16th Global Gypsum Conference, Exhibition and Awards
25 - 26 October 2016, Bangkok, Thailand
Review by conference convenor Robert McCaffrey
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The 16th Global Gypsum Conference and Exhibition has successfully taken place in Bangkok in Thailand, attracting around 300 delegates from 40 different countries and including 39 exhibiting companies and 22 presentations. The 17th Global Gypsum Conference will take place in October 2017 in Kraków, Poland.
After a well-attended reception the previous evening, the conference in Bangkok started the next day with a presentation on the local gypsum wallboard market from Supachai Hirunyanitiwana of Gypman Tech Company Ltd, a local board producer. Supachai mentioned that Thailand's GDP growth is expected to amount to 2.5% in 2016, partly based on major projects including railway and metro development, but also underpinned by improving farm incomes. The total size of the Thai wallboard sector is 200Mm2, worth in the region of 2bn THB (US$57m) per year. The market has varying characteristics around the county, with price predominating as a purchasing factor in less developed areas, but with performance and quality becoming more important in cities, especially in the largest market, Bangkok. Elephant brand is the highest priced brand in the market, suggested Supachai, followed by the USG-Boral 'House' brand and boards produced by Knauf and finally by the local brand, from GM Gypsum. The local manufacturer Gypman Tech was established in 2014, producing both gypsum wallboard and powder, with the plant located in the north part of Thailand, adjacent to the gypsum mine. The company has already made progress in market penetration into the Thai market, with many prestigious project references. Facebook and a messaging app called 'Line' are used as the main marketing channels for the company.
The second speaker at the conference was Chris Lawson, senior VP for Corporate Excellence from USG, who spoke on the implementation of business methodology Lean Six Sigma. 2007 saw the start of the Great Recession around the world, leading to many difficult decisions in business. Chris said that USG wanted to improve its profitably throughout the business cycle. Lean Six Sigma (LSS) is essentially a process to define, measure, analyse, improve and control a process. A strategy must be developed, the infrastructure must be built to be able to enact the strategy and then the resources must be allocated to allow the successful execution of the strategy. USG has 45 manufacturing sites in the US, Canada and Mexico and a total of 137 L&W distribution branches throughout the US, so that senior executive backing was crucial for the programme to succeed over its geographically dispersed employee base. Extensive training in LSS is required, for a variety of job roles, to get everyone 'singing from the same song sheet.' Selection of the correct project to pursue is crucial and there is a methodology to help with project selection. The LSS project at USG has returned US$200m, with an IRR of 250%, with 800 projects completed and over 150 projects continuously underway. In all, 5000 employees have undergone training. Chris described one real-world example where a new facility was set to build its train loading bay six inches higher than the level of the rail freight cars, a discrepancy that was caught and corrected by the LSS process.
Next, returning to the conference platform after presentations in previous years, was Rob Crangle of the United States Geological Survey, the USGS, speaking on transportation challenges for gypsum. "Wallboard is a heavy, delicate and low-priced commodity. For crude raw gypsum, specialised shipping vessels are required and syngyp is the ever-present low-priced benchmark against which rock gypsum must compete. Fuel prices also present a challenge to gypsum transportation. Robust transportation infrastructure, on the other hand, acts as an enabling factor for gypsum and gypsum-based products." Rob pointed out the huge range in transportation method capacity and cost per sheet, ranging from the largest sizes of container ship, through bulk carriers, rail transportation, barge and truck transportation. 'Last mile' transportation is typically the highest cost portion of the transportation equation. Self-unloading bulk carriers are still commonly used, nowadays often hired on contract rather than being owned by gypsum producers themselves. Prime sources of natural gypsum are from Spain, from Halifax Nova Scotia and from Mexico. Crangle pointed out that syngyp now accounts for around 50% of total gypsum consumption in the US. Lower-priced syngyp has prevented rock gypsum prices from rising, so that rock gypsum prices have not seen price rises commensurate with increasing fuel price rises. However, Rob Crangle concluded that, despite fuel and shipping prices being consistently volatile, final gypsum product prices have remained more or less unaffected by these factors.
