Pyrometallurgy Process Research Articles

A new method to recycle Li-ion batteries with laser materials processing technology

Efficient and cost-effective recycling of spent lithium-ion batteries is essential for the sustainable growth of the clean energy sector, conserves critical mineral resources, and contribute to environmental sustainability. The pyrometallurgy process, involving high-temperature smelting and solid-state reduction, plays a key role in the industrial-scale recycling of these batteries. Traditional smelting methods, however, face criticism for their substantial energy requirements and the loss of lithium in slag. In this study, an innovative laser-based in-situ pyrometallurgical process, hereinafter referred to as laser recycling, was developed to recycle Li-ion batterie materials without using slag, enabling the simultaneous recovery of Co, Ni, Mn, and Li. Lab-scale experiments were carried out to investigate the influences of laser power density and duration on the carbothermic reduction behavior of battery materials. The results showed that the maximum temperature reached approximately 1850 °C with a laser power between 1500 and 2000 W focused to an area of 20 mm in diameter within a few seconds. The laser recycling facilitates concurrent smelting and solid-state reduction, with carbothermic reduction completed in just 30 s due to rapid reaction kinetics, ultra-high temperatures, and the enhanced contact area resulting from surface tension-driven molten material flow under intense laser beam exposure. This laser recycling process reduced LiCoO2 and LiNi0.33Mn0.33Co0.33O2 to metallic Co or Co-Ni-Mn alloy, respectively, while Li was recovered as Li2CO3. The new process allowed for the near-total recovery of Co, Ni, and Mn in the alloy and virtually 100% Li recovery in the form of Li2CO3 by a vapor phase capture system. Additionally, continuous laser recycling in the battery material powder bed showed potentials to scale up for industry battery recycling. A mechanism for the laser recycling process was proposed. A preliminary discussion on the techno-economic implications of laser recycling was also provided.

Cyclability Improvement of Recycled Graphite Materials in Lithium-Ion Batteries Via Conductive Polymer Coating

In recent years, lithium-ion batteries have been widely adopted in electric vehicles and electronics. However, the growing number of retired lithium-ion batteries poses a significant environmental challenge, generating substantial material waste and potential pollution. In most commercial batteries, graphite is the prevalent choice for anode material, owing to its high electrical conductivity and mechanical stability. Therefore, recycling graphite from spent lithium-ion batteries is a potential solution to eliminate the waste and meet the increasing demand.While considerable attention has been directed toward recovering metallic components of the spent lithium-ion batteries, limited effort has been dedicated to recycling graphite. Some previously developed methods include the pyrometallurgy process and hydrometallurgy process. However, due to high energy consumption and environmental pollutions, these methods have not been applied in large scales. Additionally, graphite particles have experienced various aging mechanisms during charge and discharge cycles, such as the formation of a solid electrolyte interface (SEI) and the intercalation of solvent molecules, potentially leading to structural alterations and degradation. Hence, it is advisable to implement surface treatment to enhance capacity stability if the recycled graphite does not perform optimally following the recovery treatment.In this study, we developed a simple process to recycle spent graphite utilizing aqueous and organic wash with N-Methylpyrrolidone (NMP) and toluene, followed by surface coating with the conductive polymer poly(9,9-dioctylfluorene-co-fluorenone-co-methylbenzoic ester) (PFM). The surface coating served as a protective layer of graphite particles and a charge transport agent to enhance conductivity. The morphologies and structures of the pristine, recycled, and PFM-coated recycled graphite samples were measured by X-ray diffraction (XRD) and scanning electron microscope (SEM) analysis.To investigate the impact of employing PFM as a binder, electrochemical tests were done using anodes with both recycled graphite and PFM-coated recycled graphite. In recycled-graphite||NMC532 full cell testing, cells with PFM-coated recycled graphite exhibits higher coulombic efficiency (>99.90%) than cells without PFM coating at a rate of 0.33 C. A capacity retention of 77.49% was achieved for PFM-coated cells after 300 cycles, whereas the ones without coating have a capacity retention of 70.21% in average. Rate tests were also conducted on both the cells with and without PFM-coating. It shows that both types of cells support high-rate cycling. About 85% of charge capacity was delivered for cycling at 1 C for both cells with and without PFM-coating.Overall, the recycling method can be easily operated with minimal waste production, low energy consumption, and low economical costs. The PFM coating on the recycled graphite particles leads to enhancement of mechanical strength and efficiency in battery cycling.Fig. A, The process scheme of recycling graphite; B, Pictures of an electrode from spent lithium-ion batteries (left) and an electrode fabricated with recycled graphite (right); C, Capacity retention of recycled graphite without PFM coating (blue) and with PFM coating (green); D, Coulombic Efficiency of recycled graphite without PFM coating (blue) and with PFM coating (green). Figure 1

