Syncarb

Introduction

There are many solutions to the global warming problem on offer and I listed them years ago on our Sustainability pages under the heading Solutions to the Global Warming Problem - Wacky or Otherwise. There are a few more to add now!

There is no doubt that sequestration and better still recycling of CO2 is essential and man made carbonates should be at the forefront of our efforts, if nothing else because the technology is not so hard and the carbonate produced is thermodynamically stable. CO2 should be recycled as carbonate not stored as a gas in risky places. We need sequestration stable in geological time, not for just a few hundred years. Think of what legacy issues your descendents may face as a result of pumping CO2 underground. See Economics

The Permanence of Carbon Sinks [1]

We have a planet that is obviously in trouble. Cement and concrete can be part of the solution not the problem. There are amazing skills in that industry held down by our past short sighted thinking. It is time to break out and show what mineral thermodynamically stable sequestration in the built environment is all about and at the same time clean up our industry. It is time to move on, drop the plagerism and constant renaming of good ideas, jump out of the fishbowl that our current research resides in and consider what we should be trying to achieve to surive the medium term let alone the long term.

Cement is generally less than 20% of concretes at most and the rest is fine to coarse aggregate so making man made carbonate aggregate for concrete and other uses will achieve far greater sequestration. The technical hitch is to achieve good strength in the aggregate and we have some ideas on how to achieve this. See Making Product from Syncarb.

No cement involving a calcined product including rMgO is truly environmentally friendly unless it can be made without releases. As CO2 recycling and sequestration work best with point sources of CO2 it is ideally combined with cement manufacture. We prefer using concentrated brines as a source for the Ca, Mg and Na ions required to produce mineral carbonate and desal waste water is consitant in composition and therefore easiest to commercialise at scale. We are suggesting a tececology (aka industrial ecology) of cement plants, desal waste water plants and sequestration plants with further value extraction and no releases at all. Because the concrete industry is a big emitter of CO2 from cement making and a combined process is something we can make money with is should be an attractive proposition

The cement and concrete industry has many skilled material scientists. Once they fix their our own industry in the manner suggested here we can contribute and make money at the same time applying our materials skills thinking about other uses there are for man made carbonates from agriculture to road material.

Syncarb is the combination of previously considered seperate process in the one area as a tececology (aka industrial ecology) to make money solving sustainability problems symbiotically. A syncarb tececoloy would obviously include a point source emitter of CO2, sequestration plant, separation plant and a product plant. The concrete industry is ideal as they know about materials. A desal plant located where there is predominantly solar power and a lot of political pressure to reduce releases would have to be involved and some metal miners who are keen to think laterally and work on wet seperation of valuable elements contained in seawater such as lithium and finaciers who are prepared to back all this up.

Syncarb also involves two changes to the current state of the art for sequestration in brines. Sodium hydroxide has a high carbon cost, and too many end or pipe disposal issues and will not be used. We prefer green ammonia as it can be made electrolytically from energy from the sun or from sewerage. Furthermore it will also allow precipitation of sodium bicarboante (NaHCO3) and can be recycled or released as sulphates and chloride fertilizers.

• Syncarb is Simple
• Scalable
• Has lower cost because it tails from water de-salination processes and into further value adding seperation processes.
• It is portentiall very profitable
• Reduces environmental impacts of de-salination and seuqestration
• Doable
• Industrially symbiotic and deployable
• Results in thermodynamically stable carbonates.

Detail or our suggested process is described under the heading Sequestration of CO2 in Brine and the plant needed is described under the heading CO2 Sequestration Process Plant.

The outputs of sequestration can be recycled as product for many different uses from de acidificaiton of the oceans to agricultural lime replacement or incorporated in process to produce aggregate, ammonium fertilizer and man other products and onprocessing can occur to extract lithium and rare elements needed for a carbon free world with electric cars, low or no emissions, abundant energy from the sun and a return to a steady state atmosphere the same as it has been for the last few million years. Minerals classified as critical for future technolgies in many countries that are used in electric cars, batteries, solar panels etc.include Antimony, Beryllium, Bismuth, Chromium, Cobalt, Gallium, Germanium, Graphite, Hafnium, Helium, Indium, Lithium, Magnesium, Manganese, Niobium, Platinum-group elements, rare earth elements (REE), Rhenium, Scandium, Tantalum, Titanium, Tungsten, Vanadium and Zirconium are all to be found in desal wastewater. Although most brines, including concentrated seawater have lower concentrations of many minerals than the nodules on the sea floor for example they are ubiquitous and there are huge supplies dissolved in them. With computer controlled wet precipation and other newer technologies they could be extracted with no deletarious impacts. A by product could be fertilizer if ammonia is used as the base as we recommend. See also Sequestration of CO2 in Brine

Syncarb could use brines including bitterns and oil process water but we prefer that we start with desalination waste water because of it's consistent composition and possibilities for onprocessing. By coupling desalination with carbon sequestration, cement manufacture, mineral extraction and product recyling the environment would be improved without the salty life destroying releases from desalination which are generally more than twice the salinity of seawater [1], CO2 releases from cement manufacture could be eliminated and laying waste the land by surface mining, tailings dams and other releases reduced. One of the products from Syncarb could be aggregate for concrete using cement made from the associated cement plants. Perhaps even the calcium carbonate from desal could be used in cement manufacture. Then there is agriculture and many other uses.

