An integrated and efficient process for borax preparation and magnetite recovery from soda-ash roasted ludwigite ore under CO–CO_(2)–N_(2) atmosphere

To realize the comprehensive utilization of ludwigite ore,an integrated and efficient route for the boron and iron separation was proposed in this work,which via soda-ash roasting under CO–CO_(2)–N_(2) atmosphere followed by grind-leaching,magnetic separation,and CO_(2) carbonation.The effects of roasting temperature,roasting time,CO/(CO+CO_(2))composition,and Na_(2)CO_(3) dosage on the boron and iron separation indices were primarily investigated.Under the optimized conditions of the roasting temperature of 850℃,roasting time of 60 min,soda ash dosage of 20 wt%,and CO/(CO+CO_(2)) of 10 vol%,92%of boron was leached during wet grinding,and 88.6%of iron was recovered during the magnetic separation and magnetic concentrate with a total iron content of 61.51 wt%.Raman spectra and^(11)B NMR results indicated that boron exists asB(OH)_(4)^(-) in the leachate,from which high-purity borax pentahydrate could be prepared by CO_(2) carbonation.

One-step electrochemical reduction of stibnite concentrate in molten borax

In this study,antimony production from a stibnite concentrate(Sb2S3)was performed in one step using a molten salt electrolysis method and borax as an electrolyte.Electrochemical reduction of the stibnite concentrate was performed at 800℃under galvanostatic conditions and explained in detail by the reactions and intermediate compounds formed in the borax.The effects of current density(100 800 mA cm^-2)and electrolysis time(10 40 min)on cathodic current efficiency and antimony yields were systematically investigated.During the highest current efficiency,which was obtained at 600 mA cm^-2,direct metal production was possible with 62%cathodic current efficiency and approximately 6 kWh/kg energy consumption.At the end of the 40-min electrolysis duration at 600 mA cm^-2 current density,antimony reduction reached 30.7 g and 99%of the antimony fed to the cell was obtained as metal.

Direct electrochemical reduction of copper sulfide in molten borax

In this study,for the first time,direct copper production from copper sulfide was carried out via direct electrochemical reduction method using inexpensive and stable molten borax electrolyte.The effects of current density(100–800 mA/cm^2)and electrolysis time(15–90 min)on both the cathodic current efficiency and copper yield were systematically investigated in consideration of possible electrochemical/chemical reactions at 1200℃.The copper production yield reached 98.09%after 90 min of electrolysis at a current density of 600 mA/cm^2.Direct metal production was shown to be possible with 6 kWh/kg energy consumption at a 600 mA/cm2 current density,at which the highest current efficiency(41%)was obtained.The suggested method can also be applied to metal/alloy production from single-and mixed-metal sulfides coming from primary production and precipitated sulfides,which are produced in the mining and metallurgical industries during treatment of process solutions or wastewaters.

Effect of M/P and Borax on the Hydration Properties of Magnesium Potassium Phosphate Cement Blended with Large Volume of Fly Ash

The effect of the borax content and magnesia to phosphate ratio（M/P） on the hydration properties of the magnesium potassium phosphate cement（MKPC） with large volume of fly ash was investigated, and a five-hydration-stage for MKPCs was proposed. The results show that MKPC sets rapidly with less than 8% of borax, which is unfavorable to the application of MKPC on construction. Adding more than 8%（including 8%） of borax results in a secondary hydration peak for MKPC, in which the process of hydration can be divided into five stages, namely, pre-induction period, induction period, acceleration period, deceleration period and stable period. M/P ratios could not change the multi-step reactive stages but higher M/P ratios could accelerate the hydration. Borax tends to impact the formation of Mg-containing hydrated products.

Relationship between the Corrosion and Cr-Ni Content of Stainless Steel in Borax Bath

The corrosion of stainless steel was experimentally investigated and analyzed to improve the service-life of the crucible and fixture clamps. Through the experiment, stainless steel was found to satisfy the crucible and fixture clamps materials. As the chromium element mass percentage of the stainless steel increased, the corrosion decreased rapidly at first and then slowly increased. With the corrosion time prolonging, the corrosion growth rate is generally a downward trend. With Chromium 20%, the corrosive were the least. With Nickel element mass percentage increased, the corrosion increased rapidly at first and then decreased rapidly, flatten at the last. It was special that the corrosion had little relationship with the Chromium and Nickel mass percentage when the Nickel percentage is more than 35%. The most remarkable corrosion is corresponding with the Nickel element 12%, the least corrosion with Nickel element 80%. So Nickel element 35% is the most optional.

