Several community members have commented on reducing carbon emissions from mining and metals production through the use of low carbon processes and green energy.
A recent forum now available on the ABC looked at the issue with an expert panel. The conundrum or dilemma? Our current path to wards a lower carbon future requires significant increases in mining and metals production if the targets are to be achieved. All aspects of metals production are carbon intensive.
I thought coking coal had two purposes, the fuel aspect being a by-product of the need to add carbon to pig iron to convert it to steel of various qualities?
Don’t get me wrong I am huge supporter of replacing fosil fuels.
You forgot the reduction of the ore (metal oxide) to metal. The carbon plays and essential role in the chemical conversion process. The role of adding carbon to make carbon steel is minor, much of steelmaking is finding efficient ways to remove excessive carbon.
Above all this is cost. At the moment for bulk production of steel nothing comes close to the coke-fired blast furnace.
Most typically metallurgical or coking coal is converted to coke, and added to iron ore in a furnace to produce raw iron. Steel making is a second separate process.
Leaving the complexities out. Some of the carbon in the coke reacts with the oxygen atoms bound to the iron atoms in the ore. This converts what is basically rust in the ore back to bare metal (reduction of the ore) while also producing CO2 and CO (carbon dioxide and carbon monoxide).
This alone does not produce enough heat to sustain the process or produce a molten metal stream. Hot fresh air is forced (air blast) into the furnace through tuyeres. This air combusts with some of the coke to produce the additional heat or energy required to sustain the reactions in the furnace.
Some carbon remains dissolved in the molten iron, in percentages greater than needed to make steel. Carbon is not deliberately added to a furnace because it is essential to producing different qualities of steel. It’s mostly an unwanted byproduct of the process.
Although any process of direct reduction of iron ore that does not include a source of carbon would require some added to produce the required grades of steel.
Making steel from iron ore is traditionally a two step process.
Primary production, which converts the ore from a complex of iron oxides bound in a matrix of other minerals including silica. The most common method remains the blast furnace, although the technology and process has improved substantially over the previous 50 years.
A blast furnace produces raw iron, which may be cast into pigs, (the early 19th century way, hence the name). Most raw iron is poured molten into a hot metal ladle for transport to Secondary production for conversion from iron to steel. Typically in a BOS (Basic Oxygen Steel) plant. Previously open hearth furnaces were the most common plant used for this step.
There are various alternatives to iron and steel production by blast furnaces, variations between process, as well as tertiary processing options. If you feel the need to study for a degree on pyrometalurgy.
Lesson 1 to learn a little more.
Whatever the alternatives are for producing steel more directly from iron ore there is always a need for some form or primary or pre-processing of the ore that also consume energy.
All existing and proposed processes need to operate continuously 24x7. The energy inputs required to melt the ore and split the iron oxygen bonds are also very large. For those processes driven by electrical energy any renewable resource needs to have very large amounts of dedicated reliable stored energy. Aluminium produced by electrolysis of alumina in a smelter has often been described as liquid electricity.
Producing iron and steel by a low carbon process is going to require a total renewal of global production capacity in addition to significant investment in the alternate low carbon energy supplies.
It may partly explain why some proponents more fixed on short term economic gain spruik the ‘holy grail’ of carbon sequestration as the solution to all our GHG problems. For others, more of Walt Disney and the fairy tale of Snow White and the Seven Dwarfs, ‘One Day My Black Coal Prince Will Come’. It was carbon they were mining after all?
Have you read the link to ‘direct electrolysis’, it seems to tackle the reduction to metal aspect, using different anode materials, how fully that copes, I wouldn’t know, but seems like a good step foprward once they master doing it on a large scale.
A great prospect, apparent new capital costs aside.
Pilot processes in this area can take decades to upscale to commercial success. While the capital committed to current technology is not so readily abandoned.
Options to encourage change include legislative forced change on a global scale, or for governments to subsidise the transition sooner rather than later. All costs to the consumer.
What if a new technology came along today that was carbon neutral and overall produced cheaper steel in the next five years?
