PEMPROSESAN FIZIKAL MINERAL

1. PUSAT PENGAJIAN KEJURUTERAAN BAHAN DAN SUMBER MINERAL EBS 322/3 PEMPROSESAN FIZIKAL MINERAL Prof. madya Dr. Khairun Azizi Mohd Azizli Dr. Hashim Hussin

2. KOMPONEN KURSUS Asas penilaian 1. Kerja Kursus 30% Ujian (l dan ll) 15% Kuiz 5% Tugasan 10% 2. Peperiksaan 70% Jumlah 100%

3. BUKU RUJUKAN • B.A Wills, “Mineral Processing Technology: An Introduction To Practical Aspect of Ore Recovery”, Pergamon Press. • Hayes,P. “Process selection In Extractive Metallurgy”, Hayes Publication • Kelly and Spottiswood, “Introduction To Mineral Processing”, Willey. • Weiss, “Handbook of Mineral Processing”, SME Publication. • A.J.Lynch, “Developments In Mineral Processing: Mineral Crushing and Grinding Circuits”, Elsevier.

4. PENGENALAN • Definasi pemprosesan mineral • Kelebihan yang diperolehi daripada pemprosesan mineral • Operasi utama dalam pemprosesan mineral • Kaedah-kaedah pemprosesan fizikal

5. Kawasan perlombongan kuprum di sabah

6. Peta kawasan perlombongan MAMUT Sdn. Bhd

7. OBEKTIF KURSUS Diakhir kursus ini pelajar dapat merekabentuk helaian aliran proses (process flowsheet design) bagi suatu loji pemprosesan mineral termasuk loji komunisi (dimana perlu) dan pensaizan yang sesuai untuk sesuatu tujuan. • Mengetahui tujuan proses pemprosesan fizikal mineral (pengkonsentratan) di dalam sesuatu industri yang berkaitan dengan mineral. • Memperkenalkan konsep asas dalam proses pemprosesan mineral.

8. Mengetahui tentang teknologi dan jenis serta ciri-ciri mesin pengkonsentratan di pasaran. • Kriteria pemilihan proses pengkonsentratan serta peralatan lain untuk sesuatu mendapan mineral. • Mengetahui konsep pengiraan tertentu yang perlu dibuat sebelum merekabentuk carta-aliran sesuatu loji pemprosesan mineral. • Merekabentuk helaian-aliran proses bagi loji pemprosesan mineral yang sesuai untuk sesuatu mendapan mineral.

9. KEPUTUSAN YANG PERLU DIBUAT SEBELUM SESEORANG JURUTERA MEREKABENTUK HELAIAN ALIRAN PROSES BAGI SATU LOJI PEMPROSESAN MINERAL • Soalan Pertama : Produk 1 Produk 2 Bahan Mula Produk 3 Produk....N Produk yang mana ?

10. PROSES YANG MANA SATU ? Laluan A Bahan Mula Produk Laluan B Laluan C Bagaimana untuk menghasilkan produk ?

11. Jawapan kepada kedua2 persoalan diatas adalah faktor ekonomikseperti: • Persekitaran • Sosio-politik • Teknikal • Pemasaran • Organisasi • Di dalam analisis akhir perlombongan dan pemprosesan mineral, objektif utama yang dititik beratkan adalah menghasilkan produk yang boleh dipasarkan pada harga yang boleh bersaing diperingkat antarabangsa atau pasaran tertutup.contoh produk adalah seperti: • Konsentrat mineral • Kompoun logam • Logam • Nilai seton produk meningkat dengan ketulenan dan memerlukan lebih aktiviti pemprosesan hiliran. • Dalam pemprosesan mineral, produk yang biasa dihasilkan adalah konsentrat mineral yang kaya dengan mineral berharga.

