Accurate and reliable chemical analysis plays a crucial role in meeting the challenges in the competitive mining market. It is required to keep mining and refining operations running at peak efficiency, as well as ensuring that raw materials and products are of the specified quality. Moreover, waste streams and remediation processes require chemical analysis to ensure that environmental impact is minimal.
Ever-increasing demand
Mining produces both common and rare elements which are then refined and used in all kinds of other industries, from creating jewelry to the manufacture of electronics. The global mining industry is undergoing massive expansion to meet the increasing demand for minerals and metals. This expansion is taking place in an environment where costs of capital, labor, raw materials and other inputs are all rising, demanding that operations must be run at optimum efficiency.
Extraction and refining
In order to extract some materials, a process known as «leaching» is performed by introducing a leaching solution (such as hydrochloric acid, sulfuric acid, or nitric acid) into bore holes and fracture lines in the ground. The solution is pumped out after a certain amount of time and allowed to flow through ion exchange resins to concentrate the material (such as uranium). In some situations, rather than pumping the carrier solution down into the ore, the ore is ground up and allowed to mix with the solution, such as in gold cyanidation where cyanide is used to leach gold. The cyanide lowers the amount of oxygen in the water considerably which can affect the rate of leaching, but this waste water has severe consequences for the environment and must first be treated with oxidants to decrease its toxicity.
Electrowinning can be used instead of ion exchange resins to recover materials, in fact – this is the only process to refine aluminum from ore. In this case, the semisaturated leaching solution is electrolyzed and the material (such as copper or gold) is electroplated on a large scale. Some metals need subsequent reduction to be refined, while others can deposit at the bottom of the plating tank and form anodic sludge, which also requires further treatment before the refined material can be used.
Quality control with chemical analysis
Accurate and reliable chemical analysis plays a crucial role in meeting these challenges. It is required to keep mining and refining operations running at peak efficiency, as well as ensuring that raw materials and products are of the specified quality. Moreover, waste streams and remediation processes require chemical analysis to ensure that environmental impact is minimal. For the mining industry, continuous control of the production process, the quality of the product, and the composition of any waste streams is of utmost importance.
Examples of Metrohm Process Applications for the Mining Sector
Copper Mining & Purification:
- Chloride [Cl-] in Copper Electrolyte solution (Copper refinery, Electrolyte tanks)
- Copper [Cu2+] in refining processes (Copper electro refining, Nickel purification, Refinery Deep Electrolyte Decopperization, Smelter, Metal recovery)
- Copper [Cu2+] + Iron [Fe3+] (Copper mining)
- Metals (Cadmium [Cd] / Cobalt [Co] / Copper [Cu] / Germanium [Ge] / Antimony [Sb]) (Metal Purification, Recovery)
- Sulfuric acid [H2SO4], Copper [Cu2+], Iron [Fe2+], Iron [Fe3+], + BT (Copper refinery)
Electrowinning Processes:
- Acid, Chloride [Cl-], Iron [Fe2+], + Rx in Copper electrowinning process (Electrolysis)
- Chloride [Cl-] in Copper Electrolyte solution (Copper refinery, Electrolyte tanks)
- Copper [Cu2+] from copper electrowinning (Copper electro refining)
- Copper [Cu2+], Sulfuric Acid [H2SO4], + Chloride [Cl-] in Electrolyte (Metallurgy company, Refinery Deep Electrolyte Decopperization)
- Free Acid (Nitric Acid) [HNO3] in process (Uranium Processing, Uranium Extraction (Yellow Cake Process))
- Sulfur Dioxide [SO2] in Electrolyte solution (Manganese, SO2 Absorption into Feed Electrowinning)
- Sulfuric acid [H2SO4] (Zinc purification, Copper Electrowinning, Copper Electro Refining)
Gold Mining:
