Provenance of titanomagnetite in ironsands on the west coast of the North Island, New Zealand

Brathwaite, Robert L.; Gazley, Michael F.; Christie, Anthony B.

doi:10.1016/j.gexplo.2017.03.013

Cited by 29 publications

(15 citation statements)

References 42 publications

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“…All but SiO 2 are typically associated with the titanomagnetite (TTM) grains and are present as solid solution components within the lattice. 3,4) Thus, it is difficult to separate major impurities and obtain high-quality iron concentrates using conventional beneficiation methods such as specific gravity and magnetic separation. 5) To efficiently utilize the TTM, many pyrometallurgical processes, including blast furnace smelting and direct reduction-electric furnace smelting, have been investigated.…”

Section: Introductionmentioning

confidence: 99%

Extraction of Iron from Refractory Titanomagnetite by Reduction Roasting and Magnetic Separation

2021

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The abundant refractory titanomagnetite (TTM) provides a cheap alternative source of iron, but this ore contains impurities and is difficult to process to make suitable concentrates for the blast furnace. In this study, reduction roasting of a primary TTM concentrate followed by magnetic separation was investigated to understand the effects of reduction time, coal dosage, and CaF 2 addition on the reduction behavior of TTM and growth mechanism of iron particles. The phase composition of reduced samples was characterized by X-ray diffraction. The size distribution of iron particles was quantitatively examined using image analysis. Results showed that CaF 2 can help improve the reduction degree and particle size of metallic iron. The metallization degree increased from 85.5% to 89.5% when the CaF 2 dosage increased from 0% to 4%, while a minor increase was observed when the CaF 2 dosage exceeded 4%. Accordingly, the TTM samples were treated by reduction roasting with 4% CaF 2 and 25% coal at 1 200°C for 60 min followed by magnetic separation. A magnetic concentrate with an iron content of 91.1% and a recovery of 92.9% was achieved. In addition, the relationship between the size distributions of iron particles and grinding fineness was also studied. The size distribution using data from the diameter of iron particles was found to be close to the actual grinding fineness.

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Section: Introductionmentioning

confidence: 99%

Extraction of Iron from Refractory Titanomagnetite by Reduction Roasting and Magnetic Separation

2021

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“…Along the south Tara naki coast most beach sand is de rived from ero sion of the lahar and de bris av a lanche de pos its which flowed from the andesitic cone of Mount Tara naki (Neall et al, 1986;Turner et al, 2011;Zernack et al, 2012). The sands contain mainly titanomagnetite, augite, hornblende, and plagioclase feld spar (Mor gan and Gib son, 1927;Gow, 1967Gow, , 1968Briggs et al, 2009;Brathwaite et al, 2017). The coast is sub ject to tides (with tidal range of ~2 m) and high-en ergy, prevail ing south west waves pro duce a south to north lit to ral drift (Pickerill and Mitchel, 1979;Shep herd and Hesp, 2003).…”

Section: Study Areamentioning

confidence: 99%

“…The dis tinc tive min er al ogy of these sands has been known for some time (e.g., Cox, 1881) and be cause of the high con cen tra tion of titanomagnetite (Nichol son and Fyfe, 1958) they are lo cally known as "ironsand" (Thomson, 1917;Kear, 1965Kear, , 1979. They are both of eco nomic sig nif i cance (Kear, 1965;Brathwaite et al, 2017Brathwaite et al, , 2021 and a tour ist at trac tion.…”

Section: Introductionmentioning

confidence: 99%

Black sand properties in beach-dune system, Patea Beach, North Island, New Zealand

