《textbook of ore dressing》

CHAPTER Ⅰ.—GENERAL PRINCIPLES1

Definition and comparison with smelting1

Physical and chemical properties of minerals as applied to ore dressing2

Fundamental concepts5

CHAPTER Ⅱ.—PRELIMINARY BREAKING6

Blasting in the mine6

Calcining for friability6

Hand breaking6

Steam and drop hammers7

Rock breakers of the Blake type9

Dodge breakers and comparison with Blake11

Spindle or gyrating breakers11

Gates breaker12

Telsmith breaker14

Comparison of jaw and gyratory breakers17

CHAPTER Ⅲ.—INTERMEDIATE AND SECONDARY CRUSHING19

Reduction gyratory crushers19

Symons cone crusher19

Traylor reduction crusher22

Newhouse crusher22

Rolls; principle and purpose23

General construction24

Shells25

Feeders25

Springs25

Driving mechanism26

Width,diameter,and speed26

Space and angle of nip27

Closed circuit29

Quality of crushing29

Capacity31

Graded crushing32

Operating data and costs32

CHAPTER Ⅳ.—STEAM STAMPS33

Classification and purpose of stamps33

Steam stamps33

Foundations,anvil blocks,mortar,screen and frame33

Shoe,stamp shaft,and driving mechanism34

Floors,bins,and feeding arrangements35

Water used and capacities35

Discharge of copper nuggets36

Uses and quality of work36

Steeple-com-pound stamps37

CHAPTER Ⅴ.—GRAVITY STAMPS AND AMALGAMATION38

Principle of action38

Foundations40

Mortar blocks41

Frames42

Mortars42

Screens43

Camshaft44

Cams45

Stem,tappet,shoe,and die47

Feeders48

Finger bars,cam sticks,and overhead crab48

Nissen stamp48

Running of stamps49

Water used49

Size of feed49

Method of feeding49

Mercury fed49

Area of discharge49

Size of screen holes and percentage of opening49

Order of drop49

Height of discharge50

Number and height of drop50

Weight of stamp and energy of blow50

Power51

Operating data and costs51

Amalgamation52

Properties of mercury52

Amalgams52

Amalgamating devices53

Plates53

Treatment of plates54

Amalgamating new plates56

Dressing plates58

Cleaning plates59

Mercury traps61

Cleaning amalgam61

Cleanup barrels61

Cleanup pan63

Squeezing,retorting,and melting63

Care and purification of mercury64

Loss of mercury65

Loss of gold65

Amalgamation apart from stamp milling65

Status of gravity stamps65

CHAPTER Ⅵ.—FINE GRINDING67

Purpose67

General principles67

Classification and application68

Arras-tra68

Grinding pans69

Revolving mills69

Application69

Grinding media69

Tube mills71

Marcy mill73

Hardinge mill73

Rod mills73

Overflow discharge74

Grate discharge74

Feeders75

Electric ear75

Liners75

Operation of revolving mills75

Speed76

Size of feed and pulp density77

Closed and open circuits77

Stage grinding79

Differential grinding79

Batch grinding80

Sizes and capacities80

Ball mills with peripheral screens81

Hadsel mill82

Chili mill82

Huntington mill83

Raymond roller mill83

Swing-hammer pulverizer85

Torrey cyclone85

Jumbo mill86

CHAPTER Ⅶ.—LAWS OF CRUSHING87

Fundamentals87

Physical properties of mineral crushed87

Impact89

Abrading89

Distribution of sizes in a crushed product89

Products from homogeneous material90

Products from heterogeneous material91

Rittinger theory of work required92

Kick's law94

Practical application of laws of crushing95

CHAPTER Ⅷ.—PRELIMINARY WASHING AND HAND SORTING96

Preliminary washers96

Trough washer96

Long tom97

Log washers97

Turbo log washer99

Wash trommels99

Washing pans100

Hydraulic giants100

Jet washer100

Hand picking or sorting100

Picking tables or belts102

CHAPTER Ⅸ.—SIZING BY SCREENS104

Principles of screen sizing104

Sieve scale104

Limits of screening105

Efficiency and rate of screening105

Shape and arrangement of holes106

Per-centage of opening107

Thickness of plate or wire107

Difficulties of screening108

Feeding109

Classification of screens109

Grizzlies109

Rowand screen111

Ring grizzly111

Drop-bar grizzly112

Shaking screens or riddles112

Ferraris screen113

Gyrating screens114

Impact screen114

Vibrating screens114

Hummer screen115

