| Disaggregation of Revenue | The Company’s portfolio of products are integrated into a variety of end uses, which are described in the table below: 
|  |  |  |  |  |  |  
| Key End Uses | Key Products |  
| Industrial & process chemicals | • Silicate precursors for the tire industry |  
|  | • Silica gels for surface coatings |  
| Fuels & emission control | • Refinery catalysts |  
|  | • Emission control catalysts |  
|  | • Catalyst recycling services |  
| Packaging & engineered plastics | • Catalysts for high-density polyethlene and chemicals syntheses |  
|  | • Antiblocks for film packaging |  
|  | • Sulfur derivatives for nylon production |  
|  | • Silicate precursors for catalysts used in plastics manufacturing |  
|  | • Silicate for catalyst manufacturing |  
| Consumer products | • Silica gels for edible oil and beer clarification |  
|  | • Precipitated silicas, silicates and zeolites for the dentifrice and dishwasher and laundry detergent applications
 |  
| Natural resources | • Silicates for drilling muds |  
|  | • Silicates and alum for water treatment mining |  
|  | • Bleaching aids for paper | The following table disaggregates the Company’s sales, by segment and end use, for the years ended December 31, 2020, 2019 and 2018: 
|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  
|  |  | Year ended December 31, 2020 |  
|  |  | Refining Services |  | Catalysts |  |  |  | Performance Chemicals |  | Total |  
| Industrial & process chemicals |  | $ | 70,648 |  |  | $ | 125 |  |  |  |  | $ | 279,296 |  |  | $ | 350,069 |  |  
| 
Fuels & emission control(1)
 |  | 225,042 |  |  | — |  |  |  |  | — |  |  | 225,042 |  |  
| Packaging & engineered plastics |  | 38,772 |  |  | 93,882 |  |  |  |  | 47,451 |  |  | 180,105 |  |  
|  |  |  |  |  |  |  |  |  |  |  |  
| Consumer products |  | — |  |  | — |  |  |  |  | 235,792 |  |  | 235,792 |  |  
| Natural resources |  | 67,451 |  |  | — |  |  |  |  | 52,165 |  |  | 119,616 |  |  
| Total segment sales |  | 401,913 |  |  | 94,007 |  |  |  |  | 614,704 |  |  | 1,110,624 |  |  
| Inter-segment sales eliminations |  | (3,256) |  |  | (5) |  |  |  |  | — |  |  | (3,261) |  |  
| Total |  | $ | 398,657 |  |  | $ | 94,002 |  |  |  |  | $ | 614,704 |  |  | $ | 1,107,363 |  |  
|  |  |  |  |  |  |  |  |  |  |  |  
|  |  | Year ended December 31, 2019 |  
|  |  | Refining Services |  | Catalysts |  |  |  | Performance Chemicals |  | Total |  
| Industrial & process chemicals |  | $ | 80,661 |  |  | $ | 96 |  |  |  |  | $ | 299,651 |  |  | $ | 380,408 |  |  
| 
Fuels & emission control(1)
 |  | 252,294 |  |  | — |  |  |  |  | — |  |  | 252,294 |  |  
| Packaging & engineered plastics |  | 48,056 |  |  | 85,571 |  |  |  |  | 51,725 |  |  | 185,352 |  |  
|  |  |  |  |  |  |  |  |  |  |  |  
| Consumer products |  | — |  |  | — |  |  |  |  | 260,495 |  |  | 260,495 |  |  
| Natural resources |  | 66,070 |  |  | — |  |  |  |  | 58,692 |  |  | 124,762 |  |  
| Total segment sales |  | 447,081 |  |  | 85,667 |  |  |  |  | 670,563 |  |  | 1,203,311 |  |  
| Inter-segment sales eliminations |  | (3,397) |  |  | — |  |  |  |  | — |  |  | (3,397) |  |  
| Total |  | $ | 443,684 |  |  | $ | 85,667 |  |  |  |  | $ | 670,563 |  |  | $ | 1,199,914 |  |  
|  |  |  |  |  |  |  |  |  |  |  |  
|  |  | Year ended December 31, 2018 |  
|  |  | Refining Services |  | Catalysts |  |  |  | Performance Chemicals |  | Total |  
| Industrial & process chemicals |  | $ | 77,866 |  |  | $ | 86 |  |  |  |  | $ | 315,827 |  |  | $ | 393,779 |  |  
| 
Fuels & emission control(1)
 |  | 246,452 |  |  | — |  |  |  |  | — |  |  | 246,452 |  |  
| Packaging & engineered plastics |  | 59,168 |  |  | 72,013 |  |  |  |  | 53,623 |  |  | 184,804 |  |  
|  |  |  |  |  |  |  |  |  |  |  |  
| Consumer products |  | — |  |  | — |  |  |  |  | 272,187 |  |  | 272,187 |  |  
| Natural resources |  | 72,076 |  |  | — |  |  |  |  | 62,865 |  |  | 134,941 |  |  
| Total segment sales |  | 455,562 |  |  | 72,099 |  |  |  |  | 704,502 |  |  | 1,232,163 |  |  
| Inter-segment sales eliminations |  | (3,237) |  |  | — |  |  |  |  | — |  |  | (3,237) |  |  
| Total |  | $ | 452,325 |  |  | $ | 72,099 |  |  |  |  | $ | 704,502 |  |  | $ | 1,228,926 |  |  
|  |  |  |  |  |  |  |  |  |  |  | 
 
(1)    As described in Note 1, the Company experiences seasonal sales fluctuations to customers in the fuels & emission control end use.
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