[fb455] !Read# Unhairing Hides by Sulphide of Sodium (Classic Reprint) - Cutler Hall and Borchers ^P.D.F~
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1948 1988 583 1165 3846 1564 796 4202 125 2356
Impact, reuse of hide discharges, leather qua- lity, unhairing sodium sulphide quantities commonly used in method.
Hair can be rapidly removed from a bovine hide with caustic sodium sulfide. A rapid unhairing of the hide while still on the carcass in the slaughterhouse is an attractive alternative, because.
The average savings were 65% sodium sulphide, 33% lime and 90 % water. The limed-unhaired pelts from each cycle were further processed through tannage, retannage, drying, and finishing.
In paper pulping, in dyestuffs processing, in rayon and cellophane desulfurizing, in unhairing hides and as a bleaching reagent sodium hydrogen sulfide is used.
The enzymatic treatment of hides and skins can be considered as a cleaner technology only if the amount of sodium sulphide is reduced substantially. However it is not yet possible to use less than 1% of sodium sulphide for bovine hides.
Organic matter (especially hair) and from compounds used in the processing of hides including surfactants and unhairing agents, such as sodium sulfide (na2s).
The time required for easy unhairing through liming is greatly shortened by the use of sharpening agents, of which the principal on is sodium sulfide. The hydrolysis of sodium sulfide produces sodium sulfhydrate (sodium hydrosulfide), which acts specifically on keratin, accelerating the loosening of the hair.
Unhairing is the most polluting stage of the tanning process hide and solubilised hair proteins sodium sulfide/sodium hydrosulfide is used in combination.
54 unhairing, one of the operations during the beamhouse stage, consists in removing 55 the hair or wool off the hides and skins. The reagents conventionally being used during this operation are sodium sulfide and/or sodium hydrosulfide and56 lime. After a reductive 57 reaction, the joint action of hydrosulfide (hs-) and hydroxyl (oh-) ions.
Our work has studied the possibility of modifying the reductive unhairing process. 113 with hair recovery (using lime, sodium sulfide and sodium hydrosulfide),.
Jan 1, 2015 hair removal employs calcium hydroxide (hydrate lime) and sodium sulphide. These chemicals are added to the vessel containing the hides.
Aug 3, 2018 preparation of sulphide-lime unhairing tannery process was carried out using differences in degree of unhairing, swelling and plumping of the pelts.
Abstract— unhairing – limming process is the most polluting operation in leather industry. In hair burn unhairing -limming method, lime and sodium sulphide and a huge amount of water are used to destroy and remove hair from hides and skins generating a large amount of effluent.
Efficacy of ozone depilation and influence of ozone on the physico - chemical.
The minimum sulphide dosage for obtaining a hair-save lime-sulphide unhairing is approximately.
Biocides, surfactants, degreasers, swell regulating agents, lime, sodium sulphide, sodium hydrosulphide, low sulphide unhairing agents, caustic soda, soda ash,.
As compared with the classical sulphide unhairing method, a 50% reduction of sulphide was observed in the wastewater, as well as a 40% reduction in the suspended solids level.
Liming is a process used for parchment or leather processing, in which hides are soaked in an are denatured by the presence of alkali (particularly sodium sulfide), rendered soluble, facilitating their removal from the leather.
The soaked hides and skins are treated with lime and sodium sulphide mixture which gives desired swelling of collagen structure to open up the fiber bundle. The quality of ultimate finished leather largely depends on this operation. A common industrial practice of unhairing and liming is one step.
The use of enzymes for hair loosening in leather processing provides a sodium sulphide, which is conventionally used as sharpening.
Of salt (up to 12% on the hide weight) were added to unhairing liquors consisting of 2 % lime, 3 % commercial sodium sulphide and 100% water.
The present invention relates to an improved process for the unhairing of hides/skins. More particularly, the present invention relates to a non-enzymatic, sulfide free hair-save process of unhairing hides and skins for application in the beam house of the tanning industry.
A solution of sodium sulphide alone with admixture with lime is a strong unhairing agent. It is reported that when lime alone is used, it requires longer time to cause hair removal. Unhairing effect of sodium sulphide is maximum when sh and oh ions in the solution are present equal quantities.
Enzymes active in acid medium are employed for hide unhairing in a buffer system as sodium sulphide mixed with large amounts of lime and ammonium salts.
The tanning process aims to transform hides in stable and imputrescible products namely sodium sulphide used in the unhairing-liming step is one of the most.
This is because the traditional unhairing process requires sodium sulphide, and lime in the beamhouse phase.
In addition, the effectiveness of unhairng using the composite of protease and α-amylase was compared with that of conventional unhairing using lime and sodium sulfide. 1 materials conventional soaked cattle hides were used for unhairing trials.
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