Sand production - wet or dry?

Wet?

Washing is widely accepted to be the most efficient way of producing high quality sands for use in a variety of applications ranging from sands for use in concrete to specialist applications such as golf and silica sands.

This is because of limitations with traditional dry screening processes particularly in regard to the ability of these systems to effectively and consistently remove minus 75 micron material.

CDE Global have built a reputation on the delivery of efficient sand washing plants throughout the world over the last two decades and have been working in the Gulf for almost 10 years.

During this time we have completed many sand washing installations including two 1200 tonne per hour plants in Qatar. There are numerous other CDE washing plants in operation in many other regions of the Gulf and North Africa including KSA, Oman, Bahrain, Tunisia and Morocco.

Our entry into the Gulf came as the result of the demand for high quality washed sands in the region. This resulted in the two large 1200 tonne per hour projects in Qatar initially and since then there have been many other installations with capacities more in line with every day requirements – between 50 and 150 tonnes per hour.

Over the years CDE has developed a project list full of examples of replacing inefficient traditional sand washing plants such as bucket wheels and screw classifiers with the hydrocyclone based Evowash system.

Old sand washing technology has a number of issues, not least the loss of significant quantities of quality fines to the settling ponds or water treatment phase. In an effort to ensure effective removal of the minus 75 micron fraction these inefficient systems take a lot of commercial quality sand with them which has a negative impact on the profitability of the operation.

Operators using inefficient sand washing plants are taking a hit on two fronts. Not only is the final value of their sand product compromised by the presence of larger quantities of minus 75 micron material than is ideally the case but operational costs are also increased as a result of the requirement to clean out settling ponds regularly in an effort to recover the good material that has been lost.

There are various design features on the Evowash plant that prevent this problem from arising with the choice of hydrocyclone technology being one of the key factors. Hydrocyclones offer the most efficient means of delivering the required cut point thus ensuring a sand product that meets the desired specification. The effect of being able to guarantee a sand specification is to maximise the commercial value of the material and thus the profitability of the operation.

Investing in low cost, old technology is a false economy as the return on investment takes much longer than is the case when our washing system is specified.

Water recycling

The ability to offer operators water recycling equipment to accompany the sand washing plant has also been a key factor in the success that we have enjoyed in the Gulf.

Given the climate in the region and a scarcity of water when compared to the North European markets where CDE originally established a reputation the specification of the Aquacycle thickeners and GHT filter presses that we offer was very frequent as business grew.

You could say that Gulf operators led the way for the global washing industry in relation to the specification of water recycling equipment. We would now include our thickeners and filter presses on 80% of all global washing projects whereas as recently as five years ago this figure would only have been around 20%.

The scarcity of water in the Gulf was a major factor here and made the CDE water recycling and sludge management system a ‘must have’ rather than a ‘like to have’ as it was seen in some other territories. Environmental concerns and subsequent legislation in this area has driven demand for water recycling systems but there is also a growing realisation that their introduction does actually offer a more efficient way of operating.

When you factor in the costs of managing large settling ponds, the additional space required to accommodate the operation and the potential health and safety risks, water recycling systems offer operators a way to ensure a much more efficient and easily managed washing plant.

Dry?

Just as the introduction of effective water recycling systems was a response to the unique climate of the Gulf region we then introduced new air classification technology.

The introduction of our Sirocco air classification system was a move inspired by the need to offer a solution to operators not able to consider a washing plant due to water supply issues. Even with full closed circuit water recycling reducing the volume of fresh wash water required to around 5% of the total volume some operators are simply not able to ensure supply of the volumes needed to operate a wash plant.

The question that arises from this decision is how does it fit in with the previous assertion that dry screening of material is not as efficient a process as washing?

Well, although a dry process, the Sirocco air classification system is far removed from the traditional dry screening process which has been problematic for those seeking to produce high quality sand.

The key success of washing using our Evowash system is the capability to efficiently remove the minus 75 micron material. We prefer to describe the Sirocco as a dry wash system – or washing without the water as it is able to achieve the same results as washing in terms of minus 75 micron fines removal.

Previous to the introduction of the Sirocco air classifier to the Gulf operators wishing to produce quality washed sands were unable to do so because of a lack of water availability. With the introduction of Sirocco the option exists for these same operators to achieve the higher specification sand products that will allow them to diversify into new sectors of the construction market.

We have several Sirocco units operating in KSA and Oman which are producing concrete sands to the same specification as those being produced by our Evowash sand washing plant. With each new Sirocco unit comes a growing acceptance of the technology and a realisation that this dry wash system is a viable alternative to a washing plant.

An additional feature of the Sirocco system that has made it attractive to operators is the small amount of space required to accommodate the system. We offer the Sirocco as a stand alone unit or as part of a turnkey package. The turnkey option includes a feed system, the Sirocco air classification unit, two stockpile conveyors – one for the sand product and one for the fines – and a dust suppression system.

The fines product from the Sirocco is not a waste material but has a number of applications including its use in the manufacture of ceramic tile adhesives and grouts. This provides additional revenue for operators from what many consider to be a waste material.