Composition Variation of Borax Salt during the Process of Vanadizing by Thermal Diffusion

Vanadium pentoxide, borax, boron carbide and sodium fluoride were used to grow vanadium carbide coating on surface of Crl2 steel at 950℃ by TD process. The coating of vanadium carbide （VC） extended the serve-life period of Crl2 steel as punching die. Kinetics of vanadium carbide coating growth was brought forward and verified by comparison of the mathematical model with the experimental results. The thickness of coating was illustrated by SEM. The chemical constituent of coating and remnants were tested by X-ray diffraction （XRD） and X-ray energy dispersive spectroscopy （EDS）. To increase the thickness, rare earth silicon powder （FeSiRe23） was added to the borax salt bath. The analysis of XRD revealed that FeSiRe23 increased the depth of vanadium car-bide coating as reducing agent and catalysis.

Discovery of Borax-bearing Mirabilite Beds in Dong Co, Northern Tibet, and Its Palaeoclimatic Significance

The authors investigated lacustrine chemical sediments on terrace-I of DongCo-a salt lake in the interior of the northern Tibetan Plateau and firstly discovered borax and acomplete sedimentary section with five pure mirabilite beds. According to the sedimentarycharacteristics of rhythmic layering, palaeotemperatures for the formation of the cold-phasemineral-mirabilite-at the profiles and ^(14)C dating, the authors applied the theory and method ofcomparative salinology in the study of the history of the palaeoclimate and palaeoenvironment ofDong Co in the early and middle Holocene and drew the conclusion that the salt lake had experiencedthe following climatic evolution: the warm and moist stage (>8470 a HP and possibly to 10500 aHP)->cold and dry stage (8470-8170 a BP)->warm and moist stage (8170-7590 a BP)->stage of repeatedclimatic oscillations (7590-7400 a BP, alternation of three dry oscillations and three moistoscillations in a generally cold climatic background)->cold and dry stage (7400-6940 a BP)->warm andmoist stage (6940-6620 a BP)->cold and dry stage (6620-6410 a BP)->warm and moist stage (after 6410a HP).

EFFECT OF RARE EARTH ON VANADIZATION PROCESS IN BORAX BATH

This paper investigates the effect of rare earth elements on the kinetic process, microstructure and mechanical properties of vanadization in borax bath. The results show that addition of rare earth elements to vanadizing agent has obvious catalytic effect on the rate of vanadization, which has been enchanced by 30%. The wear and corrosion resistance of vanadium carbide layer were prompted by the addition of rare earth to the agent. Through increasing vanadium potential of the agent, activating the surface of workpieces and decreasing the activation energy of diffusion of carbon, rare earth elements accelerate the rate of vanadization process.

Mercury-Free Gold Extraction Using Borax for Small-Scale Gold Miners

Small-scale gold mining is the largest anthropogenic contributor of mercury pollution on planet Earth. The miners grind gold ore together with mercury in order to recover the fine gold grains. The gold amalgam is burned whereby the mercury evaporates and gold is left behind. This processing extracts only a fraction of the gold in the ore and the released mercury causes serious global health and environmental problems. However, a mercury-free method described below has proved to extract up to twice as much gold without need of investment in new processing equipment and without longer processing time. The method has successfully been tested in the Philippines, Indonesia, Tanzania, Bolivia and Zimbabwe.

Increasing the Burned Time and Mechanical Properties with New Mix As Flame Retardant Based in Hexametaphosphate of Sodium and Borax in Textile 100% Acrylic Fabrics

It has been worked with textile fabrics of Acrylic 100 % , that have as final use the Tapestry, this fabrics have been impregnated with a two products flame retardant: Commercial Retardant, which is formed by a combination of a resin polymeric and acid phosphoric and Borax (Na2B4O5(OH)4.8H2O) with Sodium Hexametaphosphate (Na16P14O43). These Retardants?? has the advantage of the fact that it can be applied to the substrates mixed with water in the relation 1:1, 1:2 or pure. In order to reduce the flammability, Textile fabrics are coated with flame retardants. The flame retardant capabilities, mechanical properties and structural characteristics of the textile fabrics before and after the use of these products were investigated throughout the special textile methods for inflammability and mechanical resistibility. After the use of the flame retardants the mechanical properties of the fabrics were improved or at least remained the same as compared to fabrics without any treatment. The use of Borax / Sodium Hexametaphosphate /Water results in the essential increase of combustion retardation time about 2 minutes as compared with 8 seconds for untreated fabrics.