Dłużewski

Hilton²,

Muszyński³

et al. 2021

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The study fo cuses on sand grain prop er ties in dif fer ent parts of a beach-dune sys tem built en tirely of heavy min eral par ti cles. These prop er ties are re lated to: (1) re sis tance of par tic u lar min er als to weath er ing and abra sion, (2) hy drau lic sort ing in the swash zone, and (3) ae olian sort ing dur ing grain trans port in land from the up per beach. The main waterlain and windlain sand prop er ties de pend on set tling ve loc ity which re sults from grain den sity (re flect ing grain min er al ogy), size, shape and round ness. The study was per formed on the beach and dunes at Patea on the west coast of the North Is land of New Zea land, which are com prised of heavy min er als as sem blage con tain ing a fer ro mag netic (dom i nated by titanomagnetite) and non-ferro mag netic (mainly pyroxene and am phi bole) frac tions. The re sult dem on strates that three zones of dif fer ent sand prop er ties can be dis tin guished: (1) a lower swash zone dom i nated by non-fer ro mag netic, larger and more an gu lar par ti cles which are car ried back from the up per swash zone down the fore shore by the back wash; (2) an up per most swash zone and beach with al most 100% of fer ro mag netic, smaller and more rounded par ti cles de pos ited at the back of the beach by the up rush, which dur ing high tide and storms can reach the cliff toe, and can be re worked by wind; and (3) a climb ing dune com posed of a more poorly sorted mix ture of non-and fer ro mag netic par ti cles. In terms of both min er al ogy and grain size and shape, the dune sand is less uni form than the beach sand. Ae olian seg re ga tion re sulted here in sand tex tural fea tures op po site to those found in dune sands com posed of light min er als. The re sults high light the den sity-de pend ent vari abil ity of grain size and shape of beach-dune de pos its con sist ing of only heavy min er als, and broaden our un der stand ing of mech a nisms of sed i men tary processes which is par tic u larly im por tant when re con struct ing older sed i men tary suc ces sions.

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“…The~6 m upper unit contains soil beds of predominantly andesitic parent material interbedded with tephra deposits (Duff, 1993). The cliffs at Onaero Bay are fronted by a gently sloping shore platform overlain by sand beaches derived from eroded Taranaki volcanic deposits and transported alongshore in a northerly littoral drift (Bryan et al, 2007;Brathwaite et al, 2017). Cliff retreat rates in the area are up to~1 m year À1 (Gibb, 1978).…”

Section: Onaero Bay Taranaki Nzmentioning

confidence: 99%

Wave impacts on coastal cliffs: Do bigger waves drive greater ground motion?

Thompson

Young

Dickson

2019

Earth Surf Processes Landf

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Coastal cliff erosion is caused by a combination of marine forcing and sub‐aerial processes, but linking cliff erosion to the environmental drivers remains challenging. One key component of these drivers is energy transfer from wave–cliff interaction. The aim of this study is to directly observe cliff ground motion in response to wave impacts at an individual wave scale. Measurements are described from two coastal cliff sites: a 45‐minute pilot study in southern California, USA and a 30‐day deployment in Taranaki, New Zealand. Seismometers, pressure sensors and video are used to compare cliff‐top ground motions with water depth, significant wave height (Hs) and wave impact types to examine cliff ground motion response. Analyses of the dataset demonstrate that individual impact events can be discriminated as discrete events in the seismic signal. Hourly mean ground motion increases with incident Hs, but the largest hourly peak ground motions occurred across a broad range of incident Hs (0.9–3.7 m), including during relatively calm conditions. Mean hourly metrics therefore smooth the short‐term dynamics of wave–cliff interaction; hence, to fully assess wave impact energy transfer to cliffs, it is important also to consider peak ground motion. Video analyses showed that the dominant control on peak ground motion magnitude was wave impact type rather than incident Hs. Wave–cliff impacts where breaking occurs directly onto the cliff face consistently produced greater ground motion compared to broken or unbroken wave impacts: breaking, broken and unbroken impacts averaged peak ground motion of 287, 59 and 38 μm s−1, respectively. The results illustrate a novel link between wave impact forcing and cliff ground motion response using individual wave field measurements, and highlight the influence of wave impact type on peak energy transfer to coastal cliffs. © 2019 John Wiley & Sons, Ltd. © 2019 John Wiley & Sons, Ltd.

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Provenance of titanomagnetite in ironsands on the west coast of the North Island, New Zealand

Cited by 29 publications

References 42 publications

Extraction of Iron from Refractory Titanomagnetite by Reduction Roasting and Magnetic Separation

Extraction of Iron from Refractory Titanomagnetite by Reduction Roasting and Magnetic Separation

Black sand properties in beach-dune system, Patea Beach, North Island, New Zealand

Wave impacts on coastal cliffs: Do bigger waves drive greater ground motion?

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