Numerical Modeling of Electron Beam Cold Hearth Melting for the Cold Hearth

The electron beam cold hearth melting (EBCHM) process is one of the key processes for titanium alloy production. The unique characteristic of this pyrometallurgy process is the application of the cold hearth, which is responsible for controlling the Low-Density Inclusions (LDIs) and High-Density Inclusions (HDIs) in the melt. As a key process of inclusion removal, the information such as melt residence time in the cold hearth is directly related to the control of metallurgical defects in the ingot, and may also affect the composition distribution of the ingot. In this paper, the details for the physical phenomena, namely the evolution of the pool, the evolution of the flow, and the evolution of the component in the cold hearth during EBCHM are investigated using a modified multi-physical numerical model. The effects of melting temperature and melting speed on these phenomena were investigated. The purpose is to provide more fundamental knowledge and to further enhance the applications of EBCHM for more titanium alloys.

Artificial Slags with Modulated Properties for Controlled Nickel Dissolution in Smelting Process

In pyrometallurgy process involving drying, calcination and reductive smelting steps, Saprolite ore is subjected in an electric arc furnace to produce Fe–Ni alloy and Ni matte. To optimize the nickel smelting step, the slag consisted of MgO–SiO2–FeO and having a lower viscosity and high fluidity is required. In this study, a number of new slag samples with varied degree of compositions are manufactured and used to examine the effect of their viscosity on nickel dissolution. Further correlation between the slag basicity and FeO addition on the smelting was also tested and simulated using Fe–Ni alloy from saprolite ore. As per the observations, the nickel dissolution increases with the increased content of FeO at a certain degree of activity which in turn can cause oxidation of nickel during the process. The slags with the ratio of MgO/SiO2 = 0.4–0.6, 30% fraction of FeO, and a viscosity of 1.8–1.06 poise in the olivine zone are found effective for the lowest dissolution rate of nickel with 0.021, 0.022, and 0.018 wt.%. The lowest dissolution rate is recorded for the slag with MgO/SiO2 ratio about 0.6. These slags with controlled amount of constituents could be used to recover precious metal from nickel smelter at a lower dissolution rate and thereby allowing to reduce the waste of the metal during smelting process.

Utilization of battery waste derived ZnO in the removal of dye from aqueous solution: A waste to wealth approach

Every year a huge amount of zinc carbon batteries is discarded as waste and the management of such waste has become a growing concern all over the world. However, from these waste carbon batteries different kinds of valuable materials could be recovered. On the other hand, different industries discharged large volumes of dye wastewater into the environment which has a profound impact on environment and as well as human health. In this study, ZnO was recovered from the waste carbon batteries through pyrometallurgy process and utilized it for the treatment of methylene blue and methyl orange dye water. The batch adsorption process was carried out to observe the effect of adsorbent dosage, pH, contact time, stirring speed and temperature. Under the obtained optimal conditions adsorption kinetics (Pseudo-first order and pseudo-second order) and adsorption isotherms (Langmuir, Freundlich and Temkin) were analyzed. The results disclosed that 0.5 g and 0.6 g of ZnO showed maximum removal efficiency for MB and MO dye solution (50 ppm) whereas pH 13 and 6 were the optimal for MB and MO respectively. Kinetic studies indicate that both the adsorption processes were pseudo-second order. It was also revealed that based on regression coefficient R2 value the adsorption of MB and MO on ZnO is followed Langmuir model. Furthermore, the findings revealed that the MO adsorption on ZnO is a chemical adsorption process and MB adsorption is a physical adsorption process.

