Global Cement speaks with Enrique Rozas, CEO of Drake Cement, a major producer of cement in Arizona, US.
Global Cement (GC): Please could you introduce Drake Cement to our readers?
Enrique Rozas (ER): The Drake Cement plant is located in Paulden, Arizona, US. It is owned by Skanon Inc, a holding company. Skanon itself is owned by UNACEM, a Peruvian cement, ready-mix, aggregate and energy corporation that also has interests in Peru, Ecuador and Chile.
The Drake Cement plant was conceived of between September 2003 and April 2006, with construction starting in May 2008. The kiln was first lit in December 2010, with first the ASTM clinker produced in March 2011. The plant was officially opened in June 2011. Since it began production, the plant has seen numerous upgrades, with a new separator in 2016 and an expansion to its storage facilities in 2021. The installation of a new finish mill is ongoing.
GC: Please could you take our readers through the plant’s production process as it stands in 2022?
ER: The process starts at our limestone quarry raw material extraction operations. Our quarry comprises three main limestone classifications: high stone, mix stone and low stone. This material is prepared and hauled by loader and haul trucks into a receiving hopper. This feeds a vibrating screen classifier that can handle material up to 1m3. The stone is then fed into our impact crusher, which reduces it to less than 70mm at a rate of 495t/hr. After the crusher, we have three overland conveyors (equipped with a ThermoFisher cross belt analyser) that cross over the Hell Canyon en route to a limestone storage building.
Additive materials, such as bauxite, alumina, iron ore etc., are received via truck and rail. These materials are discharged into one of our two receiving hoppers, which are equipped with vibrating feeders to ensure proper material flow. The materials are then conveyed to the plant’s additives building.
The mix components are then extracted from their respective storage buildings into our array of raw mix bins. These silos are equipped with DMO-Schenck belt weigh feeders which dose each component at a precise rate, based on our secondary ThermoFisher cross belt analyser. Thus raw mix is controlled. This mix is then fed to our Polysius high-efficiency separator where the fines are separated from the coarse material. The fines are carried to a series of cyclones while the coarse material is dropped to our roller press for further comminution. Once the material has been ground to a fine powder, it is recycled into our raw mix for further separation. This process then repeats in a closed-circuit arrangement. After the fines have been separated from the exhaust gas, they are stored in our raw meal blending silo, capable of storing 8000t. The meal is continuously blended and dispensed by an inclined aeration silo floor integrated with an inverted mixing chamber. It is then placed into a surge tank where it is lifted and introduced to the pyro process.
The pyro-processing system consists of a six-stage in-line FLSmidth calciner preheater tower fitted with two 47MW combined FLSmidth calciner burners. This is followed by a 45m-long 3.8m-diameter Vulcan kiln with two tyre supports. It is equipped with an FLSmidth Duoflex burner and a custom FCT burner tip retrofit.
Once the hot clinker has exited the kiln it enters our Claudius Peters ETA 746S cooler, capable of handling 2000t/day. The clinker is then stockpiled in one of our three storage structures.
Our cement mix consists of clinker and gypsum. It is introduced to the finish mill circuit, which consists of a roller press with HR separator. It has a similar design to that of our raw mill circuit. There is also an additional 3000hp ball mill with a Sepol SPS separator for additional classification. The cement product is cooled and stored in our cement silos, which have a combined capacity of 25,000t.
GC: What kinds of cement are produced by Drake Cement?
ER: The plant produces 100% ASTM Type II-V cement. In the future we will expand the range to include cements that contain ground pozzolans and limestone.
GC: What fuels does the plant use?
ER: We currently use 35% coal, 30% petcoke, and 35% natural gas. The coal grinding system has a capacity of around 13.4t/hr for coal and 8t/hr for hard coke. It comprises a Raymond pulveriser, pneumatic pump, baghouse and CO2 inerting system. There is a 300t pulverised coal silo with Pfister rotor weighfeeders for dosing the coal to the kiln and calciner.
GC: What kinds of environmental abatement systems are used at the plant?
ER: Here at Drake, we use a wide range of equipment to preserve the land and meet governmental compliance regulations. We control dust emissions by routinely spraying our roads and open areas with tanker trucks and operate water spray nozzles at material discharge points. Our storage buildings are all enclosed and we utilise many state-of-the-art baghouses spread throughout the plant to ensure a safe and clean operation. We also benefit from our calciner SNCR ammonia injection system to reduce NOx emissions.
GC: Are there any projects ongoing at the moment or any scheduled for the near future?
ER: We are working on three projects that are in the implementation phase: a secondary finish mill, downcomer water injection, and a new mechanical shop. The shop should be ready by the time this issue reaches your readers.