The Sirocco system is available in a variety of configurations from 50 tonnes per hour to 800 tonnes per hour in a single unit. This differentiates the Sirocco from other air classification systems on the market which offer single units at 150 tonnes per hour and multiples of this system should larger capacities be required.

Our washing plants are customised to the specific requirements of each project and our Sirocco units are built according to the same principles.  The specification of the right system needs to take account of the individual characteristics of the feed material, with the level of fines being the critical factor. Other systems take a ‘one size fits all’ approach which compromises final product quality.

The future

The introduction of the Evowash and Sirocco units reflects the approach we take to all the regions in which we operate. We will continue to respond to the specific requirements of the Gulf region and all of the other territories we are working in or aspire to work in as we seek to continue to offer operators the most efficient sand processing systems available.

And the winner is...

Following the announcement of Russia and Qatar as the hosts of the greatest show in earth in 2018 and 2022 respectively the inbox has been filling up this week with details of lots of conferences, exhibitions, networking events promising to be able to put us in front of the people writing the cheques for the Billions of dollars of investment required to ensure a successful World Cup.

While there can be no doubt that there will be significant opportunities in both Russia and Qatar due to the nature of the work to be completed I can't help feeling that the organisers of these events are doing their best to ride on the wave on enthusiasm following last week's announcement.

A large helping of caution will be exercised with a side portion of cynicism as details of these events promising a pot of gold at the end of the rainbow continue to flow in over the coming months. As is usually the case with the vast majority of these exhibitions and similar events, the main winners are the organisers who secure massive investment from participants for what is more often than not a dissapointing return.

Water recycling top of the agenda for washing plant operators

The inclusion of water recycling equipment on washing plant installations has risen dramatically in recent times as operators realise that in addition to the altruistic benefit of protecting the world’s most precious natural resource there are significant efficiency gains to be enjoyed.

The specification of equipment such as thickeners and filter presses has seemingly progressed from being seen as something that was done only at the behest of planning authorities. As awareness has grown of the real potential for these water recycling technologies to improve the efficiency of traditional quarrying and C&D waste recycling processes their introduction to existing operations and new installations has increased dramatically.

As recently as three or four years ago a thickener or filter press was only specified on around 20% of our washing plant installations. The last 12 months has seen this figure rise to around 80%.

This increase is not restricted to any specific geographical area with recent installations in Ireland, the UK, Europe, Middle East, Australia, South America and South Africa.

The key drivers behind the increased specification of this equipment differ from one installation to the next and include issues concerning:

1. The space available on site to accommodate large settling ponds
2. The availability of the volumes of water required to operate a new washing plant
3. Reducing health and safety risks on site
4. Efficiency improvements offered through significantly reduced operational costs.

We have focused on the potential efficiency gains for a number of years now when in discussion with both new and existing clients. The management of large settling ponds is a very expensive process and one which the introduction of a thickener can significantly reduce. If the full sludge management system including a filter press is specified these settling ponds can be removed completely from site.

In the UK market the specification of water recycling equipment has been most prevalent on construction and demolition waste recycling operations due to the nature of the sites where these plants are located. While it is usually the case that traditional sand and gravel or hard rock quarries are located in rural settings on large sites, the opposite is the case for recycling plants.

The nature of the material being processed means these sites are located in urban areas and as a result some degree of water recycling is essential on all of our C&D waste recycling plants. We have many plants working on sites located in built up industrial and residential areas where not only is there not the space to contemplate settling ponds but the health and safety issues surrounding these ponds rule them out of consideration at the very outset.

Outside the recycling sector the demand for equipment is coming from operators who are introducing a washing plant for the first time. Operators considering a washing plant on a site that has previously only operated a dry crushing and screening process are more focused on the volume of water required to run the plant than those already operating washing plants.

The issue of the space required for ponds is more acute for those not already operating these ponds and one of the first things they are concerned with is reducing this space requirement. The specification of a thickener and filter press is the obvious way to achieve this.

It is not exclusively the ponds issue that leads operators to specify some sort of water recycling system however. An equally pressing issue is gaining access to the volumes of fresh water required to run the washing plant should a thickener not be included.

On a recently completed project in Poland this was precisely the issue that the customer was faced with. Our customer was operating an Evowash sand washing plant after their dry screening process but had a requirement to increase sand production following the award of a new contract.

The customer chose our M2500 mobile washing plant to deliver this increased capacity but they simply did not have access to the volumes of water required to run the new plant. The introduction of an Aquacycle thickener on this upgraded washing plant ensured that the customer in this instance was able to take advantage of the increased sand and aggregate production capacity while requiring less water to do so. The introduction of the thickener on its own has allowed the customer to recycle between 85% and 90% of the water used to feed the washing plant.

It is rarely the case that operators will only have one of these issues to deal with and according to CDE it is usually a combination of factors working together that lead to the conclusion that a thickener and / or filter press is needed. In the case of a recent project in South Africa the customer had a number of concerns.

