新技术与新成果

2014001稀土冶炼分离废水联合处理方法 稀土冶炼分离废水联合处理方法,包括以下步骤：以酸性草酸沉淀废水调节皂化废水酸度,使废水中的大部分草酸和稀土以沉淀形式析出,在超声波的辅助下使乳化的有机相破乳,经澄清分相,使有机相和稀土草酸盐得到回收;     

新技术与新成果

正2014001稀土冶炼分离废水联合处理方法稀土冶炼分离废水联合处理方法,包括以下步骤:以酸性草酸沉淀废水调节皂化废水酸度,使废水中的大部分草酸和稀土以沉淀形式析出,在超声波的辅助下使乳化的有机相破乳,经澄清分相,使有机相和稀土草酸盐得到回收;分离出油相和固相的水相继续用石灰浆中和至pH值10~11,经澄清过滤,使重金属Pb、Cr及大部分残留的有机萃取剂及溶剂     

P507-N235双溶剂体系萃取稀土铈和镨的实验研究

传统的稀土元素分离提取工艺常采用单一的酸性磷酸酯类萃取剂,如使用常见的P507、P204等萃取剂来萃取稀土元素,需要先进行皂化预处理,皂化反应会产生污染性、刺激性严重的浓氨水,并产生氨氮废水及其他废水,采用这种方法会对环境造成严重污染.本实验采用P507-N235双溶剂萃取体系,以稀土铈、镨为主要萃取元素,研究对萃取稀...     

有机相及稀土回收反应器在稀土萃取废水中的应用

正稀土冶炼萃取废水中含有大量的有机相和稀土,回收可产生较大的经济效益,本文通过有机相及稀土回收设备处理稀土冶炼萃取废水,可回收有机相4L/m3,回收草酸稀土大于0.2kg/m3。稀土企业在生产过程中会产生大量萃取废水,主要分为萃取废水和草酸沉淀废水[1]。萃取废水是在萃取分离过程中产生的,通常夹带有大量的有机相,主要为煤油、P507、P204等。大量有机相的生成会造成萃取废水中油和COD的超标,大大污染了环境,即使萃取工序后立即通过气浮、石灰中和沉淀等方式进行萃取废水处理,萃取废水中的有机相也会附着在浮     

离子型稀土矿分离的工艺设计

以离子型稀土矿为原料,采用无氨氮、镁皂化萃取分离稀土专利技术以及模糊萃取分离技术,生产单一稀土氧化物,稀土回收率达94.5%。同时对生产过程中所产生的各类污染物均采取了有效防治措施,做到达标排放。     

稀土冶炼氨氮废水的处理技术现状

分析了稀土冶炼废水产生原因和组成成分,阐述了国内外稀土冶炼氨氮废水主要处理技术及研究现状,分别介绍了生化法、物化法及蒸馏法等处理技术原理,讨论了这些稀土冶炼氨氮废水处理技术实际运用中存在的问题.并着重针对目前风化壳淋积型稀土矿提取和分离过程中面临的氨氮达不到废水排放新标准等问题,提出了今后加强对风化壳淋积型稀土矿提取分离新技术工艺及新型药剂等的研究,探索氨氮废水循环利用新途径,从源头消除氨氮废水并从根本上治理氨氮污染.      

RE_x(CO_3)_y沉淀废水处理的资源化研究

为了开发稀土冶炼及沉淀废水处理方法的清洁生产工艺,本文针对稀土元素分离过程中,以氨皂化工艺为前提,萃取分离混合或单一稀土元素时所产生的RE_x(CO_3)_y沉淀废水进行研究,将RE_x(CO_3)_y沉淀废水采用电解的方法处理后,将电解产物进行资源转化研究。废水电解处理的主要产物为HCl和NH3,NH3迅速溶于电解溶液中,研究将NH3从电解溶液中分离并与CO2生成NH4HCO3,电解后的水经净化处理形成的纯水,应用于冶炼生产,形成可资源转化的循环利用工艺。文章剖析了资源化研究(N2吹脱NH3·H2O,NH3·H2O分离和NH4HCO3形成)的原理;设计了资源化实验方法;确定最佳实验条件;验证了资源化应用的产品效果。所研究的资源化工艺只引入CO2气体,不产生其他污染物。按本文提出工艺处理生产的RE_x(CO_3)_y产品与原工艺生产的RE_x(CO_3)_y产品无差别,资源化研究工艺符合清洁生产要求,渴望为RE_x(CO_3)_y冶炼的实际生产提供参考依据。     