Research Progress and Trends in Iron Metal Purification Processes

Traditional industrial pure iron can no longer meet the requirements of many core industries, such as aerospace, electronic information, and military industries. Thus, high-purity iron has attracted considerable interest. Pyrometallurgy, hydrometallurgy, and electrometallurgy provide extensive research platforms for purifying and developing novel processes for producing high-purity iron. In this paper, we review latest research advances in high-purity iron purification methods and production processes and summarize the merits of each purification method. Moreover, we propose a production process that ensures the production of high-purity iron while reducing carbon emissions. In this process, iron ore is leached using a hydrometallurgical process, high-purity iron is obtained by electrolysis from clean energy sources, such as photovoltaics and wind power, and the purity of iron is increased to over 5N with a pyrometallurgy process.

Recycling Valuable Metals from Spent Lithium-Ion Batteries Using Carbothermal Shock Method.

Pyrometallurgy technique is usually applied as a pretreatment to enhance the leaching efficiencies in the hydrometallurgy process for recovering valuable metals from spent lithium-ion batteries. However, traditional pyrometallurgy processes are energy and time consuming. Here, we report a carbothermal shock (CTS) method for reducing LiNi0.3 Co0.2 Mn0.5 O2 (NCM325) cathode materials with uniform temperature distribution, high heating and cooling rates, high temperatures, and ultrafast reaction times. Li can be selectively leached through water leaching after CTS process with an efficiency of >90 %. Ni, Co, and Mn are recovered by dilute acid leaching with efficiencies >98 %. The CTS reduction strategy is feasible for various spent cathode materials, including NCM111, NCM523, NCM622, NCM811, LiCoO2 , and LiMn2 O4 . The CTS process, with its low energy consumption and potential scale application, provides an efficient and environmentally friendly way for recovering spent lithium-ion batteries.

Recycling Valuable Metals from Spent Lithium‐Ion Batteries Using Carbothermal Shock Method

AbstractPyrometallurgy technique is usually applied as a pretreatment to enhance the leaching efficiencies in the hydrometallurgy process for recovering valuable metals from spent lithium‐ion batteries. However, traditional pyrometallurgy processes are energy and time consuming. Here, we report a carbothermal shock (CTS) method for reducing LiNi0.3Co0.2Mn0.5O2 (NCM325) cathode materials with uniform temperature distribution, high heating and cooling rates, high temperatures, and ultrafast reaction times. Li can be selectively leached through water leaching after CTS process with an efficiency of >90 %. Ni, Co, and Mn are recovered by dilute acid leaching with efficiencies >98 %. The CTS reduction strategy is feasible for various spent cathode materials, including NCM111, NCM523, NCM622, NCM811, LiCoO2, and LiMn2O4. The CTS process, with its low energy consumption and potential scale application, provides an efficient and environmentally friendly way for recovering spent lithium‐ion batteries.