Mark Flumiani next spoke about the globalisation of lightweight boards. He pointed out that board weights have been reducing since the invention of plasterboard, but with the introduction of USG's 'Ultralight' lightweight board in 2004, a new paradigm in board performance was created. All North American board producers have since followed suit, so that lightweight board has now become the market standard. Flumiani said that "performance and density are not consistent:" the denser the board, the stronger your product. The challenge with lightweight board is to provide performance with less gypsum in the product. The nail pull resistance test measures the maximum force required to push a nail through a sample and this is one of the most difficult tests for lightweight board to pass. Remarkably, Mark pointed out that multiple test results from a single sheet will give a wide variety of nail pull resistance values, illustrating his test results with a map of values from a single sheet that varied by more than 20% from the mean and well beyond any experimental error margins. Some regions (parts of Europe, Japan and China) appear to have some regulations for minimum board weights. Different technologies have been applied to increase nail pull resistance, including increasing the face paper basis weight, adding glass fibre reinforcement, using foaming agents, using pre-gelatinised starch and using phosphate salts. Mark Flumiani pointed out that over a six year period, around 60% of carpenters using boards filed an injury claim in the US and in a country that is so litigious, this is something that is to be strenuously avoided. Reducing the board weight can provide an increase in productivity, while also decreasing injury rates. However, by reducing the amount of low-cost gypsum and increasing the amount of higher-cost ingredients, lightweight board can be more expensive to produce. Transportation costs will, however, be reduced and this can finally create some cost benefits. Flumiani suggested that USG was able to charge a premium for its lightweight board for a relatively short period, before other manufacturers were able to launch their own competing products. He also suggested that a variety of performance modifiers might be required for lightweight boards, for example the use of biocides to cope with higher starch levels, fire-resistance additives to cope with lower gypsum contents and the use of constrained layer damping to cope with lower acoustic attenuation properties. The production of smaller sheets (for example ERGO and Ergolite boards) can also reduce sheet weights, while at the same time apparently maintaining worker productivity. Some manufacturers have reintroduced heavy boards as 'classic' products, with 'higher performance' characteristics.
Luoyi Xu, the director of the Gypsum Association of China Building Materials Federation gave an overview of the gypsum industry in China, which totalled a consumption of 122Mt in 2015, of which 73% was synthetic gypsum ('syngyp'). The growth rate of the gypsum industry has strongly reduced since the 2000s. In 2015, around 90Mt of gypsum was used as a set retarder in the cement industry, while 23Mt was used in the wallboard industry. Due to the decline of natural resources, increases in mining costs and increasing use of syngyp, use of natural gypsum has declined and will continue to decline in the future. Around 71Mt of syngyp is used each year, with a utilisation rate of around 50%. In turn, around 80Mt/yr of phosphogypsum is produced, with a utilisation rate of 33%. Mr Xu pointed out that by the end of 2015, the total accumulated stock of industrial gypsum byproducts in China amounted to 680Mt, increasing by around 90Mt/yr (partly due to sharply increased use of flue gas desulphurisation for coal-fired power stations). In 2015, China's wallboard production capacity reached 3.7 billion m2, but production was 2.8Bnm2. Factory capacities have grown over the last two decades from 4-10Mm2, to today's 30-60Mm2 capacities: BNBM and its subsidiary company Taishan Company now have dozens of factories each with more than 50Mm2 of capacity. Gypsum-based blocks are also commonly used in China, with more than 100 manufacturers and both hollow and solid blocks are used. The gypsum plaster sector is still developing in China, amounting to 2.1Mt in 2015: Improved water-resistance and spray-application improvements will most likely lead to wider use of plaster in the future. Luoyi Xu suggested that future trends will include the improvement in quality of synthetic gypsum, increasing use of gypsum in mortars and increasing use of gypsum in self-leveling floors, replacing cement-based materials. Continued urbanisation will underpin future gypsum-based product demand in China.
Farshid Eskandari of the Tandis Alborz Gypsum Company next spoke about the gypsum industry in Iran. The country has a population of 80m, boasts large stocks of high quality gypsum and is one of the largest gypsum producers in the world, even though there is practically no synthetic gypsum production in Iran. 120 plaster producers produce around 12Mt/yr of plaster, with almost 80% of the total produced in Semnan province. The vast majority of plaster is used for plastering walls by hand. Machine-sprayed gypsum is not yet popular, while gypsum wallboard is growing in use as the market is progressively educated through marketing and advertising. Farshid Eskandari suggested that wallboard production capacity in Iran 'could usefully be modernised.'
Robert Morrow of Innogyps next posed the question, 'So, you've decided to build a gypsum factory, what next?' Choosing where to build the factory is obviously a crucial decision and the one thing that cannot subsequently be changed. He pointed out that there are innumerable decisions to be made when selecting each piece of equipment in a factory, not least of which is the fact that they all must 'play nicely' with each other. The production capacity of the factory is another fundamental decision and will be controlled by raw materials, demand levels, competitors and likely future supply and demand trends. Perhaps most crucial is the designed operating cost, which should be as low as possible to ensure profitability through as much of the economic cycle as possible. As a guiding principle, "Customer satisfaction should be your number one priority," he concluded.
