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Limestone Crushing in India

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Thyssenkrupp Industries India Pvt Ltd, Pimpri, Pune (henceforth tkII) offers a variety of solutions to different types of limestones, which are geographically located in different areas of India.
India is a rich country in minerals with a lot of deposits of coal, iron ore, limestone, etc. Out of which limestone is one of the most important minerals in many parts of India right from Jammu & Kashmir in north to Tamil Nadu in South. Different limestones in various areas are not the same owing to their geological formation and hence every mine’s limestone is different than that of others. Eg. Limestone in North Karnataka/Telangana belt is hard, dry, with very less amount of silica whereas that of Chhattisgarh belt is medium hard, Marley type with clay. Different types of limestones ideally requires different type of crushing solutions.
Thyssenkrupp Industries India Pvt Ltd, Pimpri, Pune (henceforth tkII) offers variety of solutions to different types of limestones, which are geographically located in different areas of India. E.g. Limestone in Rajasthan (Udaipur and surrounding area) is hard, difficult to crush but easy to grind (Bond index ranging from 9-13 kWh/ST) however limestone in Karnataka region is very hard, but relatively easy to crush and difficult to grind (as bond index is between 13-17 kWh/ST) limestone. Limestone in eastern Madhya Pradesh is full of clay, very hard to crack, but easy to grind (Bond index ranging from 9-13 kWh/ST) and that appearing in Odisha region is very soft, with clay and Marley type.
For different limestones, tkII can offer different crusher. Following is the range of crushers, that tkII can offer which can cover all types of limestone, currently available in India. Speciality of tkII is, it can offer all types of solutions for very high production rate of up to 2,500 tonne per hour or customised solutions can be offered for higher capacity.
Let’s understand different types of crushers that tkII can offer1. Single or Double shaft type impact hammer crushers: Impact hammer crushers are used when generally compressive strength of limestone is <150 MPa, Moh’s hardness value is < 4 and max. Silica content is approximately 8 per cent. These crushers can take up to 10 per cent moisture for single shaft and maximum 20 per cent moisture for double shaft. Construction of an impact hammer crusher comprises of a rotor made from cast manganese steel discs, fixed on forged shaft, usually machined in square or pentagonal shape for better distribution of generated stresses.
A rotor discs comprises of 5 or 6 hammer axles mounted peripherally on which swinging hammers weighing from 90 to 160 kg are mounted. Hammers are also of cast manganese steel. This crusher crushes limestone, initially with impact when rows of hammers hit the bolder, then with impact and shear between anvil block and hammers and finally attrition takes place between grate bars and hammers. Due to grate bars fixed below rotor, material won’t come out till it achieves desired size. Generally double shaft hammer crusher can cater to most of the limestones that are occurring in India (except Tamil Nadu). This crusher can handle up to 20 per cent of clay provided it is fed with stones in between. The combination of clay and stones ensures self-cleaning of grate bars.2. Impact crusher or Impactor: tkII is capable of making single rotor impactor, which is used for hard limestones with compressive strength of up to 175 MPa. However such crusher is not recommended for sticky or Marley type limestones which causes clogging of chambers. It comprises of fabricated housing with Hardox liners and cast manganese steel grinding path. The rotor is generally a cast steel body with six rows of fixed blow bars, which can be reversed to get more life. As it does not have any grate assembly at the bottom, such crusher has application mainly for products size between 75 to 100 mm which it can generally produce from 1.5 m bolder. 3. Double roll crusher/Sizer: If the plant and mines are located separately and client needs only primary crushing in mines, then double roll crusher or sizers is a good option. These crushers are also used when the limestone is highly sticky with no stones e.g. the one appearing in Southern parts of India. Here the toothed rolls rotating in opposite direction compress the material between two rolls and crush it. Double roll crusher works on the principle of inertia and sizer works on the principle of torque. Speed of rotation in sizer is slow at 60-80 rpm whereas that in double roll crusher is high at 200-230 rpm. However limitation of these sizers/ roll crushers is crushing ratio which can be max. 1:5.4. Jaw crushers: For very hard limestone & for primary crushing, tkII can offer jaw crushers wherein it can take very hard limestones up to 400 MPa compressive strength. But crushing ratio is limited to max. 1:5. in jaw crusher, there will be one reciprocating jaw which compresses the material between another fixed jaw & crushing takes place. There will not be much size control of the product hence such crusher is generally used where there is a secondary crushing planned in the circuit. Product capacity for such crushers is also limited to 500 Tons per hour.Selection of crushers based on Applications of limestone
Maximum use of limestone is for cement production, but apart from that, limestone is also used as flux in steel making, as reaction agent in flue gas desulphurisation (FGD) systems in power plants, for emission reduction etc. Most (>90 per cent) of commercially mined limestone is used for cement production. The type of raw meal grinding systems in cement plant can have impact on selection of crushing system for limestone.
Based on onward grinding system, it is desirable to choose a crusher.

