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Sand is mixed with cement and water in measured quantity to produce concrete. These sand particles should be hard and inert with respect to cement. Due to huge silt deposition in riverbed and continuous mining of riverbed for sand, excavation condition of riverbeds is deteriorating progressively and threatening environmental disaster. This situation has forced many government agencies to ban sand mining in riverbeds, which has led to an increase in demand for M-sand.

Demand-supply scenario
Says Somnath Bhattacharjee, President & CEO, Material Handling Business and Equipment & Project Solutions, TIL, ?Due to increased demand for construction, there is a greater need for sand which has led to more riverbed mining. This in turn has resulted in the ban of sand mining mainly in Southern and Western states in India besides NCR. Thus, the demand for M-sand is seen to be rising steadily in these regions. The supply of M-sand is not adequate to meet the demand. Therefore, nowadays more and more crusher owners are looking for suitable and sustainable technology to manufacture M-sand by adding suitable equipment in their crushing plants.?

Says Saumil Sharma, Associate Vice President - Enterprise Sales, CDE Asia, ?Demand for M-sand is good in almost all regions of the country. Although no clear data is availbale on sand consumption, cement production can be used as a proxy to estimate aggregate and sand consumption in the country. India is second only to China as one of the largest consumer of sand in the world. M-sand market is directly linked to the crushing and screening business. Generally, 30 per cent of the crushed stone product comes in the form of stone dust. This crushed stone dust is the primary source of raw material for manufactured sand production.?

Sharma adds, ?M-sand markets have been particularly successful in regions where availability of river sand is scarce and cost of transporting river sand is very high. M-sand finds major application in urban infrastructure development as majority of metropolitan cities in India have scarce river sand resources at very high cost.?

According to him, sectors such as pre-cast industry, ready-mix industry, realty, and infra sector are drivers of M-sand demand, which continues to increase with new infrastructure and revival of existing infrastructure (roads, bridges, dams, houses)  all dependent on the availability of sand and aggregates. A prominent example of the use of M-sand on a wide commercial basis is the Pune-Mumbai Expressway, which was built only using M-sand.

Says V Venkataramana, Vice President - Marketing, Puzzolana Machinery Fabricators, ?Five years ago, there was a feeling that hundred per cent river sand cannot be substituted by M-sand. Even government agencies were in favour of maximum 70 per cent of M-sand and 30 per cent natural sand. The scenario has changed. Today, the demand has gone so high that we have no other option but to use M-sand. Five years ago, almost over 4,000 trucks with river sand used to enter Hyderabad city (80,000 tonne per day). Now we have almost 25,000 tonne of M-sand produced every day here. So, looking at the conversion rate, entire South and West have gone far ahead.?

Advantages of M-sand
Elaborating on the cost advantage of using M-sand, Venkatramana says, ?Today, people are more focused on the quality of M-sand, especially for Zone I and II. The advantage is that you are making consistent quality sand. For example, for a road project if the quality of M-sand is good, and the ultra fines are kept to the minimum, the quantity of bitumen needed is less. One tonne of M-sand costs Rs 1,200-1,300 whereas the cost of one tonne of bitumen is about Rs 40,000. So, if you can save 10 kg of bitumen, the cost saving becomes huge.?

Speaking about the advantages of washed M-sand, Sharma says, ?M-sand brings in better economies for business, by replacing the cost in effective river sand; it provides better concrete quality compared to concrete produces using river sand or crushed stone dust; reduces concrete production cost by saving approximately 20 per cent cement consumption, and also saves cost on water and admixtures. Plastering quality is far better and does not produce cracks with the use of washed masonry sand (fine sand).? ?The quality of sand plays a vital role here. As sand mining from river is getting banned, the only solution available is M-sand. Moreover, the gradation in M-sand is far superior, thus the consumption of cement and water is relatively lower. M-sand enhances the strength and durability of the casting produced. Therefore, all these industry sectors will have significant demand for M-sand,? says Bhattacharjee.

