24 August 2020 – A Tunisian sand quarry has partnered up with a Northern Ireland engineering company to turn a sand quarry that once focused on building materials into a profitable operation targeting the glass market in Europe.
The relative political stability and its proximity to European markets makes Tunisia one of the primary business hubs in North Africa. The business environment in Tunisia has improved significantly over the past two years, but Covid-19 delivered a blow to this rapid progress. However, the country provides a number of opportunities for those familiar with the North African way of doing business.
Tunisia’s economy is centered around agriculture and petroleum, but mining and the services sector plays a substantial role. Tunisia is the fifth largest exporter of phosphates in the world. Extraction of phosphate is the most important mining activity in the country, boosting the economy through exports by some 45%.
The mineral sector contributes about 3% of the GDP. Iron ore is extracted by government owned Société du Djebel Djerissa at the underground mine at Djerissa and at the open pit mines of Tamera and Douaria.
There are a few iron ore operations in Central Tunisia and the North-South axis area, covering an area of 43 000km2, and northeast of central Tunisia, fluorine and baryte have been mined for several years. There are several sand quarries scattered around the country with one of the main players being Somevam, a subsidiary of the Sebri Group. Somevam has been operating sand quarries in Queslatia, Tunisia, for almost 20 years. Sebri is an independent family group which brings together nine companies operating in agriculture, agricultural product processing and quarrying. Somevam recently saw an opportunity to diversify into the glass industry in North Africa and Europe and produce a range of supplementary products, including industrial sand and silica flour. The company also wanted to produce a 30-150 micron fraction that would make its offer unique in the region.
To achieve this Somevam needed an effective wet processing solution that would eliminate contaminants and offer variable cut points to increase the quality and commercial value of the end products.
Somevam extracts about 3000 tonnes of sand per day. To handle such quantities efficiently while also adhering to stringent quality standards required a tailor-made wet processing solution and Somevam turned to Northern Ireland headquartered CDE. The design process allowed CDE engineers to work directly with the Somevam team to develop a modular wet processing installation perfectly suited to the feed material (including a silica content of 99%) and the company’s production targets.
Habib Sebri, CEO of Somevam says that before the company started mining sand for the glass market, it operated the Oueslatia site to produce building materials. “However, it was clear that the material on site presented an interesting commercial opportunity in the field of silica for flat glass applications such as windows, mirrors and flat glazing,” he adds.
To guarantee precise control of sand cut points, Somevam opted for a complete turnkey CDE solution. The CDE plant has the capacity to treat up to 200 tonnes per hour (tph) of sand, producing 100tph of silica glass sand for the glass industry, as well as a range of secondary products including fine silica sand for silica flour production, foundry sand, concrete sand and road base.
The installation features a combination of CDE equipment operating in perfect synergy; an M4500 primary wash plant to classify materials, five high frequency Infinity Screens, four attrition cells, spiral separators, CDE’s Counter Flow Classification Unit (CFCU), a nano-cyclone, magnet, four EvoWash sand washing units and an AquaCycle water management solution. Combined, the system processes fine and coarse materials and eliminates contaminants to produce high-specification glass sand.
According to Bassem Idriss, project manager for the Europe and Middle East and North Africa region at CDE the M4500 demonstrates the effectiveness of CDE’s cyclone technology and the flexibility of the process and engineering teams, who have designed the process to produce very high quality glass sand to meet Somevam’s requirements.
“The hydrocyclones were built according to the specific needs of the client, based on analysis of the feed material carried out by CDE during the pre-project phase.
“The process water, loaded with undesirable fines, is removed at the level of the overflow of the cyclones while the treated sand enters the dewatering and stockpiling phase. With cutting points of incomparable precision, the products are treated according to the required standards and without risk of mixing,” says Idriss.
To produce a very clean sand product requires a very good supply of clean water. The new installation incorporates CDE’s cutting-edge water management system, the AquaCycle thickener with a capacity of 1500m³h. Waste water from the plant is processed by the AquaCycle thickener which recovers up to 90% of the process water to be recirculated back into the washing plant, minimising the size and maintenance requirements of the settling ponds, which is particularly advantageous where the site is situated in Tunisia
Idriss continues: “In Tunisia, a hot and dry country, it is important to consider the difficulties of accessing fresh water. It is essential not to waste a drop of water. CDE’s AquaCycle allows Somevam to recycle process water in a closed circuit for immediate reuse in the system,” says Idriss.
The wastewater, after passing through the deaeration chamber and after having been in contact with the flocculant injection, passes to the centre of the AquaCycle so that the flocculation process operates and acts on the sedimentation of the fines. The integrated flocculation unit allows precise dosing of premixed flocculant for effective decantation. A single motor drives the AquaCycle rake arms for optimal sludge treatment before disposal.
The CDE installation for Somevam transforms the feed material into five high specification products with exceptional commercial value. It produces glass sand (150-650 microns) and related products, including oversized (3mm) ready to be used in water filtration systems, coarse sand (650 microns-3mm) ready to be ground to make flour silica, ultrafine (30-150 microns) for ceramics or other industries, and iron-rich sand that can be used in sports fields. With a typical moisture content of 12%, the materials are market-ready straight from the belts.
Our CDE solution has made a huge impact on the glass sand industry in Tunisia and in the North African market. It represents the most advanced technology available on the North African market and has enabled Somevam to become ultra-competitive in an industry with extremely high-quality standards.