碳酸钡法去除氯化钙型矿卤中硫酸钙的初步研究

阐述了碳酸钡法去除氯化钙型矿卤中硫酸钙的原理,通过试验研究探索出最佳反应条件,讨论了该工艺的可行性。

糊精在氧化矿表面的吸附特性及作用机理

通过系统地研究糊精在赤铁矿、金红石等氧化矿表面的吸附规律发现：糊精在矿物表面的吸附与矿浆ｐＨ值有关，糊精在矿物表面的吸附密度最大值时ｐＨ值对应于矿物表面等电点，这表明糊精主要是与矿物表面金属羟基化合物发生作用，通过Ｘ射线光电子能谱（ＸＰＳ）和俄歇电子能谱（ＡＥＳ）测定发现：经糊精处理前后，赤铁矿表面Ｆｅ元素内层电子结合能有明显化学变化；金红石表面Ｔｉ元素的俄歇参数也发生明显化学位移。

氧化锌矿中基于碱焙烧法对ZnO的提取

硫化锌矿和氧化锌矿是锌矿的主要组成部分,现阶段冶炼锌的来源主要依靠硫化锌矿。本文研究一种新的氧化锌矿处理方法,经工业NaOH焙烧处理后,氧化锌矿物中的ZnO、PbO、SiO2与碱反应得到Na2ZnO2、Na2PbO3及Na2SiO3,通过溶出过滤,将ZnO、SiO2和PbO利用分步碳分工艺逐渐提取出来。

罗布泊光卤石矿制备硫酸钾镁肥的工艺研究

本文介绍了利用国投罗钾公司硫酸镁亚型卤水制取的光卤石矿进行分解浮选洗涤精制成氯化钾,另每消耗3.87吨光卤石矿,就会约有1吨氯化钾浮选尾矿产生。经物料组成主要成分是MgSO4·7H2O和氯化钠。本实验研究采用光卤石矿为原料进行分解、浮选、转化、浮选、洗涤和烘干工序生产硫酸钾镁肥的实验。结合水盐体系相图指导,分解、转化温度控制在25℃,浮选得到的软钾镁矾精矿经过洗涤、在150℃烘干后硫酸钾镁肥产品达到化工行业GB/T 20937-2018产品一等品标准。该工艺总回收率达21.42%,同时实现浮选尾矿资源回收利用,从而不被当做废弃物丢弃而产生环保等问题。

银在灼烧除汞中损失原因的研究

本文重点研究提出了银在灼烧除汞时损失的原因及对策，并据此拟定了氯化钠熔矿后，不经任何分离，直接用双硫腙萃取光度法测定银的改进方法。

Simultaneous extraction of gold and zinc from refractory carbonaceous gold ore by chlorination roasting process

A novel process based on chlorination roasting was proposed to simultaneously recover gold and zinc from refractory carbonaceous gold ore by using NaCl as chlorination agent.The effects of roasting temperature,roasting time and NaCl content on the volatilization rates of gold and zinc were investigated.The reaction mechanism and the phase transition process were also analyzed by means of SEM,EDS and XRD.The results demonstrated that under the optimal conditions of NaCl content of 10%,roasting temperature of 800℃,roasting time of 4 h and gas flow rate of 1 L/min,the rates of gold and zinc were 92%and 92.56%,respectively.During low-temperature chlorination roasting stage,a certain content of sulfur was beneficial to the chlorination reactions of gold and zinc;and during high-temperature chlorination roasting stage,the crystal structure of vanadium-bearing mica was destroyed,and the vanadium-containing oxides were beneficial to the chlorinating volatilization of gold and zinc.Eventually,the chlorinated volatiles of gold and zinc could be recovered by alkaline solution.

Co-extraction of valuable metals and kinetics analysis in chlorination process of low-grade nickel-copper sulfide ore

To efficiently co-extract Ni and Cu from low-grade nickel-copper sulfide ore,chlorination roasting with NH;Cl followed by a water leaching process was investigated.The results show that 98.4%Ni and 98.5%Cu can be synchronously extracted when the ore particle size is 75-80μm,the roasting time is 2 h,the mass ratio of NH;Cl to ore is 1.6:1 and the roasting temperature is 550°C.The evolution behavior of various minerals was elucidated using X-ray diffraction(XRD)coupled with scanning electron microscopy(SEM).The kinetics of the chlorination process based on the differential thermal and thermogravimetric analysis(DTA-TG)data was analyzed by Kissinger method and Flynn-Wall-Ozawa(FWO)method.The chlorination process of low-grade nickel-copper sulfide ore mainly contains two stages:the decomposition of NH;Cl and the chlorination of ore.The maximum apparent activation energies(Ea)at two stages are determined to be 114.8 and 144.6 kJ/mol,respectively.The condensed product of exhaust gas is determined to be ammonium chloride,which can be recycled as the reactant again,making the process economic and clean.

