Operational optimization of copper flotation process based on the weighted Gaussian process regression and index-oriented adaptive differential evolution algorithm

Concentrate copper grade(CCG)is one of the important production indicators of copper flotation processes,and keeping the CCG at the set value is of great significance to the economic benefit of copper flotation industrial processes.This paper addresses the fluctuation problem of CCG through an operational optimization method.Firstly,a density-based affinity propagationalgorithm is proposed so that more ideal working condition categories can be obtained for the complex raw ore properties.Next,a Bayesian network(BN)is applied to explore the relationship between the operational variables and the CCG.Based on the analysis results of BN,a weighted Gaussian process regression model is constructed to predict the CCG that a higher prediction accuracy can be obtained.To ensure the predicted CCG is close to the set value with a smaller magnitude of the operation adjustments and a smaller uncertainty of the prediction results,an index-oriented adaptive differential evolution(IOADE)algorithm is proposed,and the convergence performance of IOADE is superior to the traditional differential evolution and adaptive differential evolution methods.Finally,the effectiveness and feasibility of the proposed methods are verified by the experiments on a copper flotation industrial process.

Coal Gasification Wastewater Pretreatment with Coagulation and N_2 Flotation Combined System

A N 2 flotation tank combined with coagulation was developed as a pretreatment equipment of biological process to remove oil and other pollutants in coal gasification wastewater( CGW). With optimal PAC dosage of 20 mg / L,the sole coagulation process achieves removal efficiencies of 29. 34% and 26. 83% for oil and COD,respectively. For the sole N 2 floatation process,the optimal N 2 flux and HRT are 20 m3/ h and 20 min. Meanwhile,the oil and COD removal efficiencies are 35. 41% and 14. 26%,respectively. For the combined system of coagulation and N 2 floatation,the optimal parameter values are the same as the ones of separate processes. Correspondingly,the removal efficiencies are 46. 28% and 31. 89% for oil and COD, respectively. Besides,BOD 5 / COD of the effluent is improved. In contrast with conventional dissolved air floatation,the inert gas- N 2 prevents the formation of cyclopentenone, pyridine derivatives, and other heterocyclic aromatic hydrocarbons,thus improving the biodegradability of influent for the subsequent biological processes.

Treating oil wastewater with pulse electro-coagulation flotation technology

Pulse electro-coagulation flotation was used to treat oil wastewater of high oil content.Different operational conditions were examined,including current density,reactive time,electrode distance,pH and pole switching time.Orthogonal tests were carried out to identify the optimal operational conditions for this technique.Considering the treatment cost and efficiency together,the optimal operational conditions were an electrode distance of 3.3 cm,pH of 4,current density of 49.38 mA/cm2,reaction time of 15 min and pole switching time of 10 s.The removal efficiency of oil wastewater under normal conditions reached up to 96.21%.The influences of different factors on removal efficiency were in the following decreasing sequence:pH> current density > pole switching time > reactive time > board distance.

Treatment of pharmaceutical wastewater containing recalcitrant compounds in a Fenton-coagulation process

The advanced treatment using integrated Fenton＇s reaction and coagulation process was investigated in this study. Before the advancement, the pharmaceutical wastewater containing lincomycin hydrochloride was pretreated by UASB （upflow anaerobic sludge bed） and a SBR （sequencing batch reactor） process. The residual recalcitrant compounds, measured by gas chromatographymass spectrometry （GC-MS）, mainly consisted of alcohols, phenols, and nitrogenous and sulfur compounds. The experimental results indicated that when the Fenton＇s reaction was conducted at pH=3.0, H2O2CODOcr=0.27, H2O2/Fe^2＋=3：1 and 30 min of reaction time, and the coagulation process operated at a sulfate aluminum concentration of 800 mg/L and pH value of 5.0, the color and COD in the wastewater decreased by 94% and 73%, respectively; with a finale COD concentration of 267 mg/L and color level of 40 units, meeting the secondary standard of GB8978-1996 for industrial wastewater.

