how does the last one you mentioned react with acids?
Thorium and lanthanide are extracted from monazite with the help of acid cracking
Monazite
The original process for "cracking" monazite so as to extract the thorium and lanthanide content was to heat it with concentrated sulfuric acid to temperatures between 120 and 150 °C for several hours. Variations in the ratio of acid to ore, the extent of heating, and the extent to which water was added afterwards led to several different processes to separate thorium from the lanthanides.
where does the world's helium come from Most helium in the universe is helium-4, the vast majority of which was formed during the Big Bang what is helium? It  is a chemical element with the symbol He and atomic number 2 who was the first to discover this element? It was first detected  by Georges Rayet, Captain C. T. Haig, Norman R. Pogson, and Lieutenant John Herschel, and was subsequently confirmed by French astronomer, Jules Janssen where is this first person from? Georges-Antoine-Pons Rayet was a French astronomer is there anything else that he has discovered apart from the element? Yes, he discovered Wolf–Rayet stars together with Charles Wolf where can this chemical element be extracted from? Natural gas can you tell me some domestic uses of this type of gas? Natural gas can be useful in domestic cooking and heating fuel does this gas put people at any risk? Yes, explosions caused by natural gas leaks can occur also it produce  carbon monoxide which is harmful can you name a few isotopes of the chemical element? Helium-3, Helium-4 does it have any medicial uses? Helium was approved for medical use in the United States  for humans and animals is this element found naturally? Helium is found in large amounts in minerals of uranium and thorium, including uraninite and its varieties cleveite and pitchblende, carnotite and monazite, etc
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Monazite [SEP] Acid cracking
The original process for "cracking" monazite so as to extract the thorium and lanthanide content was to heat it with concentrated sulfuric acid to temperatures between 120 and 150 °C for several hours. Variations in the ratio of acid to ore, the extent of heating, and the extent to which water was added afterwards led to several different processes to separate thorium from the lanthanides. One of the processes caused the thorium to precipitate out as a phosphate or pyrophosphate in crude form, leaving a solution of lanthanide sulfates, from which the lanthanides could be easily precipitated as a double sodium sulfate.