Electrogenerative leaching of nickel sulfide concentrate with ferric chloride

In order to utilize the chemical energy in hydrometallurgical process of sulfide minerals reasonably and to simplify the purifying process, the electrogenerative process was applied and a dual cell system was introduced to investigate FeCl3 leaching of nickel sulfide concentrate. Some factors influencing the electrogenerative leaching, such as electrode structure, temperature and solution concentration were studied. The results show that a certain quantity of electrical energy accompanied with the leached products can be acquired in the electrogenerative leaching process. The output current and power increase with the addition of acetylene black to the electrode. Varying the components of electrode just affects the polarization degree of anode. Increasing FeCl3 concentration results in a sharp increase in the output of the leaching cell when c（FeCl3） is less than 0.1 mol/L. The optimum value of NaCl concentration for electrogenerative leaching nickel sulfide concentrate with FeCl3 is 3.0 mol/L. Temperature influences electrogenerative leaching by affecting anodic and cathodic polarization simultaneously. The apparent activation energy is determined to be 34.63 kJ/mol in the range of 298 K to 322 K. The leaching rate of Ni2+ is 29.3% after FeCl3 electrogenerative leaching of nickel sulfide concentrate for 620 min with a filter bag electrode.

Extraction of potassium from K-feldspar via the CaCl_2 calcination route

The extraction of potassium from K-feldspar via a calcium chloride calcination route was studied with a focus on the effects of the calcination atmosphere, calcination temperature and time, mass ratio of CaCl2 to K-feldspar ore and particle size of the K-feldspar ore. The results demonstrated that a competing high-temperature hydrolysis reaction of calcium chloride with moisture in a damp atmosphere occurred concurrently with the conversion reaction of K-feldspar with CaCl2, thus reducing the amount of potassium extracted. The conversion reaction started at approximately 600 °C and accelerated with increasing temperature. When the temperature rose above 900 °C, the extraction of potassium gradually decreased due to the volatilization of the product, KCl.As much as approximately 41% of the potassium was volatilized in 40 min at 1100 °C. The mass ratio of CaCl2/K-feldspar ore significantly affected the extraction. At a mass ratio of 1.15 and 900 °C, the potassium extraction reached 91% in 40 min, while the extraction was reduced to only 22% at the theoretical mass ratio of 0.2. Optimal process conditions are as follows: ore particle size of 50–75 μm, tablet forming pressure of 3 MPa, dry nitrogen atmosphere, mass ratio of CaCl2/ore 1.15:1, calcination temperature of 900 °C, and calcination time of 40 min.The XRD analysis revealed that a complex phase transition of the product SiO2 was also accompanied by the conversion reaction of K-feldspar/CaCl2. The SiO2 product formed at the initial stage was in the quartz phase at 900 °C and was gradually transformed into cristobalite after 30 min.

Mechanism of influence of chloride ions on electrogenerative leaching of sulfide minerals

A dual cell system was used to study the influence of chloride ions on the electrogenerative leaching of sulfide minerals. The results show that the influences of chloride ions on a series of electrogenerative leaching system are similar, and chlorine ion is involved in the electrogenerative leaching process of sulfide minerals directly. The output power increases with the increase of Cl^- concentration. The influence on the electrogenerative leaching rate decreases when the Cl^- concentration reaches a certain value. The mechanisms of anodic reaction are deduced based on the reasonable hypothesis, and kinetic equations with respect to chlorine ions for each sulfide mineral are obtained. The kinetic equations show that when concentration of Cl^- is relatively low, the electrogenerative leaching rates are predicted to have 2/5,3/7,1/3 and 1/3 order dependence on Cl^- concentration for chalcopyrite concentrate,nickel concentrate, sphalerite and galena. As concentration of Cl^- increases, the correlative dependence of electrogenerative leaching rate on concentration of Cl^- becomes weak.