Marcelo Pereira and colleague Julieta Castro Balmaceda of Argentinian company Aswell spoke on the possibilities of lightweight wallboard penetration into the South American market, based on the 'Give me Five' (5kg/m2) method. Different traditions in building have led to different development patterns for wallboard in different markets in South America. For example, in Colombia where brick and mortar construction is common, plasterboard can be used to face interior brick walls, allowing faster decoration compared to traditional plaster. In Chile, plasterboard is replacing wood as an interior construction material. In Argentina, an exterior hydrophobic cement-coated gypsum board is progressively replacing fibre-cement board. To be able to create a board with weight of less than 5kg/m2, all aspects of manufacturing must be optimised, starting from quality control in the quarry, including manufacturing and testing protocols through the production process and even techniques for delivering the intact lightweight product to the customer. For Aswell, success in the creation of these lightweight boards has led to higher margins and a board with increased strength and performance.
The final presenter on the first day of the conference was James Lyon of Owens Corning, who spoke on how fibreglass can improve product performance. Wet-use chopped strand and non-woven glass fibre veil are the two main products used in the gypsum industry. James Lyon suggested that the sizing, the chemical coating applied to glass fibres, is one of the crucial factors in product performance and is a key differentiator between products. Glass fibres added to the core improve board cohesion to wallboard assemblies during fire exposure, helping products to meet global fire codes. Sizing technology can improve glass dispersion, resulting in improved slurry feeding and lower shrinkage levels under fire situations. Glass veils on the facing of gypsum wallboard provides improved impact and abuse resistance, dimensional stability, weathering- and mould-resistance and increased fire performance. Varying the fibre length and diameter can further optimise board flexural strength when using chopped glass added to the core.
Gala dinner and Global Gypsum Awards
The Global Gypsum Awards dinner took place at the Siam Niramit theatre, featuring a spectacular Thai-themed show. The Global Gypsum Awards are decided after a two-stage online-based nomination and voting process and were presented during the dinner: USG-Boral was named gypsum company of the year and also carried off the prize for gypsum plant of the year for its Saraburi plant in Thailand. Gyptech was awarded the 'supplier of the year' certificate, while Eli Stav of National Gypsum in the US was given a special prize for his outstanding contribution to the global gypsum industry. The Gyptech Stucco Analyser was named as the 'technical innovation of the year,' and USG's NextGen board range was awarded the coveted 'product of the year' title. Finally, in a category solely decided by the staff of Global Gypsum, 'Personality of the year' was awarded to Alfred Dayem of Sicit 2000 S.p.A.
The next morning, Dany De Kock of Johns Manville spoke about his company's DuraCore chopped glass product for gypsum wallboard. Adding glass fibre helps to reduce gypsum shrinkage and water loss during fire exposure, increasing fire resistance from 10 minutes to 60 minutes and above. DuraCore offers optimal results with low dosage rates, while increasing strength and stiffness, allowing lighter board weights. Glass also increases sag resistance, allowing shipment of longer board lengths. Dany De Kock made the point that unless glass fibres are correctly dispersed, then the undispersed bundles of fibres have much lower contribution to performance. Correct sizing and effective dosage and feeding allows efficient fibre distribution and maximum contribution to board performance. Dany De Kock state that, compared to dry fibres, using wet chopped fibre allows cost-effective product usage, reduced maintenance cost, low or zero dust generation and increased line uptime. Around 4% of ceiling tiles are lost during production due to cracking of corners, whereas addition of appropriate glass fibres can reduce this level to below 1%. Dany De Kock mentioned that there is a newcomer to the dosing equipment market, Acrison, which now offers a volumetric dosage solution for DuraCore and other glass fibres.
Next up was Worachard Chawanasporn of SMS Corporation, who spoke on the use of modified tapioca starch to improve board properties. Starch is a carbohydrate consisting of a large number of glucose units joined with a glycosidic bond. Starch can be used to improve adhesion between the gypsum board and the paper facing. Mr Chawanasporn pointed out that gelatinisation of starch mainly occurs at elevated temperatures in the board dryer: starch that is dispersed in water in the slurry migrates with the evaporating water to the board surfaces and edges, where it forms an effective gypsum-paper adhesive. Worachard Chawanasporn pointed out that when less gypsum is used in the production of lightweight boards, other steps should be taken to ensure that strength is maintained, for example the use of a heavier paper, adjusting the foam structure or use of additives. His company's PB916 modified tapioca starch is suggested to increase cohesion between gypsum crystals, leading to higher core strength, increased flexural strength and increased nail pull resistance.
