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Extensive durability problems such as weathering and degradation are found in historic Scandinavian brick masonry buildings, especially from the neo-Gothic period. These are largely due to the crystallization of salts and frost action in the bricks and mortars. This article aims to show and illustrate which salts and crystals are found in historic brick masonry buildings and to describe their appearance and behavior. An additional aim is to explore possibilities of preventing salt-related damage on internal masonry wall surfaces, such as using hemp-lime sacrificial plaster beneath the plaster. The objective is to show the mechanisms behind salt-related problems and to perform a case study and a laboratory study on salt-damaged brick masonry containing sodium sulphate. In order to prevent and stop damage to the masonry, it is important to be able to identify the nature of the salt damage and the type of salt that caused the damage. Neo-Gothic brick masonry buildings require well-planned, continuous maintenance of the masonry. It is therefore of the utmost importance to have an understanding of the complex functions of the masonry and of the salts that can cause damage to these historic buildings.

Extensive durability problems such as weathering and degradation are found in historic Scandinavian brick masonry buildings, especially from the neo-Gothic period. These are largely due to the crystallization of salts and frost action in the bricks and mortars. This article aims to show and illustrate which salts and crystals are found in historic brick masonry buildings and to describe their appearance and behavior. An additional aim is to explore possibilities of preventing salt-related damage on internal masonry wall surfaces, such as using hemp-lime sacrificial plaster beneath the plaster. The objective is to show the mechanisms behind salt-related problems and to perform a case study and a laboratory study on salt-damaged brick masonry containing sodium sulphate. In order to prevent and stop damage to the masonry, it is important to be able to identify the nature of the salt damage and the type of salt that caused the damage. Neo-Gothic brick masonry buildings require well-planned, continuous maintenance of the masonry. It is therefore of the utmost importance to have an understanding of the complex functions of the masonry and of the salts that can cause damage to these historic buildings.

Extensive durability problems such as weathering and degradation are found in historic Scandinavian brick masonry buildings, especially from the neo-Gothic period. These are largely due to the crystallization of salts and frost action in the bricks and mortars. This article aims to show and illustrate which salts and crystals are found in historic brick masonry buildings and to describe their appearance and behavior. An additional aim is to explore possibilities of preventing salt-related damage on internal masonry wall surfaces, such as using hemp-lime sacrificial plaster beneath the plaster. The objective is to show the mechanisms behind salt-related problems and to perform a case study and a laboratory study on salt-damaged brick masonry containing sodium sulphate. In order to prevent and stop damage to the masonry, it is important to be able to identify the nature of the salt damage and the type of salt that caused the damage. Neo-Gothic brick masonry buildings require well-planned, continuous maintenance of the masonry. It is therefore of the utmost importance to have an understanding of the complex functions of the masonry and of the salts that can cause damage to these historic buildings.

Extensive durability problems such as weathering and degradation are found in historic Scandinavian brick masonry buildings, especially from the neo-Gothic period. These are largely due to the crystallization of salts and frost action in the bricks and mortars. This article aims to show and illustrate which salts and crystals are found in historic brick masonry buildings and to describe their appearance and behavior. An additional aim is to explore possibilities of preventing salt-related damage on internal masonry wall surfaces, such as using hemp-lime sacrificial plaster beneath the plaster. The objective is to show the mechanisms behind salt-related problems and to perform a case study and a laboratory study on salt-damaged brick masonry containing sodium sulphate. In order to prevent and stop damage to the masonry, it is important to be able to identify the nature of the salt damage and the type of salt that caused the damage. Neo-Gothic brick masonry buildings require well-planned, continuous maintenance of the masonry. It is therefore of the utmost importance to have an understanding of the complex functions of the masonry and of the salts that can cause damage to these historic buildings.

Extensive durability problems such as weathering and degradation are found in historic Scandinavian brick masonry buildings, especially from the neo-Gothic period. These are largely due to the crystallization of salts and frost action in the bricks and mortars. This article aims to show and illustrate which salts and crystals are found in historic brick masonry buildings and to describe their appearance and behavior. An additional aim is to explore possibilities of preventing salt-related damage on internal masonry wall surfaces, such as using hemp-lime sacrificial plaster beneath the plaster. The objective is to show the mechanisms behind salt-related problems and to perform a case study and a laboratory study on salt-damaged brick masonry containing sodium sulphate. In order to prevent and stop damage to the masonry, it is important to be able to identify the nature of the salt damage and the type of salt that caused the damage. Neo-Gothic brick masonry buildings require well-planned, continuous maintenance of the masonry. It is therefore of the utmost importance to have an understanding of the complex functions of the masonry and of the salts that can cause damage to these historic buildings.