Many of the minerals in seawater such as lithium are in desal wastwater and their concentrations are over twice that shown in the table below for seawater depending on the desalination plant. All of them have value and can help pay for sequestration if recovered in the same process.

Element	Concentration in  seawater (ppm)	Total oceanic abundance (tons)	Mineral reserves on Land (tons)
Na	10,800	1.40 × 1016	-
Mg	1,290	1.68 × 1015	2.20 × 109
Ca	411	5.34 × 1014	-
K	392	5.10 × 1014	8.30 × 109
Li	0.178000	2.31 × 1011	4.10 × 106
Ba	0.021000	2.73 × 1010	1.90 × 108
Mo	0.010000	1.30 × 1010	8.60 × 106
Ni	0.006600	8.58 × 109	6.70 × 107
Zn	0.005000	6.50 × 109	1.80 × 108
Fe	0.034000	4.42 × 109	1.50 × 1011
U	0.003300	4.29 × 109	2.60 × 106–5.47 × 106
V	0.001900	2.47 × 109	1.30 × 107
Ti	0.001000	1.30 × 109	7.30 × 108
Al	0.001000	1.30 × 109	2.50 × 1010
Cu	0.000900	1.17 × 109	4.90 × 108
Mn	0.000400	5.20 × 108	4.60 × 108
Co	0.000390	5.07 × 108	7.00 × 108
Sn	0.000280	3.64 × 108	6.10 × 106
Cr	0.000200	2.60 × 108	4.75 × 108
Cd	0.000110	1.43 × 108	4.90 × 105
Pb	0.000030	3.90 × 107	7.90 × a107
Au	0.000011	1.43 × 107	4.20 × 104
Th	0.0000004	5.20 × 105	1.30 × 106

Concentrations and estimated amounts of dissolved metal ions in the sea,
compared with the estimated land resources. [2]

Syncarb is very different to other desalination of brine processes so far described. Advocates of the carbonation of brines as a means of sequestering CO₂ do not contemplate precipitating sodium carbonate. They should and not just because it contains CO₂. Sodium is a very reactive metal, and hence forms a very strong bonds with the carbonate ion. As a consequence Na2CO3 does not decompose on heating. It only decomposes near its melting point of 851°C. It is however water soluble and must therefore stored in a safe dry place if not used immediately. There are many uses for sodium bicarbonate and carbonate made from it. There are also many papers discussing the use of sodium carbonate (Na2CO3) also contained in Natron [3] for making rock like materials. See Making Products from Syncarb.

There are already over 20,000 desalination plants around the world [7] few or none recycle cabonated and only a small number extract mineral from their waste brine would be profitable.

To do this efficiently the sodium, magnesium and calcium should be removed first and what better way than to recycle CO2 into carbonate product using these cations! An alkali is required to keep the pH at the right levels and at the end of the process. We have chosen ammonia for this purpose not just because it will probably be cheaper in the long run for purposes already provided and because we can all help make it when we go to the toilet! Ammonia can also be recovered or reused in the Syncarb process to make fertilizer by allowing it to combine with remaining chloride and sulfate anions at the end of the process which is a lot better than discharging concentrated brines containin these ions. It is ridiculous, but at the moment we spend as much money trying to turn ammonia back to nitrogen at sewage plants as we do making it in the first place from nitrogen mostly using the carbon intensive Born Haber process!

We need to do a lot more research to work out how much ammonia we need to adjust pH in realtion to Mg and Calcium. In relation to sodium the method is not unlike the Solvay process.The following table should give some idea as to how much money could be made per cubic metre of desal waste. It is not accurate yet and prices which are dated early 2021 need to be updated.

 

TABLE SHOWING THE VALUE OF INPUTS AND OUTPUTS OF THE SYNCARB(1) PROCESS.	Formulae	Input or production output Kg/m3 brine	Current unit price $US/Kg(2)	Revenue per m3 of brine ($US)	References
INPUT
Brine		1,000	Negligible	Negligible	Negligible
OUTPUT
Nesquehonite	MgCO3.3H20	4.44	.70	3.108	7.55
Calcite	CaCO3	1.36	0.50	.68	USGS Mineral Commodity Summary
Sodium bicarbonate	NaHCO3	11.03	.22	2.4266	USGS Mineral Commodity Summary
Potassium chloride	KCl	0.76	.25	.19	1.90
Ammonium chloride	NH4Cl	3.49	.20	.698	USGS Mineral Commodity Summary
Ammonium sulfate	NH4SO4.10H2O	0.08	.08	.0512	Alibaba
Lithium chloride	LiCl	.178.	200.00	35.60	London Metals Exchange
VALUE OF MINERALS FOR SALE/M3 SEAWATER				$ 42.75
(1) Given brine with the composition of sea water. Note that Syncarb can use brines that are more concentrated and that give greater value. (2) As at 25 Mar 21
(2) When NaHCO3 is heated above about 80°C it begins to break down, forming sodium carbonate, water and more carbon dioxide.

 

 

 

 

 

 

 

 

 

 

 

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