Appendix B6. SEM observations, experiment 2. Coating stage pre Ca(OH) 2 addition

Transcription

1 Appendix B6 Appendix B6 SEM observations, experiment 2 Coating stage pre Ca(OH) 2 addition Column Column A Major Fe Zn sulphate Habit and morphology coating with desiccation cracks, variable thickness spherical rosettes up to 20 μm diameter, often coalesced into a coating of radial splays; more rounded balls when substantial Si incorporated coating of fine (<1 μm) acicular pincushions and dendrites; occasional large bladed (30 μm x 10 μm) crystals scattered very large (200 μm x 100 μm) prismatic crystals; rare rounded fine grained euhedral crystals Chemistry Fe-K+(- Zn) -K+(Si-Fe) ; large crystals +K Zn-K ; rounded Zn-K-(Si-S) sulphate Abundance thin coating on ~75 % of chalcopyrite surfaces, one sphalerite grain coated heterogeneous coating 100% of some grains, abundant on chalcopyrite, sparse on quartz and tetrahedrite acicular cover 100 % of galena surfaces; large crystals rarely on and adjacent to galena including on -K rosettes cover ~5 % of sphalerite surfaces rare isolated on 200

2 Appendix B6 Column Column B Column C Major Habit and Chemistry Abundance morphology identical to those observed in column A with a slight increase in abundance except Zn-K s, which were less common and of acicular morphology; more common and rare -Fe observed Fe Zn to flaky welldeveloped thick (~3 μm) coating with desiccation cracks spherical rosettes up to 30 μm diameter, often coalesced into a coating of radial splays; more rounded balls when substantial Si incorporated coating of fine acicular pincushions; larger bladed and leafy crystals radial flow-like agglomerations of very fine-grained (100 nm x 10 nm) crystals; splays of acicular (50 μm x 1 μm) crystals; scattered large (200 μm x 30 μm) prismatic crystals; Fe-K+(- Zn-S) -K+(Si-Fe- Al-S) Zn-K coating on ~99 % of chalcopyrite, stannite (thick) and arsenopyrite (thin) surfaces, one tetrahedrite grain poorly coated heterogeneous coating 100% of some grains, abundant on coated chalcopyrite, scattered on quartz, clays, tetrahedrite and oxides acicular cover 100 % of galena surfaces; large crystals rarely on and adjacent to galena including on Fe-K coating and -K rosettes cover ~50 % of sphalerite surfaces, always sphalerite although often cover adjacent Fe and s 201

3 Appendix B6 Column Column C continued Column D Major Habit and morphology Chemistry Abundance fibrous crystals and Fe rare isolated () and euhedral rosettes Fe s identical to column C except generally richer in Zn and S, also poorly developed on ~10 % of sphalerite surfaces; tetrahedrite not observed s identical to column C except in greater abundance and without incorporated Si, Al or S Zn coating of fine acicular pincushions; larger prismatic and leafy crystals; to scaly coating with desiccation cracks; spheroids. radial flow-like agglomerations and rosettes of very fine-grained (100 nm x 10 nm) crystals; scattered large (200 μm x 100 μm) prismatic crystals; spheroids euhedral rosettes (, Fe); botryoidal, fibrous () and prismatic () crystals Zn-K ; spheroids contain S, and Fe acicular cover 99 % of galena surfaces; large crystals on ~10 % of galena and adjacent minerals; coatings and spheroids rare cover ~30 % of sphalerite surfaces; spheroids rare; all usually sphalerite, some isolated prisms found on grains without sphalerite well-coated grains; occasionally extensive; and Fe rare isolated 202

