Pyrrhotite flotation and its selectivity against pentlandite in the beneficiation of nickeliferous ores: An electrochemistry perspective

Mineral Processing and Extractive Metallurgy Review

et al. 2015

Iron ore pellets abrade during handling and produce dust. This study was conducted to determine what factors affect pellet dustiness, and whether dustiness can be related to the abrasion index. Factors studied included bed depth within a straight grate furnace; pellet chemistry; firing temperature; coke breeze addition; and tumble index. Abrasion indices for all pellet samples ranged from 1.9-5.0% (20 samples) and from 7.1-27.5% (5 samples). Pellets were dropped in an enclosed tower, which enabled the collection of airborne particles generated during pellet breakdown. The quantity of airborne particles generated by each pellet type was 10-100 mg= kg-drop, or 50-500 mg=kg over five drops through the tower. Pellet dustiness was predominantly affected by pellet chemistry and by pellet firing temperature. Results showed a nearly 21% increase in dustiness for every percent decrease in firing temperature -this was based on a typical firing temperature of 1280 C. Pellet dustiness was regressed to the pellet abrasion index (for AI < 5%), which yielded a correlation coefficient of 0.22. These results show that, although AI is one of the best indicators of fired pellet quality and can indicate high levels of dust, it could not explain the dustiness of good quality pellets.The second paper (Iron Ore Pellet Dustiness Part II) explains the relationship between AI and dust for good-quality pellets; and compares fines generation between pellets fired in Straight-Grate (Traveling Grate) and Grate-Kiln furnaces.

Section: Introductionmentioning

confidence: 97%

Iron Ore Pellet Dustiness Part I: Factors Affecting Dust Generation

Halt

Nitz

Mineral Processing and Extractive Metallurgy Review

et al. 2015

“…(Carlson and Kawatra 2008;Haselhuhn 2012a, 2012b, Carlson and Kawatra 2013Haselhuhn 2013aHaselhuhn , 2013bBolen 2014;Halt and Kawatra 2014;Halt et al in press;Liu et al 2014;Manouchehri 2014;Sandvik and Larsen 2014;Semberg et al 2014). During almost every iron ore beneficiation process, water and the concentrations of ions within water have a large impact on process performance.…”

Section: Introductionmentioning

confidence: 96%

Aqueous Ions in Process Water and Cake Moisture During Iron Ore Filtration

Haselhuhn

Mineral Processing and Extractive Metallurgy Review

2015

In mineral beneficiation plants, aqueous ions from the process water concentrate within the filter cake moisture. These high concentrations of ions can lead to operational issues during downstream processes. This paper examines the ionic content of iron ore slurry before it was filtered at an operating hematite beneficiation plant and compared it with the ionic content of the moisture in the resultant filter cake. Water analyses were conducted to determine the sodium, potassium, calcium, magnesium, fluoride, chloride, nitrate, nitrite, carbonate, sulfate, and phosphate concentrations in both filter feed slurry and filter cake moisture. Results have shown that all tested ions within the process are more concentrated within the filter cake moisture than in the filter feed slurry. This has been attributed to the physical and chemical interactions of these ions with the iron ore particle surfaces. Of these ions, phosphorus concentrates most with the filter cake moisture content having a phosphorus content that is 24.67 times that of the filter feed slurry.

“…Problems that have been investigated recently cover flotation reagents and chemistry (Manouchehri 2014;Sandvik and Larsen 2014), filtration (Carlson and Kawatra 2008;Haselhuhn et al 2012b), water chemistry Kawatra 2011, 2013;Westerstrand and Ohlander 2010;Haselhuhn 2012Haselhuhn , 2013Haselhuhn et al 2012a), and agglomeration (Kawatra and Halt 2011). However, the formation of fines and dust from pellets (a) is not understood well, and (b) may become a more common problem as greater quantities of pellets are produced.…”

Section: Introductionmentioning

confidence: 96%

Iron Ore Pellet Dustiness Part II: Effects of Firing Route and Abrasion Resistance on Fines and Dust Generation

Halt

Mineral Processing and Extractive Metallurgy Review

2014

Iron ore pellets abrade during their production and handling, which lowers product quality and leads to dustiness issues. Pellets were collected from a variety of plants (operating either Straight-Grate (SG) or Grate-Kiln (GK) furnaces) to understand whether furnace type affects fines and dust formation. Results showed that pellets fired in SG furnaces were less abrasion-resistant (3.5 Â lower) than pellets fired in GK furnaces. Concurrently, laboratory pellets were prepared using various ores, binders, and firing temperatures. These were tested to understand the relationship between abrasion index and dustiness. AI was observed to range from 1 to 14%. Dustiness, determined via AI and size distributions of abrasion progeny, ranged from 0.2 to 1.6%. For AI greater than 5%, AI can be used to indicate potentially high levels of dust. For AI less than 5%, there was a poor correlation between AI and dustiness. This was explained by the observation that as AI decreased, the abrasion product fineness increased. The results from parts I and II of this investigation suggest that material loss and levels of pellet dustiness may be significantly affected by pellet quality up to a certain point. Poorly fired pellets will be dusty during handling and transportation, while well-fired pellets will generate less -but finer -material as their quality improves. This could lead to little observed changes in dust generation over a wide range of pellet quality. Dust generation at each site would then depend on the quantity of material produced and their extent of handling.