GC: Where are its main markets and how do you serve them?
ER: Our main markets are the state of Arizona and southeast Nevada, primarily metro Las Vegas. We currently service these markets through trucks, as most of our customers are within a four hour radius from the plant by road. All our production is consumed within this radius, so we haven’t felt the need to reach out beyond our core market. We currently do not produce any bagged cement, so all of our cement is despatched in bulk.
In our short history over the past 10 years, nothing has fundamentally changed in terms of our markets. However, this may change in the near future in terms of the customers we serve, where we sell cement and how we get there.
GC: How has the Covid-19 pandemic affected sales over the past couple of years?
ER: Covid-19 seemed to have acted as a catalyst for sales growth in our markets for two reasons. Firstly, the construction industry was considered as an ‘essential service’ during the pandemic and hence was excluded from the most stringent measures. This allowed normal work, and even some more, to continue in Arizona.
Secondly, given the good climate and the absence of natural calamities for the most part, Arizona has seen a huge influx of both people and industries from more densely-populated areas. The rising population in Arizona, which was always growing but received an additional boost due to Covid-19, has now led to a spate of growth in infrastructure, residential starts, multifamily housing, commercial construction and so on.
All this has fed into a construction boom in Arizona, which has inflated demand much beyond what indigenous plants in Arizona can supply. Our production capacity, and that of our competitors in Arizona, is maxed out right now. We are selling everything we can produce!
GC: How will the Arizonan and wider south west US market develop over the coming 2 - 5 years?
ER: The national and southwest US macro-economic situations are extremely dynamic. The construction industry may go through a few changes in the coming months. Arizona typically lags a few months behind this cycle, so it is very difficult to predict what is in store in the coming months and into the start of 2023.
That said, the underlying indicators, such as demographic growth and the industries moving into Arizona, are promising trends that are feeding into the growth of the construction sector. It is hard to predict how long this cycle will last before we hit a slow down or a recession.
GC: What are the main threats and opportunities for Drake Cement over the same period?
ER: With the expansion and growth plans we are investing in right now, our assumption is that the market will continue to grow at a decent rate. The biggest risk would be a recession or contraction of the construction sector, which would put a dent into our future plans.
Over the next 2 - 5 years, we are primarily looking to expand our grinding capacity, which will also allow us the flexibility to grind clinker or pozzolan. We intend to capitalise on the current growth in the market through our investment in these capacity expansions.
GC: Thank you for your time today Enrique.
ER: You are most welcome. It was a pleasure!
Plant equipment summary
Quarry and Additives
Classifier: Type DU-STK 14-1.6 x 4.8 (5.2) ED ThyssenKrupp Screening Machine.
Primary crusher: Type P 160/150 CR ThyssenKrupp Impact Crusher • 495t/hr • Feed size: 1000mm • Output: 95% < 70mm.
Cross Belt Analyser: ThermoFisher CB Omni Fusion.
Reclaimer: Claudius Peters Portal Reclaimer GP2 455/37.5
455t/hr.
Additives / Unloading: Syntron MF-200-C
Electromechanical Feeder.
Raw mill
Weighfeeder: Schenck DMO weighfeeder • 170t/hr.
Separator: Polysius HR 16/27 high-efficiency separator
Input: <65mm • Max gas vol. after separator: 225,000Bm3/hr.
Roller press: Polysius High-pressure grinding roll POLYCOM PM 5-16/8 • 165t/hr • Input: <65mm.
Storage: Claudius Peters Mixing Silo Mixing Chamber • 7250t.
Cross Belt Analyser: ThermoFisher CB Omni Fusion
Pyro-proces
Preheater: FLSmidth six-stage in-line calciner preheater tower.
Kiln: Vulcan kiln • L = 45m • Ø = 3.8m.
Burner: FLSmidth Duoflex • 35 MW thermal capacity
Modified burner tip by FCT.
Cooler: Claudius Peters ETA 746S • 2000t/day
Dust Collector: 136,000 ACFM IAC M-Type 6 compartment jet-pulse dust collector.
Clinker Storage: Dome: L = 45,500t • Ø = 60m.
Silo: 12,500t • H = 27m • Ø = 24m.
Coal mill: 280kW Raymond pulveriser
DWR Pfister roto weighfeeder.
Finish grinding
Separator: Polysius HR 12/21
Max gas vol. after separator: 140,000Bm3/hr
Roller press: Polysius High-pressure grinding roll POLYCOM PM 5-16/8 • 100t/hr (2400t/day) • Input: >65mm.
Ball mill: Single chamber Marcy ball mill.
