A Study of the Feasibility of Using Ammonium Sulfate in Copper—Nickel Ore Processing

Abstract

The possibility of applying a combined concentration and metallurgical method for processing low-grade and refractory copper–nickel ores was considered. The resulting rougher and scavenger flotation concentrate contained 2.07% nickel and 0.881% copper at a recovery of 85.44% and 89.91%, respectively. The concentrate was then roasted with ammonium sulfate, followed by aqueous leaching of clinker to dissolve nickel and copper. The roasting temperature, the ratio of concentrate to (NH4)2SO4 in the mixture, and the temperature were varied. Based on the study findings, the following process conditions were found to be optimal: roasting temperature 400 °С, rougher concentrate to ammonium sulfate ratio 1:7, and grinding size −40 μm. A roasting temperature of 400 °C is significantly lower than the temperature applied in conventional pyrometallurgical processes. The possibility of collecting off-gases allows the reagent to be regenerated and makes the process even more cost-effective. End-to-end recovery into pregnant solution was 81.42% for nickel and 82.81% for copper. The resulting solutions can be processed by known hydrometallurgical methods.

A study of copper leaching from the tailings of the Karagaily (Republic of Kazakhstan) concentrating factory using an electric hydropulse discharge

“…Uncovering of "encapsulated" metals of mineral raw materials with ammonium bifluoride has undeniable advantages: fluorination occurs at a temperature not higher than 200 o C, and some reactions do not require heating at all, fluorination by-products (water and ammonia vapours) do not contain fluorine, which ensures environmental safety of production and allows to use them in a condensed state in the processes of ammonia hydrolysis. [5][6][7][8] The release of NH4F during the hydrolysis of fluoroammonium salts or NH3 and HF during the thermal decomposition of these substances create favorable conditions for the regeneration of NH4HF2 and the creation of environmentally friendly technological industries. The transition of copper into solution is a complex and staged…”

“…Quantitative analysis of metals in the working solution (Table I) after separation of the solid phase, showed the presence of copper, iron and zinc in it. Al, Cr, Mn and partly Fe, forming following fluorides which remain in the solid phase, 11,14 reactions (8)(9)(10)(11):…”

“…First of all, an effective and complete uncovering of raw materials and deep separation of target and by-products occur due to this method. [5][6][7][8] However, all known leaching methods require a large amount of reagents, high temperatures, high pressures, and a long duration of the process itself. For the treatment of mining waste in particular the tailings of concentrating plants which are technogenic mineral raw materials in terms of resource value, new technologies are required that allow deep selective separation of metals with a high degree of their extraction from the feedstock.…”

Methods for processing copper-nickel raw materials in the Arctic

“…The processing of substandard and low-grade sulfide and mixed ores by low-temperature roasting followed by water leaching can be considered as a promising and environmentally friendly process. This process is characterized by a high degree of metal recovery, the selectivity of the reactions occurring during the roasting process, energy efficiency and low cost [9,10].…”

Thermal Decomposition and Kinetics of Pentlandite-Bearing Ore Oxidation in the Air Atmosphere

“…It is known that nearly all of nickel in its sulfide ores occurs in the form of binary sulfide mineral pentlandite ((Ni,Fe) 9 S 8 ). Pentlandite is the most common and abundant mineral used for nickel extraction, accounting for over 60% of worldwide nickel production, mostly from sulfide copper-nickel ore deposits [13][14][15]. Pentlandite is usually associated with iron sulfides-pyrite (FeS 2 ) and pyrhotite (Fe 7 S 8 ) and copper-iron sulfide chalcopyrite (CuFeS 2 ).…”