Obtaining Nickel Concentrates from Sludge Produced in the Process of Electrochemical Metal Surface Treatment

The article presents the possibility of recovering nickel from waste produced as a result of wastewater neutralization during the electrochemical surface treatment of metals. Leaching the sludge with concentrated hydrochloric acid enabled the metals contained in the sludge from precipitate to the solution with the efficiency of 74.4% (Se) to 100% (Zn). The content of elements was determined using the ICP-OES method. The next step was the precipitation of metals from the obtained solution using various reagents. The precipitating reagents used were 0.5 M sodium hydroxide solution, 0.5 M sodium sulphide solution and 1% dimethylglyoxime solution. Selective precipitation made it possible to obtain nickel concentrates with the content of nickel ranging from 15.3 to 98.2% for the first two methods, whereas in the case of the third method based on a dimethylglyoxime solution, the obtained nickel concentrate purity was 94.3%. The process of leaching nickel-dimethylglyoxime complex (Ni-DMG) with sulphuric acid and crystallization enabled obtaining 99.4% purity nickel sulphate, which can be reused in the nickel plating of selected metals. The research shows that waste generated in the process of neutralization of wastewater from electroplating plants is a potentially important source of recycled nickel concentrates.

A possibility of using nickel concentrate, obtained as a result of hydrometallurgical enrichment of manganese-containing raw materials, at steel alloying

At production of stainless steel expensive alloying elements, containing nickel, are used. To decrease the steel cost, substitution of nickel during steel alloying process by its oxides is an actual task. Results of analysis of thermodynamic and experimental studies of nickel reducing from its oxide presented, as well as methods of nickel oxide obtaining at manganese bearing complex raw materials enrichment and practice of its application during steel alloying. Technology of comprehensive processing of complex manganese-containing raw materials considered, including leaching and selective extraction out of the solution valuable components: manganese, nickel, iron, cobalt and copper. Based on theoretical and experiment studies, a possibility of substitution of metal nickel by concentrates, obtained as a result of hydrometallurgical enrichment, was confirmed. Optimal technological parameters, ensuring high degree of nickel recovery out of the initial raw materials were determined. It was established, that for direct steel alloying it is reasonable to add into the charge pellets, consisting of nickel concentrate and coke fines, that enables to reach the through nickel recovery at a level of 90%. The proposed method of alloying steel by nickel gives a possibility to decrease considerably steel cost at the expense of application of nickel concentrate, obtained out of tails of hydrometallurgical enrichment of manganese-bearing raw materials, which is much cheaper comparing with the metal nickel.

The High Temperature Co-Processing of Nickel Sulfide and Nickel Laterite Sources

The pressure oxidation of low-grade nickel sulfide concentrate with high iron sulfides content generates significant amounts of sulfuric acid that must be neutralized. This acid can be utilized to leach metal values from ores such as nickel laterites. The present study demonstrates the use of a low-grade nickel concentrate generated from Poseidon Nickel Mt Windarra ore to enable additional nickel and cobalt extraction from a Bulong Nickel Operation nickel laterite blend. The co-processing of these materials at 250 °C, with oxygen overpressure, using total pulp densities of 30% or 40% w/w, and a range of nickel concentrate to nickel laterite mass ratios between 0.30–0.53, yielded base metal extractions of 95% or greater. The final free acid range was between 21.5–58.5 g/L, which indicates that enough in situ sulfuric acid was generated during co-processing. The acid was shown from mineralogical analysis to be efficiently utilized to dissolve the laterite ore, which indicates that the primary iron hydrolysis product was hematite, while the aluminum-rich sodium alunite/jarosite phase that formed hosts approximately 5% of the hydrolyzed iron.

Filtration of Pulp of Complex Processing of Iron-Nickel Concentrate – a Waste Product of Magnesium Oxide Production

The granulometric characteristics of the precipitate were investigated, and the chemical composition of the solution for complex processing of iron-nickel concentrate was established. The filtering process was carried out using a model of a chamber and chamber-membrane filter press. Separation of the suspension was implemented using chambers with a depth of 10 and 20 mm. It was established that washing is possible only with the use of a weak HCl solution due to the need to inhibit the development of hydrolysis of iron salts in the pores of the sediment. A scheme for optimizing the water balance of the washing process is proposed. Initial data are formulated for designing a filtration section of a complex processing plant for iron-nickel concentrate. Criteria for process automation are defined.

Relating to the rational utilization of manganese-containing raw materials

Data on main manganese ores deposits by Russian Federation subjects presented. It was shown, that main part of manganese ore raw materials prognostic resources are concentrated in Altaj-Sayan and Enisej-East-Sayan metallogenic provinces. Estimation of metallurgical value of manganese ores deposits, located at the territory of Altaj-Sayan metallogenic province, carried out. A technological flow-chart of manganese-containing raw materials elaborated, comprising high quality manganese concentrate obtaining, its preparation, synthesis of marokite and mono-phase CaMnO3 material, marokite briquetting with a reducing agent and application for steel processing in ladle-furnace facility. A possibility shown to utilization of CaMnO3 mono-phase material mixed with a reducing agent and high quality manganese concentrate for production of metal manganese. Thermodynamic calculations and experiment studies on polymetallic manganese-containing raw material beneficiation enabled to determine main technological parameters of extraction and elaborate a technological flow-chart of beneficiation. The elaborated technology enables to obtain high quality manganese, nickel, iron and cobalt concentrates. Application of optimal technological parameters of beneficiation enables to extract from a polymetallic manganese-containing raw materials up to 95–97% of manganese, 98–99% of nickel, 96–98% of iron. It was shown, that it is reasonable to use the manganese concentrate for low phosphor metal manganese smelting, that will enable to decrease the dependence from manganese-containing materials import. A technology of steel alloying by obtained nickel concentrate elaborated. The substitution of metal nickel by nickel concentrate will considerably reduce expenses for alloying. A technology of metalized iron production by a solid-phase reducing method from an iron concentrate also elaborated, which will enable to decrease impurities content in steel during its application.