Sodium sulfate is one of the most damaging and complex salts typically involved in the deterioration of our architectural heritage. One of the main difficulties is to determine which of its crystalline phases, that is, thenardite, mirabilite, or the metastable heptahydrate, will precipitate under certain conditions. Indeed, there is a significant range of temperature and relative humidity in which these phases can crystallize. Furthermore, one precipitated crystalline phase may under certain conditions transform to another one. Here, we show that nuclear magnetic resonance can be successfully used to non-destructively define the phase being precipitated. We investigate delamination of Anc¸ã limestone due to sodium sulfate crystallization, a type of decay which is representative of those occurring in real constructions. The decay was achieved during isothermal drying of stone specimens under different environmental conditions. The work allowed concluding that both mirabilite and heptahydrate can be responsible for this type of decay in different conditions. The heptahydrate tends to crystallize when there is no previous presence of mirabilite crystals in the porous material.

The idea of using hydrated salts as working media for thermal energy storage has increased the interest in understanding their phase transitions. During studying the phase transition of mirabilite into thenardite, the crystal structure and water content are monitored by three experimental techniques. With the help of NMR, homogeneous drying of mirabilite crystals over the entire grain is observed. According to the drying behavior, the mobility of water molecules should be high inside the grain during dehydration. XRD experiments show that during this phase transition no disordered phase or other metastable phases like Na2SO4·7H2O or phase III appear. With Raman spectroscopy, these experiments are repeated at several relative humidities and again no metastable phases are observed.

This work considers the crystallisation mechanisms of the most common and aggressive salts that generate stress in porous building stones as a result of changing ambient conditions. These mechanisms include the salt crystallisation that result from decreasing relative humidity and changes in temperature and, in hydrated salts, the dissolution of the lower hydrated form and the subsequent precipitation of the hydrated salt. We propose a new methodology for thermodynamic calculations using PHREEQC that includes these crystallisation mechanisms. This approach permits the calculation of the equilibrium relative humidity and the parameterization of the critical relative humidity and crystallisation pressures for the dissolution–precipitation transitions. The influence of other salts on the effectives of salt crystallisation and chemical weathering is also assessed. We review the sodium and magnesium sulphate and sodium chloride systems, in both single and multicomponent solutions, and they are compared to the sodium carbonate and calcium carbonate systems. The variation of crystallisation pressure, the formation of new minerals and the chemical dissolution by the presence of other salts is also evaluated. Results for hydrated salt systems show that high crystallisation pressures are possible as lower hydrated salts dissolve and more hydrated salts precipitate. High stresses may be also produced by decreasing temperature, although it requires that porous materials are wet for long periods of time. The presence of other salts changes the temperature and relative humidity of salt transitions that generates stress rather than reducing the pressure of crystallisation, if any salt has previously precipitated. Several practical conclusions derive from proposed methodology and provide conservators and architects with information on the potential weathering activity of soluble salts. Furthermore, the model calculations might be coupled with projections of future climate to give a

This work considers the crystallisation mechanisms of the most common and aggressive salts that generate stress in porous building stones as a result of changing ambient conditions. These mechanisms include the salt crystallisation that result from decreasing relative humidity and changes in temperature and, in hydrated salts, the dissolution of the lower hydrated form and the subsequent precipitation of the hydrated salt. We propose a new methodology for thermodynamic calculations using PHREEQC that includes these crystallisation mechanisms. This approach permits the calculation of the equilibrium relative humidity and the parameterization of the critical relative humidity and crystallisation pressures for the dissolution–precipitation transitions. The influence of other salts on the effectives of salt crystallisation and chemical weathering is also assessed. We review the sodium and magnesium sulphate and sodium chloride systems, in both single and multicomponent solutions, and they are compared to the sodium carbonate and calcium carbonate systems. The variation of crystallisation pressure, the formation of new minerals and the chemical dissolution by the presence of other salts is also evaluated. Results for hydrated salt systems show that high crystallisation pressures are possible as lower hydrated salts dissolve and more hydrated salts precipitate. High stresses may be also produced by decreasing temperature, although it requires that porous materials are wet for long periods of time. The presence of other salts changes the temperature and relative humidity of salt transitions that generates stress rather than reducing the pressure of crystallisation, if any salt has previously precipitated. Several practical conclusions derive from proposed methodology and provide conservators and architects with information on the potential weathering activity of soluble salts. Furthermore, the model calculations might be coupled with projections of future climate to give a

The idea of using hydrated salts as working media for thermal energy storage has increased the interest in understanding their phase transitions. During studying the phase transition of mirabilite into thenardite, the crystal structure and water content are monitored by three experimental techniques. With the help of NMR, homogeneous drying of mirabilite crystals over the entire grain is observed. According to the drying behavior, the mobility of water molecules should be high inside the grain during dehydration. XRD experiments show that during this phase transition no disordered phase or other metastable phases like Na2SO4·7H2O or phase III appear. With Raman spectroscopy, these experiments are repeated at several relative humidities and again no metastable phases are observed.