12. EXAMPLE 1 Coal consists of organic matter (95%C,3%H,plus O,N,S,) mixed with fine grains of clay and coarse bands of clay and shale. Dilution also results from roof and floor removed during mining. Consider the Tarong plant, where the coal is typically mined as 60% organic matter and 40% mineral matter. The objective is to produce a saleable product to adjacent power station with the specifications of a maximum of 28% ash and 14% moisture. Basis : note that coal can be considered as a binary mixture of a low ash coal(density 1.25) and high ash shale (density 2.7). Therefore the density differences between the required coal-rich particles and undesirable high ash particles can be utilised

13.  Process • Crush to ,75mm in the Bradford Breaker to separate coarse bands of shale – also reject some high ash oversize material • Classify into different size fractions (-75 + 13mm:-13mm) and treat each size in a jig optimised for that particular size fraction • Retreat the fines (<2mm) in coal washing spirals Note that this is different form a typical export coal plant which would treat coarser particles (50mm x 0.5mm) in dense meduim cyclones and the finer (<0.5mm) material by flotation. In these plants the final product typically contains only 8% mineral matter (the finer grains of intrinsic clay), and is sold as a high grade coking coal.

14. When assessing a new reserve, fundamental questions such as what product to make have to be answered. For example, coking coal attracts a higher price, but has to be produced to tighter specifications often at a lower yield and in a flatter market. Steaming coal has a lower price, but easier specifications and a higher yield and the market is firmer. But the market is changing – what will be the impact of PCI coal, and coal-water mixtures? Generally the mineralogy of the resources dictates the range of available options, but tchnology changes with tine and yesterday unusable resources may be attractive today

15. EXAMPLE 2 Copper occurs primarily as the mineral chalcopyrite : 34.7% Cu in CuFeS2. The mineral typically constitutes 0.5 to 4.0% of the host rock (0.2-14% Cu) and the remainder is silica, pyrite (FeS2), dolomite, etc. The mineral grains are typically about 400 µm diameter.  Process • Crush and grind all rock to < 100 µm: most grains are liberated, some with adhering gangue (complex pr binary particles). • Flotation separates chalcopyrite particles from the gangue : some misplaced gangue (pyrite,silica,etc) report to the concentrate. • Procudes a concentrate of 80% chalcopyrite (~28%Cu) which is economical to process to copper metal in the smelter.

16. EXAMPLE 3 Titanium from ilmenite the raw materials are beach sands which typically consist of 98% quartz and 2% heavy mineral (ilmenite FeO.TiO2, rutile TiO2, zircon ZrSiO4, and monazite).  Process • Wet gravity concentration to produce a HMC (heavy mineral concentration. • Drying followed by magnetic and electrostatic separation and further gravity concentration to produce individual minerals products (including ilmenite at <$100/tonne. • SR (synthetic rutile) production by roasting and acid leaching of ilmenite to remove FeO) produces SR worth $ 350/tonne. • Fine pure TiO2, used a as a paint pigment and worth than $1000/tonne, is produced by a chloridizing fluidized bed roast • Reduction smelting with magnesium produces titanium metal worth more than $4000/tonne.

17. KELEBIHAN YANG DIPEROLEHI DARIPADA PEMPROSESAN MINERAL • Penjimatan dalam proses pengangkutan • Pengurangan kehilangan logam dalam ‘slag’ atau ‘leaching residue’ • Pengurangan yang besar dalam pembayaran dan perawatan seperti peleburan. • Jika kaedah pemprosesan cekap dan murah,membolehkan kaedah perlombongan yang kos-rendah dan tanan tinggi untuk mendapan bijih yang bergred lebih rendah. • Membolehkan merawat bijih yang mungkin tidak boleh diproses kerana kaedah lain terlalu mahal.

18. PENGKELASAN BIJIH MENGIKUT SIFAT (NATURE) YANG BERHARGA. • Bijih asli (native) - logam hadir dalam bentuk asas (elementary) • Bijih sulfida – logam hadir dalam bentuk sulfida • Bijih oksida atau bentuk terhidrat – logam hadir dalam bentuk oksida, sulfat, silikat, karbonat • Bijih kompleks – mengandungi lebih daripada mineral berharga.