4 Appendix B6 Coating stage post Ca(OH) 2 addition Column Column A Column B Major Habit and morphology Chemistry Abundance Fe phase abundance, morphology and chemistry identical to that observed before Ca(OH) 2 addition except no incorporated Zn was detected Ca Fe spherical rosettes up to 20 μm diameter, often coalesced into a coating of radial splays; rare acicular crystals coating of fine (<1 μm) acicular pincushions; occasional large bladed crystals (30 μm x 10 μm) fine-grained granular agglomerations euhedral rosettes and botryoidal agglomerates (); acicular (-K) and prismatic (Ca) crystals coating with desiccation cracks, usually thin (<1 μm), occasionally granular and poorly-coalesced, especially when Ca, K or Al-rich -K-Ca pincushions +Ca-K ; large crystals -Ca Ca+K, -K, Ca (gypsum) Fe-K+Ca-- Al-(Si-S) heterogeneous coating 100% of some grains, abundant on chalcopyrite, sparse on quartz and tetrahedrite acicular cover 100 % of galena surfaces; large crystals rarely on and adjacent to galena rare rare ; more common and associated with well-coated grains thin coating on ~75 % of chalcopyrite surfaces, one pyrite grain poorly-coated 203

5 Appendix B6 Column Column B continued Column C Major Habit and morphology Chemistry Abundance spherical rosettes -K-Ca+S- heterogeneous up to 20 μm Si coating 100% of diameter, often ; some grains, coalesced into a rare abundant on coating of radial chalcopyrite, splays; more sparse on quartz rounded balls and tetrahedrite when substantial Si or S incorporated coating of fine (<1 +Ca acicular and μm) acicular botryoidal pincushions cover (+Ca), 100 % of galena spheroids and surfaces; large botryoids (- crystals cover up Ca); large bladed to 10 % of coated (), prismatic galena; (+Ca) and spheroids and acicular crystals acicular crystals () (up to 100 rare μm x 10 μm) Zn radial flow-like Zn-Ca cover <5 % of agglomerations of ; sphalerite very fine-grained Zn-K surfaces; prisms (100 nm x 10 nm) rare, associated crystals (Zn-Ca); with sphalerite large (100 μm x 50 μm) prismatic crystals (Zn-K) Ca fine-grained Ca+K rare granular and flaky clay-like agglomerations euhedral rosettes, Ca-K, rare ; and botryoidal -K-Ca agglomerates more common (); prismatic and associated (Ca-K), (-K-Ca) with well-coated crystals grains Fe phase abundance, morphology and chemistry identical to that observed before Ca(OH) 2 addition except incorporated was detected occasionally and rare acicular Fe-K crystals were observed; thin coatings also observed on pyrite and bournonite; no coating observed on tetrahedrite 204

6 Appendix B6 Column Column C continued Column D Major Habit and Chemistry Abundance morphology phase abundance, morphology and chemistry identical to that observed before Ca(OH) 2 addition except that Ca was always incorporated and that Si, Fe and Al were not detected; when significant S was incorporated the phase formed a very fine precipitate phase abundance, morphology and chemistry identical to that observed before Ca(OH) 2 addition except for the presence of common acicular pincushions and granular coats of -Ca-K and rare granular -Al Zn Ca radial flow-like agglomerations of very fine-grained (100 nm x 10 nm) crystals (Zn-K-S); scattered large (200 μm x 30 μm) prismatic crystals (Zn-K); botryoidal agglomerates and euhedral rosettes (Zn-Ca) fine-grained granular agglomerations euhedral rosettes and botryoidal agglomerates (+K); prismatic crystals (-K) Zn-K+S ; Zn-Ca Ca+K +K, -K cover ~50 % of sphalerite surfaces, always sphalerite although often cover adjacent Fe and s rare rare ; more common and associated with well-coated grains Fe phase abundance, morphology and chemistry identical to that observed before Ca(OH) 2 addition except generally richer in, poorer in Zn and S and with occasional incorporated Ca; tetrahedrite uncoated phase abundance, morphology and chemistry identical to that observed before Ca(OH) 2 addition except that Ca was always incorporated 205

7 Appendix B6 Column Column D continued Major Zn Habit and morphology coating of fine acicular pincushions (); larger prismatic (30 μm x 10 μm) and acicular (90 μm x 5 μm) crystals(); fine (<1 μm) granular agglomerations (-Ca+-K); rounded balls (+Ca-Zn) acicular splays (200 μm x 3 μm) (Zn+K); large bladed crystals (300 μm x 50 μm) (Zn+Ca-K); agglomerates (Zn-Ca) euhedral rosettes; botryoidal crystals Chemistry ; -K ; -Ca+- (K-Zn) Zn+ K ; Zn-Ca+K Abundance acicular cover 99 % of galena surfaces; large crystals on ~10 % of galena and adjacent minerals including anglesite heterogeneous, usually rare, not closely sphalerite extensively developed on well-coated grains 206