- Cyanide, Free [CN-] in gold mining (Gold winning, WWTP)
- Cyanide, total [TCN] (Gold mining, Detoxination Plant (CIP/CIL Plant))
- Cyanide, Weak Acid Dissociable [CN-WAD] (Gold mine, WWTP, Gold winning, Electroplating)
Leaching Processes:
- Ammonia [NH3] + Carbon Dioxide [CO2] (Nickel, Leaching S/X Circuit)
- Metals (Total) + pH (Leach plant)
- Silica [SiO2] in Ammonium sulfate [(NH4)2SO4] in Manganese processing (Leaching, Thickening, and Purification)
- Sulfuric acid [H2SO4], pH, Redox, + Chloride [Cl-]
- (Copper mining, Leaching)
- Zinc [Zn2+] + Sulfuric Acid [H2SO4] in process (Zinc production, zinc leaching)
- H2S in metal precipitation
Nickel Mining Purification:
- Aluminum [Al3+] (Nickel Purification)
- Ammonia [NH3] in process (Nickel, Solvent Extraction, WWTP)
- Ammonia [NH3] + Carbon Dioxide [CO2] (Nickel, Leaching S/X Circuit)
- Copper [Cu2+] in Nickel(II) sulfate [NiSO4] refining process (Deep removal copper process)
- Nickel [Ni2+] from purification processes (Nickel Purification)
- Sulfide [S2-] gas in flue gas in acid smelter in Nickel mine (Nickel)
- Zinc [Zn2+] (Nickel Purification) Mining
Waste Water:
- Ammonia [NH3] in process (Nickel, Solvent Extraction, WWTP)
- Cadmium [Cd] in Zinc sulfate [ZnSO4] (Zinc Purification, WWTP)
- Calcium [Ca2+] in waste water (Zinc Copper mining, WWTP)
- Hexavalent Chromium [Cr6+] in Waste Water Treatment Plant (Nickel, PN Feed)
- Cyanide, Free [CN-] in waste water (WWTP)
- Cyanide, total [TCN] in Process Waste (Polymetallic mining, Cyanide Destruction Plant)
- Cyanide, Weak Acid Dissociable [CN-WAD] in waste water (WWTP)
- Fluoride [F-] in waste water (Waste water treatment) Hydrochloric acid [HCl] in Waste Water Treatment Plant (Nickel, PN Feed)
- Manganese [Mn2+] in Waste Water Treatment Plant (Nickel, PN Feed)
- Metals (Total) in effluent (Waste water treatment)
- Phosphate [PO 3-] in waste water (Grit Chamber, precipitation of particles, WWTP)
- Silica [SiO2] in waste water Metallurgy company, WWTP)
- Sulfate [SO 2-] in waste water
- Sulfide [S2-] in waste water (Zinc & Lead Production, WWTP)
Other Applications for the Mining Industry:
- Acid and Chloride [Cl-] in copper electrolyte solution Acidity (Total + Free), Zinc [Zn], Iron [Fe], + Chloride [Cl-] in process (Acid Recovery Plant)
- Chromic acid [H2CrO4] (Chrome production) Dinitrogen trioxide [N2O3] in H2SO4 (Reactor, Sulfuric Acid by absorption of SO2)
- Hypochlorite [OCl-] in a scrubber system for exhaust gas (mining)
- Metals (Total) and Acid in spent electrolyte (Autoclave Spent Electrolyte)
- Monitoring Moisture Content in Concentrated Iron Ore Samples (NIRS)
- Sodium Hydrosulfide [NaHS] in copper production (Molybdenum selection)
- Acid, pH, Redox, + Caustic [NaOH] in multiple sample streams (Platinum refineries)
- Molar Ratio [Ni/NH3] (Platinum refineries) Zinc Mining & Purification:
- Acid + Iron [Fe2+] in Zinc Mining
- Acidity in zinc production processes (Zinc Purification)
- Cadmium [Cd] in Zinc sulfate [ZnSO4] (Zinc Purification, WWTP)
- Cobalt [Co2+] in Zinc Electrolyte (Zinc electrolysis)
- Cobalt [Co2+] in Zinc-plant liquid purification (Zinc plant)
- Copper [Cu2+] + Iron [Fe3+] (Copper mining)
- Hydrogen Sulfide [H2S] in Process (Zinc production)
- Hydrogen sulfide [H2S] in zinc purification processes (Zinc purification)
- Iron [Fe2+] (Zinc purification)
- Iron [Fe] + Sulfuric Acid [H2SO4] in Electrolysis (Zinc production, Electrolysis)
- Sulfuric Acid [H2SO4] in Electrolysis (Zinc production, Electrolysis)
- Zinc [Zn2+] + Manganese [Mn2+] in Electrolysis (Zinc production, Electrolysis)
- Zinc [Zn2+], Manganese [Mn2+], + Sulfuric Acid [H2SO4] in Electrolysis (Zinc production, Electrolysis)
- Zinc [Zn2+] + Sulfuric Acid [H2SO4] in process (Zinc production, zinc leaching)
Metrohm Process Analytics offers several analytical techniques in many different analyser configurations for any need: titration, photometry, ion chromatography, NIR spectroscopy, and ion selective measurements. Metrohm online process analysers and custom sample preconditioning systems are manufactured in the Netherlands and supported by Metrohm Australia service engineers nationwide.