Treatment of backwater in bauxite flotation plant and optimization by using Box-Behnken design

Flotation indexes gradually decrease with the increase of cycle time of the backwater in bauxite floatation,and discharge of backwater brings environmental risk.In this study,methods such as Fenton-oxidation,adsorption and coagulation were used in the treatment of backwater,the flotation indexes were checked after backwater treatments,and Box-Behnken design(BBD)was used in the optimization of the main operating parameters.The results reveal that flotation indexes are effectively improved after coagulation treatment by polyaluminum ferric chloride(PAFC).The optimum parameters predicted by BBD are pH 7.55,1.09 g/L PAFC dosage and temperature of 25℃.Under these optimum conditions,a maximum recovery of Al2O3 of 82.83%and a minimum A/S of 1.30 of tailings are gained,while the deviations are less than 3%from the predicted values.These findings encourage the application of BBD for the optimization of critical parameters in backwater treatment.

Electric-oxidation extraction of molybdenite concentrate in alkaline NaCl electrolyte

The dissolution of molybdenite concentrate in NaC1 electrolyte was investigated. The results show that the dissolution rate increases with the increase in liquid-to-solid ratio, stirring speed, NaCl concentration and temperature. When the liquid-to-solid ratio is 30：1, stirring speed is 400 r/min, concentration of NaCI is 4 mol/L at pH=9 and room temperature, the leaching efficiency of molybdenite concentrate will reach 99.5% in 240 min. Molybdenite concentrate cannot be electro-oxidized directly on the anode. The kinetic studies show that the dissolution of molybdenite concentrate is represented by shrinking core model with diffusion through a porous product layer of element sulfur, and the apparent activation energy for the dissolution reaction is 8.56 kJ/mol.

Electro-oxidation process for molybdenum concentrates

Sodium hypochlorite was used to treat the standard molybdenum concentrates; the oxidization conditions for sodium hypochlorite were investigated, and the electro-oxidation process was performed. The results indicate that in the suitable conditions, such as temperature around 25℃, NaCl concentration 4.0mol/L, mass ratio of ore slurry liquid to solid （mL/mS） 20, electric charge per gram Mo 0.522C, pH value of original slurry 8, anodic current density 700A·m-2 （cell potential 2.72.9V）, the Mo leaching rate and the current efficiency reach 98% and 36%, respectively. In order to overcome some shortages of the electro-oxidation process, such as low current efficiency, low Mo concentration in the leaching solution, ultrasonic was adopted to intensify the leaching process. The results show that the Mo leaching rate exceeds 98%, current efficiency increases from 36% to 50% and the Mo concentration in the leaching solution reaches about 60g/L at low mL/mS of 8 and low electric charge of 0.373C.

Galena-pyrolusite co-extraction in sodium chloride solution and its electrochemical analysis

The co-extraction behavior of galena-pyrolusite in a sodium chloride solution and the electrochemical mechanism of this process were investigated,and some factors affecting the leaching rate of Pb and Mn were optimized.The results show that all the factors such as the concentration of NaCl,HCl and pyrolusite ore,reaction time,temperature,adding times of HCl,affect the leaching rate of Pb.The main affecting factors are the concentration of NaCl,reaction time and temperature.The Tafel polarization curves and EIS plots of the galena and pyrolusite in the NaCl solution demonstrate that during the oxidation process of galena mineral electrode,film forms on the galena surface,which prevents galena from deeper oxidation.However,the film resistance can be greatly reduced in the presence of sodium chloride,thus promoting the reaction rate of galena.

Vanadium extraction from vanadium-bearing titanomagnetite by selective chlorination using chloride wastes (FeClx)

Vanadium extraction of vanadium-bearing titanomagnetite was investigated by selective chlorination. Thermodynamics analyses on the interactive reactions among related species in the system were made before the experiments. Some fundamental experiments for extracting vanadium by FeClx as chlorinating agent were conducted over the temperature range of 900-1300 K under air or oxygen atmosphere. The results show that vanadium can be extracted by the selective chlorination, using FeClx, based on thermodynamic analysis and experiment. Vanadium extraction ratio first increases with the increase of temperature, and then decreases with the increase of temperature over the range of 900-1300 K under air or oxygen atmosphere. The higher molar ratio of FeCI3 to oxides （nchl：noxd） reacting with FeC13, the higher ratio of vanadium extraction. Under oxygen atmosphere, the vanadium extraction ratio is up to 32% at 1100 K for 2 h by using FeCI3 as chlorinating agent.

