2019/06/06 1
2019/06/06 About NAMWOLL - 1 2 • The Team ➢ Bruce Stride – Managing Director; ➢ Dry separation system; ➢ Riana Mulder – Personal Assistant to MD; ➢ Life of mine 1 million tonnes drilled reserves. Estimated total ➢ Cheryl Willemse – Accountant; reserves 3 million tonnes; ➢ Gerrit Visser – Mine Subordinate manager; ➢ The mine is 18km out of Garies, and the fine product ➢ Fabian Adams – Process systems supervisor; and processing plant is in Garies and produces 5 different sizes ➢ Charl Willemse – Mechanic and Safety Rep. of Wollastonite product.
2019/06/06 About NAMWOLL - 2 3 The Mining process Crushing and Screening Plant Truck Loading Bin Mine Pit Wollastonite Processing Plant
2019/06/06 Wollastonite - 1 4 • What is Wollastonite? ➢ Wollastonite is named after the English chemist and mineralogist William Hyde Wollaston (1766 – 1828) and is a calcium inosilicate mineral ( CaSiOɜ ) that may contain small amounts of iron, magnesium, and manganese substituting for calcium. ➢ It is usually white but also found in a pearly grey colour. ➢ It forms when impure limestone or dolostone is subjected to high temperature and pressure sometimes in the presence of silica-bearing fluids as in skarns or contact metamorphic rocks. ➢ Associated minerals include garnets, vesuvianite, diopside, tremolite, epidote, plagioclase feldspar, pyroxene and calcite. ➢ Some of the properties that make wollastonite so useful are its high brightness and whiteness, low moisture and oil absorption, low volatility and enhancement of flexural and compaction strcngh. Wollastonite is used primarily in ceramics, friction products (brakes and clutches), metal making, paint filler and plastics. ➢ Despite its chemical similarity to the compositional spectrum of the pyroxene group of minerals where magnesium and iron substitution for calcium ends with diopside and hedenbergite respectively it is structurally very different, with a third SiO 4 tetrahedron in the linked chain (as opposed to two in the pyroxenes).
2019/06/06 Wollastonite - 2 5 • What is Wollastonite? Wollastonite in nature. Fine Crystals. Wollastonite in nature. Cluster of crystals Wollastonite cluster. with carnet and dioptase inclusions. Wollastonite needles under a microscope. Wollastonite end product. Wollastonite cluster.
2019/06/06 Wollastonite - 3 6 What is Wollastonite? - continued • Metallurgy/ceramic Construction/coating/ Metallurgy application Plastic/painting/coating application painting/friction application application Picture Microscope image
2019/06/06 Wollastonite – 5 7 • Uses ➢ Wollastonite has industrial importance worldwide. ➢ It is used in many industries, mostly by tile factories which have incorporated it into the manufacturing of ceramic to improve many aspects, and this is due to its fluxing properties, freedom from volatile constituents, whiteness, and acicular particle shape. ➢ In ceramics, wollastonite decreases shrinkage and gas evolution during firing, increases green and fired strength, maintains brightness during firing, permits fast firing, and reduces crazing, cracking and glaze defects. ➢ In metallurgical applications, wollastonite serves as a flux for welding, a source for calcium oxide, a slag conditioner, and to protect the surface of molten metal during the continuous casting of steel. ➢ As an additive in paint, it improves the durability of the paint film, acts as a pH buffer, improves its resistance to weathering, reduces gloss, reduces pigment consumption and acts as a flatting and suspending agent.
2019/06/06 Wollastonite – 6 8 • Uses - continued ➢ In plastics, wollastonite improves tensile and flexural strength, reduces resin consumption, and improves thermal and dimensional stability at elevated temperatures. ➢ Surface treatments are used to improve the adhesion between the wollastonite and the polymers to which it is added. ➢ As a substitute for asbestos in floor tiles, friction products, insulating board and panels, paint, plastics, and roofing products, wollastonite is resistant to chemical attack, inert, stable at high temperatures and improves flexural and tensile strength. ➢ In some industries, it is used in different percentages of impurities, such as its use as a fabricator of mineral wool insulation or as an ornamental building material. ➢ Plastics and rubber applications were estimated to account for 25% to 35% of U.S. sales in 2009, followed by ceramics with 20% to 25%; paint, 10% to 15%; metallurgical applications, 10% to 15%; friction products, 10% to 15%; and miscellaneous, 10% to 15%. Ceramic applications probably account for 30% to 40% of wollastonite sales worldwide, followed by polymers (plastics and rubber) with 30% to 35% of sales, and paint with 10% to 15% of sales. The remaining sales were for construction, friction products, and metallurgical applications. The price of raw wollastonite varied in 2008 between US$80 and US$500 per tonne depending on the country and size and shape of the powder particles.