8 Appendix B6 Dissolution stage Column Column A Major Fe Ca Habit and morphology coating with desiccation cracks, variable thickness; occasional disaggregated rosettes are possibly slightly developed coating spherical rosettes up to 20 μm diameter coalesced into a coating of radial splays coating of fine (<1 μm) acicular pincushions (); botryoidal crust (-Ca); fine wispy (-K) fine-grained granular agglomerations bladed crystals Chemistry Fe-K -Ca-K ; -Ca ; -K Ca Abundance thin coating on ~75 % of chalcopyrite surfaces, ~25 % arsenopyrite surfaces; rosettes on one tetrahedrite grain heterogeneous, coat 95 % of grains where observed, absent otherwise acicular and crusts cover 100 % of galena surfaces, wispy rare rare Zn Zn rare sulphate identical to those observed after Ca(OH) 2 addition except no -K were observed. Column B Fe s identical in chemistry and morphology to that observed after Ca(OH) 2 addition except that no incorporated Al, Ca,, Si or S was detected, pyrite was uncoated and stannite was ~50 % thinly coated s identical in chemistry, morphology and abundance to those observed in column A after the dissolution stage 207

9 Appendix B6 Column Column B continued Column C Major Zn Ca, arsenates Fe Habit and morphology coalescences of fine (<1 μm) acicular pincushions (+Ca, ); flow-like agglomerations, spheroids and rosettes (); large bladed (), prismatic ( +/- Ca) and acicular crystals (-Ca) (up to 100 μm x 8 μm) bladed (Zn) and tabular (Zn-Ca) crystals; flow-like agglomerations of acicular crystals (Zn-); some tabular crystals show evidence of corrosion fine-grained granular agglomerations euhedral rosettes (, Ca, Fe); botryoidal agglomerates (), prisms, platelets, coverings (); dustings of fine (<1 μm) crystals (Fe-As) to flaky welldeveloped thick (~3 μm) coating with desiccation cracks Chemistry +Ca ; - Zn+Ca, Ca, Ca (gypsum),, Fe, Zn ; Fe-arsenate (scorodite?) Fe-K+-Zn- (As) Abundance acicular cover 100 % of galena surfaces; large crystals cover up to 10 % of coated galena; spheroids and acicular crystals rare isolated, usually associated with sphalerite rare on clays and Fe oxides only and common and well-coated grains; other rare coating on ~99 % of chalcopyrite and stannite (thick), 90 % arsenopyrite (thin) surfaces 208

10 Appendix B6 Column Column C continued Column D Major Zn K Fe Habit and morphology spherical rosettes up to 30 μm diameter, often coalesced into a coating of radial splays (-Ca-K); flowlike coatings and tabular crystals (-Zn) coating of fine acicular pincushions radial flow-like agglomerations of very fine-grained (100 nm x 10 nm) crystals (Zn-K); scattered large (150 μm x 30 μm) tabular crystals, rosettes (Zn+K); blocky prisms (40 μm x 20 μm) and acicular pincushions (Zn- Ca); some tabular and blocky crystals show evidence of corrosion platy irregular coating euhedral rosettes, dendrites and botryoidal agglomerates (); prismatic crystals (Zn) to flaky welldeveloped thick (~3 μm) coating with desiccation cracks Chemistry -Ca- K+(Fe-S) ; -Zn +Ca Zn ; Zn-K ; Zn-Ca K-(), Zn Fe-K+Ca Abundance heterogeneous coating 100% of some grains, abundant on coated chalcopyrite, scattered on other ; -Zn on well-coated grains only acicular cover 100 % of galena surfaces cover ~50 % of sphalerite surfaces, always sphalerite rare coating on tetrahedrite common and well-coated grains, Zn rare coating on ~99 % of chalcopyrite and stannite (thin), 50 % arsenopyrite (thin) surfaces 209