Leahy screen117

Niagara screen118

Symons screen119

Allis-Chalmers screen119

Capacity of vibrating screens119

Revolving screens or trommels120

Feeding122

Sizes123

Slope123

Revolutions123

Material123

Power124

Capac-ity124

Operating data and costs125

Tandem and concentric trommels125

Callow traveling-belt screen125

CHAPTER Ⅹ.-CLASSIFYING AND SETTLING IN WATER128

Laws of classifying by settling in water128

Free settling128

Richards spitz-lutte130

Free-settling velocities130

Formulas130

Free-settling ratios136

Hindered-settling ratios136

Tubular classifier tests on hindered settling137

Full-teeter velocities of quartz and galena139

Free settling versus hindered settling141

Application to classifier design141

Extent of classifica-tion142

Added increment142

Definition and classification of classifiers143

Classifiers using rising currents of clear water144

Principles of action144

Free-settling classifiers145

Richards-Coggin145

Evans145

Richards deep-pocket classifier147

Calculations147

Richards annular vortex classifier152

Hydraulic gold traps154

Hindered-settling classifiers154

Richards154

Constriction-plate classifier154

Fahrenwald156

Richards pulsating classifier156

Operating data157

Classifiers not using rising currents of clear water157

Rittinger spitzkasten158

Allen cone159

Callow and Caldecott cones160

Dorr thickeners160

Dorr hydroseparator162

Operating data163

Mechanical classifiers163

Dorr rake classifier163

Dorr bowl classifier165

Federal Esperanza166

Akins168

Hardinge168

Operation of mechanical classifiers168

Classification and differential grinding170

Operat-ing data and costs170

CHAPTER ⅩⅠ—COARSE-SAND CONCENTRATING BY JIGS172

Principle,purpose,and definitions of jigs172

Movable-sieve hand jigs173

Continuous movable-sieve power jigs175

Hancock jig175

Fixed-sieve jigs176

Harz jigs176

Cooley jig180

Bendelari jig180

Woodbury jigging system181

Richards pulsator jig183

Pan-American jig186

Denver min-eral jig186

Details of jigs in general187

Frames and tanks187

Hutches187

Plungers and mechanism188

Accelerated mechanisms189

Hydraulic water190

Sieves190

Number of compartments191

Height of tailboard191

Feeding and bottom bed192

Removal of coarse concentrates192

Skimming192

Automatic discharges192

Removal of tailings194

Capacity and power194

Field of work194

Theory of jigging195

Pulsion; general principles195

Pulsion-jig tests on hindered settling195

Pulsion velocity196

Number of strokes196

Length of stroke197

Suction; general principles198

Tests on suction199

Conclusions201

Bring's tests202

Effect of jig bed204

Sizing before jigging204

Operating data and costs204

CHAPTER ⅩⅡFINE-SAND AND SLIME GRAVITY CONCENTRATION206

General principles206

Concentrators with separating surface stationary206

Riffles207

Cornish frames208

Canvas tables208

Corduroy tables208

Corduroy versus amalgamation209

Fixed,circular,convex slime table210

Theory of film sizing210

Concentrators with separating surface in motion211

Cradle or rocker211

Mechanical batea211

Jerking tables212

Wilfley table212

Foundation213

Head motion213

Frame,deck,and riffles214

Feed,capacity,power,and water217

Operating conditions217

Investigation of Wilfley table work218

Agitation ratio220

Butchart table221

Deister table222

Tabling in modern mills223

Operating data and costs223

Van-ners224

Frue vanner224

Belts226

Johnston vanner226

Comparison of side-shake and end-shake vanners226

Operation of vanners227

Capacity and power229

Principle of separation229

Field of vanners229

Johnson concentrator229

Revolving,circular,convex slime tables or round tables230

Anaconda round table231

CHAPTER ⅩⅢ.—FLOTATION232

Definition,principle and application232

History of development233

Theo-retical basis234

Froth formation235

Chemical treatment of minerals235

Formation of bubble-mineral complexes236

Contact angles236

Pulp pre-paration237

Particle size237

Pulp density237