The role of zinc sulfide in the electrochemical extraction of molybdenum

The main form of molybdenum in nature is molybdenum sulfide. It also exists in iron ore magnetic separation tailings together with zinc sulfide. Considering separating and extracting molybdenum and zinc, a large amount of SO2 is released and environmental pollution is caused by high energy consumption for the traditional pyrometallurgy process. This research proposes a novel process to achieve efficient extraction and separation of molybdenum and zinc through co-desulfurization of MoS2-ZnS in molten salt. It was found that the sulfur in MoS2 and ZnS could be effectively removed and collected as solid sulfur by constant potential electrolysis in molten NaCl-KCl at 750 °C. Furthermore, electrochemical testing showed that the decomposition of MoS2 was carried out in two steps, ZnS was reduced in one step, and the decomposition voltage of ZnS was smaller than that of MoS2. Zinc was obtained at the first stage, and the MoS2 or its intermediate compounds were wrapped around by liquid zinc. The substitution reaction, 2Zn + MoS2 = Mo + 2ZnS, was able to promote the decomposition of MoS2 in the electrolysis process. Zinc sulfide was then formed in the second stage, and it can be electrolyzed to metallic zinc again for reduction of MoS2. Zn/ZnS played the role of a reducing agent in the process of MoS2-ZnS co-desulfurization, which facilitated the process of desulfurization, and enabled the reduction of MoS2 at a smaller voltage while zinc could be reused. In this work, molybdenum metal containing zinc was extracted at a cell voltage of 2.7 V. Metallic zinc and molybdenum were separated and purified in the final stage by vacuum distillation.

Recycling lead from waste lead-acid batteries by the combination of low temperature alkaline and bath smelting

Recycling lead from waste lead-acid batteries has substantial significance in environmental protection and economic growth. Bearing the merits of easy operation and large capacity, pyrometallurgy methods are mostly used for the regeneration of waste lead-acid battery (LABs). However, these processes are generally operated at the temperature higher than 1300 °C. To shorten the energy consumption, a novel pyrometallurgy process which consisted of low temperature alkaline and bath smelting was proposed in this work. The reduction of lead and smelting of slag system are the key factors determine the energy consumption. Thermodynamic calculation suggested that the addition of Na2CO3 can make the reduction of PbSO4 spontaneously at the temperature higher than 288 °C (PbSO4 → PbCO3 → PbO → Pb), while direct reduction of PbSO4 necessitated the temperature higher than 1499 °C (PbSO4 → PbO → Pb). To achieve the efficient reduction of PbSO4, the molar ratios of C/PbSO4 and Na2CO3/PbSO4 should be higher than 0.5 and 1.0, respectively. Meanwhile, a new smelting system (i.e., FeO-SiO2-CaO-Na2O) was established in the presence of Na2CO3. Phases with low melting temperatures, such as NaFe2O3, Na2FeSiO4, Na2Ca2Si2O7, Na14Fe6O16 and Na0.5FeO2, were formed. The melting temperature of Fe-Si-Ca-Na system was lowered to 1050 °C at the mass dosage of Na2CO3 at 30%. Recovery of lead under various reduction conditions were systematically evaluated. Under optimum operational conditions, i.e., the dosages of C and Na2CO3 at 10% and m(actual)/m(theory) ratio of 1.3 (all in mass), smelting temperature of 1050 °C, and smelting time of 75 min, respectively, the lead recovery efficiency reached >98.0%. Moreover, this method has been successfully applied for the industrial recovery of lead at the scale of 200, 000 tons annually since 2019. Taken together, this method is robust for recovery of lead from the waste LABs and is helpful for building the resource-conserving society.

Innovative and green utilization of zinc-bearing dust by hydrogen reduction: Recovery of zinc and lead, and synergetic preparation of Fe/C micro-electrolysis materials