11 Appendix B6 Column Major Habit and morphology Chemistry Abundance s identical in chemistry and morphology to that observed after Ca(OH) 2 addition except significant Fe was often incorporated; coalesced rosette coats occasionally graded into sulphate coats Zn coating of fine acicular pincushions; larger prismatic (40 μm x 5 μm) crystals; botryoids; amygdales acicular splays (200 μm x 3 μm) and large bladed crystals (300 μm x 50 μm) (Zn); bean-shaped platelets (Zn-Ca) euhedral rosettes; fine-grained coatings; botryoids and fibrous (), acicular (-Fe) and prismatic (Ca) crystals Zn ; Zn-Ca, -Fe and Ca acicular cover 99 % of galena surfaces; large crystals on ~10 % of galena and adjacent minerals including anglesite heterogeneous development, common on wellcoated grains extensively developed on well-coated grains, other rare 210

12 Appendix B6 Additional SEM micrographs, experiment 2 Detail of coalescence of -K rosettes, column A, post-coating stage, pre-ca(oh) 2 addition. Large prismatic Zn-K crystals precipitated on otherwise uncoated sphalerite, column A, post-coating stage, pre-ca(oh) 2 addition. Scaly coating of on galena, column D, post-coating stage, pre-ca(oh) 2 addition. 211

13 Appendix B6 Tabular crystals covered by calescence of -Ca-K rosettes, column B post-dissolution stage. Granular to botyroidal s precipitated on galena, column D postdissolution stage. sulphate rosettes, column D post-dissolution stage. 212

14 Appendix B7 Appendix B7 SEM observations, experiment 3 Coating stage Column Column A Major Mn Fe Habit and morphology generally thick (>3 μm) coatings (Fe or ); of flaky, globular, granular and finegrained rosette () aggregates, all usually with desiccation cracks. spherical rosettes up to 100 μm diameter, occasionally coalesced into a covering of radial splays; coating with desiccation cracks; granular () thick (~10 μm) coating with desiccation cracks, usually covered in turn by granular Mn large (100 μm x 30 μm) tabular and acicular radial splays and isolated crystals Chemistry Mn-K+Ca,, Fe,, S, Zn, related to substrate, eg Mn-K- on galena, Mn- K-Fe on chalcopyrite -K+Ca ; Fe-K +Ca-K Abundance coating on >99% chalcopyrite, galena, stannite, >75 % sphalerite, >50 % tetrahedrite; coatings only observed on chalcopyrite and galena; arsenopyrite and pyrite uncoated rosettes heterogeneous, cover 90 % of some coated grains, absent on other minerals; rare coating rare coating on chalcopyrite rare scattered on coated galena 213

15 Column Column A continued Column B Major Habit and morphology sulphate hexagonal rosettes (10 μm diameter) and prismatic crystals Mn K-Ca Column C Chemistry sulphate Abundance Appendix B7 sulphate rosettes coalescences of rosettes cover <5% of grains; prisms rare chemistry, morphology and abundance of coatings generally identical to those in column A except Mn-K-Fe coats more abundant and globular/granular/rosette less abundant; tetrahedrite less well-coated; globular Mn-K often on quartz and clays demonstrating its precipitate nature chemistry, morphology and abundance of coatings generally identical to those in column A except rosettes often contain significant Mn, rare coatings also contain K and occasional rosettes are pure fine-grained (0.5 μm x 5 μm) acicular pincushions (- Ca); granular (- Ca); bi-pyramidal crystal (); euhedral booklets () granular ; coating +Ca K-Ca+S pincushions cover ~5 % of coated galena surfaces; other scattered rare coats and on tetrahedrite, chalcopyrite, clays and quartz identical to those observed in column A; very rare -Al- and Fe-Zn- also observed spherical rosettes up to 10 μm diameter often coalesced into a coating of radial splays -Ca-K+(S, Fe) heterogeneous development, cover 100 % of some grains, chalcopyrite or sulphate substrates 214

