Ruling on sugar of which the refining process uses bone char
Question

Is refining cane sugar haram? Because the factories use burned bones (bone char) in the refining process, which may be bones from livestock but we do not know their precise source and whether it is halal or haram.
Praise be to Allah.Firstly:
Using burned bones in the manufacture of sugar refers to using bone char and ash during the process of refining the juice of sugar cane or sugar beet in order to extract the white table sugar.
It says in al-Mawsoo‘ah al-Fiqhiyyah al-‘Aalamiyyah (17:249):
Two types of charcoal are more well-known than others. They are: charcoal, which is made from wood, and bone coal (bone char), which is also called “animal coal”; the latter is made from the remains of animals, especially their bones. “Bone coal” or bone char is primarily found in the form of ashes and contains some carbon and other elements.
Manufacturers use bone char in ground-up or powder form to thicken colours and make them stick to inner surfaces. This process is also used in the manufacturing of white sugar. End quote.
Secondly:
The bone char that is used in refining sugar is one of two things:

Either the bones are pure (taahir), if they come from animals that are permissible to eat and are slaughtered in the prescribed manner; in this case there is no problem, because they are halal and taahir (pure).
Or the bones are impure (najis), if they came from an animal that was not slaughtered in the prescribed manner (maytah).

The correct view concerning such matters is that by being burned and turned to ashes, it becomes pure, because impurities are purified by means of transformation (istihaalah – i.e., being turned into a different substance), according to the correct scholarly view, as is the view of the Hanafis and Malikis.
It says in al-Mawsoo‘ah al-Fiqhiyyah al-Kuwaitiyyah (10/278):
The view of the Hanafis and Malikis, and one view narrated from Ahmad, is that something that is impure in and of itself may be deemed pure after being transformed. So the ashes of something that was impure are not impure, and the “salt” that is left after the remains of a donkey or pig and the like dried out and disintegrated are not regarded as impure; and any impure substance that fell into a well and disintegrated and turned into mud is not regarded as impure. The same applies to wine when it turns into vinegar, whether that happened by itself or through human actions, or otherwise, because its essence has changed; although the Lawgiver described that particular substance as impure, it is no longer deemed impure when it has transformed into something else.
So if the bones and flesh have turned into “salt”, they come under the same rulings as salt, because salt is something other than bones and flesh.
There are many similar examples in Islamic teaching. For example, the sperm drop is impure, but when it turns into a mudghah [embryo at an early stage] it becomes pure; juice is pure but when it turns into wine it becomes impure.
From this it becomes clear that when the characteristic that led to the ruling is no longer present, the ruling no longer applies. End quote.
This view was favoured by Shaykh al-Islam Ibn Taymiyah and his student Ibn al-Qayyim.
Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him) said:
The view that a thing becomes pure when it is transformed is more correct, because if an impure substance turns into “salt” or ashes, its true essence has changed, and its name and characteristics have also changed. The texts that speak of the prohibition on maytah (meat from animals that were not slaughtered in the prescribed manner), blood and pork do not speak of salt, ashes and dust, either in the wording or the meaning. The reason why these substances were deemed unclean is not present in these (transformed) substances, so there is no justification for saying that they are unclean and impure."(Majmoo‘ al-Fatawa  20/522).
Ibn al-Qayyim (may Allah have mercy on him) said:
Wine becomes pure by being transformed, based on sound argument. It is deemed to be impure because of its unclean qualities, but if the reason for that ruling is no longer present, then the ruling is no longer applicable. This is the basic principle of Islamic teaching, and in fact is the basis of reward and punishment.
Based on that, the sound argument is that this is applicable to all types of impurities, when they are transformed… There is no need to look at its source or origin; rather everything is to be regarded as it is in and of itself.
It does not make sense to rule that something is impure when, after being transformed, it has a different name and different characteristics. The ruling is connected to the name, and the characteristics are also connected to the name.
The texts that speak of the prohibition on maytah, blood, pork and wine do not refer to crops, fruits, ashes, salt, dust and vinegar, either in the wording or the meaning, in the text or by analogy.
Those who differentiate between the transformation of wine and other things say that wine only became impure through transformation, so it can become pure again through transformation.
Thus it may be said to them: The same may be said concerning blood, urine, and faeces: they only became impure through transformation, and may be purified through transformation.
End quote from I‘laam al-Muwaqqi‘een (3/183-184).
This view is the view favoured by many contemporary scholars, including the scholars of the Permanent Committee for Academic Research and Iftaa’, in Fatawa al-Lajnah ad-Daa’imah (22/299).
And Allah knows best.