我国将进一步规范稀土企业排污行为

正为统一规范稀土生产企业的排污行为,环境保护部近日发布《稀土冶炼行业污染防治可行技术指南》(征求意见稿),并公开征求意见。近年来,我国稀土冶炼行业进入高速发展阶段,并成为世界最大的稀土生产国。统计显示,我国现有稀土冶炼企业多达百家,稀土矿产品产量约占世界的95%。然而,高速增长的稀土产品产量在带来经济效益的同时,也给环境带来了严重的污染。如,稀土生产过程中存在氨氮废水、氟废水排放问题。同时,还会产生含氟和硫氧废气。该指南编制说明中表示:"以各类     

稀土冶炼分离废水中稀土及萃取剂回收的研究

采用稀土冶炼过程不同性质废水相混合的方法回收废水中的稀土和萃取剂,考察了皂化废水与草沉母液废水的摩尔混合比(Rm)对稀土回收的影响,pH、超声辅助强度及时间等对萃取剂回收的影响。结果表明,当Rm=1:1.2时稀土回收率达到最大值62%,pH=1~2时萃取剂的回收率在51%~52%,超声波辅助有助于萃取剂回收,超声频率对萃取剂回收无明显影响,当超声时间为30min时萃取剂回收率达到59%。     

反渗透处理稀土冶炼高氨氮废水及膜污染特征分析

稀土冶炼产生大量的氨氮废水,直接排放会对环境造成严重的危害.采用反渗透技术处理稀土冶炼碳酸稀土沉淀过程产生的高氨氮洗涤废水,考察了反渗透膜对废水中各污染物的处理效率,结果表明反渗透对污染物具有较高的截留效率,当跨膜压差为3.5 MPa～4.0 MPa时,氨氮和COD的平均去除效率分别为73.97％和68.33％,Pb、...     

冕宁稀土矿泥中锰与稀土分离及回收的研究

以Ｎａ２ＳＯ３为还原剂,采用还原浸出法处理四川冕宁稀土矿泥,实现了矿泥中锰和稀土的分离,提高了矿泥氯化焙烧时稀土的氯化率。对锰浸出液,用ＫＭｎＯ４氧化,水解聚合法去除杂质铁,生成ＲＥ（ＯＨ）３法回收稀土,制备出合格的产品ＭｎＣＯ３,并讨论了有关工艺原理与条件。     

Clean separation technologies of rare earth resources in China

After a review on the conventional separation process of rare earths (RE), hyperlink extraction technology was introduced and a potential process was proposed for clean separation of RE. A great amount of acid, base and water was consumed in the conventional RE separation process which included the procedures of raw material dissolving, extraction separation and precipitation. Therefore hyperlink extraction technology had been developed, by which the repeated consumption of acid and base could be avoided during the extraction process. And based on the theory and successful applications of the hyperlink extraction technology, we proposed the integral hyperlink process in which the intermediate acid resulted in individual procedures would be recycled and reused after being treated. The proposed process would make it feasible to consume no chemicals except for oxalic acid, and so could be a promising clean separation technology with a significant reduction on consumption and emission.     

Recovery of rare earths from spent FCC catalysts by solvent extraction using saponified 2-ethylhexyl phosphoric acid-2-ethylhexyl ester(EHEHPA)

A process to recover rare earth(RE) metals from spent fluid catalytic cracking(FCC) catalysts by solvent extraction was studied, using saponified 2-ethylhexyl phosphoric acid-2-ethylhexyl ester(EHEHPA or P507). The recovery process involved three steps:(1) leaching REs(mainly lanthanum and cerium);(2) solvent extraction by applying saponified P507-kerosene system;(3) stripping. Experiments to assure optimal operating conditions were conducted. Results indicated that RE metals could be recovered effectively from spent catalyst with saponified P507-kerosene-HCl system. At room temperature of 25 oC, 10 g spent catalyst with 110 m L of HCl(1 mol/L) could achieve a leaching efficiency of 85%. For extraction, initial pH value of 3.17, organic/aqueous ratio(O/A ratio) of 2:1 with an extractants' saponification rate of 20% could obtain 100% efficiency. In the stripping process, 1 mol/L HCl with O/A ratio of 1:1 led to a stripping efficiency of 96%. In the present study, RE metals from spent FCC catalysts were effectively recovered, which avoided wasting a large amount of RE resources. It provides a theoretical support for commercial recycling of RE resources.     

化学沉淀—折点氯化法处理稀土氨氮废水

采用化学沉淀—折点氯化法去除稀土氨氮废水中的氨氮。化学沉淀试验表明,调节废水pH=7,沉淀时间15min,废水中氨氮的去除率可达90.64%;折点氯化试验表明,调节废水pH=7,次氯酸钠溶液加入量为理论量的1.4倍,反应时间15min,废水中氨氮浓度可降至8.35mg/L,处理后的废水满足稀土工业废水氨氮排放标准,并且本工艺是经济可行的。     

稀土电解废熔盐的综合利用研究

主要研究了从氟化体系熔盐电解过程产生的废熔盐回收合格熔盐和氧化稀土的工艺条件；采用本工艺得到的熔盐可直接返回电解生产线使用，制取的氧化稀土质量都达到国家标准，稀土总收率达90．09％。     