16 Appendix B7 Column Column C continued Column E Major Fe Ca Mn Habit and morphology coating (-Ca- K); acicular pincushions (+Ca); large (100 μm x 5 μm) acicular crystals (-Ca); radial splays (-K); rosettes(-ca-k) coating with desiccation cracks granular and globular ; coats with desiccation cracks rosettes, fibres, dendrites (); prisms (K-Ca) generally thick (>5 μm) coatings of granular (Mnrich), (Fe-rich), rosette (-rich) aggregates often with desiccation cracks; coat often covered by granular or rosette phase; granular at top of column cement grains together forming induration 3 cm thick Chemistry ; +Ca-K (Zn) ; Fe-K- Ca+K, K-Ca Mn-K-Ca+Fe,,, (Zn, As), metal related to substrate Abundance pincushions cover ~75 % of galena surfaces; other common on coated galena, rare on other minerals thin coating on <50 % of chalcopyrite scattered and coats covering <10 % of chalcopyrite, tetrahedrite, other, clays and quartz scattered, extensive on well-coated grains covering ~5 % of surfaces coating on ~99 % chalcopyrite, galena, >50 % sphalerite; pyrite uncoated, tetrahedrite and arsenopyrite not observed possibly obscured by s; on all including quartz 215

17 Appendix B7 Column Column E continued Column F Major Ca Habit and morphology spherical rosettes up to 100 μm diameter, often coalesced into a coating of radial splays acicular pincushions (); granular (- Ca) granular ; large (100 μm x 50 μm) euhedral prisms and radial splays rosettes, dendrites(); prisms (Ca) Chemistry -Ca K+ S ; -Ca Ca+K Ca, Abundance rosettes coat 50 % of some grains, preferentially grains with welldeveloped granular and coatings scattered on coated galena scattered on all, prisms and splays often relict Trifos granules scattered preferentially on well-coated grains Mn identical in morphology and chemistry to the observed in column E except richer in Ca and significant Al, S and Si often incorporated into coatings; and rosette forms less common and granular coatings more abundant though often only thin dustings on grains; induration at top of column thinner (~1 cm) and less well-developed Ca identical to the observed in column E identical to the observed in column E though more common, cover <1 % of grains; large euhedral prisms cement some grains together in the induration at the top of the column rosettes sulphate heterogeneously scattered covering up to 10 % of well-coated grains 216

18 Appendix B7 Column Major Habit and morphology Chemistry Abundance Column G Ca thin (<1 μm) granular to aggregates often with desiccation cracks; granular at top of column cemented together grains forming thin (1 cm) fragile Ca+, Fe, Al, S,, Cl (As, Zn), related to substrate; Ca heterogeneous covering >80 % chalcopyrite (Ca- Fe-Al), ~50 % galena (Ca-) and arsenopyrite (Ca-Fe-As), ~40 % tetrahedrite (Ca--Fe); sphalerite and bournonite uncoated induration spherical rosettes and botryoids (Fe, Cl) up to 70 μm in diameter, usually -Ca+Fe, Cl heterogeneous development, cover 80 % of some grains coalesced into coverings of radial splays rosettes sulphate scattered usually rosette coalescences 217

19 Appendix B7 Dissolution stage Column Major Column A Mn Column B Mn Habit and Chemistry Abundance morphology identical in morphology and chemistry to those observed in column A post-coating stage material except for presence of scattered prismatic Mn+Zn crystals and radial splays; flaky, granular and globular less abundant; coatings appear more abundant and observed heterogeneously on all sulphides (including tetrahedrite, pyrite, sphalerite and arsenopyrite); often observed on quartz and clays spherical rosettes -Mn+Caalways coalesced K, Fe, (S, Cl) into coatings of radial splays, more Mn more granular; rare evidence of corrosion coalesced finegrained (<1 μm) acicular pincushions; euhedral (25 μm x 5 μm) prisms heterogeneous, extensive where present (covers ~90 % of grain); no scattered rare on or adjacent to coated galena identical to observed in column A postcoating stage material except no prismatic crystals were observed identical in morphology and chemistry to those observed in column B post-coating stage material except for presence of scattered euhedral radial splays of Mn+Ca and rare Mn-Zn prisms; globular/granular less abundant; coats observed on sphalerite, arsenopyrite and pyrite; Fe-rich coats rare identical in morphology, chemistry and abundance to those observed in column B post-coating stage material fine-grained (0.5 μm x 5 μm) acicular pincushions -Ca cover ~1 % of coated galena surfaces 218

