How does AFS grain fineness number affect foundry sand?

The American Foundry Society (AFS) grain fineness number measures the average grain size. Lower AFS numbers (45-55) represent coarser sand providing high gas permeability for heavy iron and steel castings, while higher AFS numbers (65-80) provide smooth surface finish for aluminum and precision brass castings.

Where are the highest-grade silica sand deposits in Pakistan?

The Datta Formation sandstones around Mianwali in Punjab and Pezu in Khyber Pakhtunkhwa produce Pakistan's highest-grade silica sands for glass production, while the Dadu and Jamshoro deposits in Sindh supply extensive container glass and foundry operations.

Does Enigma Earth supply bagged dried silica sand?

Enigma Earth structures commercial supply contracts for both damp washed bulk sand and rotary-kiln dried, classified quartz sand packed in 1.5 MT big bags or 50 kg valve sacks, verified by accredited sieve and XRF certificates.

SILICA SAND • INDUSTRIAL MINERAL

Silica Sand Context & Buyer Requirements in Pakistan

Q: What makes silica sand suitable for glass manufacturing?

Glass manufacturing requires high chemical purity (typically SiO2 >= 98.5%) and critically low iron content (Fe2O3 < 0.04% for clear glass). Additionally, grain sizing must be tightly controlled between 106 and 600 microns, with zero refractory heavy mineral inclusions (such as chromite or zircon) that cause un-melted defects in glass containers.

Silica sand evaluation in Pakistan depends entirely on target application requirements—distinguishing between glass manufacturing, metal casting foundry sands, construction chemicals, and water filtration. Do not claim glass-grade or foundry-grade suitability without comprehensive grain sizing and trace iron (Fe2O3) assay testing.

Primary Application

Glass / Foundry Moulding / Mortars

Main Testing

Purity (SiO2 %) & Grain Size (AFS)

Product Form

Washed, Screened & Dried Fractions

Evidence Category

Official Production Evidence (P)

Representative industrial mineral material: Washed and classified quartz silica sand grains associated with Pakistan sedimentary deposits.

Representative material specimen. Occurrence does not constitute available inventory. Consignment verification required.

Mandatory Claim Boundary & Sourcing Notice: This page describes mineral/material evidence and buyer requirements. It does not represent current Enigma Earth inventory. Source, ownership, grade, quantity and availability must be verified for the specific enquiry.

GEOLOGICAL APPRAISAL

Mineralogy & Geological Occurrence

Pakistan hosts extensive sedimentary silica sand deposits derived from quartz-rich sandstones and friable quartzite formations. Crucial for domestic industrial manufacturing, the material provides the principal silica source for flat glass, container glass, ceramic glazes, sodium silicate synthesis, and metal casting foundries.

Geological Setting & Host Formations

Major deposits occur in the Mesozoic Datta Formation of the Salt Range and Surghar Range (Punjab and Khyber Pakhtunkhwa), where friable white sandstones yield high-silica quartz grains upon mechanical disaggregation. In southern Pakistan, extensive Tertiary sandstone horizons outcrop in Sindh (Dadu, Jamshoro, Thatta) and Tharparkar.

Key Mineralogy & Chemical Formula

Predominantly monocrystalline alpha-quartz (SiO2 >= 95% - 99%). Accessory mineral contaminants include heavy minerals (ilmenite, rutile, zircon, tourmaline), feldspars (orthoclase, plagioclase), clay minerals (kaolinite), and iron hydroxide grain coatings.

Formula: Silicon Dioxide (SiO2 / Quartz)

PAKISTAN EVIDENCE

Pakistan Evidence & Regional Context

Silica sand is extensively quarried and processed across Punjab, Sindh, and Khyber Pakhtunkhwa through licensed surface concessions, supplying national glass manufacturers, foundries, and chemical plants.

[P]Official Production Evidence

PunjabRegional Context

Mianwali (Datta, Chichali) & Salt Range Belts

Pakistan's premier commercial source for glass-grade silica sand, hosted in friable Jurassic sandstones; supported by mechanical washing and classifying plants.

