Gold mine oxygen generator - Foxolution Systems Engineering CC

The Need For On-Site Gas Production in Mining

 

The most important industrial gases needed for metals processing in the mining industry are Oxygen, Nitrogen and Hydrogen.

Oxygen is needed for the following processes:

  • Gold leaching
  • Oxy-fuel for furnaces
  • Refining
  • Furnace lancing
  • Water treatment

Hydrogen is used for:

  • Welding
  • Cutting metals
  • Platinum refining
  • Nickel production
  • Heat treating application
  • Annealing
  • Furnace brazing

Nitrogen’s uses are:

  • Cooling
  • Stirring
  • Protection from oxidation
  • Interting vessels and equipment
  • Eliminating the formation of explosive mixtures
  • Purging gas
  • Inflating earthmoving machinery tyres

Nitrogen for tyre filling

Using nitrogen to inflate the tyres of large machinery is a growing trend in the mining industry. Rugged terrain takes its toll on tyres and as mining vehicles are essential to the extraction process it is vital that they are kept functional. These vehicles operate in environments of temperature extremes, and it is because of this that nitrogen is perfect for tyre filling. The tyres stay inflated for longer and are extremely resistant to changes in temperature, operating well in hot climates as well as at icy cold high altitudes. Being an inert gas, nitrogen doesn’t react with other materials. Another thing that adds to the safety of using nitrogen is that it is corrosion resistant.

Oxygen for ventilation

There are various gases that penetrate mining pits – hydrogen sulphide, nitrogen oxides and carbon monoxide. This can cause the atmosphere in the mine to be unsafe for the workers. Sufficient oxygen needs to be supplied to the miners. Several m3 of oxygen per miner needs to be pumped into the mines every hour. This supply needs to be uninterrupted to ensure the safety of the miners. Being able to generate oxygen on-site is crucial for this to happen.

Oxygen and gold

Oxygen plays a vital part in the process of gold extraction. Where gold is extracted on a large scale, mines generally use the cyanide leaching process. Gold-bearing rock is ground up and a sodium cyanide solution is seeped through it. This solution needs to be enriched with oxygen. The chemical reaction that results causes the gold complexes to rise. These are then washed out of the rock and sent on for further processing.

Hydrogen’s new role in mining

Hydrogen is going to play an increasingly important role in mining as the industry looks to decarbonize more and more. Green hydrogen has many uses – storing renewable energy so that electricity can be generated, powering equipment and vehicles and as a reductant in various mining processes. The Raglan mine in Canada has produced its own electricity since 2015. It is generated by a wind turbine generator (artic rated) that is connected to a hydrogen energy storage unit. This is a huge reduction in carbon emission due to the reduction in the use of diesel to generate power.

The Mogalakwena mine in South Africa trialled the use of the world’s biggest hydrogen powered mine haul vehicle in 2019.  The truck weighed in at 290 tons. Another platinum mine using hydrogen in their process is the Impala mine, also in South Africa. They are using hydrogen fuel cells for their forklifts and refuelling stations.

Green Steel

Steelmaking uses blast furnaces with are powered by coke (made from coal). Coke is a good reducing agent meaning it removes oxygen from the iron ore. Hydrogen is also an excellent reducing agent. Hydrogen is now being used as a partial replacement of coke is some steel operations.

Foxolution

For all of the above, the most cost-effective way of running a mining facility is to be able to produce the gases you need on-site. Foxolution has the answer for you! Contact us to find out more about our nitrogen and oxygen generators.

Oxygen

What are the most common gas types?

Argon

Argon makes up approximately 1% of the Earth’s atmosphere. It is the third noble gas. Argon is chemically inert and is colourless and odourless in both its liquid and gas forms. Argon is used when an inert atmosphere is required. This is needed in the production of some reactive elements including titanium. Argon is used by welders to protect the area of welding. It is also used in incandescent light bulbs.

Oxygen

Oxygen is colourless, tasteless and odourless. It is a gas and is vital to all living organisms. Animals take up oxygen and convert it to carbon dioxide. Plants use this carbon dioxide and then produce oxygen which is returned to the atmosphere.

21% of our atmosphere is made up of oxygen.

Helium

Helium is an inert gas. It is the second lightest element and has no colour, smell or taste. Helium becomes liquid at −268.9 °C. In order for helium to become a solid pressure of 25 atmospheres is required as well as a temperature of -272 °C.

Helium is used for welding various metals, to pressurize fuel tanks for rocket propulsion.  It is used as a lifting gas for balloons carrying meteorological equipment.

 

Hydrogen

This is the lightest element. Hydrogen is a gas – colourless, odourless, tasteless and very combustible. It is non-toxic. Hydrogen makes up approximately 75% of all matter in the universe.

Hydrogen is used to make ammonia for fertilisers as well as cyclohexane and methanol used in the production of plastics and pharmaceutical products.