Firstly, they were spending considerable time and money cleaning out their existing ponds and reprocessing material due to the inefficiency of their existing sand washing plant so the first priority for them was more efficient sand washing. They were also adamant that they wanted to address their ponds issue and reduce not only the space they were occupying but the cost of managing them.

While thickeners are much used in the mining sector in South Africa it is believed that this is the first instance of a thickener system being installed on a traditional quarrying operation. A further consideration for this customer was the location of the washing plant adjacent to a local river. With this at the forefront of the customers’ mind the safe storage of waste material from the washing plant was of paramount importance.

We fully expect this trend towards thickeners and filter presses to continue. Given the fact that this year has seen the installation of our first water recycling systems in six new countries the expectation is that this will lead to more in the coming months and years.

The whole is greater that the sum of it's parts

If I hear the word ‘challenges’ or any variation on it once more in an analysis of the state of the industry in Ireland at the minute, I swear something destructive is going to happen. I am sure this is something that many others have thought over the last twelve to eighteen months which has seen our industry change dramatically. Faced with this dramatic change everyone working in our industry is faced with having to adapt to this new world order and decide how they are to continue to grow and develop in the years to come.

The key thing here is that it is ‘our industry’ and collectively we all must take responsibility for doing our bit to ensure that it continues to be an industry where the new talent emerging from our schools and universities want to work. As is usually the case, the development of such a mindset requires a facilitator. The ‘Addressing the Challenges’ event organised by Machinery Movers magazine presented us with a great opportunity to start shaping the future of our industry in Ireland and beyond. We made our way to the Osprey Hotel in Naas positive in the knowledge that a forum had now been provided for us all to work together and exchange views and opinions that would help us enjoy future success.

I personally found the event in Naas very worthwhile and it was useful to hear the comments and experiences of people from different corporate backgrounds on what the best way forward is. What was disappointing about the event was the numbers in attendance. There are so many companies working in our industry at the minute facing the same problems and looking for solutions to these problems. Whether those problems relate to balancing quarry production with a reduced demand for product, or trying to find ways of demonstrating that investment in new equipment now will prove cost efficient in the long term the problem is essentially the same. The whole face of the industry has changed. Given the nature and extent of this change I don’t think there is one company in Ireland who is able to tackle this change on their own and come out the other side smiling. We are all interdependent – a vibrant, thriving industry is to the benefit of us all.

I left the event in Naas even more committed to working with Brian Coogan and the team at Machinery Movers to build this network of people who want to see our industry grow and prosper in the years to come. This is all of us. Everyone involved or employed with any company working in the quarrying, mining and recycling sector in Ireland has a vested interest here – be they materials producers or equipment and component suppliers.

Despite the trials and tribulations of the last twelve to eighteen months the industry in Ireland has a lot to be proud of. Our business takes us all over the world and there is not one country we go to where to do not meet someone from this little island working in the industry at a very senior level. The natural skill set that exists within us and our approach to work wins us a lot of friends and this continues to be the case. This reputation is borne out a strong industry at home so to continue to ensure that opportunities exist for Irish companies outside this island we must ensure a strong image is portrayed.

A strong industry at home is also essential to ensure the techniques and processes used in production, and the equipment we produce for the global market continues to improve. Without this we will lose the best young engineering talent to our competitors overseas and that does spell trouble for the industry as a whole. We must not let this country slip back to the ‘brain drain’ days where all of the top talent is lost. A huge amount of work has been done over the last 20 years to stop the flood of young people from Ireland and we must work together to ensure that this situation is not reversed.

The approach that CDE have taken as a company over this most recent period of time has been to continue to develop and innovate. Whether that be new industries that we can target, new markets we should be looking into or new products that we can develop. Only by continuing to adapt to the external factors that lie out of our immediate control and making the best that we can of the opportunities will we be able to sustain the growth that has characterised our recent history. However, we can’t do this on our own and welcome any opportunity to work as part of a group with the same collective aim. I believe that the work that Brian Coogan will continue to do through the ‘Addressing the Challenges’ initiative provides the ideal platform for us to do this.

Another thing that you notice on chance encounters with fellow Irish men and women who find themselves working in foreign lands is a fierce and unbreakable loyalty to their home. After all, it was largely here that they did their apprenticeships working in our local industry. It was this experience that gave them the tools to develop personally and professionally and find the career opportunities that exist outside this island. Let’s continue to give them an industry to be proud of and one which commands the same level of respect – even envy – that has allowed this country to punch well above its weight. Speaking from our own perspective I can safely say that no matter how many countries we may be present in, this market in Ireland is our home market and will always remain the most important.  By embracing the ‘Addressing the Challenges’ initiative we can go some way to doing this because the whole is greater than the sum of its parts.

I am not in the employ of Machinery Movers magazine, nor am I receiving any financial benefit from writing this article. What I am offering here is simply my opinion on the opportunity that is presented to all of us by the ‘Addressing the Challenges’ initiative and why I think it is essential for as wide a cross section of people from our industry to get involved.