The rough with the smooth

By Siobhan Lismore-Scott
Published: Friday, 22 February 2013

Abrasives have had a hard time in the last few years as demand has waned on the back of an uncertain economy, but all sectors are set to enjoy growth as manufacturing returns to the black. Siobhan Lismore, Editor, takes a look at an industry on the up

Abrasives, both natural and synthetic, are substances that are used to grind, scour, clean or otherwise remove material by rubbing or blasting.

They are commonly used to prepare the surface of a material for treatment, for example, for painting as part of a corrosion prevention strategy.

The important physical properties of materials that qualify as an abrasive is the hardness, rigidity, grain shape and size, friability and purity.

The hardness of minerals is frequently defined using the Mohs scale Ñ although this has been considered as inadequate by Gretchen K Hoffman, writing for Industrial Minerals and Rocks, “because the methods of testing are very crude and the intervals between the steps are not uniform”.

Offered as an alternative to this is a diamond indentation method of measuring hardness, devised by Knoop, Peters and Emerson in 1939, which is still used today.

Traditionally, abrasives have been naturally occurring minerals such as garnet, industrial diamond and silica. But there are now many manufactured abrasives also on the market, such as fused alumina and silicon carbide. These are sometimes preferred as they have a homogenous consistency and can be more cost effective.

The broader industry splits between naturally occurring and manufactured abrasives, bonded (for example, sand paper), loose (sand blasting) and between disposable and recyclable abrasives.

The loose abrasives market chiefly serves the oil and gas, marine and fabrication sectors.

The bonded abrasives market is largely separate from the loose abrasives sector and usually employs high-end manufactured abrasives, although some naturally occurring ones are also used.

France’s Saint-Gobain is the world-leader in the bonded-abrasives businesses, although it also manufactures thin grinding wheels, coated abrasives, superabrasives and construction products.

3M and Tryolit follow, but there are also many other smaller producers.

The industry is also split further between the standard abrasives (such as silicon carbide and fused alumina [see pp47-54]) and superabrasives, such as diamond and cubic boron nitride.

What influences demand?

Abrasives markets are mainly influenced by activity in a range of manufacturing sectors, as well as in construction, shipping, and oil and gas drilling. Manufacturing sectors include the aerospace, automotive, furniture, housing and steel industries.

The US manufacturing industry has shown some recovery, seeing its fastest rate of growth for nine months in January 2013, according to PMI compiler Markit Research.

The index posted 55.8 for January 2013, up from 54 in December 2012, meaning that manufacturers received a larger volume of new orders in January and that the overall rate of growth was the fastest since May 2010.

In Asia, manufacturing continued to improve in January 2013. The Chinese index posted 52.3 in January 2013 up from 51.5 in December 2012, the highest level seen since January 2011.

The Eurozone recession continued to create a negative picture for European manufacturing but, despite this, the index posted 47.9 - its highest result for 11 months.

In the loose abrasives sector, demand was stable during the economic downturn because of a buoyant petrochemical sector, a market source told IM.

“Petrochemical demand remained somewhat stable, owing to long-term project planning and maintenance schedules, though some rigs associated with exploration were furloughed,” he said. Sand blasting of oil and gas rigs is a major application.

Trends

“In general, there has been lower demand of abrasive grain in Europe, especially in southern countries like Spain, Italy and partly France,” Hans-Georg Leitner, Treibacher Schleifmittel sales manager, told IM.

The recession in Europe led to declining industrial activity in the larger driving markets such as steel, construction and auto production,” Leonardo Curimbaba Ferreira, general manager, US Electrofused Minerals, Curimbaba Group said.

“This slowdown in world demand, coupled with Chinese overcapacity, affected the abrasives industry and also reshaped the marketplace (...) European manufacturers started entering in North America due to slowdowns in their traditional markets.”

He added that he had seen an increase in demand in emerging markets such as China, Thailand, Brazil and South East Asia.

The Gulf Cooperation Council (GCC) states continue to enjoy strong petrochemical demand, which has fed into the market, a second source told IM, although the source noted that fabrication remains flat.