Jiawei Chen of the Jiansu Efful Science and Tchnology Co. Ltd., next spoke about the preparation of high strength alpha gypsum plaster using industrial by-product gypsum as a raw material. Mr Chen suggested that the most complicated process for preparing high strength alpha gypsum is the wet process, but that this offers the best product quality. Essentially, crystal whiskers are grown from solution, but dissolved organic additives or inorganic salts must be added to the solution to constrain crystal growth, despite these additives reducing growth rates. Selection of the crystal modifiers is a crucial step, while optimisation of process parameters and the gypsum separator design are also important steps that Jiansu Efful has overcome. His company has now built an industrial processing plant in Lianyungang, Jiangsu Province, using a salt factory's effluent steam to make 15,000t/yr of high strength alpha gypsum, the quality of which exceeds the highest strength standards for gypsum in China.
The first paper in a session on gypsum handling and processing was given by Nikolai Velten of Aumund, who gave an overview of his company's capabilities in the area. Nikolai Velten gave a case study of British Gypsum's Sherburne plant in Yorkshire, which receives 640,000t/yr of flue gas desulphurisation (FGD) gypsum from the Drax power plant. The plant offers examples of a variety of equipment and technology from Aumund, including Samson surface material feeders, outlet chutes with special linings to avoid material sticking to the walls, traveling tripper cars, a portal reclaimer for material recovery from storage and even Centrex silo discharging machine for recovery of gypsum from reclaimed scrap boards (a material that Nikolai Velten said was even more difficult to handle than sticky FGD gypsum). Nikolai Velten suggested that in a world in which new capacity is being built less frequently, that optimisation of equipment is a potential new area of business growth for equipment producers.
Continuing with the material handling theme, Oliver Pralle of Haver & Boeker spoke about screening options for gypsum. "The best innovation is to recall what has already been forgotten," according to Pralle and the use of tried-and-tested screening and scalping for gypsum raw materials can enhance profit and process stability. Scalping is the process of separating out larger blocks from smaller ones, so that only the larger lumps are sent to the crusher, leading to a capacity increase and reducing wear and maintenance. In the next process step after secondary crushing, a screen may be used to separate different particle sizes to send material to different processes, such as for further grinding, for shipment to customers without further grinding or for calcination. Oliver Pralle suggested that there is zero tolerance of oversize particles (such as coarse particles in plaster) and this can be achieved with fine screening technology. Finally, screening technology is crucial in the burgeoning sector of wallboard recycling, to achieve separation of paper and gypsum components, particularly when used with wind-sifting technology.
Robert Schnatz of Gebr. Pfeiffer spoke on the improvement of gypsum plaster properties. The company's MPS vertical roller mill can be used for simultaneous drying, calcination and grinding of gypsum. Moisture levels and temperature of calcination will affect the stucco mineral phases produced, while the particle size distribution of the product gypsum from the mill will critically affect a variety of plaster characteristics, including water demand, strength development and set times. Robert Schnatz concluded that MPS-mill-produced plaster allows a higher percentage of the original gypsum to be used to form strength-generating mineral phases. The produced plaster is highly reactive and responds well to set accelerators, while at the same time avoiding early stiffening which promotes better bond and core strength.
Steve Becker of Schenck Process next spoke about how to achieve accurate and reliable additive feeding for wallboard production. Steve Becker pointed out that volumetric feeders use a number of assumptions to calculate the amount of material fed to the process, whereas a gravimetric feeder uses measurements to determine the exact amount of material being fed. Hopper levels can have a significant influence on both accuracy and precision of rates for volumetric feeders, particularly at lower feed rates, due to hopper head load influence. To avoid this problem, Steve Becker pointed out that a refill device, such as a slide gate, rotary valve or screw, should be selected to be consistent with the feed rate of the feeder itself. Steve Becker concluded that reliability and precision of feeding improve markedly when feeders are converted from volumetric to gravimetric feeding, particularly for poorly flowing materials.
The first paper in the next session, on gypsum production technology advances, was given by Markus Mueller of Sika Services AG, on controlling gypsum set times. Quick setting and hardening of the gypsum slurry is of crucial importance to run the gypsum board line at high speed for maximum capacity utilisation. The use of set accelerators, typically finely ground gypsum (ball mill accelerator, BMA), or K2SO4, is the state of the art and it might seem that additional use of set retarders would be counter productive, but there are sound reasons for using both additives simultaneously. The higher the accelerator dosage, the earlier the setting occurs, which can lead to an undesired increase in water demand, resulting in higher energy costs for board drying. Early setting can also increase the risk of agglomerations occurring in the mixer, while early setting can also prevent the release of large air bubbles from the slurry, resulting in board defects. Markus Mueller suggested that the best setting behaviour is a 'snap set,' to retard setting until after exit from the mixer and after bubble release, but soon afterwards and quickly. Different setting retardants can be used, but each have their own 'side effects,' such as crystal morphology changes and potentially strength reduction. Sika's Retardan 200 set retarder seeks to avoid these side effects, while allowing a good 'snap set,' at low dosage.