Documented Regional Occurrence

SindhRegional Context

Dadu, Jamshoro (Thano Bula Khan, Meting) & Tharparkar

Tertiary sedimentary sandstone outcrops supplying container glass manufacturers and Karachi foundry and construction clusters.

Documented Regional Occurrence

Khyber PakhtunkhwaRegional Context

Pezu (Dera Ismail Khan) & Abbottabad Belts

Sandstone horizons yielding industrial silica sand for regional construction chemicals and ceramic industries.

Documented Regional Occurrence

Evidence Boundary: Raw unwashed sandstone contains variable clay, silt, and iron oxide film. Sourcing for high-clarity glass or precision casting requires multi-stage washing, scrubbing, magnetic separation, and hydro-cyclone classification.

PRODUCT ARCHITECTURE

Commercial Forms & Processing Stages

Commercial requirements must strictly differentiate between raw extraction, sorted grades, and processed products.

Glass-Grade Washed Silica Sand

High-purity, low-iron quartz sand subjected to attrition scrubbing, magnetic separation, and hydro-classification to achieve tight chemical and sizing specifications for glass furnaces.

Sub-angular grains: 100 to 600 microns (SiO2 >= 98.5% - 99.2%, Fe2O3 < 0.03% - 0.08%)

Foundry & Metal Casting Sand

Uniformly graded, sub-angular to rounded silica sand with controlled acid demand value (ADV) and high refractory thermal stability, used in resin-coated and green sand foundry molds.

Screened sand: AFS grain fineness number 45 to 70 (SiO2 >= 97.0%)

Construction Chemicals & Mortar Sand

Dried, dust-free quartz aggregate classified into narrow particle fractions for dry-mix mortars, tile adhesives, epoxy floor screeds, and grouts.

Graded sizes: 0.1 - 0.3 mm, 0.3 - 0.6 mm, 0.6 - 1.2 mm (Moisture < 0.1%)

Water Filtration Media Sand

Clean, acid-washed quartz sand meeting AWWA B100 standards for municipal and industrial water treatment filtration beds.

Effective size (ES) 0.45 - 0.55 mm; Uniformity coefficient (UC) < 1.4

TECHNICAL QUALIFICATION

Buyer Specification Requirements

Prospective buyers and project owners should specify the parameters below. Values represent typical industrial targets and do not imply universal Pakistani deposit compliance.

Chemical Composition & Trace Oxides

6 Parameters

Silicon Dioxide (SiO2)

Clear Glass: >= 99.0% - 99.5%; Container Glass: >= 98.0%; Foundry: >= 96.0% - 98.0%

XRF / gravimetric validation

Iron Oxide (Fe2O3)

Ultra-Clear Glass: < 0.020% (200 ppm); Container: < 0.040% - 0.080%; Colored Glass: < 0.15%

Primary coloring impurity controlling optical transmission

Alumina (Al2O3)

Typically 0.20% - 1.20%

Provides chemical durability to glass melt

Titanium Dioxide (TiO2)

Target <= 0.030% - 0.060% for flint glass

Coloring oxide

Calcium & Magnesium Oxides (CaO + MgO)

Typically < 0.20% - 0.50%

Controls fluxing balance

Loss on Ignition (LOI at 1000°C)

Target <= 0.20% - 0.40%

Indicates residual organic or carbonate gangue

Physical & Sizing Distribution

4 Parameters

Particle Size Distribution (Glass)

Retained on 600 µm (30 mesh): <= 0.5%; Passing 106 µm (140 mesh): <= 3.0% - 5.0%

Oversize causes un-melted stones; fines cause refractory carryover

Grain Fineness (AFS Number)

AFS 45 to 65 for steel/iron foundries; AFS 60 to 80 for non-ferrous

Tested according to AFS 1105-00-S

Grain Shape / Angularity

Sub-angular to rounded (Angularity coefficient 1.2 - 1.4)