Up to 80 million tons of zinc-bearing dusts are discharged by the steel industry in the word annually, and the traditional pyrometallurgy process of recycling these hazardous wastes with solid carbon as the reducing agent has high energy consumption, large carbon emissions and little added value of products. In this study, we proposed an innovative utilization of zinc-bearing dusts by hydrogen reduction to recover zinc and lead and synergistic prepare iron-carbon micro-electrolysis (ICME) materials for wastewater treatment. The hydrogen reduction behaviors of zinc-bearing dusts pellets were investigated, as well as the properties of the prepared ICME materials (HR) were comprehensively analyzed. The results indicated that the metallization degree, zinc and lead removal degree of zinc-bearing dusts pellets were 98.5 %, 96.8 % and 71.1 %, respectively, under the optimal reduction condition. The synergistic prepared HR with Fe/C of 15:1, specific surface area of 5.158 m2/g and pore volume of 0.01004 cm3/g could remove more than 60 % of COD in wastewater within 2 h. The tight iron-carbon bonding and well-developed pore structure of HR made it equivalent wastewater treatment effects compared to commercial materials. Therefore, the novel process provides a clean and high-value way out for these hazardous wastes.

Repurposing of spent lithium-ion battery separator as a green reductant for efficiently refining the cathode metals

Developing green and high-efficient pyrometallurgy processes to recycle precious metals from spent lithium-ion batteries (LIBs) is of great importance for resource sustainability and environmental protection. Herein, a novel reduction roasting approach relying on spent LIB separator to refine the spent cathode is proposed. The efficiency of repurposing separator as a reductant for roasting the spent LiCoO2 cathode and the underlying mechanisms were investigated. After the separator-mediated roasting at 500 °C for 2 h, Li+ leaching efficiency of the cathode reached 93.2 %, >2.6 times higher than those after roasting without reductant (25.2 %) or with benchmark reductant graphite (26.1 %). Under the separator-added roasting condition, the cathode was converted to the desired products, CoO and Li2CO3. Based on the analysis of in-situ reaction using thermogravimetric/differential scanning calorimetry and pyrolysis gas species identification, the separator-mediated reduction roasting of cathode was composed of two stages, i.e., reducing gas generation due to separator pyrolysis, followed by the reducing gas mediated LiCoO2 reduction. During the process, the generated C2H4 and CO dominated the reduction. The use of co-existing separator to recover precious metals from spent LIBs is an effective and sustainable strategy to maximize the utilization of spent LIBs.

Effects of MnO on the smelting process of vanadium titanomagnetite pre-reduced pellets in an electric furnace

MnO is proven as an effective fluxing additive for high-temperature pyrometallurgy processes. The effects of MnO on the electric furnace smelting of vanadium titanomagnetite pre-reduced pellets were systematically studied in this study. The results indicated that MnO addition could reduce the titanium slag viscosity. The activities of titania and silica in the slag decreased with the increasing MnO content. The external views of slag-iron separation showed that the addition of MnO was beneficial for the separation of iron from the slag. The EPMA results indicated that the reduction degree of vanadium oxides was improved with the MnO additions of 1 wt% and 2 wt%, but mitigated with the further increase of MnO. Moreover, the reduction of titanium oxides was suppressed with the increasing MnO content. Finally, it was concluded that the suitable addition of MnO was 2 wt% under the present smelting conditions.

Experimental and modelling waste rice husk ash as a novel green corrosion inhibitor under acidic environment

The ubiquitous role of green corrosion inhibitors and their adsorption nature unveils deeper insight into forming inhibitor-metal binding complexes. This work studied mild steel’s corrosion and mitigation behaviors under HCl 1 M solution with the newly waste rice husks inhibitor at the 298 K temperature. The liquid smoke (LS) inhibitor is synthesized and prepared from the waste rice husks with the help of the Pyrometallurgy process. The anti-corrosion performance was evaluated using Electrochemical Impedance Spectroscopy (EIS), Raman Spectroscopy, Scanning Electronic Microscopy and Machine Learning. Moreover, the time to corrosion method is considered to predict inhibitor duration at their respective concentration. Total Phenolic Content (TPC) advanced characterization was used to determine the amount of phenolic ligand’s molecule to donate its electron to 3d orbital of Fe. The inhibition efficiency stood at 97.73% of 80 ppm solution with approximate inhibition effectiveness for 17 days. The Raman Spectroscopy results show that LS comprises phenolic, cellulose, and complex heterocyclic functional groups. The latter becomes the key factor influencing the strength of inhibitors’ adsorption. The Raman Shift at approximately 3500–4000, 3000, 1800–2000, 800–1000 nm correlated to the presence of –OH, cellulose, C=O, and complex molecules. Furthermore, the experimental and modelling results are in good agreement. The Multicollinear Matrix shows a strong correlation between impedance and Bode phase angle. This work can be used as practical guidance to analyze and evaluate the effectiveness of inhibitors using intelligence systems and laboratory activities.