Sodium sulfate is one of the most damaging and complex salts typically involved in the deterioration of our architectural heritage. One of the main difficulties is to determine which of its crystalline phases, that is, thenardite, mirabilite, or the metastable heptahydrate, will precipitate under certain conditions. Indeed, there is a significant range of temperature and relative humidity in which these phases can crystallize. Furthermore, one precipitated crystalline phase may under certain conditions transform to another one. Here, we show that nuclear magnetic resonance can be successfully used to non-destructively define the phase being precipitated. We investigate delamination of Anc¸ã limestone due to sodium sulfate crystallization, a type of decay which is representative of those occurring in real constructions. The decay was achieved during isothermal drying of stone specimens under different environmental conditions. The work allowed concluding that both mirabilite and heptahydrate can be responsible for this type of decay in different conditions. The heptahydrate tends to crystallize when there is no previous presence of mirabilite crystals in the porous material.

More than half the book is devoted to three chapters on sodium sulphate deposits, each with a substantial reference list. Chapter 1, on the origin of sodium sulphate and its deposits, covers gypsum and other sources as well as deposits of mirabilite, thenardite, glauberite, astrakanite and burkeite and accompanying dolomite and magnesite. Chapter 2, on ancient, buried deposits, surveys deposits in Argentina, Canada, Chile, China, Mexico, Europe, Namibia, the former Soviet Union, Spain, Turkey and the USA, while chapter 3, on recent lake, playa or surface deposits, includes deposits in Antarctica, Argentina, Canada, Chile, China, Egypt, Iran, Mexico, the former Soviet Union, Spain, Turkey, the USA, Australia, India, Peru, South Africa, Botswana and elsewhere. The chapter on processing covers current and former commercial operations as well as general processing methods and environmental considerations. Uses of sodium sulphate discussed include detergents, the textile industry, the Kraft pulping process, glass and other chemicals. Finally, there are chapters of production statistics for natural sodium sulphate, phase data and physical properties, plus a subject index., More than half the book is devoted to three chapters on sodium sulphate deposits, each with a substantial reference list. Chapter 1, on the origin of sodium sulphate and its deposits, covers gypsum and other sources as well as deposits of mirabilite, thenardite, glauberite, astrakanite and burkeite and accompanying dolomite and magnesite. Chapter 2, on ancient, buried deposits, surveys deposits in Argentina, Canada, Chile, China, Mexico, Europe, Namibia, the former Soviet Union, Spain, Turkey and the USA, while chapter 3, on recent lake, playa or surface deposits, includes deposits in Antarctica, Argentina, Canada, Chile, China, Egypt, Iran, Mexico, the former Soviet Union, Spain, Turkey, the USA, Australia, India, Peru, South Africa, Botswana and elsewhere. The chapter on processing covers current and former commercial operations as well as general processing methods and environmental considerations. Uses of sodium sulphate discussed include detergents, the textile industry, the Kraft pulping process, glass and other chemicals. Finally, there are chapters of production statistics for natural sodium sulphate, phase data and physical properties, plus a subject index.

Acigol Lake is currently the leading source of natural sodium sulphate in Turkey; it is produced from brines underlying a large playa. Large production reservoirs are formed on the lake by barriers and production is carried out in six steps: pumping, evaporation, crystallisation on cooling, drainage, dehydration and winning of the evaporate. Because the natural and climatic conditions around the lake are used in the production process there are many impurities, including stones and soil. Autogenous grinding and gravity concentration (jigging) and classification were investigated to remove these impurities. As a result of the investigations a gravity concentrator for preconcentrating Glauber's salt has been designed by Dedegil and is in use at the production plant., Acigol Lake is currently the leading source of natural sodium sulphate in Turkey; it is produced from brines underlying a large playa. Large production reservoirs are formed on the lake by barriers and production is carried out in six steps: pumping, evaporation, crystallisation on cooling, drainage, dehydration and winning of the evaporate. Because the natural and climatic conditions around the lake are used in the production process there are many impurities, including stones and soil. Autogenous grinding and gravity concentration (jigging) and classification were investigated to remove these impurities. As a result of the investigations a gravity concentrator for preconcentrating Glauber's salt has been designed by Dedegil and is in use at the production plant.