Australia and Russia, meanwhile, are displaying robust growth.

“We can see a general increase in higher-quality raw materials like fused zirconia alumina and Sol Gel grain. For coated abrasives, we see also a general trend to finer sizes,” Leitner said.

“Demand for abrasives is driven by durable goods manufacturing automotive, machinery, metals and construction,” Curimbaba Ferreira said.

“Therefore, all the countries that have a strong durable goods industry will demand more abrasives. Coated abrasives demand is also driven by repairs and maintenance besides durable goods,” he added.

In terms of products, parts are being produced “near-net-shape”, Curimbaba Ferreira added.

This means that demand has risen in fine grit sizes and also in high performance products such as semi-friable, Sol-Gel and diamonds.

But in general, the market declined between 5-7%, market sources said. The decline was not as widely noted because although the key industries had fallen off the automotive and aerospace industries, which use abrasives, were still strong.

Also, Curimbaba Ferreira added, although construction fell overall, this promoted growth in home repairs, which meant higher use of coated abrasives.

Prices

Rising energy costs has driven up prices, along with increases in raw material costs. Bauxite prices, for example, have risen on the back of scarce supply (see pp41-49).

This is the largest input cost the industry faces, because creating an abrasive takes so much energy.

However, one possible solution comes at International Innovative Technologies Ltd (IIT), where George Milburn, Applications Manager, told IM that its process using dry milling can use up to between 25-30% less energy than jet milling for finer abrasive grades. The IIT mill can also save considerable energy as a pre-milling stage for ultra-fine grades, Milburn said.

“Our m-series mill uses markedly less energy for size reduction than typical ball mills or jet mills,” he said.

“And, with very hard materials such as SiC and zirconia, the Specific Grinding Energy, measured in kilowatt hours per ton, is amongst the highest applied for size reduction in the world,” he added.

Each abrasive is priced differently. SiC prices have come off from highs (see below), while natural abrasives, such as garnet, are now trading at levels 25% higher than their peak price levels enjoyed in 2009, according to market sources.

“SiC is priced higher than BFA and typically higher than WFA and other white aluminas,” Curimbaba explained, although other market sources said that SiC sits between BFA and WFA, with BFA being the lowest-price grade (see pp47-54).

“SiC pricing over the past four years has gone up and then back down. Pricing for SiC seems to have leveled off, or dropped a bit more as suppliers are continuing to fight over market share,” he added.

In regards to alumina-zirconia, as zircon sand pricing has increased over the past few years, this has made alumina-zirconia higher in price than SiC.

Zircon prices have dropped recently, to a range of $1,250-$1,550/tonne (FOB Australia) after rising to a range of $2,600-2,400/tonne in late 2011 and over 2012, according to the IM prices database.

The full range of garnet prices, incorporating all grades (blasting and waterjet cutting), high and low quality is Û150-450 ($200-600) FOB.

Premium grades are priced between Û240-300 ($320-400) range.

“This is the sweet spot for premium, low-chloride blasting grades, with specialist coarse grades above and waterjet cutting (finer particles) and poor-quality blasting grades below,” a market source told IM.

Selected manufactured abrasives

Silicon carbide and fused aluminium oxide

Traditionally, SiC’s main end markets have been refractories and abrasives, and in particular, steel refractories and silicon wafer cutting in the solar cell market have been areas of growth since the recession.

China is the world’s leading producer of both fused alumina and silicon carbide, with an output of 700,000 tpa of fused alumina and 455,000 tpa silicon carbide in 2012, according to USGS.

Germany is the second largest-fused alumina producer, with an output of 80,000 tonnes in 2012.

North America and Brazil accounted for 60,400 tonnes and 50,000 tonnes of the world’s share of fused alumina, and 42,600 tonnes and 43,000 tonnes of silicon carbide in 2012, respectively (see pie chart).

The price of silicon carbide on a FOB basis in the US rose slightly in 2012 to $1,280/tonne from $1,260/tonne, USGS said.