Copper and arsenic substance flow analysis of pyrometallurgical process for copper production

The metabolism of copper and arsenic in a copper pyrometallurgy process was studied through substance flow analysis method. The mass balance accountsand substance flow charts of copper and arsenic were established, indicators including direct recovery, waste recycle ratio, and resource efficiency were used to evaluate the metabolism efficiency of the system. The results showed that, the resource efficiency of copper was 97.58%, the direct recovery of copper in smelting, converting, and refining processes was 91.96%, 97.13% and 99.47%, respectively. Meanwhile, for producing 1 t of copper, 10 kg of arsenic was carried into the system, with the generation of 1.07 kg of arsenic in flotation tailing, 8.50 kg of arsenic in arsenic waste residue, and 0.05 kg of arsenic in waste water. The distribution and transformation behaviors of arsenic in the smelting, converting, and refining processes were also analyzed, and some recommendations for improving copper resource efficiency and pollution control were proposed based on substance flow analysis.

Effect of Unburned Pulverized Coal on the Melting Characteristics and Fluidity of Blast Furnace Slag

A substantial amount of attention has been paid to viscosity due to its substantial effect on the fluid dynamics of molten blast furnace slag and slag metal reaction kinetics during the pyrometallurgy process. To clarify the influence mechanism of unburned pulverized coal (UPC) on blast furnace (BF) slag viscosity, the effects of different contents of UPC on the BF slag viscosity, free-running temperature and viscous flow activation energy were investigated. The slag viscosity was measured by the rotating cylinder method, and the microstructure of the cooled slag was observed by SEM. As a result, the main reason for a change in the slag viscosity, free-running temperature and viscous flow activation energy was that the UPC entering the slag formed a large number of white particles that predominantly comprised deposited carbon and a high melting point solid solution. In addition, the disintegration or polymerization of the SixOyz- structure was also a contributing factor. When the content of the UPC was 0.6%, the free-running temperature and viscous flow activation energy of slag were 1623 K and 120.969 kJ/mol, respectively, which are lower than those of the slag without UPC. However, the free-running temperature and viscous flow activation energy increased to 1668 K and 286.625 kJ/mol, respectively, when the content of UPC increased to 4%, which are higher than those of slag without UPC.

Characterization and Pyrometallurgical Removal of Arsenic from Copper Concentrate Roasting Dust

This paper describes the experimental results of removing arsenic from the dust collected in electrostatic precipitators of a fluidized bed roasting furnace (RP dust). The fluidized bed roasting process generates 600 kilotons of copper concentrate per year with 3 - 6 wt% of concentration of arsenic, producing a roasted product with a low content of arsenic below 0.3 wt%. The process generates 27 kilotons of RP dust per year with a concentration of arsenic of the order of 5 wt% and copper concentration of around 20 wt%. Subsequently, the dust collected in the electrostatic precipitators is treated by hydrometallurgical methods allowing the recovery of copper, and the disposition of arsenic as scorodite. This work proposes to use a pyrometallurgy process to the volatilization of arsenic from RP dust. The obtained material can be recirculated in copper smelting furnaces allowing the recovery of valuable metals. The set of experiments carried out in the roasting of the mixture of copper concentrate/RP dust and sulfur/RP dust used different ratios of mixtures, temperatures and roasting times. By different techniques, the characterization of the RP dust determined its size distribution, morphology, and chemical and mineralogical composition. RP dust is a composite material of small particles (<5 μm) in 50 μm agglomerates, mostly amorphous, with a complex chemical composition of sulfoxides. The results of the roasting experiments indicated that for a 75/25 weight ratio of the mixture of the copper concentrate/PR dust under 700℃, 15 minutes of roasting time with injection of air, the volatilization of arsenic reached 96% by weight. The arsenic concentration after the roasting process is less than 0.3% by weight. For a 5/95 mixture of sulfur/RP dust, at 650℃, the volatilization of arsenic reached a promissory result of 67%. Even that this study was carried out for a particular operation, the results have the potential to be extended to dust produced in the roasting of concentrates of nickel, lead-zinc, and gold.