Jeff Warren of Gyptech next told delegates that calorimetry to evaluate gypsum set point is easy, powerful and inexpensive. Calorimetry measures the amount of heat given off during chemical and physical reactions and these measurements can be used to understand and control the setting behaviour of stucco. Set modifiers, equipment settings and other additives can all affect setting behaviour and these changes must be evaluated to be able to control the process. Jeff Warren used the Gyptech Stucco Analyser to measure reaction temperatures in a series of tests during stucco mixing tests, to evaluate the efficacy of different set modifiers.
Neil Wooliscroft of Derco then gave an update on developments in thermoplastic forming belts for the wallboard industry. Neil Wooliscroft pointed out some of the advantages of thermoplastics over rubber belts, including the fact that they experience no chemical changes when heated, that they can be remoulded and reconditioned many times and repaired easily and quickly, that they are produced in a continuous process to form a blemish-free surface of up to 3m wide and that they experience no decrease in flexibility with time. Lasers are used for perfect alignment of belts to increase joint quality and strength and to create less production waste. A premium-quality belt has now been launched by Derco, which is particularly chemical-, wear- and abrasion-resistant and which is likely to be used for fibre-reinforced boards based on both gypsum and/or cement.
Ivan Sigfrid of Gyptech next asked delegates, "What should we do with an ageing dryer?" He answered his own question by pointing out that older dryers can be optimised as well as subjected to upgrades and retrofits. As the boards pass through the dryer, the drying front, the surface of dryness, becomes deeper in the boar, so that capilliary action and diffusion becomes increasingly more important. Depending on the efficiency of the dryer, the energy consumption will range 570-780kCal/kg of water evaporated. Gas and oil can be used as fuels, as can coal where an indirect heating medium such as thermal oil will be required. Firstly the dryer must be optimally maintained, but after this, fans, burners, ducts, air flows and temperatures can all be optimised. Retrofits might include zone additions, edge-cooling capabilities, heat exchangers and preheaters and co-generation through waste heat recovery.
Enrico Drews of Fluke Process Instruments presented the penultimate paper at the conference, on automated defect detection using pattern recognition for gypsum wallboard. Pattern recognition uses data processing to classify patterns in data and in this case this data would come from an infrared board scanner installed after the dryer. Enrico Drews underlined the fact that the scanner does not measure the moisture content of the board, but rather the temperature signature of areas that are incompletely or partially dried. The system can recognise a number of different defect types and with further use of algorithms the boards can be automatically rejected if warranted. The TIP900 system from Fluke Process Instruments can therefore avoid the possibility of sending defective boards out of the factory gate and hence reduce or eliminate customer complaints and litigation.
The final presentation was given by Anshuman Pandey of OPRA Turbines B.V., who spoke about turbine-based electric generation concepts for gypsum and gypsum wallboard plants. Captive power-generation is typically economic where fuel costs are low and electricity costs are high, although co-generation of heat and power can also be favoured if electricity supply is less reliable and where captive-generation can provide some certainty of supply. Anshuman Pandey pointed out that 'waste' heat in the exhaust gases from the turbine unit can be reused in the production process. He finally gave details of a 28Mm2/yr gypsum wallboard production plant in the Netherlands that has installed its own turbine-based electricity generation capacity, which delivered the entire electrical demand of the plant. A factory of around 15Mm2/yr capacity is typically serviced by a 1MW turbine unit.
Prizes and farewells
At the Farewell Reception, a number of conference prizes were awarded. In the best presentation awards, calculated using normalised attendee voting, third place was awarded to Worachard Chawanasporn of SMS Corporation, for his paper on the use of modified tapioca starch to improve board properties, while in second place was Ivan Sigfrid of Gyptech for his paper on upgrade options for ageing dryers. However, the winner of the best presentation award was Markus Mueller of Sika Services AG, for his presentation on controlling gypsum set times. Siam Cement Group (SCG) was awarded the prize for the best exhibition stand.
Delegates agreed that this was the best Global Gypsum conference ever staged, giving it top marks in a number of areas. Attendees promised to meet again, in October 2017, for the 17th Global Gypsum Conference in Kraków, Poland.