Conditioning237

Reagent addition and feeders238

Special treatments239

General considera-tions240

Frothing agents and their action240

Collecting agents and their action242

Modifying agents245

pH and pulp-control reagents245

Depressing agents246

Activating agents247

Sulphidizing agents247

Dispersing agents,'deflocculators,and protective colloids248

Summary list of reagents249

Flotation machines251

Vortex type251

Minerals Separation standard and subaeration machines251

Fahrenwald (Denver subaeration)255

Operation and capacity256

Pneumatic machines256

Callow256

Mac-Intosh257

Air-jet type258

Southwestern air-lift258

Air supply259

Comparison of machines259

Flotation circuits260

Use of regrinding263

Unit cell263

Disposal of concentrates264

Flotation practice264

Sulphide copper ores265

Mixed copper ores266

Anaconda mill266

Miami mill268

Noranda mill271

Native copper ores275

Lead,zinc,and lead-zinc sulphide ores275

Balmat mill277

Gold and silver ores278

McIntyre-Porcupine mill280

Copper-lead sulphide ores282

Copper-zinc sulphide ores282

Copper-lead-zinc-iron sulphide ores283

Copper-nickel sulphide ores283

Molybdenum sulphide ores283

Metallic oxidized ores284

Nonmetallic ores and coal284

Agglomeration and tabling285

Present and future286

CHAPTER ⅩⅣ.—MISCELLANEOUS PROCESSES OF SEPARATION288

Magnetic separation and concentration288

Application288

Electromagnets289

Action of substances in magnetic field291

Preparation,dust,drying,and current291

Classification292

Primary-magnet type292

Cobbing magnets292

Magnetic pulleys293

Tramp iron293

Dry drum-type293

Grondal294

Dry belt-type294

Wetherill294

Ball-Norton296

Crockett wet-belt magnet298

Davis magnetic log washer298

Edison magnet298

Induction-magnet type298

Stearns298

Dings300

Johnson300

Roasting and calcining for magnetism300

Sulphides301

Oxides302

Carbonates302

Experiments302

Furnaces303

Electrostatic separation303

Pneumatic concentration305

Air-blast machines306

Mumford and Moodie306

Ray-mond306

Gayco307

Pape-Henneberg momentum separator309

Air jigs309

Hooper-Paddock309

Pneumatic tables310

Sutton,Steele and Steele310

Dry blanket311

Dry panning311

Comparison of dry and wet separations311

Adhesion; greased table312

Disintegrating and screening312

Decrepitation and screening312

Roasting for porosity312

Centrifugal separation313

Weathering313

Agglomeration and tabling313

Heavy-liquid and heavy-density processes314

Lessing,duPont,Wuensch,and Chance processes314

Air-sand process315

CHAPTER ⅩⅤ.—ACCESSORY APPARATUS316

Bins and receiving floors316

Samplers and sampling317

Automatic feeders322

Distributors325

Water regulators325

Conveyors326

Blaisdell sys-tem of ore handling328

Bucket elevators329

Sand wheels332

Centrifugal pumps332

Wilfley sand pump332

Diaphragm pumps332

Frenier spiral sand pump333

Launders336

Unwaterers339

Filters340

Oliver filter342

American343

Dorrco345

Genter346

Driers347

Dust collection and removal349

Removal of wood and chips350

Weighing350

CHAPTER ⅩⅥ.—MILL PRINCIPLES AND PROCESSES351

Summary of principles and unit processes351

Combinations353

Mill data and flow sheets354

Mill site and arrangement355

Hillside type; Alaska Juneau mill356

Flat-site plant; Southeast Missouri lead mill361

Gently sloping site; Copper Queen mill365

Flow sheets of copper concentrators371

Magna mill372

Calumet and Hecla mill375

Lead and zinc concentrators380

Bonne Terre mill381

Tri-State zinc-lead mills386

Eagle-Picher central mill388

Hecla mill394

Midvale mill398

Sullivan mill403

Precious-metal concentrators409

Homestake mill410

Montezuma-Apex mill412

Scrub Oak magnetite mill417

Nonmetallic plants420

Phosphate concentration421

International phosphate washer 92422

Pembroke phos-phate flotation mill422

CHAPTER ⅩⅦ.—GENERAL CONSIDERATIONS426

Mill location; general principles426

Flat and sloping sites427

Mill design and construction428