2019/06/06 Wollastonite - 7 9 • Uses continued Application Field Specific Application Wollastonite Function Ceramic Industry Various ceramics, glass and moulds • Reduce the burnt temperature; • Shorten the burnt period; • Reduce the firing shrinkage. Improve deflection and cracking; • Optimisation of porcelain glaze glossiness and sleek flatness; • Improve the mechanical strength abrasion and scratch resistance. Metallurgical Industry Protection slag for heat insulation material • Ensuring composition stabilized and uniformity of slag; and cast steel • Better adapted to steel types; • Reducing the possibility of steel surface embrittlement and longitudinal cracking; • Strong absorbsion and dissolving capacity of impurity; • The viscosity varies little along with temperature in the process of continues casting; • Lubrication and protection without effecting the crystallisation and cooling of casting billet; • Reduces fluoride pollution and equipment corrosion. Building Materials Industry Calcium silicon plate, cement fibrolite plate, • Being innocuous, flavourless and non-radioactive it reduces pollution and production costs; fire insulation board • Increases shock resistance, flexural strength and abrasive resistance; • Good corrosion resistance, sound and heat insulation and fireproofing. Rubber and Plastics Industry Styrene butadiene rubber • Increases wear and scratch resistance; • Increases shock strength and enables products to enjoy high electrical and thermal insulation; • Increases thermal and dimensional stability; • Increases surface finish quality; • Good reinforcing function; • Increases the tensile strength, tearing strength, elongation at break, wear resistance; • Improves moistening and dispersion. Coating and Paint Industry Anticorrosive paint, thermal insulation Wear, corrosion and ultra violet resistance; • coating, construction paint Make paint show higher surface gloss and better water proof corrosion and buffers ph-value; • Improve thermal stability; • Reduce consumption of cementing substance. •
2019/06/06 Our Product - 1 ( Specifications of the various Wollastonite sizes) 10 The Company produces 4 different sizes of Wollastonite Product: 1. -100 MICRON PHYSICAL PROPERTIES % CHEMICAL ANALYSIS % Oil Absorption 23-25g/100g Calcium CaO 46.5 – 47.5 Refractive Index 1.63 Magnesium MgO 0.16 – 0.3 Hardness moh 4.5 – 5.0 Silica SiO 2 48 – 49.5 Whiteness SABS 137 Dry 80 – 85 Sodium Na 2 O Trace Specific gravity 2.8 – 2.9 Potassium K 2 O 3 0.08 – 0.88 Melting Point 1540c Phosphorus P 2 O 5 0.01 – 0.05 Appearance White Titanium TiO 2 0.03 – 0.04 Shape Acicular Iron Fe 2 O 3 0.5 – 0.55 Aluminium Al 2 O 3 0.8 – 0.9 PARTICULAR SIZE DISTRIBUTION MICRON L.O.I 2.6 – 2.7 Retained on cumulative PHYSICAL PROPERTIES % 250 micron 0.00 pH 9.8 - 10 150 micron 0.09% 75 micron 10 – 12% Moisture (110 dec C at 24 hrs) 0.5 45 micron 22 – 25%
2019/06/06 Our Product – 2 ( Specifications of the various Wollastonite sizes) 11 2. -150 Micron CHEMICAL ANALYSIS % PHYSICAL PROPERTIES % Calcium CaO 46.5 – 47.5 Refractive Index 1.63 Magnesium MgO 0.16 – 0.3 Hardness moh 4.5 – 5.0 Silica SiO 2 48 – 49.5 Whiteness SABS 137 Dry 80 – 85 Sodium Na 2 O Trace Specific gravity 2.8 – 2.9 Potassium K 2 O 3 0.08 – 0.88 Melting Point 1540c Phosphorus P 2 O 5 0.01 – 0.05 Appearance White Titanium TiO 2 0.03 – 0.04 Shape Acicular Iron Fe 2 O 3 0.5 – 0.55 PARTICULAR SIZE DISTRIBUTION MICRON Aluminium Al 2 O 3 0.8 – 0.9 Retained on cumulative L.O.I 2.6 – 2.7 250 micron 0.05% PHYSICAL PROPERTIES % 150 micron 6-8% pH 9.8 - 10 100 micron 15-17% Moisture (110 dec C at 24 hrs) 0.5 75 micron 39-44% Oil Absorption 14-15g/100g 45 micron 72-74%
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