Optimum for resin binder efficiency in molds

Free Moisture Content

Dried Sand: <= 0.10% - 0.20%; Damp washed sand: 3.0% - 6.0%

Rotary kiln dried for bagged products

Packaging & Logistics

3 Parameters

Packaging Formats

50 kg polypropylene bags; 1.0 MT - 1.5 MT big bags with bottom discharge; Bulk pneumatic tankers

Moisture-sealed packaging

Consignment Volume

Full truckloads 40 - 60 MT; Bulk vessel charters 5,000 - 25,000 MT

Direct rail or road delivery

Testing Standard

ASTM C144 / ASTM C1422 / BS EN 12904 (Water treatment)

Independent laboratory sieve and assay analysis

VERIFICATION PROTOCOL

Testing & Verification Requirements

Testing and quality verification must be conducted by an appropriate independent laboratory. Commercial transactions require representative sampling, assay, chemical analysis or gemological appraisal, and third-party inspection. Enigma Earth does not maintain a private testing monopoly.

Representative Sampling

Automatic cross-belt stream sampling or tube increment collection across bagged production runs according to ISO 11648-2 standards. Homogenized rotary sample splitting.

Standard Test Methods

ASTM C146 (Standard Test Methods for Chemical Analysis of Glass Sand)
ASTM C136 (Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates)
AFS 1105-00-S (AFS Grain Fineness Number Determination)
AWWA B100 (Granular Filter Materials Standard)

Laboratory Independence

Trace iron, titanium, and chromium must be quantified by high-precision ICP-OES or fused bead XRF to ensure compliance with glass-melting tolerances. Particle sizing requires certified calibration sieves.

QUALITY CRITERIA

Impurity Tolerances & Critical Penalty Factors

Commercial specifications require explicit thresholds for penalty elements, structural soundness, color uniformity, and treatment parameters.

Refractory Heavy Minerals (Chromite, Zircon, Andalusite)

Quality Parameter

Operational Impact: Do not melt in glass furnaces at standard temperatures; form insoluble solid inclusions ('stones') that cause bottle breakage

Tolerance: Strictly limited to zero grains > 250 µm in clear glass specifications

Excess Iron Oxide (Fe2O3 > 0.08%)

Quality Parameter

Operational Impact: Imparts an undesirable green or amber tint to flint glass containers and reduces solar panel glass transmission

Tolerance: High-clarity glass contracts reject sand above 0.040% Fe2O3

Excess Fine Dust (< 75 microns / 200 mesh)

Quality Parameter

Operational Impact: Causes severe dusting, filter clogging, and flux volatilization in furnace regenerators

Tolerance: Glass specifications strictly cap fines passing 106 µm to < 5%

Acid Demand Value (ADV > 5.0 ml in foundries)

Quality Parameter

Operational Impact: Neutralizes acidic chemical binders in furan and polyurethane no-bake foundry sand systems, causing weak mold curing

Tolerance: High-performance resin casting requires ADV < 3.0 ml

SUPPLY CHAIN INTEGRITY

Sourcing, Provenance & Preparation Logistics

Due diligence guidelines for legal chain of custody, packaging standards, and maritime export protocols.

Origin Verification & Licensing

Consignments require provincial transit challans from the Department of Mines & Minerals Punjab or Sindh, verifying legal extraction from permitted sandstone concessions.

Quarries operate under provincial mineral concession rules. Processing plants must comply with industrial water recycling standards and environmental dust mitigation regulations.

Provenance Caution: White appearance does not prove low iron content. High-iron feldspar grains can appear superficially white but ruin glass clarity upon melting. Comprehensive multi-element assay is essential.

Packaging & Maritime Transport

1.0 MT to 1.5 MT heavy-duty woven polypropylene bulk bags with polyethylene inner liners and discharge spouts
50 kg woven polypropylene valve bags packed on stretch-wrapped pallets
Bulk pneumatic bulk tankers for direct discharge into silo storage

Transport via multi-axle dump trucks to domestic glass manufacturing clusters, or containerized freight via Karachi Port / Port Qasim for export consignments.

