P&K flotation reagents

FROTH FLOTATION

P&K flotation reagents

Newly developed flotation reagents are improving the selectivity and grade/recovery of phosphate and potash concentrates.

NOURYON

Diverse and sustainable potash mining reagents

Dr Krzysztof Kolman, scientist, Jan-Olof Gustafsson, senior scientist, and Dr Odair Lima, global strategic marketing manager

Typical sylvite flotation test in Nouryon’s application lab.

PHOTO: NOURYON

Potash mining and processing are important initial steps in the value chain that produces fertilizers and ultimately food. Nouryon offers products that can assist at nearly every step in the production of high-quality potash concentrate from potash ore. These boost process performance and help reduce adverse environmental impacts along the way.

Introduction

Potash is a water-soluble mineral salt valued for its potassium content that is almost always accompanied by sodium and magnesium chloride1 . Potassium is a crucial crop nutrient in agriculture. It can be applied directly as ‘straight’ potassium chloride (KCl, known as sylvite or muriate of potash, MOP) or potassium sulphate (K2 SO4 , commonly known as sulphate of potash, SOP). It is also incorporated and applied alongside other primary nutrients in NPK blends and complex NPK fertilizers.

MOP is the most widely consumed potash fertilizer – with demand from around the world exceeding 55 million tonnes annually2 . This type of potash is primarily applied to broad acre crops and chloride-loving vegetables such as sugar beet and corn. It also helps to build disease resistance in plants2 .

SOP, meanwhile, has the advantage of combining two key plant nutrients: potassium and sulphur. This premium quality product can be extracted from mineral deposits (primary SOP) as well as manufactured chemically (secondary SOP). SOP is ideal for chloride-sensitive crops, improving both quality and yields, while also making plants more resilient to drought, frost, insects, and disease. In addition, SOP is known to enhance the appearance and taste of vegetables and boost crop uptake of other essential nutrients such as phosphorus and iron. For these reasons, SOP is commonly used on high-value crops such as fruits, vegetables, nuts, tea, coffee and tobacco2 .

Potash production is dominated by the underground mining and surface processing of MOP. This predominant type of potash is also converted to SOP via the chemical Mannheim process. This synthesis method involves reacting MOP with sulphuric acid in a muffle furnace and heating to above 600°C. Alternatively, SOP can be manufactured by reacting potassium chloride with various sulphate compounds. These form a double salt from which it is possible to make SOP plus sod ium chloride2 .

Enhancing potash recovery

As a global leader in specialty chemicals, Nouryon possesses more than 50 years of expertise in mineral processing functions, such as flotation collectors, depressants, and processing aids, with solutions to enhance the recovery of a variety of ore types – including calcite, phosphate, iron, silicate, graphite, sulphide, and potash.

“We partner with our customers to deliver essential solutions for a sustainable future,” says Brad Pearson, global marketing director at Nouryon.”

Table 1: Nouryon’s mining product range for potash ores

The froth flotation challenge

Processing potash ore by separating off its different components can be a challenge as many of these are water-soluble. However, this processing challenge can be met and overcome by selecting the right froth flotation technique – as this enables improved separation performance in a cost efficient way.

Nouryon, for example, offers innovative and individually customised flotation agents for unique ores including potash. These deliver superior performance combined with a strong focus on sustainability. These capabilities are possible thanks to decades of mineral processing expertise and the company’s track record of customer collaboration.

For Nouryon, environmental stewardship – and the creation of more value for its customers – starts with the sustainable sourcing of bio-based raw materials. Nouryon has a broad portfolio of flotation agents for the potash industry. The company’s main potash processing products are listed in Table 1 together with their respective functions.

The use of selective collectors that efficiently make mineral surfaces hydrophobic – and therefore susceptible to separation – is critical for successful flotation. To this end, Nouryon has designed and developed several collectors suitable for diverse potassium-bearing minerals and conditions. Many of these are based on fatty amine technology, one of Nouryon’s core areas of expertise.

“Nouryon’s individually customised flotation agents for potash deliver superior performance combined with a strong focus on sustainability.”

“Our collectors can efficiently balance recovery and selectivity during the flotation of sylvite from sylvinite in MOP production across a variety of ore types, brine compositions, and process temperatures,” says Henrik Nordberg, global section manager for mining at Nouryon.