19. UNTUK MEMBOLEHKAN PEMILIHAN CARA PEMPROSESAN YANG PALING SESUAI, BEBERAPA CIRI PENTING PERLU DIPERTIMBANGKAN • Fasa mineral yang hadir dan komposisinya • Jumlah setiap fasa mineral yang hadir. • Saiz dan bentuk butiran mineral. • Sifat fizikal dan kimia mineral-mineral di dalam bijih. • Variasi ciri-ciri mineral tersebut didalam bijih dan mendapan bijih. • Kos yang diperlukan untuk mengeluarkan bijih daripada mendapan bijih iaitu perlombongan.

20. CONTOH-CONTOH MENDAPAN MINERAL DALAM GRED YANG BERBEZA

21. PEMPROSESAN MINERAL APAKAH YANG DIMAKSUDKAN DENGAN PEMPROSESAN MINERAL ? • Pengkonsentratan atau penumpukan mineral atau mineral-mineral yang dikehendaki (mineral berharga) secara kaedah fizikal. • Tidak menukar sifat fizikal atau kimia, ia hanya menukarkan menjadi konsentrat yang boleh dijual. Proses yang terlibat adalah: • Membebaskan mineral berharga daripada batuan sisa. • Memisahkan mineral ekonomik daripada mineral sisa. • Membuang hampas dengan kaedah yang tidak mencemar alam sekitar. • Metalurgi pengekstrakan (pirometalurgi, hidrometalurgi, elektrometalurgi) melibatkan perawatan kimia mineral untuk menghasilkan logam tulen secara komersil.

22. TAKRIFAN • Mineral suatu bahan homogenos yang wujud secara semula jadi dan mempunyai komposisi dan struktur kristal yang nyata. • Bijih satu mineral yang boleh dieksploitasikan sebagai satu punca bahan tertentu. • Mendapan bijih satu penumpukan yang setempat yang cukup besar dan boleh dieksploitasikan secara ekonomik. • Sisa batuan yang tidak mempunyai nilai ekonomik. • Konsentrat satu komoditi yang boleh dijual dengan peningkatan kandungan mineral berharga. • Hampas bahan yang tertinggal selepas konsentrat dikeluarkan.

23. OPERASI UTAMA DALAM PEMPROSESAN MINERAL PEMBEBASAN MINERAL BERHARGA PENGKONSENTRATAN MINERAL

24. Mineral Liberation Jaw Crushing Rod Milling Total Liberation Ball Milling Pengurangan saiz partikel dan pembebasan mineral Partial Liberation

25. Produk yang dihasilkan semasa proses kominusi dalam keadaan sebenarnya • Consider the particle shown,which will produce the daughter products shown, along with gangue on grinding • Particle 1 will report to the concentrate, although the grade would be limited by amount of locked gangue • Particle 4 is tailings, representing a loss of values • Particles 2 and 3 could be midlings(possibly concentrate) although they require different degrees of grinding to achieve liberation.

26. PEMPROSESAN MINERAL BIJIH YANG DILOMBONG (ROM) PEMBEBASAN MINERAL PEMISAHAN MINERAL (PENGKONSENTRATAN) HAMPAS KONSENTRAT MIDLING (mengandungi mineral berharga) (mengandungi mineral sisa) Pembuangan hampas Pengendalian produk

27. Run – of – mine ore Comminution Separation Product handling Simple block flowsheet

28. Ore Crushers (+) Screens (-) Grinding (+) Classification (-) Separation Tailing Concentrate • Line flowsheet (+) indicates oversized materials returned for further treatment and (-) undersized material which is allowed to proceed to the next stage.