Precipitation transformation of rare earth sulfate into chloride with p-dodecylphenoxy carboxylic acids

Methods for transforming rare earth(RE) sulfate into chloride mainly include extraction process with organophosphonic mono-acids or aliphatic acids and precipitation process with ammonium bicarbonate(NH_4 HCO_3).In this paper,alkylphenoxy carboxylic acids(HAs) ofp-dodecylphenoxy acetic acid(HA-Ⅰ),pdodecylphenoxypropanoic acid(HA-Ⅱ) and p-dodecylphenoxybutyric acid(HA-Ⅲ),which were liquid at room temperature were synthesized and characterized.The precipitation mechanisms of RE elements with the HAs were investigated and the HA/RE molar ratios of the solid complexes were determined as3:1 by equi-molar series method which accord with the principle of charge balance.Applicability of HAs for the transformation of RE sulfate from concentrated sulfuric acid roasted RE concentrate into chloride via precipitation method was discussed.100% HA-Ⅱ was selected as the liquid organic precipitant without dilution of volatile solvent soracceleration of phase separation by phase-modifiers.The RE sulfate solution can be precipitated by HA-Ⅱ after neutralization with liquid NaOH and stripped with concentrated HCl at room temperature.High concentration of RE chloride of 218.1 g/L with low residue of sulfate radical of 0.536 g/L was obtained.The residual organic precipitant in the raffinate solution was tested to be lower than 8 mg/L at 25℃and the chemical oxygen demand(COD) in wastewater was less than 50 mg/L.     

A novel process for recovering rare earth from weathered black earth

A novel process for recovering rare-earth (RE) elements from weathered-black-earth slime is developed. This process involves the initial removal of Mn by reduction leaching using SO₂ followed by ammonium chloride roasting of the residual solids from the leaching process. The controlled roasting selectively converts RE oxides to water-soluble RE chlorides. The roasted materials are then dispersed in warm water (75 °C) to extract RE, while water-insoluble iron oxides remain in gangue sludge, minimizing iron impurities in final RE products and hence simplifying the purification process. Leadchloride precipitates are obtained by cooling the leachate to −10 °C, and RE is recovered using oxalic acid precipitation. With this new process, a product of 92 pct purity at a RE recovery greater than 65 pct is obtained. In addition, Mn and Pb are recovered as by-products, with a recovery of 64 and 54 pct, respectively. The effect of operating variables on RE recovery is examined and the process chemistry described.     

稀土元素在洁净重轨钢中存在状态的热力学模型研究

建立了可以定量描述洁净稀土重轨钢凝固过程中成分偏析与夹杂物析出的耦合热力学模型,经文献验证,模型具有较高精度。通过模型分析了稀土加入量对洁净钢中夹杂物的析出规律与稀土存在状态的影响。得出在洁净重轨钢中加入稀土可以变质钢中MnS、Al₂O₃夹杂;钢中首先析出稀土氧硫化物(或稀土铝酸盐),其次是稀土硫化物,最后是稀土氮化物;在同一稀土加入量条件下,固溶La的量要大于固溶Ce的量。     

含氟废水处理的机理和工艺流程的研究

根据广州某公司特定的含氟废水,探讨了含氟废水的处理机理和处理工艺流程。实验表明:用熟石灰调pH值,同时采用沉淀剂氯化钙+混凝剂PAC的联合处理,可使含氟废水的氟离子浓度下降到10mg/l以下,达到国家污水综合排放的一级标准。     

氰化废水回收技术综述

氰化浸出工艺至今仍是占绝对统治地位的提金方法,金矿石中常常伴生含量不等的各类杂质金属矿物,导致氰化物消耗和氰化尾液中氰化物含量显著增加。目前普遍应用的氰化废水净化工艺对处理简单的含游离氰化物的废水是非常有效的。如果矿石中存在其他有价金属如铜等,则氰化物将流失于尾矿、尾渣中难以有效回收,杂质元素的存在增加了氰化物的消耗,严重时甚至使整个金氰化回收工艺失效。针对黄金矿山含氰废水的性质和特点,已研究开发了多种回收技术和方法。由于各种杂质金属的累积效应,含氰废水直接返回工艺通常很难实现。AVR法及由此技术衍生的方法如硫化物沉淀技术生产成本较高、且不能有效回收含氰废液中的有价金属。受制于对氰化物的吸附能力,活性炭只能处理低氰废水。树脂吸附和溶剂萃取工艺可以针对含氰废水性质进行合理的选择性设计,但通常生产成本较高,操作工序繁琐复杂。采用液膜和其他如渗析法等技术仍然处于实验室研究阶段,能够有效应用于工业实践的氰化废液回收技术仍有待开发。