Nitrogen

Nitrogen is a gas that has no taste, smell or colour.  It is a gas that is found in all living matter. Nitrogen is the most common element in the earth’s atmosphere.

Nitrogen is used in fertilisers, dyes, explosives, nylon, and nitric acid.  Nitrogen needs to be reacted with hydrogen in order to produce ammonia.

If people are exposed to high concentrations of nitrogen, it is harmful to health.

Because it displaces oxygen in an enclosed space, it can build up to dangerous levels.

Approximately 78% of our atmosphere is made up of nitrogen. Nitrogen is essential for all life.

Acetylene

Acetylene is a hydrocarbon and is the simplest alkyne. It is a colourless gas with a pleasant odour.

Acetylene is used as a fuel and a chemical building block. It is commonly handled as a solution due to the fact that in its pure form it is unstable.

One major use of acetylene is in the fabrication industry.  It is used for welding, cutting, brazing, hardening and texturing.

Acetylene is inflammable but it has the potential to explode in both liquid and solid form when under pressure of approximately 15 pounds per square inch.

Carbon Dioxide

Carbon dioxide is very important as part of the earth’s air. It is non-flammable and colourless.  At normal pressure and temperature, it is a gas.

Carbon dioxide is used in fire extinguishers and for inflating life rafts and jackets.  It is used as a refrigerant and for blasting coal.  It is helpful in promoting plant growth in greenhouses.

Air

The atmosphere of earth is known as air. It is the layer of gases that surround the planet.  The atmosphere protects life on earth – it creates pressure which allows for liquid water to exist on the surface of the earth. It absorbs ultraviolet radiation from the sun and allows the earth surface to be warm.  It also reduces the temperature extremes of day and night. Air is mainly made up of nitrogen and oxygen.

How Is Wastewater Treated?

How Is Wastewater Treated?

We are very fortunate to live in a time when we have so many products that make our lives easier and more comfortable. However, it does come at a price. One of the byproducts is wastewater. This can be in the form of runoff on wet roads, shower water, water from your washing machine or sewerage. Wastewater is not fit for human consumption.

There are various methods used to treat wastewater:

Physical Wastewater Treatment

Methods such as screening, sedimentation and skimming are used to remove solid waste from the water.  There are no chemicals used in this process.

  • Sedimentation is when the insoluble particles in the water are suspended. These particles then settle to the bottom and can be separated from the water.
  • Aeration is a method where air is circulated through the water. This provides the water with a lot of oxygen. This oxygen is used by the bacteria to cause biodegradation. The bacteria break down the organic matter to form carbon dioxide and water. (Foxolution – wastewater treatment)
  • Filtration uses special filters to filter out the contaminants. A sand filter is the most common filter.

Biological Wastewater Treatment

Organic matter like soaps, faeces, oil and food particles can be broken down using biological methods.

Organic matter is metabolized by microorganisms.

  • An aerobic process using oxygen allows bacteria to decompose the organic matter. It is converted into carbon dioxide. (Foxolution – wastewater treatment)
  • An anaerobic process uses fermentation to break down waste matter
  • Composting is a kind of aerobic process. Wastewater is mixed with sawdust. The solids are then removed however dissolved nitrogen and phosphorous may remain.

Chemical Wastewater Treatment

This process involves using chemicals is the wastewater. Chlorine is usually used to kill bacteria. Ozone is also used to purify the water. When an acid or base is added to bring the pH of the water to 7, this is called neutralization.

Sludge Wastewater Treatment

This process separates solids and liquids where the least residual moisture is needed in the solid phase and the lowest solid particle residues are needed in the separated liquid phase. A centrifuge is required for removing the solids from the water.

Municipal Wastewater Treatment

Most of our wastewater is directed to a sewage treatment plant for cleaning. Industrial wastewater is sometimes taken to a separate industrial wastewater treatment plant.

There are 3 treatment processes:

Primary Treatment

In the primary phase, wastewater is temporarily stored in settling tanks where the heavier solid matter sinks to the bottom of the tanks and the lighter solids float to the top.

These solids are then held back while the rest of the water is moved onto the second phase of treatment.

The settling tanks usually have mechanical scrapers that continuously drive the sludge at the bottom of the tank to a hopper.  The hopper then pumps it to sludge treatment facilities.

Secondary Treatment

This works on a deeper level that the first process.  It is designed to degrade the biological content of the waste using various aerobic biological processes. Once this process is complete the water is safer to be released into the environment. There are three ways this can be done.

  • Biofiltration – Various types of filters are used to remove sediment from the wastewater.
  • Aeration – The process uses oxygen. The water is saturated with oxygen and the process can take up to 30 hours.
  • Oxidation – Oxidation ponds use natural bodies of waters – dams, lagoons – allowing wastewater to run through them for a certain period of time before being retained for a couple of weeks.

Tertiary Treatment

The process is aimed at raising the quality of the water so that it can be used again in domestic and industrial situations. This could also involve the removal of pathogens which makes the water safe for drinking.