硼砂煅制工艺优化及质量评价

目的 优化硼砂煅制工艺,并对其进行质量评价。方法 以铺设厚度、煅制温度、煅制时间为影响因素,失水率、蓬松度、粉碎率、四硼酸钠含量为评价指标,星点设计-效应面法优化硼砂煅制工艺。采用扫描电镜(SEM)、热重分析(TG)、拉曼光谱、X射线衍射(XRD),比较硼砂煅制前后质量差异。结果 最佳条件为铺设厚度2 cm,煅制温度365℃,煅制时间100 min。煅制后,硼砂微观形态、成分组成、晶型结构发生变化,失去全部结晶水而转变为非晶体状态。结论 该方法稳定可行,可用于工业大批量生产煅硼砂。

硼砂-硅酸钠碱激发矿渣砂浆干缩和微观特性试验研究

碱激发材料(AAMs)具有高强、低碳等优点,但是其相较于水泥基材料较大的干燥收缩率限制了其应用和推广。该文设计了一种复合激发剂,开展了硼砂-硅酸钠碱激发矿渣(AAS)砂浆的干缩和微观特性试验研究。采用压汞法(MIP)、X射线衍射(XRD)、扫描电子显微镜(SEM)和傅里叶变换红外光谱(FTIR)对样品进行测试和表征,分析了复合激发剂减缩机理。试验结果表明,硼砂-硅酸钠复合激发剂有效降低了AAS砂浆的干缩;XRD结果显示AAS砂浆中存在钠硼解石相(NaCaB_(5)O_(6)(OH)_(6)(H_(2)O)_(5));FTIR分析表明,最优硼砂比例下(20%),AAS砂浆的Si—O—T(T代表Si、Al或B)谱带明显增强,通过MIP分析得到AAS砂浆的中孔(<50nm)数量减少,这有助于缓解收缩应力,降低砂浆的干缩率。该研究结果可以为AAMs的减缩和应用提供参考依据,激发学生在建筑领域的碳减排思维,提升解决关键问题的能力。

复合缓凝剂改性硫铝酸盐水泥注浆材料性能试验研究

为了改善硫铝酸盐水泥注浆材料(HSAC)的注浆效果,降低硼砂对HSAC强度产生的不利影响,测试和分析了单掺和复掺硼砂与柠檬酸钠的HSAC浆体凝结时间、流动度、强度以及微观结构。结果表明:单掺硼砂的缓凝效果显著,但会对HSAC强度产生不利影响。掺入适量的柠檬酸钠可以有效挽回硼砂导致的HSAC强度损失,且对浆体的流动度与凝结时间无不利影响。其中,硼砂掺量为0.15%时,复掺柠檬酸钠对HSAC强度的提升效果最明显;通过对水泥水化后期结石体中钙矾石(AFt)生成量的测定,发现硼砂掺量一定时,复掺适量的柠檬酸钠能够促进AFt的生成,减少六方板状的Ca(OH)2(CH)生成量,有效减缓HSAC水化速度,从而改善其工作性能。

Toxicity detection of sodium nitrite,borax and aluminum potassium sulfate using electrochemical method

Based on the inhibition effect on the respiratory chain activity of microorganisms by toxicants, an electrochemical method has been developed to measure the current variation of a mediator in the presence of microorganisms contacted with a toxicant. Microelectrode arrays were adopted in this study, which can accelerate the mass transfer rate of an anaiyte to the electrode and also increase the total current signal, resulting in an improvement in detection sensitivity. We selected Escherichia coli as the testee and the standard glucose- glutamic acid as an exogenous material. Under oxygen restriction, the experiments in the presence of toxicant were performed at optimum conditions （solution pH 7.0, 37℃ and reaction for 3 hr）. The resulting solution was then separated from the suspended microorganisms and was measured by an electrochemical method, using ferricyanide as a mediator. The current signal obtained represents the reoxidation of ferrocyanide, which was transformed to inhibiting efficiency, IC50, as a quantitative measure of toxicity. The IC50 values measured were 410, 570 and 830 mg/L for sodium nitrite, borax and aluminum potassium sulfate, respectively. The results show that the toxicity sequence for these three food additives is consistent with the value reported by other methods. Furthermore, the order of damage degree to the microorganism was also observed to be： sodium nitrite 〉 borax 〉 aluminum potassium sulfate 〉 blank, according to the atomic force microscopy images of E. coli after being incubated for 3 hr with the toxic compound in buffer solutions. The electrochemical method is expected to be a sensitive and simple alternative to toxicity screening for chemical food additives.

电感耦合等离子体质谱(ICP-MS)法测定锆钛矿中的铪

锆钛矿中存在耐高温的锆、钛化合物,铪以类质同象进入锆矿物中,准确测定锆钛矿中的铪对选矿研究、矿物综合利用及工业生产有重要作用。通过考察锆钛矿成分及熔融方法,以碳酸钠-硼砂高温熔融锆钛矿,以178 Hf为分析同位素及185 Re为内标,使用电感耦合等离子体质谱法测定锆钛矿中含量不均的铪。结果表明,碳酸钠-硼砂高温熔融效果最好,可完全溶解耐高温难分解的锆钛矿,当碳酸钠-硼砂质量配比为2∶1时熔融效果最佳。ICP-MS蠕动泵转速为45 r/min、雾化气流量为1.06 L/min时雾化效率最优。在选定的实验条件下,HfO_(2)质谱强度与质量浓度在0.01~250 ng/mL呈良好的线性关系,相关系数为0.9997,背景等效浓度为0.029 ng/mL,方法检出限为0.0032 ng/mL。按实验方法对中国国家标准物质中的HfO_(2)进行测定,测定值与认定值一致,相对标准偏差在1.6%~3.2%。按实验方法对锆钛矿样品中的HfO_(2)进行测定并进行加标回收实验,测定结果的相对标准偏差(RSD,n=9)为0.90%~3.4%,加标回收率在96.0%~106%,满足国家地质矿产行业标准DZ/T 0130—2006的要求。