Handling Caution: Inhalation of respirable crystalline silica (RCS) poses severe occupational silicosis hazards. Dry sand handling must utilize closed pneumatic transfer systems and certified dust extraction.

REGIONAL CONTEXT

Relevant Regional Context

Punjab

Primary silica sand mining district centered on Mianwali and the Salt Range Datta Formation.

Sindh

Extensive Tertiary sandstone deposits in Dadu, Jamshoro, and Tharparkar supplying southern industrial hubs.

Khyber Pakhtunkhwa

Sedimentary quartz sandstone formations in Pezu and Abbottabad.

ASSOCIATED COMMODITIES

Related Minerals & Materials

Iron Ore Barite Gypsum

TECHNICAL SUPPORT

Technical Support for Industrial Mineral Requirements

Enigma Earth provides technical due diligence, commercial facilitation, and exploration services to de-risk mineral procurement in Pakistan.

Mineral Trading & Material Supply

Processing supervision, particle size classification audit, and continuous industrial supply contracts.

Explore Service

Mineral Exploration & Grain Analysis

Sandstone core logging, grain roundness appraisal, heavy mineral separation, and silica resource modeling.

Explore Service

Mining Consultancy & Washing Plant Design

Hydro-cyclone washing circuit engineering, magnetic separation optimization, and environmental water reclamation.

Explore Service

MARKETPLACE & COMMERCIAL CHANNELS

Commercial Pathways for Silica Sand (Industrial Quartz Sand)

Whether you are an international buyer seeking verified mineral supply or a licensed Pakistani mine operator looking to qualify off-take.

OFF-TAKE INQUIRIES

Mineral Buyers Registry

Review documented off-take requirements from industrial and international buyers.

View Buyer Demands

MINE OPERATORS

Sell Your Mineral

Submit verifiable Silica Sand (Industrial Quartz Sand) parcels, stockpiles, or concessions for third-party qualification.

Supply Verification

PUBLIC NOTICES

Mining Tenders & Leases

Monitor provincial DGMM lease auctions, block bidding, and concession notices.

Browse Tenders

GEOLOGICAL CONTEXT

Pakistan Mining Regions

Explore provincial mineral directorates, logistics corridors, and geological belts across Pakistan.

View All Regions

INQUIRY SUBMISSION GUIDE

What to Send: Technical Requirement Checklist

To evaluate feasibility and structure compliant off-take, please include the following technical details in your enquiry.

1Target industrial application (Container glass vs Float glass vs Foundry casting vs Construction chemicals)

2Required SiO2 purity percentage and maximum acceptable iron oxide (Fe2O3 %)

3Grain size distribution specification (Sieve sizing curve / AFS grain fineness number)

4Moisture requirement (Kiln-dried <= 0.1% vs Damp washed sand 4-6%)

5Consignment volume (Trial delivery vs Recurring monthly tonnage)

6Packaging format (Bulk pneumatic tanker vs 1.5 MT big bags vs 50 kg bags)

7Delivery incoterm and destination facility location

Incomplete RFQs lacking grade cutoffs or consignment volumes cannot be processed.

Submit a Silica Sand Specification

FREQUENTLY ASKED QUESTIONS

Frequently Asked Questions: Silica Sand (Industrial Quartz Sand)

Key questions regarding Pakistani mineral availability, testing protocols, and trade qualification.

Glass manufacturing requires high chemical purity (typically SiO2 >= 98.5%) and critically low iron content (Fe2O3 < 0.04% for clear glass). Additionally, grain sizing must be tightly controlled between 106 and 600 microns, with zero refractory heavy mineral inclusions (such as chromite or zircon) that cause un-melted defects in glass containers.

Structured Mineral Qualification

Structure a Compliant Silica Sand (Industrial Quartz Sand) Requirement

Submit required SiO2 grade, Fe2O3 limits, and grain size distributions for technical qualification.

Submit a Silica Sand Specification