Use of classifiers
What are the factors that necessitate the use classifiers? Says Sharma, ?Ultrafines (particles below the size of 75 micron) in the feed material such as crushed stone dust, crushed sand, river sand, riverbed material, etc, need to be removed because their presence reduces the quality of sand and in turn the quality of concrete. Sand washing or dry classification offers the separation of the ultrafines from the feed material, resulting in high-quality well-graded sand, as per the Indian Specifications for fine aggregates (sand) IS 383. Under the third revision of IS 383, Bureau of Indian Standards is expected to bring in our country?s sand specifications at par with the world standards by introducing a low silt cut-off percentage for particles of 75 micron and below. Any source of crushed rock material requires reduction of silt percentage from the existing 15-20 per cent down to 2-5 per cent for suitable usage of the material in concrete applications. M-sand also creates a business imperative on the commercial side as the crushing companies can bring in value addition to waste crushed stone dust stockpiles. M-sand is a suitable and sustainable replacement for river sand, and thus, fetches a far better value that the crushed stone dust in the market.?

Sharma adds, ?Wet washing process is independent of the atmospheric moisture conditions or the moisture content of the feed material. On the contrary, dry classification requires the feed material moisture content as well as the atmospheric moisture content to very low. However, in a country like India, with four months long rainy season, it is difficult to achieve extremely low moisture levels, which drastically lowers the plants running efficiency. So, dry classifiers have limited geographical scope, and can work only in dry places like Rajasthan.? He further adds, ?Also, the final product quality of a wet washing system is far better than a dry air classification system and across different sand markets in the country, a wet system washed sand fetches much better value than dry air classifier sand. Hence, dry air classifiers may only be suitable for regions that have practically no availability of water.?

According to Bhattacharjee, the main factor that necessitates the use of classifier is the percentage of moisture content. He says, ?TIL-Astec high frequency screens can work efficiently when the moisture content is less than 5 per cent. The power consumed, space required, and additional equipment needed in a wet classifiers are much more as compared to High Frequency Screen (HFS). Thus, HFS is an extremely sustainable and cost-effective solution.?

Sharma observes, ?O&M cost for sand washing varies in the range of 5-10 per cent of the river sand prices in India. Sand washing process has been streamlined through the use of the latest in-house technology. Today?s advanced wash plants are one-stop solution for sand and aggregate washing. A single integrated plant can feed, clean, wash, grade, recycle water, and stockpile the product. Continuous R&D efforts have led to extreme mobility, clean power, easy maintenance, and minimal footprint of the washing plants.?

Trends
According to Sharma, end-users have been welcoming M-sand due to frequent fluctuations in river sand price and availability. The ability to continuously produce in-house M-sand at a much cheaper cost compared to river sand provides end-users with confidence and consistency of material quality and availability. This leads to huge cost savings on all concrete applications and stability in the design mix of concrete. Overall advantage of washed M-sand for the country as a whole is that real estate, infrastructure, irrigation, power, and similar key projects are not stalled because of issues related to river sand such as price volatility, NGT introduced river sand mining ban, etc.

He says, ?Individual suppliers have a major scope of transition from the traditional and diminishing market of river sand to the upcoming and innovative market of M-sand. There always exist traps in the market with sub-standard washing technology. For sand suppliers who are in the market for the long run, a dependable washing solution not only provides advantage of better product quality that fetches better price, but also helps to diversify into the M-sand market that promises long term steady returns. CDE works closely with the individual sand suppliers to identify their market, business needs, and nature of material and supplies them with a customised sand washing solution, which also happens to be the world?s best sand washing experience.?

According to Bhattacharjee, the general trend in the end-user segments is to use equipment that will produce M-sand. He says, ?Our HFS provides this option of producing M-sand with low operational cost and sustainable quality of recovered sand is far superior than M-sands produced by other alternative solution. The demand for M-sand is growing at a rapid rate since the riverbed mining is getting banned in more and more states.?