  • Ball mills: As the ball mills requires lesser product size of < 25 or 30 mm, a hammer type crusher is highly recommended for such applications. The advantage that hammer type crusher provides for limestone is high crushing ratio which ensures -25 mm can be achieved in single pass/stage. For most parts of Indian limestone, tkII double rotor hammer crusher is suitable & can easily crush to -25 mm.
  • High pressure grinding roll: As high pressure grinding rolls are sensitive to feed size, it is desirable to feed them with product from hammer crusher. Also the size of < 40 – 60 mm may not be possible in single stage in any other crusher so hammer crusher has an edge if you wish to use HPGR for raw meal grinding.
  • Vertical roller mills: As VRM can accommodate larger product size of < 75 – 90 mm and the same can be done in single stage in crusher like impactor, a single stage impactor can be a good solution for crushing. tkII can offer single stage impactor crusher for such requirements.

tkII is capable of offering all above systems. So for most plants which are in between 5000 TPD to 10000 TPD, the crushing plant capacity turns out to be 1200 TPH to 2000 TPH, tkII can offer either impactor or hammer crusher. Following is the comparison of impactor hammer crusher. Ramp height for Hammer crusher is less compared to Double rotor impactor. As every mine’s limestone is customised, it is advised to refer the requirement to us so that customised solutions can be offered.
Impact Hammer Crusher Impactor (Fixed blow bar type)
Crushes by Impact, shear & Attrition. Suitable for medium hard materials.
Hammer crusher will be self-cleaned when hard stones will be fed with the sticky material. Crushes by Impact and shear.
Suitable for medium hard and hard materials.
Not suitable for sticky materials
Impact is due to heavy swing hammers
(135 to 160 kg) Impact is due to Fixed blow bars fixed by side wedges.
Reduction ratio is high up to 1:100 in single stage Reduction ratio is limited up to 1:20 per rotor stage (for higher reduction two rotor compound impactor is used)
Can accept higher moisture up to 20% and higher clay and silica Moisture is up to 10 % and silica up to 6%, limitation due to wear
Crusher product size is governed by the gap in the grate bars. Within limits product size is adjusted by adjusting impact plates and grinding path
Consistent product size throughout the use, no adjustments needed to compensate for wear. This crusher is far more suitable for HPGR which is sensitive to input product size. Frequent adjustment of impact walls/ grinding path necessary to compensate the rotor blade wear & grinding/ impact plates. In impactor, with wear of grinding path & blow bars, product size changes.
Due to swinging hammers, part of shock loads absorbed in the hammer deflection and remaining load transferred to the rotor bearings.Due to rigid construction of rotor, 100% shock goes to rotor bearings.
Hidden cracks are left in the crushed products – that is favorable for onward grinding. This crusher produces finer product granulometry which is favorable to increase throughput of HPGR / Ball Mill. Cubical products without any hidden cracks and coarse product granulometry limits the capacity of the VRM / Ball mill.
In case of double shaft hammer crusher, each rotor shares theoretically equal loads – hence installed power is lower (2 x 800 kW for say 1200 TPH at -40 mm) as well as consumed power per ton (0.68 kWh/T) lower than compound Impactors. In case of compound rotor Impactors each rotor handles 100% material – hence installed power (2 x 1200kW) as well as consumed power (1 to 1.1 kWh/T) are higher. ABOUT THE AUTHOR:
Sanjeev Nargund, Senior GM – Crusher & Screen Design at Thyssenkrupp industries India Pvt Ltd.
He can be contacted on: Sanjeev.nargund@thyssenkrupp.comMilind Kulkarni, Senior Manager – Marketing at Thyssenkrupp industries India Pvt Ltd.
He can be contacted on: milinds.kulkarni@thyssenkrupp.com

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Price hikes, drop in input costs help cement industry to post positive margins: Care Ratings

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Region-wise,the southern region comprises 35% of the total cement capacity, followed by thenorthern, eastern, western and central region comprising 20%, 18%, 14% and 13%of the capacity, respectively.