29. Feed Primary grind Pre – concentration Midlings Tailings Re – grind Separation Concentrate Midlings Tailings • Flowsheet for process utilising two stage separation

30. Ore from mine Crushing Grinding Sizing (classification) Flotation Galena concentrate Tailing Filter Tailing pond storage Dry concentrate to smelter • Schematic flowsheet

33. DUA KELAS UTAMA PENGKONSENTRATAN GRAVITI PEMISAH GRAVITI Pemisahan berlaku dalam air sebagai medium PEMISAH MEDIUM BERAT (HMS) Pemisahan yang berlaku dalam suatu cecair atau medium yang mempunyai ketumpatan intermediate diantara pecahan mineral berat dan ringan

34. PENGKONSENTRATAN GRAVITI Suatu proses dimana zarah-zarah (berbagai saiz, bentuk dan graviti tentu) boleh dipisahkan diantara suatu dengan yang lain dengan menggunakan daya gravit atau emparan Kelebihan • Mudah dioperasikan • Kos pengoperasian yang rendah • Tiada atau paling minima kesan pencemaran alam Merupakan kaedah paling utama untuk mendapatkan konsentrat besi, kasiterit dll.

35. Paling sesuai digunakan untuk • Bijih yang kaya dengan mineral berharga • Bijih yang menunjukkan pembebasan/ liberasi pada saiz yang kasar > 75 µm • Mendapan lanar seperti bijih timah lanar dan emas lanar di Malaysia • Pra – pengkonsentratan • Sebab-sebab ekonomi dimana situasi menunjukkan perbelanjaan yang rendah • Galian dimana proses pengapungan , pemisahan magnetik dll tidak berkesan • Bahan yang berisipadu besar dan/ atau bergred rendah

36. Kriteria pengkonsentratan “ concentration ratio” boleh digunakan untuk menganggar samaada pengkonsentratan graviti boleh digunakan untuk memisahkan suatu campuran mineral yang berbeza dari segi graviti tentu, dan juga anggaran julat saiz yang boleh dirawat Kriteria pengkonsentratan =Dh - Df (concentration criterion) Dl - Df • Dimana • Dh = graviti tentu mineral berat • Dl = graviti tentu mineral ringan • Df = graviti tentu media bendalir

38. PEMISAHAN GRAVITI / PENGKONSENTRATAN GRAVITI Penyediaan suapan – amat perlu bagi pemisahan secara graviti • pemisahan terbaik untuk suapan yang mempunyai julat ketumpatan yang terhad ; suapan yang mempunyai julat saiz yang kecil (narrow). Palingberkesan pada saiz yang kasar. Sensitif kepada kehadiran lendir – akan meningkatkan buburan, memberi kesan terhadap pemisahan dan mengurangkan kecekapan pemisahan Perlu ada cukup pembebasan dan mengelaskan bahan yang hendak dirawat kepada julat saiz yang diperlukan Penyahlendiran biasa dilakukan menggunakan hidrosiklon

39. GRAVITY SEPARATORS / GRAVITY CONCENTRATION There are two main classes of gravity concentrators: gravity separators , in which the separation is effected in water ; and dense medium separators, in which the separation is effected in a fluid or slurry with a density intermediate between the light and heavy fractions • Feed preparation is an essential part of gravity separation. • Classifiers work best on feeds with a restricted density range; gravity separators work best on feeds with a narrow size range. • Gravity separation is most efficient at larger sizes. • Apart from the need to effect liberation and sort the material to be treated into appropriate size ranges such separators are sensitive to slimes which increases the viscosity of the slurry in which the separation is being effected and hence decrease separation efficiency. • Desliming is usually performed by hydrocyclones.

40. In gravity separators the particles are held slightly apart sp that they can separate into layers of heavy and light particles. The major classes of gravity separator are classified according to how this dispersion is included. • Jigs apply a vertical oscillatory motion • Shaking concentrators (tables, panning) apply a horizontal motion. • In gravity flow concentrators a slurry flows down an inclined surface. Many different gravity separators have been designed a lot of which are obsolescent. This course will concentrate on those of current (and emerging) industry significance.

41. FILM CONCENTRATORS Concentration in a layer of liquid flowing down a inclined surface • Two types: • Deposits transport : particles may reside on the surface for a considerable time • Non deposit transport : the particle remains in suspension (pinched sluice, spiral) Deposits Devices Long, parallel sided washers, operated on a semibatch basis with the heavy mineral collecting on the bottom which may have cloth to hold the mineral and being removed while the feed is off. Historically used for gold and cassiterite little commercial significance today.