Following a general overview of China's mineral deposits, their distribution and genesis and the current situation with regard to mineral resources in China, individual energy, metallic and non-metallic resources are discussed in turn. Each section has a map showing the locations and relative sizes of deposits, and an English abstract outlining the characteristics of the Chinese deposits and their distribution, giving ore types, reserves and grades of key deposits or overall. Production is indicated and the supply-demand situation summarised. Commodities surveyed are coal, oil and gas, oil shale, uranium, iron, manganese, chromite, vanadium, titanium, copper, lead and zinc, bauxite, nickel, cobalt, tungsten, molybdenum, tin, bismuth, antimony, mercury, gold, silver, platinum group metals, lithium, beryllium, tantalum, niobium, zirconium and hafnium, rare earth elements, scandium, germanium, gallium, indium, thallium, rhenium, cadmium, selenium, tellurium, magnesite, fluorite, refractory clay, sulphur, phosphorus, potash, boron, salt, mirabilite, trona, barite, diamond, mica, graphite, asbestos, gypsum, talc, zeolites, diatomite, wollastonite, kaolin, bentonite, perlite, glass sand, cement limestone, granite and marble., Following a general overview of China's mineral deposits, their distribution and genesis and the current situation with regard to mineral resources in China, individual energy, metallic and non-metallic resources are discussed in turn. Each section has a map showing the locations and relative sizes of deposits, and an English abstract outlining the characteristics of the Chinese deposits and their distribution, giving ore types, reserves and grades of key deposits or overall. Production is indicated and the supply-demand situation summarised. Commodities surveyed are coal, oil and gas, oil shale, uranium, iron, manganese, chromite, vanadium, titanium, copper, lead and zinc, bauxite, nickel, cobalt, tungsten, molybdenum, tin, bismuth, antimony, mercury, gold, silver, platinum group metals, lithium, beryllium, tantalum, niobium, zirconium and hafnium, rare earth elements, scandium, germanium, gallium, indium, thallium, rhenium, cadmium, selenium, tellurium, magnesite, fluorite, refractory clay, sulphur, phosphorus, potash, boron, salt, mirabilite, trona, barite, diamond, mica, graphite, asbestos, gypsum, talc, zeolites, diatomite, wollastonite, kaolin, bentonite, perlite, glass sand, cement limestone, granite and marble.

An outline of world sodium sulphate resources, their occurrence, major producers, markets and uses is presented., An outline of world sodium sulphate resources, their occurrence, major producers, markets and uses is presented.

The Cayirhan-Beypazari evaporite sequences contain large amounts of trona together with nahcolite, pirrsonite, gaylussites and sulphate minerals such as thenardite, mirabilite, glauberite and gypsum. The evaporites originated within the Miocene to Pliocene basin which was formed due to the neotectonic instability of the Anatolian platform. The thenardite-glauberite-mirabilite and gypsum accumulations form a part of the gypsum-rich rocks which intercalate with glauberites and Na-Ca sulphate-rich layers. Microscopic studies revealed that glauberites precipitated first within the basin, followed by mirabilite and finally thenardite., The Cayirhan-Beypazari evaporite sequences contain large amounts of trona together with nahcolite, pirrsonite, gaylussites and sulphate minerals such as thenardite, mirabilite, glauberite and gypsum. The evaporites originated within the Miocene to Pliocene basin which was formed due to the neotectonic instability of the Anatolian platform. The thenardite-glauberite-mirabilite and gypsum accumulations form a part of the gypsum-rich rocks which intercalate with glauberites and Na-Ca sulphate-rich layers. Microscopic studies revealed that glauberites precipitated first within the basin, followed by mirabilite and finally thenardite.

An analysis is presented of the advantages and disadvantages of existing solution mining techniques for rock salt deposits. The principle and applications of multi-well hydraulic fracturing and controlled solution mining are reviewed and the use of the technique in the mining of mirabilite from the Yuncheng Salt Lake, China, is described. Use of the method results in increased rock salt recovery and reduced production costs., An analysis is presented of the advantages and disadvantages of existing solution mining techniques for rock salt deposits. The principle and applications of multi-well hydraulic fracturing and controlled solution mining are reviewed and the use of the technique in the mining of mirabilite from the Yuncheng Salt Lake, China, is described. Use of the method results in increased rock salt recovery and reduced production costs.

Details are presented of the successful pilot trials conducted by Messo-Chemietechnik on a new process for converting sodium sulphate and potassium chloride to glaserite and then to potassium sulphate and usable sodium chloride in continuous crystallisers. The process can accept by-product Glauber's salt and waste potash brines in place of high-grade raw materials., Details are presented of the successful pilot trials conducted by Messo-Chemietechnik on a new process for converting sodium sulphate and potassium chloride to glaserite and then to potassium sulphate and usable sodium chloride in continuous crystallisers. The process can accept by-product Glauber's salt and waste potash brines in place of high-grade raw materials.