The cement industry is expected to post positive margins on decent price hikes over the months, falling raw material prices and marked drop in overall production costs, said an analysis of Care Ratings.

Wholesale and retail prices of cement have increased 11.9% and 12.4%, respectively, in the current financial year. As whole prices have remained elevated in most of the markets in the months of FY20, against the corresponding period of the previous year.

Similarly, electricity and fuel cost have declined 11.9% during 9M FY20 due to drop in crude oil prices. Logistics costs, the biggest cost for cement industry, has also dropped 7.7% (selling and distribution) as the Railways extended the benefit of exemption from busy season surcharge. Moreover, the cost of raw materials, too, declined 5.1% given the price of limestone had fallen 11.3% in the same aforementioned period, the analysis said.

According to Care Ratings, though the overall sales revenue has increased only 1.3%, against 16% growth in the year-ago period, the overall expenditure has declined 3.2% which has benefited the industry largely given the moderation in sales.

Even though FY20 has been subdued in terms of production and demand, the fall in cost of production has still supported the cement industry by clocking in positive margins, the rating agency said.

Cement demand is closely linked to the overall economic growth, particularly the housing and infrastructure sector. The cement sector will be seeing a sharp growth in volumes mainly due to increasing demand from affordable housing and other government infrastructure projects like roads, metros, airports, irrigation.

The government’s newly introduced National Infrastructure Pipeline (NIP), with its target of becoming a $5-trillion economy by 2025, is a detailed road map focused on economic revival through infrastructure development.

The NIP covers a gamut of sectors; rural and urban infrastructure and entails investments of Rs.102 lakh crore to be undertaken by the central government, state governments and the private sector. Of the total projects of the NIP, 42% are under implementation while 19% are under development, 31% are at the conceptual stage and 8% are yet to be classified.

The sectors that will be of focus will be roads, railways, power (renewable and conventional), irrigation and urban infrastructure. These sectors together account for 79% of the proposed investments in six years to 2025. Given the government’s thrust on infrastructure creation, it is likely to benefit the cement industry going forward.

Similarly, the Pradhan Mantri Awaas Yojana, aimed at providing affordable housing, will be a strong driver to lift cement demand. Prices have started correcting Q4 FY20 onwards due to revival in demand of the commodity, the agency said in its analysis.

Industry’s sales revenue has grown at a CAGR of 7.3% during FY15-19 but has grown only 1.3% in the current financial year. Tepid demand throughout the country in the first half of the year has led to the contraction of sales revenue. Fall in the total expenditure of cement firms had aided in improving the operating profit and net profit margins of the industry (OPM was 15.2 during 9M FY19 and NPM was 3.1 during 9M FY19). Interest coverage ratio, too, has improved on an overall basis (ICR was 3.3 during 9M FY19).

According to Cement Manufacturers Association, India accounts for over 8% of the overall global installed capacity. Region-wise, the southern region comprises 35% of the total cement capacity, followed by the northern, eastern, western and central region comprising 20%, 18%, 14% and 13% of the capacity, respectively.

Installed capacity of domestic cement makers has increased at a CAGR of 4.9% during FY16-20. Manufacturers have been able to maintain a capacity utilisation rate above 65% in the past quinquennium. In the current financial year due to the prolonged rains in many parts of the country, the capacity utilisation rate has fallen from 70% during FY19 to 66% currently (YTD).

Source:moneycontrol.com

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Wonder Cement shows journey of cement with new campaign

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The campaign also marks Wonder Cement being the first ever cement brand to enter the world of IGTV…

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Cement manufacturing company Wonder Cement, has announced the launch of a digital campaign ‘Har Raah Mein Wonder Hai’. The campaign has been designed specifically to run on platforms such as Instagram, Facebook and YouTube.

#HarRaahMeinWonderHai is a one-minute video, designed and conceptualised by its digital media partner Triature Digital Marketing and Technologies Pvt Ltd. The entire journey of the cement brand from leaving the factory, going through various weather conditions and witnessing the beauty of nature and wonders through the way until it reaches the destination i.e., to the consumer is very intriguing and the brand has tried to showcase the same with the film.