It would quickly push every old tech producer out of business leaving orphaned assets and lost capital of recession driving proportions globally. Irrational fear by investors of disturbance of the current economic equilibrium is perhaps one reason positive change has met so much resistance from one sector of the community.
It’s another discussion about whether the current economic system can ever deliver the changes needed for a low carbon future.
The problem of cost over concern. We need to be thinking of ways even if currently expensive to reduce the use of fossil fuels. I agree some carbon is needed for steel production but even if the process to reduce the amount of carbon is currently high what is the cost of not adopting the processes? It may be a cost a majority of us want to face but many are still blindly heading towards an outcome no amount of money saved now will ever offset the monetary and life cost of the future.
This is much broader than providing zero carbon metals production. It affects the whole of the GHG reduction debate.
The scale of investment required to accelerate delivery of better solutions sooner challenges the norm. Those most at physical risk of no effective change are the majority. Those most at risk financially are the minority. Some would say the minority controls the thinking of our political leadership.
How do you convince a wealthy neighbour to surrender hard earned value and lifestyle to the benefit of the greater neighbourhood?
For industries such as mining and minerals/metal production the average consumer has little direct control. Although as the discussion so far has indicated there are potential low carbon solutions in many areas of need.
Without government commitment to drive change:
For that the Government needs to change its attitude that change risks the economy, or …?
It’s noteworthy the world economy is busy building new weapons of war rather than weapons of GHG reduction.
Carbon does and is needed to change the properties of steel…and the volumes needed to satisify global steel production is significant. It could be replaced with say biomass based carbon, but this may also have impacts as well.
But it takes about 600 kg of coke (around 95% carbon) to make each 1000 kg of steel in the blast furnace so even if the residue of carbon left in the steel averages 0.5%, ie 5kg, there is a hundred times more goes up the chimney. I think you are making rather too much the issue of finding some carbon to add to the steel if it is not made in a blast furnace compared with the saving in GHG generated, or the cost of hydrogen or electricity to make steel ex blast furnace.
Perhaps those who are testing other methods of ore reduction have thought of this and found a solution as part of their method?
It would be interesting to figure out the real costs. Coal is cheap because most of the cost is externalised. We are now paying (in global warming, droughts, fires, etc.) the accumulated debts of the industrial revolution. Future generations will continue paying. How much they pay depends partly on us.
Assuming a de-carbonised economy, what would zero carbon emissions steel cost? Australia has obscene renewable energy riches. Over-building for export has been suggested. We could readily do that and export the energy as refined metals. How low could we push the price of energy, given coordinated efforts and capable government? Might we refine metals cheaper than the traditional ways?
Making the change will not come cheap, but it would set Australia up for a much brighter future. All we’d need is courageous leadership, not corrupted by vested interests.
Good point, all we have on the books are the tangible immediate costs. But this has been the way since the first days of the industrial revolution. The great growth and apparent prosperity since then has been fueled by burning cheap fuel and largely ignoring what happens to the emissions.
The cost is in much more than just coal. It is just one input.
The analysts in the large merchant bankers and investment houses have all the data at their finger tips to lay out the economics, conventionally.
On one hand they know the value of the committed capital and debt in any selected industry sector, nationally and notionally globally.
On the other they know the current cost of new investment in any sector and have the ability with some technical guidance to cost alternatives.
It would be interesting to see for each carbon intensive industry sector the total capital costs and cash flow estimates required over the next 30 years to achieve the zero carbon outcome.
Before any other community members dive in to say green energy is free or the cost is irrelevant when compared to doing nothing or little. I’m simply pointing out the way our world economic order functions. There may be other ways to get to the end point economically. The carbon tax and carbon trading was/is the preferred conservative don’t rock the world economic order solution of choice. It has not been globally effective.
With the global economic scale of effort and expenditure required for mining and metals laid out, perhaps a real discussion on how to restructure economically will come about and the current hesitation to act disappear. To date conventional economic thinking has not delivered for most nations, particularly those like Australia that are trade dependent on minerals exports.