Figure 1 illustrates the performance of amine blends used in potash flotation, while a typical sylvite flotation test is shown in the article’s main photo.

Reverse flotation for halite removal

Nouryon’s Armoflote619 ® collector is unique, as it enables the successful reverse flotation of halite (sodium chloride) from carnallite (a potassium chloride and magnesium chloride mixture) and other double salts such as schoenite (a mixture of potassium and magnesium sulphates). In reverse flotation, the unwanted gangue mineral is floated while the valuable mineral remains as the bottom product. When used as collector in carnallite flotation, Armoflote 619 exhibits an impressive ability to remove halite from the valuable potash-bearing mineral (Figure 2).

Removal of slimes

Certain potash ores contain clay minerals in addition to the salt minerals that typically occur. These fine clay particles – also known as slimes – negatively impact potash flotation due to their high charge and high surface area. This prevents separation by depleting collector concentration. Solutions to this problem include:

• Mechanical desliming using hydro separators and cyclones
• Physico-chemical separation via slime flotation or the use of a depressant that blocks slime surfaces from interfering with sylvite flotation.

Fig. 1: Performance of Nouryon’s ArmeenM/ArmeenHT ® ® collector blend in sylvite flotation: typical grade-recovery curves

Fig. 2: Separation of carnallite from halite by reverse flotation using Nouryon’s Armoflote619 ® collector

Fig. 3: Use of Celect® CMC depressants to optimise sylvite recovery

Of these two options, physico-chemical separation via flotation is usually preferred, since mechanical desliming causes the loss of fine potash particles, while total potash recovery can also be improved through selective reverse flotation of the slimes. A range of products demonstrates Nouryon’s proficiency with slime collectors. These include EthomeenHT/40 ® and Berol® non-ionic collectors as well as the PhospholanPE65 ® anionic collector.

Nouryon is also a leading global manufacturer of carboxymethylcellulose (CMC) depressants (Celect® and Finnfix® ) for mining applications. This enables the company to maximise recovery grade profiles for its customers by offering holistic and individually tailored flotation options. CMC, a bio-based anionic polymer, functions as an efficient depressant in the flotation of a wide variety of minerals, including potash. CMC optimises sylvite recovery (Figure 3) by ensuring that flotation collectors are fully adsorbed on the surface of the target mineral by ‘blinding out’ the active surface area of clays.

Potash coating

Once successfully separated via froth flotation, the high quality potash concentrates obtained need to be prepared for storage and transportation. This is usually achieved by applying a mineral coating, typically an anticaking agent, to prevent potash adsorbing water and becoming lumpy and sticky. Nouryon offers a range of anticaking agents (ArmeenHT, ArmeenT, ArmeenO, ArmeenM, ® ® ® ® and ArmofloAC-59P) ® which use fatty amine technology to preserve potash concentrates in their desired form until they reach their ultimate destination.

References

1. Garrett, D., 2012. Potash: deposits, processing, properties and uses. Springer.

2. Pistilli, M., 2021. Potash Fertilizers: What’s the Difference Between SOP and MOP? Agricultural Investing News. 22 June 2021. Accessed: 4/1/2021.

BASF MINING SOLUTIONS

Phosphate flotation reagents

Dr Jan Bennewitz, lab leader, flotation, and Gabriela Budemberg, global developer, non-sulphide flotation

Sustainable, high-performance products

The mining industry is shifting towards improving environmental sustainability. Individual companies are pursuing this objective by optimising ore recovery in a sustainable manner as well as by managing tailings more effectively.Sustainable ore recovery is being achieved by replacing or reducing the use of toxic and non-biodegradable materials, for example, and by lowering the consumption of reagents.

BASF mining solutions provides the mining industry with sustainable solutions which increase productivity, recovery and flexibility. Our expertise and capabilities cover every type of hydrometallurgical process, including leaching, solvent extraction, flotation, solid/liquid separation and tailings management. The company provides mining operators worldwide with innovative products and industry leading technical expertise backed up by global field support.

BASF supports its mining customers on their journey towards sustainability with products that meet the highest regulatory standards. These improve the sustainability of mineral extraction processes by offering innovative chemistry in combination with operational support and digital solutions.