Study on durability of concrete in coal mine

There are sulfate and chloride ions corrosion and carbonation to concrete in coal mine. Based on taking test of accelerated carbonation, corrosion of 3.5% weight of NaCl solution and 5% weight of Na2SO4 solution of coal mine concretes, durability of con- cretes which include spray concrete of C20,high performance concretes of C30 and C50 and effect of fly ash on durability have been studied. Results suggest that the coal mineral high performance concretes show good resistance capacities of carbonation, sulfate and chloride corrosion to meet the coal mine construction. And the higher the strength grade is, the better the resistance capacity of corrosion of carbonation is, chloride and sulfate. Moreover, fly ash improves resistance capacity of high performance concrete(HPC) to chloride and sulfate but decreases the resistance capacity of C30’s to carbonation and average dynamic modulus.

Dissolution kinetics of low grade complex copper ore in ammonia-ammonium chloride solution

The leaching kinetics of Tang-dan refractory low grade complex copper ore was investigated in ammonia-ammonium chloride solution.The concentration of ammonia and ammonium chloride,the ore particle size,the solid-to-liquid ratio and the temperature were chosen as parameters in the experiments.The results show that temperature,concentration of ammonia and ammonium chloride have favorable influence on the leaching rate of copper oxide ores.But,leaching rate decreases with increasing particle size and solid-to-liquid ratio.The leaching process is controlled by the diffusion of the lixiviant and the activation energy is determined to be 23.279 kJ/mol.An equation was also proposed to describe the leaching kinetics.

Effects of Surfactant on Zinc Recovery by Solvent Extraction during Leaching in HCl-FeCl_3 Solution

The effects of surfactant on the solvent extraction in leachingsphalerite were investigated. It is found that sodium dodecylsulfonate is the effective surfactant in improving the zinc recoveryfrom sphalerite in the aqueous FeCl_3-HCl-tetrachloroethylene system.Through the measurements of surface tension and viscosity of thesphalerite Slurry modified with different surfactants, it isconcluded that sodium dodecyl sulfonate in the concentration rang Of0.05 to 0.2 g·L^-1 can improve the viscosity of sphalerite slurry inthe water, decrease the surface tension of Leaching solution, preventthe aggregation of ore particles, and give very high zinc extraction.

Flotation separation of calcareous minerals using didodecyldimethylammonium chloride as a collector

The flotation separation of scheelite from fluorite and calcite using dodecyltrimethylammonium chloride （DTAC）, dodecyldimethylbenzylammonium chloride （DDBAC）, or didodecyldimethylammonium chloride （DDDAC） as the collector has been investigated. The results show that the selectivity of these collectors for these three calcareous minerals falls in the order： DDDAC 〉 DDBAC 〉 DTAC. A significantly different flotation response of scheelite compared to the other two calcareous minerals was observed over the pH range from 7 to 8 for DDDAC as the collector. A concentrate containing 41.40% W03 could be produced from a feed mixture containing 23.22% WO3 at the DDDAC concentration of 4.0× 10^-4 mol/L. The WO3 recovery was 92.92% under these conditions. The results of zeta potential measurements suggest that electrostatic interactions are the main forces between DDDAC and the minerals. When the concentration of DDDAC is from 2× 10^-4 to 4×10-3 mol/L large differences in adsorption density, and adsorption kinetics, of DDDAC onto scheelite, calcite, and fluorite provide desirable conditions for achieving high selectivity.

Molybdenum removal from copper ore concentrate by sodium hypochlorite leaching

The removal of molybdenum from a copper ore concentrate by sodium hypochlorite leaching was investigated. The results show that leaching time,liquid to solid ratio,leaching temperature,agitation speed,and sodium hypochlorite and sodium hydroxide concentrations all have a significant effect on the removal of molybdenum.The optimum process operating parameters were found to be：time,4 h;sodium hydroxide concentration,10%;sodium hypochlorite concentration,8%;liquid to solid ratio,10：1;temperature,50℃;and, agitation speed,500 r/min.Under these conditions the extraction of molybdenum is greater than 99,9%and the extraction of copper is less than 0.01%.A shrinking particle model could be used to describe the leaching process.The apparent activation energy of the dissolution reaction was found to be approximately 8.8 kJ/mol.