2~9.4,水滑石部分溶解,溶解速率与pH值无关,受表面交换反应控制。另一方面,对水滑石溶解反应的Gibbs自由能变进行定量估算,其值为29.516 kJ·mol-1。经实验验证,理论估算可很好地与实验结果吻合。     

钛铁矿硫酸浸出动力学研究

研究了攀枝花钛铁矿在硫酸溶液中浸取反应的动力学行为,发现在温度为１００℃－１９８℃、酸矿比为５００：１５时,钛精矿在８５％硫酸溶液中的反应速率同时受矿粒表面反应和表面产物层传质阻力影响,表观反应活化能约６８．４ｋＪ／ｍｏｌ。浸出反应动力学方程为ｔ＝「０．００７６６／（２．７４＊１０＾７ｅ＾－６８４００／ＲＴ）」「１－ｘ）＾１／３」｛１＋（１１－０．０１６Ｔ）「１＋（１－ｘ）＾１／３－２（１－ｘ）＾２／３」｝在酸矿比更低的非等温和准绝热实验中,该方程式可以很好地模拟反应的动力学特性。     

蛇纹石硫酸浸出过程动力学研究

首先确定了蛇纹石硫酸浸出过程中影响浸出速率的主要因素,以此为条件,对蛇纹石中MgO的浸出速率进行了研究。结果表明：MgO的浸出动力学能适用容积反应模型,其浸出速率可表示为样品中残留MgO量的二级反应,其表观活化能约为93.20kJ/mol,属化学反应控制。     

沥滤法制备骨架镍催化剂的过程动力学

详细探讨了镍铝合金在氢氧化钠水溶液中的沥滤机理,用 EDTA 滴定的方法测得其动力学数据,拟合得到动力学方程式:log[x/(1-x)]=α·log(β·t),求得几种条件下的参数α、β值及沥滤过程的活化能 E_(n)=71.17 kJ·mol~(-1),同时研究了合金颗粒尺寸和氢氧化钠浓度对沥滤速率的影响。     

海因酶法生产N-氨甲酰-D-苯丙氨酸的动力学及温度的影响

利用从Burkholderia cepecia njut1中纯化得到的纯海因酶建立了利用苄基海因生产N-氨甲酰-D-苯丙氨酸的酶转化过程的动力学模型.研究表明,底物的消旋对转化有重要影响.探讨了温度对转化过程的影响,测定了不同温度下苄基海因的溶解常数、消旋常数及米氏常数.结果表明,温度对苄基海因转化过程有重要影响,提高海因酶的热稳定性对D-氨基酸的生产有重要意义.     

肌苷发酵和分离耦合过程的动力学

许多发酵过程都受到高浓度产物的抑制,肌苷发酵亦存在明显的产物反馈抑制作用。为了降低产物抑制效应,采取发酵和离子交换分离产物、流加补料结合起来的耦合发酵方法。本文结合肌苷合成代谢途径,建立了肌苷耦合发酵动力学模型,用于指导工业生产。     

KINETICS OF ALKALINE LEACHING OF ROASTED ZINC CONCENTRATE

In the leaching kinetics of roasted zinc concentrate in NaOH solution, during the early stage of the leaching process, the rate-determining step is diffusion through the zinc ferrite, while in the later stage, it is surface reaction on the zinc oxide. In the shrinking core model, diffusion through a solid layer can be the rate-determining step even in the early stage of the leaching process, not only in later stage. The solid layer changed from zinc ferrite to the porous iron oxide as leaching proceeded, and this substance then thickened progressively due to the selective dissolution of zinc ferrite.     

超临界水氧化法去除废水有机氮的工艺和动力学研究

<正> 引言 超临界水氧化法(SCWO)是一种新型高效的废水和废物处理技术.水在超临界条件下具有独特的物理化学性质,它能与非极性物质如烃类和其他有机物完全互溶,而无机物特别是盐类在超临界水中的溶解度很低.另外,超临界水可以与气体(如空气、氧气、二氧化碳等)完全互溶.这些性质使得超临界水作为反应介质的超临界水氧化法具有独特的优势.在超临     

THERMAL DEWATERING OF DILUTED ORGANIC SUSPENSIONS: PROCESS MECHANISM AND DRYING KINETICS

Drying of raw hog manure, a highly diluted suspension of organic and inorganic matter was studied experimentally in the multistage screw-in-trough dryer. Laboratory tests included material characteristics (rheological properties, thermodynamic equilibrium, critical settling point), boiling pattern, and kinetics of convective drying at temperatures from 90 to 120°C and air velocity from 0.5 to 1.5 m/s. Three phases of manure drying were identified, namely boiling and release of volatile compounds, evaporation from viscous liquid, followed by drying of a soft paste, and finish drying of semi-dry granular product. Drying kinetics were quantified in terms of reduced moisture content and a generalized drying curve using the characteristic drying time concept. Field tests were carried out in the pilot multistage screw-in-trough dryer to validate design calculations.     

THERMAL DEWATERING OF DILUTED ORGANIC SUSPENSIONS: PROCESS MECHANISM AND DRYING KINETICS

ABSTRACT

Drying of raw hog manure, a highly diluted suspension of organic and inorganic matter was studied experimentally in the multistage screw-in-trough dryer. Laboratory tests included material characteristics (rheological properties, thermodynamic equilibrium, critical settling point), boiling pattern, and kinetics of convective drying at temperatures from 90 to 120°C and air velocity from 0.5 to 1.5 m/s. Three phases of manure drying were identified, namely boiling and release of volatile compounds, evaporation from viscous liquid, followed by drying of a soft paste, and finish drying of semi-dry granular product. Drying kinetics were quantified in terms of reduced moisture content and a generalized drying curve using the characteristic drying time concept. Field tests were carried out in the pilot multistage screw-in-trough dryer to validate design calculations.

     

POLYMERIZATION KINETICS AND MODELING OF SLURRY ETHYLENE POLYMERIZATION PROCESS WITH METALLOCENE/MAO CATALYSTS

Polymerization methods of ethylene include the slurry, solution, and gas-phase processes. This study investigates polymerization conditions and kinetics under slurry process. Typical metallocene catalyst/cocatalyst Cp₂ZrCl₂/MAO system was used for ethylene polymerization. Two kinds of polymerization kinetics were compared in this study, multiple active-site model and transfer-effect model. The kinetic studies used metallocene-type polymerization kinetics, including catalyst activation, initiation, chain propagation, chain transfer, and termination steps. In addition, kinetic constants of polymerization reaction model were calculated. Calculation results of catalyst activity and molecular weight were compared with experimental results, indicating their good correlation. Moreover, the conventional polymerization was modified to accurately predict the molecular weight behaviors under various reaction conditions with the proposed transfer-effect model. Exactly, how reaction time, pressure, catalyst concentration, and cocatalyst ratio affect catalyst activity and molecular weight of the polymer were also discussed.