Effect of mineral processing wastewater on flotation of sulfide minerals

The effects of mineral processing wastewater on sulfide minerals were investigated by flotation,infrared spectrometry and electrochemistry test. The results show that lead-concentrate water can improve the flotation of galena,while the sulfur-concentrate water has negative effect on flotation of galena compared with distilled water. The flotation behavior of pyrite is contrary to that of galena in three kinds of water. Infrared spectra indicate that the residual collector in the lead-concentrate water is beneficial to the formation of lead xanthate on the surface of galena. Electrochemistry results indicate that electrochemistry reaction on galena surface has apparent change. The anode polarization is improved and cathode polarization is depressed.

Process mineralogy of copper-nickel sulphide flotation by a cyclonic-static micro-bubble flotation column

In our study we investigated a refractory copper-nickel sulfide ore separation by using a cyclonic-static micro-bubble flotation column (FCSMC). The process mineralogy of the main products was studied. Using a scanning electron microscope-energy dispersive system (SEM-EDS) and an X-ray spectrometer the mineral category and content of samples were analyzed. By using a mineral liberation analyzer (MLA) the mineral liberation characteristics were revealed. It is shown that in roughing feed the monomers liberation degree of nickel pyrite and chalcopyrite take up 84.11% and 88.82%, respectively. In tailings, the lost nickel pyrite and chalcopyrite are mainly monomers. Therefore, strengthening the micro-fine particle recovery capacity is the key to increase recovery.

Oil droplet movement and micro-flow characteristics during interaction process between gas bubble and oil droplet in flotation

Flotation is an efficient pre-treatment technology for oily water.In this work,the interaction process between the moving oil droplet and the gas bubble was studied by high-speed camera and Bassset-Boussinesq-Oseen(BBO)theoretical model,and the experimental and simulation results of the oil droplet trajectory were compared.Moreover,the micro-particle image velocimetry system was utilized to observe the flow inside and outside of the moving oil droplet.The results show that the BBO model with the mobile bubble’s surface can reflect the velocity change trend of the oil droplet during the interaction process between the moving oil droplet and the gas bubble,but there are some significant differences between the experimental and simulation results.While the oil droplet is moving on the bubble’s surface,the velocity of the area near the contact point of oil droplet–gas bubble is less than that of the other areas inside the oil droplet.Meanwhile,the flow of water above the oil drop is more biased towards the gas bubble.

Pilot study on treatment of low turbidity and low temperature water by coagulation-immersed membrane process

The objective of this paper was to investigate the practicability of coagulation-immersed membrane process during low-temperature period through the study of steady operation,chemical cleaning methods,water quality and agent consumption.Experimental results showed that:membrane performance decreases with the reduction of temperature,but low temperature has little effect on stable operation of immersed membrane when coagulation as pretreatment.EFM with 1200 mg/L sodium hypochlorite after every 48 filtration cycles was made for reducing membrane fouling efficiently,and the method,with 1.5% sodium hydroxide and 3500 mg/L sodium hypochlorite for 10 h and then 2% hydrochloric acid for 4 h,is an appropriate cleaning method under low temperature.Compared with convention treatment process,immersed membrane process not only has same agent consumption,but also permeated water quality is more superior such as fine removal effect on turbidity with average 0.10 NTU.Therefore,coagulation-immersed membrane process is more appropriate for increasing water quality demand and the treatment of low turbidity and low temperature water.

Correlation Analysis of Control Parameters of Flotation Process

The dosage of gold-antimony flotation process of 5 main drugs,including Copper Sulfate,Lead Nitrate,Yellow Medicine,No.2 Oil,Black Medicine,with corresponding visual features of foam images,including Stability,Gray Scale,Mean R,Mean G,Mean B,Mean Average,Dimension and Degree Variance,were recorded.Parameter correlation analysis showed that the correlation among Copper Sulfate,Yellow Medicine,Black Medicine,as well as the correlation among Gray Scale,Mean R,Mean G,Mean B,is strong,and the correlation among Dimension,Gray Scale,Mean R,Mean G,Mean B,as well as the correlation between Stability and each dosing parameter,is week.It also indicated a feasible way to decrease the complexity of flotation control system by reducing some parameters.

