A method is provided of moulding a shaped article having a porous structure, comprising: introducing into a mould a paste comprising e.g. OPC 10-50wt% of solids, and clinker 90-50wt% of solids and water and allowing it to harden. In an alternative embodiment the paste may be of clinker, gypsum and lime, or it may be of OPC. Initial set is allowed to take place in a first period at a relatively low temperature with minimal loss of water but sufficient to allow achievement of initial set. Further hardening to a green state in which the shaped article is removable from the mould is allowed to take place in a second period at a relatively high temperature and at high humidity with minimal or no loss of water. A flexible plastics mould e.g. of LDPE may be used to permit de-moulding of the articles e.g. by flexion of the mould. After the second hardening period the article may be removed from the mould and allowed to harden for a third hardening period at a higher temperature than for the first period and while maintaining its water content. It may then be water-soaked to remove fines and cure unreacted material. In an alternative embodiment after the second hardening period the article may be removed from the mould and may be subjected for a third period to combined hardening and soaking in water. In either case, it may then be dried at 70- 120°C at 0.01-1bar for 2-12 hrs. The invention also provides a porous article hydraulically moulded from (a) clinker, gypsum and lime, (b) OPC and clinker or (c) OPC. The article has a face that was adjacent the mould with a nominally even pore distribution of 25-35% by area with pore sizes 2-10μm, a mid-depth having < 1-2μm pores evenly distributed and representing 20-25% by area and a face furthest from the mould having 2-5 μm pores representing 20-25% of the surface by area. It may have a water absorption measurable after drying at 120°C of 26-30 wt% and/or an oil absorption measurable at an oil temperature of 36-40°C and on drying at 120°C of 14-20 wt%, it may have a 3-point bend strength of 5-9.5 Mpa and a bulk density of 1.6-1.8. When placed in cooking oil at frying temperature it should not give rise to substantial foaming.
In the moulding of cementitious articles, a flexible plastics mould e.g. of LDPE may be used to permit de-moulding of the articles e.g. by flexion of the mould. Moulds filled with hydraulically settable material may be supported in frames configured e.g. with plug and socket formations on upper and lower faces for cooperation with moulds to retain them in position and for cooperation with overlying and underlying frames to permit stacking.
2) 1-2 wt % and optionally further ingredients selected from calcium silicate, magnesium silicate, aluminum silicate, natural feldspars, natural sodium zeolites, natural calcium zeolites, synthetic sodium zeolites, synthetic calcium zeolites, wollastonite, calcium hydroxide, clays, pillared clays, activated clays/earths, talcs/kaolinite, amphiboles, granite porphyry, rhyolite, agalmatolite, porphyry, attapulgite and diatomaceous earth. It has the properties that calcium and magnesium substantially do not leach into the oil and that it is porous so that oil can diffuse into it and contaminants can be deposited on and within it.
B01J 20/02 - Solid sorbent compositions or filter aid compositionsSorbents for chromatographyProcesses for preparing, regenerating or reactivating thereof comprising inorganic material
B01J 20/28 - Solid sorbent compositions or filter aid compositionsSorbents for chromatographyProcesses for preparing, regenerating or reactivating thereof characterised by their form or physical properties
A23D 9/00 - Other edible oils or fats, e.g. shortenings or cooking oils
C04B 111/00 - Function, property or use of the mortars, concrete or artificial stone
C04B 111/80 - Optical properties, e.g. transparency
A method is provided for preserving cooking oil which may be cold or heated or during frying operations, which comprises in situtreatment of the oil withat least one oil-permeable cement body which has been hydraulically hardened from a paste comprising cement clinker and cement e.g. white OPC clinker and white OPC. The invention further comprises cooking oil having therein at least one oil-permeable cement body which has been hydraulically hardened from a paste comprising cement clinker and cement and an oil-permeable cement body for use in the above method.
A method is provided for treating cooking oil during frying operations, which comprises in situ treatment of the oil with a source of calcium or magnesium combined with silicate such that the calcium or magnesium substantially does not leach into the oil. The filter treatment materials may be cement clinker, OPC, calcium silicate and combinations or mixtures thereof e.g. a combination of white OPC clinker and white OPC. The filter treatment materials may be in the form of a free briquette or block immersed in the oil. In other embodiments a decontaminating or filter cartridge is provided for fitting to a deep oil or fat cooker or a frying basket and comprises a foraminous housing containing filtering or decontaminant material. The cartridge may be used in association with a deep oil or fat fryer having a base formed with a depression defining a cool spot, the cartridge fitting in or on said cool spot.
Amethod is provided for preservingcooking oilwhich may be cold or heated or during fryingoperations, which comprises in situtreatment of the oil withat least one oil- permeable cement bodywhich has been hydraulically hardened from a paste comprising cement clinker and cement e.g. white OPC clinker and white OPC. The invention further comprises cooking oil having therein at least one oil-permeable cement body which has been hydraulically hardened from a paste comprising cement clinker and cement and an oil-permeable cement bodyfor use in the above method.
B01J 20/10 - Solid sorbent compositions or filter aid compositionsSorbents for chromatographyProcesses for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
patents