Table 1: BASF’s portfolio of collectors for phosphate flotation

In keeping with this approach, the mining solutions team at BASF continues to work intensively to develop new flotation collectors for phosphate ores. Tailored to customer needs, these reagents are designed and optimised for both direct flotation of apatite and/or reverse flotation of carbonate gangue (Table 1).

With high-grade ores diminishing, the demand for chemicals offering improved selectivity and higher recovery is correspondingly rising. Indeed, the need to continuously improve the product formulations applied in low grade and complex ore deposits is making sustainable mining solutions essential.

BASF’s Lupromin® portfolio (Table 1) offers an innovative and sustainable range of collectors, co-collectors, frothers, modifiers and flocculants. These are suitable for phosphate operations as well as the beneficiation of other ore types.

Beyond its standard portfolio, BASF also develops tailor-made formulations in close collaboration with its customers and partners. This includes support for laboratory, pilot plant and industrial test work. These customised formulations achieve superior flotation performance due to their defined froth characteristics. They are capable of delivering yield increases of up to 10 percent at reduced dosage rates and costs – fulfilling the classic sustainability mantra of ‘doing more with less’. On top of this, BASF also provides reliable data and tools to quantify the contribution flotation reagents make to sustainability.

Fig. 1: Effects of BASF’s LuprominFP A 1210 Base ® co-collector on grade and recovery: lab scale tests on a weathered igneous phosphate ore from South America

Enhanced flotation with co-collectors

LuprominFP A 1210 Base ® – one of BASF’s latest product developments – has been successfully applied on igneous weathered phosphate ore from a mine in South America. This co-collector product was used to boost the performance of a standard flotation reagent (NaOH-neutralized soy oil fatty acid) applied in the direct flotation of the mine’s silicate-bearing phosphate ore (4.5% P2 O5 and 32.0% SiO2 ).

Initial lab-scale flotation tests with LuprominFP A 1210 Base ® demonstrated significant grade and recovery improvements (Figure 1). These beneficial results were achieved due to the synergistic effect between the co-collector and the fatty acid collector. In recent test work on this mined ore, LuprominFP A 1210 Base ® delivered the following advantages:

• P2 O5 grade remained at around 32 percent while recovery increased by six percent
• The addition of a co-collector at a dose of 10 percent allowed a 30 percent reduction in the fatty acid collector dosage
• Operational CO2 emissions were reduced by six percent (per tonne of phosphate production) and accompanied by additional savings in energy consumption
• Tailings disposal was also lowered.
• “Customised formulations are capable of delivering yield increases of up to 10 percent at reduced dosage rates and costs — fulfilling the classic sustainability mantra of ‘doing more with less’.

Performance gains with other collectors

In addition, BASF recently performed further flotation tests on the following two phosphate ores:

• North European igneous phosphate ore: direct flotation with LuprominFP A 1341BW, ® a non-ionic modifier resistant to temperature variations, achieved a 2.5 percent increase in recovery at a 40 percent lower dose rate, compared to the previously applied product. CO2 emissions were also reduced by 2.5 percent (per tonne of phosphate production).
• South American igneous phosphate ore: direct flotation with LuprominFP A 712, ® a highly selective collector, increased recovery by 18 percent. This product, being a replacement for APEOs, also improved health and safety during material handling. CO2 emissions were reduced by as much as 11 percent too, depending on the exact customer site.

References

1. BASF, 2020. BASF Report 2020. Economic, environmental and social performance. p43.

Calculating product carbon footprints (PCFs)

As part of its commitment to sustainability, BASF plans to make available individual carbon footprints for its entire portfolio of around 45,000 sales products by the end of 20211 . This is being achieved with the help of a new digital calculator that was developed in-house for measuring product carbon footprints (PCFs). PCFs cover all of BASF’s product-related greenhouse gas emissions that occur during manufacturing up until the point the product leaves the factory gate for the customer: from the purchased raw material to the use of energy in production processes (Scope 1-3 emissions). Calculating PCFs creates transparency for our customers and partners, enabling us to develop plans to collectively reduce CO2 emissions along the value chain up to the end-product.