热处理红宝石中填充物硼砂的定量研究

红宝石的热处理属于优化处理,常用硼砂作助熔剂。在市场中热处理红宝石被以天然红宝石出售,价值颇高,但裂隙中硼砂的含量多少会影响到售价的高低。因此,对此类红宝石中的硼砂进行定量研究,应用NanoVoxel-4000X型射线计算机断层扫描仪对样品进行扫描分析,从而获得裂隙中充填物硼砂的2D图像。用明暗灰度值表征裂隙中不同密度的物质;充填物硼砂分布的3D图像中用不同的颜色表征其三维厚度。通过比较表征厚度的色标,可直观看到硼砂的整体含量小。同时样品的硼砂的厚度分布直方图显示所有裂隙内硼砂的厚度都小于130μm,所有硼砂的厚度和体积比都小于10%,也说明填充量小。最后通过Avizo 9.0软件对红宝石样品和硼砂的含量进行阈值分割,得到两者的实际体积,然后可计算出硼砂含量的体积占红宝石总体积的百分比。本实验样品中充填物硼砂体积比例为10.69%,这既是热处理红宝石中硼砂定量检测中的一个重要指标,也为研究热处理红宝石中硼砂的定量分级标准提供了数据支撑。

硼砂交联PVA降失水剂的合成及滤失性能研究

以聚乙烯醇(PVA1788)为水泥浆降失水剂基础原料,考察了交联剂种类和用量、反应温度、溶液pH值等对PVA胶液粘度和水泥浆滤失性能的影响规律,发现硼砂水解后对PVA的交联效果最显著,而且随着硼砂与PVA配比、反应温度和pH值升高,PVA胶液粘度及水泥浆滤失性能呈现显著增高趋势,所形成的滤饼更加致密,保水能力更好。但一旦超过最佳配比时,水泥颗粒表面降滤失剂膜层变厚,滤饼致密性变差,反而不利于水泥浆保水,滤失性能下降。

离心浇铸复合机筒双金属层开裂原因

在对某高强度离心浇铸复合机筒进行成品检测过程中,发现多件机筒的双金属层开裂。采用低倍组织检验、化学成分分析、金相检验等方法,并结合工艺分析,研究了复合机筒开裂的原因。结果表明:复合机筒的双金属层有疏松缺陷,在压力的作用下,机筒发生开裂;机筒产生疏松缺陷的原因为离心浇铸加热温度不足、保温时间较短、使用的硼砂质量较差等。

硼砂生产厂区自然修复状态下的土壤影响因素含量测定及分析

采用布点区采样与室内分析相结合的方法,对硼砂生产厂区自然修复状态下的土壤影响因素含量测定,考察土壤影响因素的改变,分析生产过程中影响因素迁移可能发生的污染。结果表明:碳碱解车间和精制车间不同取样深度硼含量差异较大,pH值处于碱性,两者垂直地下方向均呈现低-高-低走向趋势,办公区对照点土壤受到一定程度的污染,宿舍区对照点硼含量、土壤pH值与当地土壤状况一致。杂填土及生产原料所含有的重金属、硼、碱性物等污染物通过自身重力垂直向下迁移,有污染土壤及地下水环境的风险。

一种控制中性盐雾试验pH的方法

结合笔者的实际工作经验,对盐雾腐蚀的成因和中性盐雾试验做了简要的分析。中性盐雾试验过程中容易出现盐溶液pH值降低的现象,从而使得无法满足中性盐雾试验相关标准的要求,并且在标准中也未给出有效的解决方法。对此,通过查阅相关资料,发现硼砂作为一种pH缓冲剂,可以调控溶液的pH值。故通过理论探讨和试验验证对硼砂对中性盐雾试验盐溶液pH值的影响进行了分析,结果表明,硼砂可以有效地控制盐溶液的pH值,从而使得盐溶液的pH值在中性盐雾试验的全周期内稳定在6.5~7.2之间,并且在参比试验中,腐蚀性也可达到中性盐雾试验腐蚀的要求。提出的这种有效控制pH的方法,可供从事研究、制定和使用盐雾试验标准的人员进行参考。