Salt Production

Introduction 

Over 100 countries produce a significant amount of salt with many others on a small scale. The USA is the biggest producer of salt in the world, accounting for approximately 21%, with China providing about 15% and Europe just over 20%, of which Germany and France are the biggest contributors. Other major producers are India, Australia, Mexico and Canada

Sales of salt grew in South Africa at an average rate of 2,2 percent per annum and reached a record high of R90 million in 2006, which represented 0.05 percent of total revenue generated from mining. 

Salt, or sodium chloride, is a readily available inexpensive bulk mineral that can be produced by a variety of methods: 

• Solar brine – seawater evaporation in shallow coastal basins or artificial ponds. Lake brine is also used as feed in conventional solar ponds. 

• Underground deposits of halite or rock salt, mined by room and pillar, or solution mining which forms a large underground cavity. 

• Vacuum evaporation – brine dehydration to crystallise salt in a series of multiple-effect evaporators operated under vacuum to reduce process temperatures. 

The main uses of salt irrespective of production method are: 

• Chemical production; 

• Cooking and food processing; 

• De-icing of roads in winter; 

• Agriculture; 

• Other industrial uses such as oil and gas exploration, textile dyeing, aluminium refining, glazing, soap making and leather tanning. 

The biggest consumer of salt is the chemical industry. The chloralki sector is a major consumer using salt to manufacture chlorine and sodium hydroxide. Salt is a popular raw material in the industry as it is the cheapest and most common source of soda and chlorine. About 1, 75 tons of salt are required to make 1 ton of chlorine and 1,1 ton of caustic soda co-product. 

Locality 

South Africa ’s salt resources are confined to underground brines associated with inland saltpans, coastal saltpans and seawater. Sea salt is produced in Port Elizabeth. Production is based primarily on the evaporation of seawater,  which usually contains 3,5 percent of dissolved solids, of this 74,8 percent is sodium chloride. At the saltworks, the seawater is concentrated by solar evaporation in artificial ponds until a relative density of 1,204 is attained, the brine is then fed into crystallisation pans for eventual harvesting. 

There are two salt companies based around Port Elizabeth, the one is situated in Coega which supply branded salt to the major retailers and another situated in Swartkops that supplies the wholesale market, particularly the Free State, Eastern Cape and KZN regions. 

Volumes

South Africa  ’s production of salt from 1974 – 2006 is estimated at 17 Mt, including production from coastal pans and Walvis Bay. South Africa has 18 operating salt companies, of varying size, including one co-operative operation with more than forty small-scale producer members.  Production has been on the increase from 2004 and reached 465 kt in 2006. The trend seems to be in line with strong performance of the economy. The top six companies contributed 82 percent to local production. Because local production cannot supply all of South Africa’s salt, imports are necessary. Imported salt  is sourced mainly from Botswana and Namibia.  The plant in Coega producers approximately 32 000 tons of salt on an annual basis and supplies South Africa, Botswana and Lesotho with salt. 

Product 

Various types of salt have unique production, processing and packaging factors that determine their selling price. Salt sold in bulk is naturally less expensive than salt that has been packaged, pelletised or pressed into blocks. Vacuum pan salt is the most expensive because of the higher energy cost involved in processing and purifying the product. 

Development in the salt industry 

According to the mineral economics directorate, the Coega based company  has recently announced a R85 million expansion and relocation project into the Coega Industrial Development Zone (IDZ). The project will see the company using innovative technology to produce high purity sodium chloride known as pure vacuum dried salt (PVD), which is of better quality and produced through an environmentally friendlier process. The new facility in the Coega IDZ will include state of the art technology with a production capacity of 45 000 tons per annum.  

Another company plans on spending R5,8 billion on a chlorine manufacturing and water desalination plant at the Coega IDZ. The project will involve seawater desalination and thermal evaporation technologies would create around 630 000 t/y of 99,9% pure salt, some of which would be used at the plant, while the rest would be sold to the local market. The plant will have the capacity to produce 600 tons of chlorine per day and will supply both the local and export market. 

The first phase of the investment will total R1,1 billion and construction is expected to take between 18 and 24 months and the plant is to be officially commissioned in mid-2009. The project is expected to create 600 jobs during construction and once operational, will employ about 250 people on a three shift basis, excluding management positions. 

Transport 

The goods are packaged and distributed by road to the various markets. The vehicles used will vary from rigid vehicles for local delivery to articulated and interlink vehicles , used for the longer hauls into South Africa, Botswana and Lesotho. The vehicle types will vary from box/pantechnicons, where the vehicle is enclosed, to flatdeck and dropsided vehicles.