The pyrometallurgical recovery of zinc from electric arc furnace dust (EAFD) with active carbon

The reduction of minor impurities (e.g., Ferrite, Magnesium, Lead, Chromium) from Zinc rich-EAFD with active carbon addition was investigated at temperature between 900-1300 °C. The result was powder with higher zinc content which then analysed by X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD) and scanning electron microscope (SEM) equipped with X-Ray energy dispersive spectrometry (EDS). The thermogravimetry (TG) and differential thermal analysis (DTA) of EAFD and carbon mixture was conducted previously to grasp the temperature of thermic reaction of mixture. Recovery of 90wt% zinc from EAFD available was achieved up to 99.2wt% after the pyrometallurgy process at temperature 900 °C in atmosphere pressure while the extension of the time corresponds to the amount of recovered zinc dross.

Radiotracers and Nucleonic Control Systems Applied in Industry—Polish Case

Nuclear and radiation technologies play an important role in Polish power sector, oil industry and mining sector, starting from fossil fuels exploitation, their transport and distribution and finally power generation. Application of environmental isotopes, stable and radioactive, in ground water monitoring in the vicinity of open cast lignite mine, and radon monitor applied for miner’s safety in deep coal mines and nucleonic control systems for ash in coal quality control is often used in mining industry. Other applications of nuclear techniques reviewed, concern the oil industry, oil field recovery, transportation pipelines and refineries. Finally, the application of beta radiation-based gauges for air borne fly ash monitoring and radiation technology for flue gas treatment are the examples of using this technique in power sector equipped with coal and oil fired boilers [1]. The radiotracers techniques were used also in glass industry (determination and optimization parameters of the furnaces), cement industry (test of aggregates for the production of cement and optimization media transport in pipelines), metallurgy of Cu, Pb, Zn (investigation of pyrometallurgy processes and new techniques), cellulose industry, environmental and (mainly hydrological) research etc. [2]. The article is brief review of present status of radiotracer and nucleonic gauges techniques as applied to polish industry.

An Environment-Friendly Process Featuring Calcified Roasting and Precipitation Purification to Prepare Vanadium Pentoxide from the Converter Vanadium Slag

Converter vanadium slag is a byproduct of the iron making process when the vanadium titanomagnetite is used as iron raw material. A cleaner process including calcified roasting, dilute acid leaching, precipitation purification, vanadium precipitation with ammonium salt, followed by thermal decomposition was proposed to extract vanadium resource from this slag. And then vanadium pentoxide with purity over 98% was prepared, which can be used as additives for high strength low alloy steel production. A total vanadium recovery beyond 80% was achieved in this whole process. Since no sodium and potassium salt was introduced, wastewater generated was closed-circulating after removing the enriched impurities of P, Si, Ti and Cr with adding powder CaO. The content of V2O5 in residues after vanadium extraction was lower than 1.2 wt.%, while other valuable metals like Fe, Mn, Cr and Ti were concentrated. With no alkaline metal salts added in this process, the metal resources of Fe, Mn, Cr and Ti in the residues were more feasible to be recovered with pyrometallurgy processes.