20 Column Column B continued Column C Major Habit and morphology rosettes up to 50 μm diameter(); fine-grained (2 μm x 0.2 μm) acicular pincushions (K- Mn) Zn Fe Ca spherical rosettes up to 70 μm diameter often coalesced into a coating of radial splays acicular pincushions; tabular crystals; radial splays; globular agglomerates; botryoids; beanshaped crystals rosettes up to 50 μm diameter; large (50 μm x 10 μm) prisms coating with desiccation cracks; granular and globular granular rosettes, radial splays (+Ca, Zn); globular agglomerates (Fe); subhedral prisms and (+) Chemistry and K-Mn -Ca- (K)+Zn, S +Ca, K, Zn, Zn-Ca ; Zn Fe-K- ; Fe-K-Ca Ca+K +Ca,Zn; Fe; +, Abundance Appendix B7 rosettes coalescences of rosettes cover <5% of grains; pincushions rare heterogeneous, extensive where observed, sulphate and occasionally chalcopyrite substrates pincushions cover >90 % of galena surfaces, other common on galena, scattered on sphalerite (Znrich only) rare sphalerite thin coating on ~25 % of chalcopyrite surfaces; scattered on chalcopyrite and tetrahedrite rare on all minerals and common on well-coated grains; Fe rare 219

21 Appendix B7 Column Major Column E Mn Column F Ca Mn Ca Habit and morphology Chemistry Abundance identical to observed in column E postcoating stage except richer in Ca and more heterogeneous; chalcopyrite usually well-coated, ~10 % of grains completely uncoated; galena 99 % coated; tetrahedrite ~30 % coated; arsenopyrite not observed; induration persisted through dissolution stage spherical rosettes -Ca+Mn extensive where of ~10 μm observed, cover diameter, often 50 % of some coalesced into a grains; coating of radial form splays; Mn-rich preferential rosettes more substrate, granular occasionally on acicular pincushions granular rosettes and dendrites (); prisms and fibres (Ca); -(Ca-Mn) Ca+Mn, Ca quartz scattered on coated galena scattered on all, appears more abundant than in columns post-coating stage scattered preferentially on well-coated grains; Ca more abundant than in coated columns and often relict Trifos granules identical to observed in column F postcoating stage; tetrahedrite also ~20 % coated; coatings appear abundant and granular less abundant identical to observed in column E postdissolution stage except often significant S incorporated identical to observed in column F postcoating stage except granular more abundant 220

22 Column Column F continued Column G Major Ca Appendix B7 Habit and morphology Chemistry Abundance identical to observed in column E postdissolution stage except or the presence of botryoidal and scattered radial splays of prismatic (7 μm x 2 μm) Ca identical in morphology and chemistry to observed in column G post-coating stage except for presence of radial splays of large (200 μm x 50 μm) prisms; phase less abundant; granular not observed on tetrahedrite; induration appeared degraded granular -Ca+S, usually extensive agglomerates Fe, (Cl, Al) where observed (Ca-S rich) and associated grading to with substrate of euhedral rosettes sulphate, (-rich), usually rarely forming precipitated on coalesced coating quartz rosettes, botryoids (); prismatic (7 μm x 2 μm) radial splays (Ca), Ca scattered ; abundant -Ca s; Ca commonly precipitated on quartz 221

23 Appendix B7 Additional SEM micrographs, experiment 3 Coating of Mn-K- on galena showing extensive desiccation cracks, column A post-coating stage. Spherical rosettes of - Ca-K precipitated on Mn-K-- coating, column A post-coating stage. Coating of Mn- Ca-K-Fe with extensive desiccation cracks covered by of Mn-Ca-K, column F postcoating stage. 222

24 Appendix B7 Botryoidal coalescence of -Ca-(Cl) rosettes precipitated on quartz and chalcopyrite. Spherical Ca possibly a partially dissolved remnant fertiliser granule, column G postcoating stage. Prismatic Mn-Zn crystals precipitated on Mn-K coating with occasional desiccation cracks, column A postdissolution stage. Globular to Mn- coating on galena, column A postdissolution stage. 223