Flotation Separation on Rare Earth Minerals and Gangues

The flotation process of native rare earth minerals such as bastnasite, monazite, mixed minerals of bastnasite and monazite, using the new effective collector Dh was studied, respectively, and the flotation properties were described. The good qualities of the new collector Dh were revealed through comparing with other collector of rare earth minerals. The test results of different ore samples showed that at moderate pulp pH (8.5～9.5), rare earth minerals could be effectively separated from barium, calcium and silicon bearing intergrowth minerals (barite, calcite and silicate minerals) and high quality rare earth concentrates could be obtained successfully by the new collector Dh, acid silica gel, turpentine and reagents fitting together rationally. In order to determine optimum technical conditions, the effect of pulp pH, pulp temperature, pulp density and the effect of dosage of reagents (Dh and acid silica gel) on the flotation were investigated in the test. Simultaneously, the mechanism of the flotation of rare earth minerals from intergrowth minerals was explored. The infrared spectra for Dh and rare earth cation by analysis in theory showed that Dh formed chelate complex with rare earth cation and were adsorbed on the surfaces of rare earth minerals. The mechanism of the intergrowth minerals depressed by acid silica gel can be explained as gummy colloid hydrolyzed from acid silica gel which were selectively absorbed on the gangue minerals, making them hydrophilic and depressed, with pulp pH value of alkalescent.

DYNAMIC MODEL AND SIMULATION OF THE PLATELETS'ROLE IN BLOOD COAGULATION

In order to confirm which process is the most important in the blood coagulation cascade,a dynamic model on the function of platelets in blood coagulation is presented based on biochemical experiments.Based on qualitative analysis and mathematical simulation,a series of conclusions about the influence of the activation rate of factor VIII and factor IX on the generation of thrombin(IIa)are drawn.It is evident that the pro-coagulation stimulus must exceed a threshold value to initiate the coagulation cascade.The value is related to the binding constant d_2 of the platelet. The stability of the equilibrium value is also related to the pro-coagulation stimulus. This article also evaluates the influence of the stimulus strength and the activated rate parameter of platelets on thrombin.The proportion of platelets activated at any given time is designated c.To each c,we obtain a maximum concentration of thrombin.It is evident that when the level of factor IX is below 1% of the normal level,the rate of thrombin generation reduces dramatically,resulting in severe bleeding tendency.

Upgrading graphite by flotation at Bogala Mines in Sri Lanka

Graphite is naturally floatable due to its hydrophobic pro pe rty and also soft and smears on other gangue particles, rendering the gangue mor e or less floatable too. Due to this reason it is important to concentrate on ar eas such as suitable flotation reagents, depression agents, pH modifiers, and pa rticle size to be fed during the process. The paper surveys and analyses the sui table particle size to be fed to achieve high-grade concentrate. According to t h e work carried out the author suggested the ideal cost effective flotation f low sheet for improved results at Bogala Mines in Sri Lanka.

A honeycomb-tube packing medium and its application to column flotation

We address problems in the development of large-scale flotation columns that use short cylinders. As a starting point, we investigated the packing medium to identify a highly efficient internal packing for the flotation column. The chosen packing was a honeycomb structure with an aperture diameter of 80 mm, a web thickness of 0.80 mm, a film height of 1000 mm, packed into a 400 mm diameter space, which completely filled the vessel at optimal cost. The column consisted of a modular ring of single-hole hexagonal honeycomb tube packing made from atactic polyproplene (PP-R). The packing was tested in a cyclonic, static micro-bubble flotation column. Computational fluid dynamic modeling was used to analyze the flotation fluid in a honeycomb tube packed flotation column. Our results show that the fluid axial movement was maximized and that the transverse fluid velocities were zero in the vicinity of axial flow. Using the honeycomb tube packing for copper sulfide flotation we observed that the average concentration in the product was increased to 25.41%, from an average feed concentration of 0.729%, with an average recovery of 92.92%. The demands of on-site industrial production were met.

