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Table 3 Potential materials of construction for mills to grind dilute acid-pretreated samples. Corrosion rate tests were performed at the sulfuric acid boiling temperature [47]

From: Promise of combined hydrothermal/chemical and mechanical refining for pretreatment of woody and herbaceous biomass

Material Condition, other factors and comments Concentration (%) Duration (h) Corrosive rate (mm/year)
Irons and steels
 Altemp A-286 Solution treated 10 NRa 0.75
 Stainless steels
  AL 29-4-2 Diluteb 10 NR 0.46
  Altemp 625 Diluteb 10 NR 0.64
  E-Brite Dilute, nonactivated 5 48 0.356
  Type 316 stainless steel NR 0.25 24 0.0686
 Titanium
  Ti-3-8-6-4-4 Plus 1 g/L FeCl3 10 NR 0.15
  Ti-3A1-2.5 V ASTM grade 9 0.5 NR 0.35
  Titanium Grade 7 plus 16 g/L Fe2(CO4)3 10 NR 0.178
  Titanium Grade 12. naturally aerated 1 NR 0.91
 Tantalum
  Tantalum NR 10 NR <0.02
 Alloys
  Alloy C-22 NR 20 NR 0.838
  Alloy C-4 NR 10 NR 0.787
 Alloys
  Ferralium NR 5 NR 0.30
  Hastelloy B SO2 purge 10 NR 0.05–0.25
  Hastelloy B-2 SO2 purge 10 NR 0.05–0.25
  Hastelloy C Lab test 10 120 >0.25–0.51
  Hastelloy G Lab test 10 120 >0.25–0.51
  Hastelloy G-3 Lab test 10 120 >0.25–0.51
  Hastelloy G-30 Plus 42 g/L Fe2(SO4)3 50 NR 0.171
  Hastelloy G-30 Plus 10 % nitric acid 50 NR 0.406
  Inconel 617 Average of two tests 5 NR 0.61
 Others
  Columbiumc   10 NR <0.12
  Niobium NR 10 NR 0.125
  1. aNR means not reported
  2. bActivated before tests
  3. cSusceptible to embrittlement