The two men made all sorts of small talks and minor decisions along the way, with Harun additionally promising to start making appropriate arrangements for the silver mines.
In this way, Alexander finally got to a very large, flat piece of the hillside, around the middle section of the hill, where the apple of his eye stood- The blast furnace!
It was close to fifteen meters high with a belly diameter of two meters, and a hearth size of one meter, and was in full swing, with hundreds if not thousands of workers around the massive industrial complex.
Its size, and capacity though nothing when compared to the standards of Alexander’s twenty-first century, was enormous for the time being, and knowing what did structure represented, made Alexander’s eyes glow with desire and longing as he laid his eyes on this magnificent hot, roaring beast, finding the stretched part of the furnace’s belly almost as beautiful as the curves on his women.
In his mind, this was the greatest invention that he would use to change his and his city’s fate and that’s why he had spent more than twelve hours a day every day for last the last month and a half overseeing its construction.
And it was not just the blast furnace that need constructing, but many other periphery equipment and furnaces, an effort that need the muscle power of close to ten thousand men, and was only completed last week.
“Even though it’s been almost a week since it started, the amount this thing can produce still blows my mind,” This unreserved praise was awarded by Harun, who looked at the beautiful white structure with sparkling eyes.
And there was justification behind this praise as the current civilization had barely learned to smelt iron, much less mass produce it at such a scale.
“….” Alexander only lightly smiled at the man as his mind drifted to the extremely primitive way iron was currently extracted.
In this time period, to smelt an iron product, first, a miner had to collect the iron ores.
And the primary source of this was from surface pits or from deposits just a few meters underground, which could be extracted by simple shovels, or even just by human hands.
This type of iron ore would be called bog iron ore and the iron smelted from it bog iron.
Large, deep mines that would become the norm in later times existed only in major deposits and were owned by men who counted among the richest men in the world.
This was because constructing mines like the ones in Zanzan, one that went deep into the mountains, with multiple stories below and above the surface was very expensive to not only set up but also to run.
And if one did not have an enormous army of workers ready to smelt the extracted iron which was a snail-paced process using the traditional method, even recouping the running cost would be difficult.
And this problem was compounded by the fact that it was not the supply of the iron ore that was the bottleneck for iron production, but the smelting technique.
Once this bog iron was collected, the processing would move into the next step- Roasting the iron ore for ten hours.
This process was really simple and just involved digging a large hole in the ground, putting the pieces of iron ore into it along with the necessary kindling, firewood, and sawdust, and then lighting it on fire, while adding fuel from time to time as necessary.
This had two basic effects.
One was drying the iron as all the water content of the iron ore would be released, and its structure would become looser, making it easier to smelt.
Two was a bit of desulphurization, i.e- removing some of the sulfur bonded to iron as iron sulfide (FeS) by reacting with oxygen to form sulfur dioxide (SO2).
Though this would not remove all the sulfur, it would help, as sulfur was toxic to steel, making it weaker and more brittle.
Next came the smelting process.
But before getting the now roasted and crushed ore into the fuel, the fuel that would be used to run the furnace- the charcoal, that had to be manufactured.
This step involved, chopping wood into small pieces, placing it into a pit with a chimney in the middle, and then coving the surrounding area with a layer of leaves and soil to make the pit, not impermeable, but restricted to oxygen.
The charcoal pile would then be ignited through the chimney, and through pyrolysis (the process whereby wood becomes charcoal by losing its water content) charcoal would be slowly created over one to a few days.
This charcoal would be then transferred to a furnace, built using clay mixed with sand, and with tuyeres, or the nuzzle used to connect the bellows and the furnace, built into them and be used as fuel.
One side note to note here would be the tuyeres would also be made of clay and required a lot of skill and experience to build, thus making furnaces generally very expensive equipment.
And with all these done, finally, the actual smelting could start.
At first, the furnace would be pre-heated by filling it up with burning charcoal over which a layer of roasted bog iron ore would be placed and then another layer of charcoal alternately.
After this, the furnace entrance would be closed using mud and clay and for the next several hours the mixture would be constantly heated using the blowers and by adding fresh charcoal through the chimney.
This would cook the ore and produce a thin layer of slag, primarily non-iron substances from the iron ore and some iron that could not be reduced from the ore and would be tapped from the furnace through a slag-tapping hole built near the entrance of the furnace.
It is important to note here that, unlike modern steel-making, the iron stays in a solid state throughout the smelting process, only changing from the solid rock-like state to a kind of sponge-like structure called the iron bloom which formed in the hearth of the furnace.
This sponge iron would be full of slag impurities and be removed once the smelter felt it had become large enough by breaking open the sealed entrance.
This would then move the iron smelting to the last step, the forging.
Blacksmiths would use heavy, repeated strikes to shape the iron bloom into a piece of iron by wielding large hammers and it would take hours of slow, tedious, and back-breaking work to produce a single piece of iron.
And ironically, for all that work and effort, the blacksmith would not have a very good piece of iron to show for it, as due to all the slag inclusions, it would not only be much more difficult to forge a piece of iron than modern steel but also because these iron contained harmful impurities that would make the iron very weak and brittle.
This huge presence of so many impurities was the reason blacksmiths were not able to make large pieces of iron, as making the structure long would many times cause the iron to split and open up during the forging process, resulting in cracks in the material.
In this way, about 20 kg of bog iron using 30 kg charcoal would be obtained from the smelting process in about 10-12 hours, which was almost equal to a rounding error when compared to the tens of tons of steel Alexander was capable of producing per day.
And hence, Harun’s admiration for the white, blazing beast was very understandable.
As the two men silently observed the workers working like tiny ants all over the huge plant, an assistant of Harun suddenly appeared, bowed to Alexander, and then whispered something into his master’s ears
The information did not seem to be something untoward, as Harun’s face lit up not with concern but surprise, as he quickly ordered, “Okay, you go escort the lords. And tell them I’m here with the pasha.”
Then he turned to Alexander with a gentle smile and relayed, “My lord, it seems the military and civilian lords that you invited are waiting at the foot of the hill.”
“Mmmmn, then let us wait here for them before starting the tour,” Alexander suggested.
He had asked his retainers to come and bear witness to Zanzan city’s capabilities and to discuss future policies by taking into account such changes.
As the two men chatted, Harun raised, “My lord, it is quite rude that you should arrive before them. This is a great breach of etiquette,” .
It was an Adhanian tradition for the lower classes to wait upon the upper classes and such duties were even applied to the nobility, with the lower ranks serving those above them.
“Haha, no worries,” But Alexander simply waved these concerns while fanning his large palms, and excusing the others by saying, “It was I who arrived early because I was too eager. They are actually on time.”
Alexander was never a slicker for such stuffy rules and regulations and unless the other side blatantly disrespected him, he would usually turn the other cheek.
The two then further continued the small talks, until finally, the large group of all the council members had managed to catch up with them.
And the real tour could finally begin.
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