Vale can reopen Itabira after coronavirus measures

Brazilian iron ore miner Vale SA has received permission to reopen mines in the Itabira complex shuttered due to coronavirus concerns, the company said in a Wednesday filing, adding there was no change to its production guidance.

Vale said it had received permission to reopen the mines from Minas Gerais state labor inspectors. They concluded that the measures Vale had taken to mitigate the threat from the virus and protect its workforce were sufficient to restart works, the company said.

Nonetheless, Vale said work would kick off gradually.

The Itabira complex produced almost 36 million tonnes of iron ore in 2019, according to Vale, of a total production of roughly 302 million tonnes.

A court had previously ordered the Itabira complex shut in late May, but that decision was immediately overturned.

Then, in early June, a judge ordered the closure after 188 workers tested positive for the coronavirus.

Ball Mill Liner Material Selection

Different crushed material, different working conditions need different material liners to suit. Also, the coarse grinding compartment and fine grinding compartment need different material liners.

H&G Machinery supplies the following material to cast your ball mill liner:

Manganese Steel

The manganese content of the high manganese steel ball mill lining plate is generally 11-14%, and the carbon content is generally 0.90-1.50%, most of which are above 1.0%. At low impact loads, the hardness can reach HB300-400. At high impact loads, the hardness can reach HB500-800. Depending on the impact load, the depth of the hardened layer can reach 10-20mm. The hardened layer with high hardness can resist impact and reduce abrasive wear. High manganese steel has excellent anti-wear performance under the condition of strong impact abrasive wear, so it is often used in wear-resistant parts of mining, construction materials, thermal power, and other mechanical equipment. Under the conditions of low impact conditions, high manganese steel cannot exert the characteristics of the material because the work hardening effect is not obvious.

Chemical Composition

Name	Chemical Composition（%）
Name	C	Si	Mn	Cr	Mo	Cu	P	S
Mn14 Mill Liner	0.9-1.5	0.3-1.0	11-14	0-2.5	0-0.5	≤0.05	≤0.06	≤0.06
Mn18 Mill Liner	1.0-1.5	0.3-1.0	16-19	0-2.5	0-0.5	≤0.05	≤0.06	≤0.06

Mechanical properties and metallographic structure

Name	Surface Hardness（HB）	Impact value Ak（J/cm2）	Microstructure
Mn14 Mill Liner	≤240	≥100	A+C
Mn18 Mill Liner	≤260	≥150	A+C
C -Carbide \| Carbide A-Retained austenite \| Austenite

Product specification

Size	Hole Dia.（mm）		Liner Length（mm）
Size	≤40	≥40	≤250	≥250
Tolerance	+20	+30	+2	+3

Chrome Alloy Steel

Chromium alloy cast iron is divided into high chromium alloy cast iron (chromium content 8-26% carbon content 2.0-3.6%), medium chromium alloy cast iron (chromium content 4-6%, carbon content 2.0-3.2%), low chromium Three types of alloy cast iron (chromium content 1-3%, carbon content 2.1-3.6%). Its remarkable feature is that the microhardness of M7C3 eutectic carbide is HV1300-1800, which is distributed in the form of a broken network and isolated on the martensite (the hardest structure in the metal matrix) matrix, reducing the cleavage effect on the matrix. Therefore, the high-chromium alloy liner has high strength, ball mill toughness, and high wear resistance, and its performance represents the highest level of current metal wear-resistant materials.

Chemical Composition

Name	Chemical Composition（%）
Name	C	Si	Mn	Cr	Mo	Cu	P	S
High Chrome Alloy Liner	2.0-3.6	0-1.0	0-2.0	8-26	≤3.0	≤1.2	≤0.06	≤0.06
Middle Chrome Alloy Liner	2.0-3.3	0-1.2	0-2.0	4-8	≤3.0	≤1.2	≤0.06	≤0.06
Low Chrome Alloy Liner	2.1-3.6	0-1.5	0-2.0	1-3	0-1.0	≤1.2	≤0.06	≤0.06

Mechanical properties and metallographic structure

Name	Surface（HRC） Ak（J/cm2）				Microstructure
High Chrome Alloy Liner		≥58		≥3.5		M+C+A
Middle Chrome Alloy Liner		≥48		≥10		M+C
Low Chrome Alloy Liner		≥45		≥15		M+C+P
M- Martensite	C – Carbide		A-Austenite		P-Pearlite

Product specification

Size	Hole Dia.（mm） Liner Length（mm）
Size	≤40	≥40	≤250	≥250
Tolerance	+20	+30	+2	+3

Cr-Mo Alloy Steel

H&G Machinery uses Cr-Mo alloy steel to cast ball mill liner. This material based on Australia standard, (AS2074 Standard L2B, and AS2074 Standard L2C）it’s provides superior impact and wear resistance in all semi-autogenous milling applications.

Chemical Composition

Code	Chemical Elements（%）
Code	C	Si	Mn	Cr	Mo	Cu	P	S
L2B	0.6-0.9	0.4-0.7	0.6-1.0	1.8-2.1	0.2-0.4	0.3-0.5	≤0.04	≤0.06
L2C	0.3-0.45	0.4-0.7	1.3-1.6	2.5-3.2	0.6-0.8	0.3-0.5	≤0.04	≤0.06

Physical Property & Microstructure

Code	Hardness（HB）	Ak（J/cm2）	Microstructure
L2B	325-375	≥50	P
L2C	350-400	≥75	M
M-Martensite, C-Carbide, A-Austenite, P-Pearlite

Ni-hard Steel

Ni-Hard is a white cast iron, alloyed with nickel and chromium suitable for low impact, sliding abrasion for both wet and dry applications. Ni-Hard is an extremely wear-resistant material, cast in forms and shapes which are ideal for use in abrasive and wear environments and applications.

Chemical Composition

Name	C	Si	Mn	Ni	Cr	S	P	Mo	Hardness
Ni-Hard AS2027 Gr Ni Cr 1-550	3.2-3.6	0.3-0.8	0.2-0.8	3.0-5.0	1.5-3.0	≤0.12	≤0.15	≤0.5	550-600HBN
Ni-Hard AS2027 Gr Ni Cr 2-550	2.8-3.2	0.3-0.8	0.2-0.8	3.0-5.0	1.5-3.0	≤0.12	≤0.15	≤0.5	500-550HBN
Ni-Hard AS2027 Gr Ni Cr 2-550	3.2-3.6	1.5-2.2	0.2-0.8	4.0-5.5	8.0-10.0	≤0.12	≤0.15	≤0.5	630-670HBN

White Iron Steel

White iron liner is recommended to be using at low impact working condition such as :

1. Belt conveyor liner for the Mining industry.

2. Cement plant ball mill.

3. Chemical industry ball mill.

Chemical Composition

Name	Chemical Composition(%)
Name	C	Si	Mn	Cr	Mo	Cu	P	S
White Iron Steel Liner	2.0-3.3	0-0.8	≤2.0	12-26	≤3.0	≤1.2	≤0.06	≤0.06

Physical Property & Microstructure

Name	HRC	Ak(J/cm2)	Microstructure
White Iron Steel Liner	≥58	≥3.5	M+C+A
M-Martensite C- Carbide A-Austenite

If you have a special material inquiry, please contact our engineer to service you!

Nick Sun NICK@XZHUAGANG.COM

Post time: Jun-19-2020