According to the IM prices database, the European markets remained relatively stable, in the ranges pegged in 2011, between Û1,500-1,800/tonne ($2,000-2,400/tonne) for refractory grade min 98%.

But other market participants say that the price is a lot lower, citing levels between €1,200-1,300/tonne ($1,600-1,740/tonne).

Meanwhile, fused alumina prices, FOB US, slipped to a $555/tonne average for regular grade and $1,180/tonne for high-purity grade. This compares with $627/tonne and $1,360/tonne respectively the previous year.

“Imports and higher operating costs continued to challenge abrasives producers in the US and Canada [in 2012],” USGS said.

Sol-Gel Abrasives

These are prepared by gelling a form of alumina derived from boehmite, adding various precursors to enhance the properties with a nucleation agent and then extracting the water to produce a hard material. This is then crushed.

Sol-Gels are patented and produced solely by Saint-Gobain and 3M.

“In 1991, Sol-Gel abrasives were predicted to dominate the high-quality abrasives market; the market share has not materialised, however, because of high manufacturing costs,” Hoffman writes.

Saint-Gobain reported in its 2011 results that it was “invest[ing] in new capacity and targeted acquisitions to keep up with the very rapid pace of abrasives market growth in Asia and South America”.

Sintered bauxite (see pp41-47) is used as an alternative.

“Sintered bauxite is a cheaper alternative to aluminium oxide, around 75% of price,” a source told IM.

“Al203 in sintered bauxite is 76%, whereas brown aluminium oxide is at 92%. This means, in practice, it is softer, although cost- effective in applications which allow it,” the source added.

Natural minerals

Garnet

Global production of garnet today is approximately 1.7m tonnes, according to USGS. Substitutes include fused alumina and staurolite as a sandblasting material.

“Diamond, corundum and fused aluminium oxide compete for lens grinding and for many lapping operations. Emery is a substitute in non-skid surfaces,” USGS said.

Garnet is an interesting market area because it is presented as an attractive alternative to silica sand as a natural abrasive.

“The trend is toward cleaner abrasives for both occupational health and safety as well as for the environment,” a market source told IM.

“This means countries rightly continue to ban the use of silica sand and are also making it difficult to cost-effectively dump the mineral’s slag abrasives, which form the bulk of loose disposal abrasives, after use,” the source added.

“Garnet falls somewhere between cheap disposable and a specialist abrasive. This is owing to the various grades [fine to expensive coarse] and applications presented, but also since its performance and occupational health and safety and environmental profile is appealing.

“As such, it has been difficult for producers to meet increasing demand for the commodity and, save for a short period after the crisis, prices rises are a constant in this space,” the source said.

Diamond

The US was the world-leader in industrial diamond production in 2012, with an estimated 104m carats production. There are two firms which produce industrial diamonds. Total US secondary production of industrial diamonds was estimated to be 37m carats.

“About 97% of the US industrial diamond market now uses synthetic industrial diamond because its quality can be controlled and its properties can be customised to fit specific requirements,” USGS said.

Demand is expected to continue to be high for US industrial diamonds as the country continues to build, mill and repair its highway system.

China leads the world in synthetic diamond production, with an annual output or more than 4bn carats, according to USGS.

Materials that can compete with industrial diamonds in some applications include manufactured abrasives, such as cubic boron nitride, fused aluminium oxide, and silicon carbide. Globally, synthetic diamond rather than natural diamond is used for about 99% of industrial applications, USGS said.

Outlook

Foreign competition, particularly from China, is expected to persist and further curtail production of manufactured abrasives in North America, USGS said.

It expects demand for synthetic diamond grit and powder to remain greater than that for natural diamond material.

Elsewhere, producers told IM that they expected prices to rise into the new year on the back of increased demand from the manufacturing and petroleum sector.

“As a business, we are expecting volumes and margin recovery in 2013, which clearly separate it from the years of the crisis,” a raw materials producer for the abrasives industry told IM

“The market outlook for the first half of 2013 shows a slight decline over 2012,” Curimbaba Ferreiro said.