42. PINCHED SLUICES • Sluices are very old separating devices. An inclined launder about 1 metre long narrows from about 200 mm at the feed end to about 25 mm at the discharge • Pulp of between 50-65% solids enter gently and strafies as it descends,before being separated on discharge by adjustable splitters • Pinched Sluice

43. REICHERT CONES • An extension of the pinched sluice that achieve high capacities by having the pinching effect occurring as the slurry flows to the centre of a comical surface. • Cross section through Reichert cone concentrator system

44. Each unit consists of a number (typically four) of cones in a stack to provide roughing, scavenging and cleaning operations in one unit • Basically a sluice folded back on itself, increasing capacity and reducing sidewall effects. The problem with these devices are that they are sensitive to feed solids concentration. Typically feeds are 65% solids but even very small variations have a significant effect on separation efficiency. • It is necessary to be very careful in installing cones to ensure that the feed percent solids is carefully controlled. As a sedimentation device, the separating efficiency is critically dependent upon feed rate, percent solids and heavy mineral content. • Initially widely in the minerals sands and iron industries in Australia, cones now appear to be finding less favour.

45. SPIRALS • Spirals are widely used in coal and minerals sands, as the separation is relatively unaffected by percent solids in the range 20-40%. • As particles flow down the spiral they are stratified by centrifugal action and the differential settling rates of the particles in the complex water flows set up. • The denser particles ‘slump’ to the inside of the spiral being removed by intermediate cutters and discharge cutters; the lighter particles remain in the faster flowing, more turbulent transport zone. • Spirals are used to treat 0.15-2.0 mm coal; 25 spirals plants treat about 5% of Australian washed coal. In what has traditionally been regarded as a difficult to process size fraction. • Spirals are stable, low maintenance reliable device. • A further major applications is the concentration of the 1-10% heavy mineral from quartz in beach sands plants.

46. Spirals take a feed of 15 – 45% solids and as the pulp flows down the spiral, the coarse, heavy particles concentrate in a band along the miner side of the profile • There are two fluid flows on the spiral : primary flow which is the transport flow down the spiral; and the secondary flow , which is the radial flow which effects separation • A variety of profile types are used depending on the application. Capacities range from 1-5 tph per spiral; typical spirals have 5-6 turns.

47. Binaan sebuah pilin

48. Finer materials may be treated on a jig where the screen aperture is larger than the dense particles and a layer of ragging or coarse grained heavy minerals overlies the screen. • The evenly sized ragging is large enough to be relatively unaffected by the water movement. • Efficient separation requires more than one stage : a typical coal jig would have five to seven hutches. • Large jigs (up to 1000 tph) are used in iron and coal processing ; overseas, jigs are also used for cassitierite (SnO2), tungsten and gold. • Advantages • Cheap, low installation costs, efficient separator in the absence of significant near gravity material Disadvantages • Poor separation efficiency unless run well (experienced operators) inefficient separator for difficult separations.

49. If the feed is close sized (3-10 mm) then efficient separations can be made even over a narrow density range (flourite 3.2 vs quartz 2.7) • When the density range is large (coal 1.25 vs shale 2.6) good concentration is posibble over a wide size range – say 10-80mm) • Uses • Coal (coarse) • Iron ore (coarse) • Cassiterite , gold (fine) – good recoveries to 150 microns acceptable to 75 microns

50. Basis of separation : pulse water through a bed of materials; bed dilation, hindered settling and interstitial trickling result in stratification. • Short fast strokes : best for fine minerals (initial accelaration is independent of size) • Longer slower strokes : more control and better stratification, especially for larger particles. Therefore best to screen feed into different size ranges. • Hindered settling : upward water current can be adjusted to remove small light particles and facilitate settling of coarse heavies. • Consolidated trickling : the bed is compact the larger particles interlock and the finer particles move down under gravity. Significant in the separation of fine minerals.