Sanjay Joshi, executive director, Wonder Cement, said, "Cement as a product poses a unique marketing challenge. Most consumers will build their homes once and therefore buy cement once in a lifetime. It is critical for a cement company to connect with their consumers emotionally. As a part of our communication strategy, it is our endeavor to reach out to a large audience of this country through digital. Wonder Cement always a pioneer in digital, with the launch of our IGTV campaign #HarRahMeinWonderHai, is the first brand in the cement category to venture into this space. Through this campaign, we have captured the emotional journey of a cement bag through its own perspective and depicted what it takes to lay the foundation of one’s dreams and turn them into reality."

The story begins with a family performing the bhoomi poojan of their new plot. It is the place where they are investing their life-long earnings; and planning to build a dream house for the family and children. The family believes in the tradition of having a ‘perfect shuruaat’ (perfect beginning) for their future dream house. The video later highlights the process of construction and in sequence it is emphasising the value of ‘Perfect Shuruaat’ through the eyes of a cement bag.

Tarun Singh Chauhan, management advisor and brand consultant, Wonder Cement, said, "Our objective with this campaign was to show that the cement produced at the Wonder Cement plant speaks for itself, its quality, trust and most of all perfection. The only way this was possible was to take the perspective of a cement bag and showing its journey of perfection from beginning till the end."

According to the company, the campaign also marks Wonder Cement being the first ever cement brand to enter the world of IGTV. No other brand in this category has created content specific to the platform.

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In spite of company’s optimism, demand weakness in cement is seen in the 4% y-o-y drop in sales volume. (Reuters)

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Cost cuts and better realizations save? the ?day ?for ?UltraTech Cement, Updated: 27 Jan 2020, Vatsala Kamat from Live Mint

Lower cost of energy and logistics helped Ebitda per tonne rise by about 29% in Q3
Premiumization of acquired brands, synergistic?operations hold promise for future profit growth Topics

UltraTech Cement
India’s largest cement producer UltraTech Cement Ltd turned out a bittersweet show in the December quarter. A sharp drop in fuel costs and higher realizations helped drive profit growth. But the inherent demand weakness was evident in the sales volumes drop during the quarter.

Better realizations during the December quarter, in spite of the 4% year-on-year volume decline, minimized the pain. Net stand-alone revenue fell by 2.6% to ?9,981.8 crore.

But as pointed out earlier, lower costs on most fronts helped profitability. The chart alongside shows the sharp drop in energy costs led by lower petcoke prices, lower fuel consumption and higher use of green power. Logistics costs, too, fell due to lower railway freight charges and synergies from the acquired assets. These savings helped offset the increase in raw material costs.

The upshot: Q3 Ebitda (earnings before interest, tax, depreciation and amortization) of about ?990 per tonne was 29% higher from a year ago. The jump in profit on a per tonne basis was more or less along expected lines, given the increase in realizations. "Besides, the reduction in net debt by about ?2,000 crore is a key positive," said Binod Modi, analyst at Reliance Securities Ltd.

Graphic by Santosh Sharma/Mint
What also impressed analysts is the nimble-footed integration of the recently merged cement assets of Nathdwara and Century, which was a concern on the Street.

Kunal Shah, analyst (institutional equities) at Yes Securities (India) Ltd, said: "The company has proved its ability of asset integration. Century’s cement assets were ramped up to 79% capacity utilization in December, even as they operated Nathdwara generating an Ebitda of ?1,500 per tonne."

Looks like the demand weakness mirrored in weak sales during the quarter was masked by the deft integration and synergies derived from these acquired assets. This drove UltraTech’s stock up by 2.6% to ?4,643 after the Q3 results were declared on Friday.

Brand transition from Century to UltraTech, which is 55% complete, is likely to touch 80% by September 2020. A report by Jefferies India Pvt. Ltd highlights that the Ebitda per tonne for premium brands is about ?5-10 higher per bag than the average (A cement bag weighs 50kg). Of course, with competition increasing in the arena, it remains to be seen how brand premiumization in the cement industry will pan out. UltraTech Cement scores well among peers here.

However, there are road bumps ahead for the cement sector and for UltraTech. Falling gross domestic product growth, fiscal slippages and lower budgetary allocation to infrastructure sector are making industry houses jittery on growth. Although UltraTech’s management is confident that cement demand is looking up, sustainability and pricing power remains a worry for the near term.

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