Process and flow sheet428

Size of mill and expected life430

Choice of equipment430

Power and its transmission432

Mill layout and arrangement434

Horizontal and vertical organization435

Con-struction of mill buildings436

Complete plant437

Heating,lighting,and ventilation438

Mill operation438

Continuity438

Repairs,maintenance,and lubrication439

Labor439

Water440

Storing and shipping concen-trates440

Disposal of tailings441

Records,testing,and control441

Eco-nomic factors443

Smelter schedules for calculating the value of copper, silver,lead,and zinc ores443

Accounts and reports451

Milling costs452

First or construction cost452

Overhead costs453

Operating costs454

Operat-ing-cost data456

Snap estimates456

Evaluation of results461

Metal-lurgical balance461

Recovery462

Concentrate grade463

Ratio of con-centration463

Extent of concentration463

Efficiency indices464

CHAPTER ⅩⅧ.—ORE EXAMINATION AND TESTING466

Scope and methods466

Sampling and assaying466

Crushing467

Sizing467

Screen tests468

Ro-tap sieving470

Elutriation470

Air elutria-tion471

Haultain Infrasizer472

Sedimentation472

Recording and plot-ting of sizing tests472

Calculations of average particle size474

Assay-size analyses476

Heavy-liquid tests476

Visual examinations476

Microscope477

Polished sections477

Briquettes477

Mineralogical analysis of bri-quettes478

Process testing478

Hand picking478

Jigging, vanning, and panning479

Tabling480

Haultain Superpanner481

Classifiers482

Magnets483

Davis magnetic tube tester484

Roasting for magnetism484

Amalgamation and stamp milling485

Flotation testing486

Preparation of sample486

Reagents487

pH measurement488

Machines and procedure488

Pilot-plant testing490

Locked-batch tests490

Tabulation and com-putation of results491

Distribution of middlings492

Comparison of labora-tory results with plant results493

Records and data494

Summary of testing procedure494

One variable at a time496

CHAPTER ⅩⅨ.—COAL DRESSING497

Problem, purpose, and advantages498

Impurities499

Methods500

Deg-radation500

Summary of operations; anthracite501

Bituminous502

Essential steps503

Breaking503

Rolls505

Needle crushers and pick breakers507

Hammer mills507

Pulverizers507

Bradford breaker507

Sizing and grading508

Screening510

Van Lear screening and picking tipple512

Hand picking513

Mechanical pickers513

Emery513

Pardee spiral514

Flat pickers515

Mechanical cleaning516

Wet versus dry meth-ods517

Sizes cleaned517

Heavy-density methods518

Chance518

Lessing, Conklin, deVooys, and Wuensch processes522

Ascending-current washers522

Hydrotator523

Menzies Hydroseparator524

Menzies Cone526

Launder washers; Rheolaveur process526

Jigs530

Wilmot-Simplex530

Elmore531

Link-Belt Simon-Carves533

Vissac535

Tables535

Flotation and the Trent process536

Pneumatic tables536

Pneumatic jigs; Stump Air-flow539

Air-sand process539

Float-and-sink tests540

Wash-ability curves543

Sizing tests545

Evaluating results546

Efficiency for-mulas546

Daily control tests549

Dewatering and drying549

Purposes549

Moisture in coal549

Natural drainage550

Centrifugal dewatering550

Thickening and filtering552

Heat drying553

Recovery of fines; water clarification and circulation553

Moving coal in the plant554

Breakage and degradation554

Chutes554

Conveyors555

Elevators557

Feeders557

Pyrite recovery557

Dedusting557

Chemical and oil treatment558

Plant practice559

Delta jig plant559

United Pocahontas wet-jig and dry-table plant561

Fidelity Rheolaveur plant562

Kehoe-Berge Chance anthracite breaker564

Costs, power, water, and labor566

APPENDIX569

Equivalents of weights and measures569

Atomic weights570

Specific gravi-ties of minerals and common metals571

Weight of broken ore572

Mill formulas and calculations573

Standard gages for brass and iron wire576

Tyler standard testing sieves576

Diameters and areas of circles577

Quartz diameters and velocities for computing classifiers580

INDEX585