Chinese steel giant eyes Simandou

Chinese steel company Baowu is at the head of a group of steelmakers seeking to develop the massive Simandou iron mine in Guinea, taking over from Aluminum Corp. of China (Chalco) as it seeks to secure supply of the raw material, Caixin Global reported Tuesday.

The state-owned giant wants to develop the iron ore mine after acquiring shares of the project held by Chalco in cooperation with other steelmakers.

China’s steel association and major steelmakers have called for an increase in domestic iron ore production as well as greater investment in exploration overseas to ensure supplies. The country last year produced 56% of the world’s steel. 

China is the world’s top iron ore consumer, with its demand set to hit 1.225-billion tonnes in 2020, according to a government think tank. But it has a heavy reliance on imports, having shipped in one-billion tonnes of ore in 2019.

Baowu estimates getting Simandou up and running could require more than $15 billion all told after factoring in the necessary infrastructure build-out, such as a cross-country railroad and deep-water port.

Industry experts widely consider Simandou to be the largest high-grade iron ore deposit in the world, but it has struggled to enter production for years. 

Rio Tinto had previously held rights to develop all four blocks of Simandou before being stripped of the rights to blocks 1 and 2 in 2008. Those rights went to a joint venture between Israeli billionaire Beny Steinmetz’s BSG Resources and Vale.

In March, Guinea selected the China-backed consortium SMB-Winning to develop blocks 1 and 2, which holds estimated reserves of more than 2 billion tonnes of high-grade iron ore.

Demand

Benchmark iron ore futures in China moved in a tight range on Tuesday, as coronavirus demand uncertainties held back trading ahead of public holidays starting later this week.

The most actively traded iron ore futures on the Dalian Commodity Exchange, for September delivery, closed down 0.3% at 757 yuan ($107.05) a tonne, a second straight loss.

Trading on the exchange will be closed from Thursday for China’s Dragon Boat festival and re-open on Monday.

Iron ore shipments from Australia and Brazil rose by 1.4 million tonnes from the previous week to 26.57 million tonnes for the week ended June 21, data from consultancy Mysteel showed, mainly driven by increase from Australia.

AG/SAG Mill Liner Material Selection

Different crushed material, different working conditions need different material liners to suit. In order to meet the requirements for customer AG or SAG mill liners, the materials of large mill liners are mainly high manganese steel, high alloy white cast iron, high carbon chromium-molybdenum steel, medium carbon chromium-molybdenum steel, etc. The matrix structure includes austenite, martensite, bainite, and pearlite.

H&G Machinery supplies the following material to cast your AG or SAG mill liners:

High Manganese Steel

High manganese steel is a traditional material for abrasion resistance and mill lining. It is widely used in various wear conditions because of its remarkable work hardening effect. The reason why the high manganese steel lining plate has a long service life is that the large ball mill has a slow speed and a large impact force between the grinding ball and the ore. The work hardening effect of the high manganese steel is significant, and the relative between the ore and the lining plate The speed is small. However, high manganese steel also has a fatal weakness, that is, in the case of large impact, due to its low yield strength, it is easy to rheology, resulting in large deformation of the liner, difficult to disassemble the liner, and the bolt will be broken in severe cases.

Alloy white cast iron

The representative material of alloy white cast iron is high chromium cast iron, and the Cr content is usually greater than 12%. Because it contains isolated rod-like high-hardness M7C3 type carbides, it shows higher hardness and better impact toughness (compared to white cast iron), and it has been widely regarded as a new generation of wear-resistant materials, and It has been applied to the liner of ball mill. However, the impact toughness of high-chromium cast iron is still relatively low (usually 5~7 J/cm2), so high-chromium cast iron is only suitable for the mining of small-size liners and large-size liners in cement mills Wet small-diameter mills (diameters below 2.5 m) are not suitable for large-diameter mills with large impact strength, especially large SAG mill.

Alloy Steel

Alloy steel as a wear-resistant material has also achieved good results in practical applications. The main reason is that the carbon content of alloy steel and the types and contents of alloy elements can be varied within a large range. With different heat treatment processes, The structure and properties of alloy steel can be adjusted within a relatively large range to obtain better comprehensive mechanical properties and meet the requirements of different working conditions. Research and practice  have shown that alloy steel is suitable as a mill liner for large self-grinding machines and semi-self-grinding machines, as shown in the table:

It can be seen that the martensitic Cr-Mo alloy steel lining plate has a good use effect in the self-grinding machine, followed by the pearlite Cr-Mo alloy steel lining plate. Pearlite Cr-Mo alloy steel lining has been widely used in semi-automatic mills. Although its wear resistance is slightly worse than martensitic Cr-Mo alloy steel, its impact toughness is higher than martensitic Cr -Mo alloy steel, so it is suitable for large semi-self-milling machine with relatively large impact.

@Nick Sun       NICK@XZHUAGANG.COM