The Effects of Water Recycling on Flotation at a North American Concentrator—Part 1

Water chemistry and its impact on mineral processing operations are not well understood and often not adequately monitored. CanmetMINING, as part of its water management research program, has been involved in a project initiated to identify opportunities for improving water recovery, water treatment, and recycling in the mining and mineral processing operations. One of the main objectives of this work is to evaluate and assess water chemistry and identify factors that impact mineral recovery, concentrate grade, and metal extraction efficiencies in order to understand and mitigate negative impacts of water recycling and improve process efficiency. In collaboration with a North American concentrator, CanmetMINING has been involved in assessing the water chemistry in the mill and evaluating water recycling options for select process streams to reduce fresh water intake and maximize recycling. The overall goal of the project is to investigate options for water recycling (increase the thickener overflow recirculation from thickener overflow tank) without affecting nickel and copper metallurgy. The results of the sampling campaigns showed that the water chemistry of the streams was fairly consistent throughout the year with no significant seasonal variations. The laboratory tests illustrated that when higher quantities of thickener overflow from thickener overflow were used, the nickel + copper grade versus nickel recovery curves shifted towards lower values. These observations were observed for the plant water samples obtained in April, June and August 2019.

Study on the Axial Dispersion of Liquid in Column Flotation

An experimental study on the axial dispersion of liquid was carried out in a 0.382-m-ID flotation column packed with different structured packings or free of packings. The correlations of axial Peclet numbers with the liquid and gas superficial Reynolds numbers were developed for various packings. Among the packings tested, it is found that in the column packed with 250Y or 350Y packings the axial dispersion is the lowest. The addition of frother can decrease the axial dispersion. By the simulation analysis of the one-dimension dispersion model of packed flotation column, it is found that small axial dispersion, high collection rate constant and low axial liquid velocity can increase the collection zone recovery.

Research on Effect of Magnetized Pulp on Coal Slime Flotation

Effect of magnetization on oxygen concentration, pH, surface zeta potential, and wet heat of flotation pulp were researched. The result shows that magnetization treatment can improve the floatablility of coal and increase the difference in wet heat among coal, refuse, and pyrite, which is favorable for slime flotation and for removing sulfur and ash from coal.

凝固剂及加工条件对豆腐凝胶形成及品质影响研究进展

豆腐的本质是一种蛋白质凝胶体,是大豆蛋白(主要是7S和11S球蛋白)在热处理下发生变性使蛋白质分子结构展开,再通过盐离子、氢离子或酶等凝固剂作用下发生聚集,形成致密均匀且具有网状结构蛋白凝胶。豆腐凝胶的形成及豆腐品质受多种因素的影响。本文从凝固剂种类(盐类、酸类和酶类凝固剂)以及加工条件(加工原料、制浆方法、豆浆体系pH、热处理条件)角度出发,阐明凝固剂及加工条件对豆腐凝胶形成以及品质的影响研究进展。以期为豆腐制品的工业化生产提供理论指导,为豆腐食品的研究开发与品质调控提供科学依据。

不同矿浆温度下Ca^(2+)、Mg^(2+)对黄铁矿可浮性的影响

这是一篇矿物加工工程领域的论文。通过单矿物浮选实验、浮选溶液化学、Zeta电位、XPS,研究了不同矿浆温度下Ca^(2+)、Mg^(2+)对黄铁矿浮选效果的影响机理,结果表明:低温能够明显抑制黄铁矿的浮选,且温度降低能够明显弱化Ca^(2+)、Mg^(2+)对黄铁矿浮选的抑制作用。当矿浆温度从20℃降至5℃时,矿浆中带电粒子运动速度减慢,Zeta电位增大,生成氢氧化钙镁沉淀的临界pH值增大,纯水矿浆中黄铁矿表面的FeO/OH的比例减小,Ca^(2+)、Mg^(2+)矿浆中黄铁矿表面FeO/OH含量的降低幅度减小,减少了黄铁矿表面的氧化程度和活性吸附位点,减少了Ca^(2+)、Ca(OH)+,Mg^(2+)和Mg(OH)+等离子在黄铁矿表面的吸附;但低温并不改变Ca^(2+)、Mg^(2+)在黄铁矿表面的存在形式和吸附状态,pH值为9时,钙镁均以Ca^(2+)、Ca(OH)+、Mg^(2+)、Mg(OH)+的形式存在并吸附在黄铁矿表面。