Product solutions
Speaking about the solution offered Sharma says, ?CDE Asia is the only company present in India that offers a real solution to manufacture sand - Sand Washing. CDE?s cutting-edge technology for M-sand inludes its flagship products - Combo? sand washing plant, Oremax? multi-product wash plant, and Sirocco? air classifier. Each of these is a leading product in the market in terms of technology, productivity, and value for money. CDE is not just a plant manufacturer, but a turnkey washing solution provider who understands its customer?s requirements and delivers a ?plant for life? with highest efficiency and maximum output.? He adds, ?In addition to that, all CDE plants are fully computerised and operate through an integrated PLC. A premium range offering of these plants comes with custom fit remote data monitoring systems that allows the client to monitor his sand washing operations on his or her mobile phone, and also allows CDE to monitor the plant vitals 24/7, through which CDE supports with live corrective measures and proactive service support.?

TIL offers HFS for the separation of M-sand. Says Bhattacharjee, ?HFS is driven by vibro motors. It has an operating angle of 38-45o. The screening media vibrates with a frequency of 0-4,200 rpm. HFS is used for separating M-sand (0.8-6.4 mm).?

Speaking about the features that enhance operator/environment-friendliness and optimisation of fuel/energy consumption, Bhattacharjee says, ?The patented ratchet pulley mechanism for mesh change is very easy to operate. The screen cloth prevents air pollution, thus the operation remains environment-friendly. A 30 HP motor is used and therefore, energy consumption is very less and significantly lower compared to other solution when compared for per tonne M-sand recovery.?

?We have come off the age where M-sand was a text book innovation. Today, M-sand is being used in almost all markets across the geography of this country. However, the challenge remains to break the status quo. Some market players have been complacent to embrace the new reality, a systematic phasing out of river sand and an increase in dependence on M-sand. We have witnessed a lot of our clients enjoying the first mover advantage in markets like Mumbai, Pune, Bengaluru, etc. India remains CDE Asia?s largest growing sand washing market, and with the increase in M-sand usage it will remain so for a long time to come,? Sharma observes.

Future potential
The proposed development of infrastructure projects such as highways, industrial corridors, ports, airports, and power projects coupled with the renewed focus on the housing sector is expected to contribute to the demand for CE sector which have seen record lows in recent years. The housing and infrastructure sectors have found a pride of place in this Budget. Housing will be impacted positively through the various Budget proposals namely, smart cities, real estate investment trusts (REITs), easing of FDI norms, enhancing of the tax deduction limit on interest for housing loans, the urban renewal programme and the housing for all programme.This will boost the demand for M-sand which in turn will help the growth of the manufacturing equipment segment.

M-sand is the inevitable future. With or without the NGT imposed river sand mining ban - M-sand has established commercial value for small and large projects cutting across diverse sectors: namely, stone crushing, ready-mix concrete, real estate, infrastructure, hydro-power, and other related construction sectors.

Pros& cons of classifiers
Pros:
Wet classifier is the option when the moisture content is above 5 per cent. There is no water requirement in dry classifier so no slurry formation thus it is an environment and friendly solution

Cons:
Large quantity of fresh water is required in case of wet classifier. Dry classifier would not work efficiently if the moisture content is above 5 per cent Wet classifier is more expensive as compared to dry classifier in terms of cost per tonne production of manufactured sand

- Somnath Bhattacharjee, President & CEO, Material Handling Business and Equipment & Project Solutions, TIL
?Nowadays, more crusher owners are looking for suitable and sustainable technology to manufacture M-sand by adding suitable equipment in their crushing plants.
- Saumil Sharma, Associate Vice President Enterprise Sales, CDE Asia
?Individual suppliers have a major scope of transition from the traditional and diminishing market of river sand to the upcoming and innovative market of manufactured sand.?
- V Venkataramana, Vice President - Marketing, Puzzolana Machinery Fabricators
?Today, the demand has gone so high that we have no other option but to use M-sand.?
Advantages Of M-Sand
Uniform sand grain size and quality
Provides better strength to concrete
Free of impurities
Competitive cost per tonne