Tert-Butyl peroxybenzoate (TBPB) a chemical compound from the group of peresters. It is often used as a radical initiator in polymerization reactions, such as the production of LDPE from ethylene, and for crosslinking, such as for unsaturated polyester resins.
TBPB is a low volatility ,high purity,liquid, aromatic peroxuester.it is effective as medium of a broad spectrum of monomers e.g .styrene.ethylenn,acrylics.it is also used to cure (copolymerzation) unsaturated resins .
TBPB is a clear light yellow liquid, which is little soluble in water but well in many organic solvents such as ethanol or phthalate.
As peroxo compound, TBPB contains about 8.16 wt% of active oxygen and has a self accelerating decomposition temperature (SADT) of about 60 °C. The SADT is the lowest temperature at which self-accelerating decomposition in the transport packaging can occur within a week, and which should not be exceeded while storage or transportation.[2] TBPB should therefore be stored between minimum 10 °C (below solidification) and maximum 50 °C. Dilution with a high-boiling solvent increases the SADT. The half-life of TBPB, in which 50% of the peroxy ester is decomposed, is 10 hours at 104 °C, one hour at 124 °C and one minute at 165 °C. Amines, metal ions, strong acids and bases, as well as strong reducing and oxidizing agents accelerate the decomposition of TBPB even in low concentrations.[ However, TBPB is one of the safest peresters or organic peroxides in handling. The main decomposition products of tert-butyl peroxybenzoate are carbon dioxide, acetone, methane, tert-butanol, benzoic acid and benzene.
Initiator Tbpb,Tert-Butyl Peroxybenzoate Formula,Tert-Butyl Peroxybenzoate Activation,Tert Butyl Peroxybenzoate Formula Jiangxi Zhewei Material Technology Co.,Ltd , https://www.jxzwchem.com
Copper-sulfur ore has two types of dense copper-bearing pyrite and disseminated copper-bearing pyrite. The characteristic of dense massive copper-bearing pyrite is that the ore is mainly pyrite and has few gangue minerals; in the disseminated copper-bearing pyrite, the sulfide content of copper and iron is low, and it is impregnated. Distributed in the gangue.
1. Flotation process of copper-sulfur ore
(1) Priority flotation: Generally, the copper is floated first, and then the sulfur is floated. Tight block-like copper-bearing pyrite, the content of pyrite in the ore is quite high, often using high alkalinity (pH = 11 ~ 12, CaO content = 600 ~ 800g / m 3 ), high yellow pharmaceutical dosage method Copper inhibits sulfur, and its tailings are mainly pyrite, and there are few gangues, so the tailings are sulfur concentrates. The disseminated copper-bearing pyrite, the tailings after floating copper should also float sulfur. In order to reduce the consumption of sulfuric acid during the floating sulfur, the copper should be carried out under low alkali conditions as much as possible.
(2) Mixed flotation: It is advantageous to use this process for the copper ore ore with low sulfur content in the ore and copper minerals that are easy to float. Generally, mixed flotation is carried out in a neutral medium (pH=7 or so), and the mixed concentrate is added with lime to separate copper and sulfur in the high alkaline pulp.
(3) Semi-priority mixing-separation flotation: This process is characterized by selective collectors such as Z-200 and OSN-43, which first float out of the easily floating copper minerals and obtain partially qualified copper concentrates. Then, copper-sulfur mixed flotation is carried out, and the obtained copper-sulfur mixed concentrate is further subjected to copper-sulfur separation. The advantage of this process is to avoid the inhibition of easy-floating copper minerals by high lime dosage, and to achieve the purpose of early harvesting; at the same time, it does not need to consume a large amount of sulfuric acid to activate pyrite.
Of course, for the refractory copper-sulfur ore, it is more advantageous to use the stage grinding and floating process from the grinding and floating process. For example, the use of coarse concentrates and mixed concentrates for re-grinding, re-grinding or returning to separate treatments has been adopted in many foreign selection plants.
Second, copper and sulfur separation
Regardless of which flotation scheme is used for copper-sulfur ore, there is a problem of separation of copper and sulfur. The principle of separation is generally copper floating to suppress sulfur.
(a) Lime method: Lime is a commonly used inhibitor of pyrite. When the lime and sulfur method is used for the separation of copper and sulfur, the pH value of the pulp or the free CaO content in the slurry can significantly affect the separation effect. The general rule is to treat dense iron ore with a large amount of pyrite. For the impregnated ore containing less pyrite, the pH value is about 9 to float copper to suppress sulfur.
(2) Lime + cyanide method: For pyrite with large floating activity, it is effective to suppress by lime and cyanide. However, since cyanide is highly toxic and pollutes the environment, people try to replace it with other methods such as lime and sulfite.
(III) Lime + Sulfuric Acid Method: This method is a widely used method for inhibiting pyrite without cyanide. For copper ore ore with raw ore containing sulfur, high mud or pyrite with high planktonic activity and not easily inhibited by lime, lime and sulfite (or SO 2 ) may be used to inhibit the separation of copper and sulfur from pyrite. The key to this method is to control the appropriate pulp pH and the amount of sulfurous acid (SO 2 ) according to the nature of the ore, and pay attention to the appropriate aeration and agitation. Experimental studies have shown that in the weakly acidic medium with pH=6.5~7, it is more effective to inhibit pyrite by using lime and sulfite. Compared with the lime method, this method has the characteristics of stable operation, good copper index and low dosage of activator such as sulfuric acid.
(4) Heating Oxidation Method: This method can be used for the more difficult copper-sulfur mixed concentrate. This method can be divided into steam heating method with or without lime, which can accelerate the oxidation of pyrite surface and inhibit pyrite. For example, if a company adds lime to adjust pH=11, and then uses steam to heat to 60-70 °C, a good sorting effect is obtained.
In the copper-sulfur separation flotation, some people have also done research on lime and sodium humate, and also achieved significant sorting results. In addition, the use of a selective collector or a mixture of collectors can not only reduce the amount of inhibitors and activators, but also stabilize the operation. If a beneficiation plant with butyl xanthate butyryl amine or butyl xanthate plus black powder mixed medication OSN-43, as a result of the greatly increased copper concentrate grade and recovery.
Pyrite is inhibited upon activation, in order to save the amount of activator sulfate, copper sulfate, sodium carbonate, carbon dioxide gas or the like, to float the copper tailings Hydrocyclone concentrated slurry to remove a portion of the high alkalinity of water, Then add fresh water to dilute.
Copper- sulphur ore is one of the main types of copper deposits in China. Its deposits are mostly copper-bearing pyrite deposits and copper-bearing skarn deposits, which are widely distributed. Such as Tongling, Anhui, Gansu, white silver, Daye, Hubei and Jiangxi Yongping and other regions.
April 29, 2023