25 Appendix B7 Granular Mn-Fe-Ca-(As) coating which becomes more with increasing Fe content, column E post-coating stage. sulphate rosettes precipitated on coalesced -Ca-K rosettes which are precipitated on prismatic Ca crystals and -Ca-K-Mn coating, column E postcoating stage. Bean-shaped -Zn crystals precipitated on acicular pincushions, column C post-dissolution stage. 224

26 Appendix B7 Botryoidal -Zn- on quartz, column C postdissolution stage. Granular K-Ca-Mn which forms the induration cementing grains together at the top of columns E and F (column E post-dissolution stage). Detail of -Mn-K-Ca coalescence showing desiccation cracks, column B postdissolution stage. 225

27 Appendix B8 Appendix B8 Phosphate coating and precipitate phase characterisation Representative EDS traces of common formed in the coated columns X-axis in kev. Fe-K-Ca-(?) coating on chalcopyrite, experiment 1 post-coating stage. Similar to material shown in Fig 3.4a,b,d. -Ca, column D, experiment 1 post-coating stage. 226

28 Appendix B8 Flow-like Zn-K, column C, experiment 1. Shown in Fig. 3.4b and appendix B5 Coalescence of -K rosettes, column A, experiment 2 pre-ca(oh) 2 addition. Note absence of Ca. Shown in Fig. 3.10b 227

29 Appendix B8 Globular Mn-K- (Ca-) coating, column A, experiment 3. Similar to material shown in Fig 3.16a. Granular precipitate of Ca-Fe--(Si-Al-S), column G, experiment 3. Similar to material shown in Fig. 3.16c. 228

30 Appendix B8 GADDS traces of selected Lin (Counts) Quartz d - Scale Potassium Zinc Phosphate - KZnPO4 Lin (Counts) d - Scale Lead Phosphate Hydroxide - 5 (PO 4 ) 3 OH Lead Hydrogen Phosphate - HPO Note: GADDS analyses were performed on only two or three samples. As the technique only reads the surface of the sample crystal not all diffraction peaks may show on each trace (A. Chappell pers comm 2002). This may explain the apparent poor fit for the lead hydroxide in the above trace. The listed above represent the best fit for any phase containing the correct chemistry (known through SEM-EDS). 229

31 Appendix B9 Appendix B9 Phosphate fertiliser dissolution experiment and characterisation Dissolution experiment methodology The aim of the dissolution experiment was to determine the chemistry of any impurities released into solution by the dissolution of the fertilisers. Sufficient fertiliser was immersed into 1 litre of distilled water to ensure saturation of the solution was attained. Thus, 500 g of MKP and 100 g of Trifos were each immersed into a beaker containing 1 litre of distilled water which was sealed using plastic food wrap. The beakers were kept at room temperature (25 o C) for 14 days. 100 ml of solution was then decanted from each beaker and submitted to the AAC, JCU for analysis by ICP-MS. The results give an estimation of the total amount of elemental release through fertiliser dissolution during the coating stage of experiment 3. Dissolution experiment ICP-MS results MKP Trifos Ag μg/l < Al mg/l As μg/l Ca mg/l Cd μg/l < μg/l Fe mg/l Hg μg/l <0.50 <0.50 K mg/l Mg mg/l Mn μg/l Na mg/l P mg/l μg/l <0.05 SO 2-4 mg/l Sb μg/l Si mg/l Zn μg/l

32 Appendix B9 Trifos fertiliser XRD trace Lin (Counts) d - Scale Calcium Hydrogen Phosphate Hydrate - Ca(H 2 PO 4 ) 2 H 2 O Calcium Ammonium Hydrogen Phosphate - CaNH 4 HP 2 O 7 Calcium Hydrogen Phosphate Hydrate - Ca(HPO 3 H) 2 (H 2 O) Note: The chemical with the peak closest to that on the trace is the same as the major ingredient listed in the fertiliser by the manufacturer Ca(H 2 PO 4 ) 2 H 2 O. There has possibly been a shift in the peak trace or the fertiliser chemicals have a slightly different crystallography to the chemical used to create the standard, explaining the poor fit of the XRD trace. 231